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feat(gateway): forward HTTP requests to the Python proxy (#49604)

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* feat(gateway): forward HTTP requests to the Python proxy

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(gateway): preserve required forwarding headers and separate upgrades

* test(gateway): clarify hash compatibility and relocate forwarding docs

* test(gateway): define URL fragment forwarding behavior

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
This commit is contained in:
yujonglee 2026-11-06 04:03:34 +09:00 • committed by GitHub
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32 changed files with 5448 additions and 24 deletions
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2
litellm-rust/.agents/skills/rust-gateway/SKILL.md
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@ -7,7 +7,7 @@ metadata:
# Rust gateway
`crates/gateway` mounts endpoint routers and serves the listener. `crates/gateway-inference`, `gateway-mcp` and `gateway-ui` own their endpoints, `gateway-auth` is the inbound authentication middleware and `gateway-management` holds management logic that has no router yet. A crate's `AGENTS.md`, where it has one, says what belongs in it. Read the reference for the part you are touching
`crates/gateway` mounts endpoint routers and serves the listener. `crates/gateway-inference`, `gateway-mcp` and `gateway-ui` own their endpoints, `gateway-auth` is the inbound authentication middleware and `gateway-management` holds management logic that has no router yet. `gateway-forward` is the reverse proxy that relays every request to the Python proxy and has no routes of its own. A crate's `AGENTS.md`, where it has one, says what belongs in it. Read the reference for the part you are touching
- [surfaces](references/surfaces.md)
- Each API surface mirrors the envelope the Python proxy returns there, so the shapes differ on purpose

59
litellm-rust/Cargo.lock generated
View file

@ -547,7 +547,7 @@ dependencies = [
"http 1.4.2",
"http-body 0.4.6",
"hyper 0.14.32",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-rustls 0.24.2",
"hyper-rustls 0.27.9",
"hyper-util",
@ -736,7 +736,7 @@ dependencies = [
"http 1.4.2",
"http-body 1.1.0",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-util",
"itoa",
"matchit",
@ -1000,7 +1000,7 @@ dependencies = [
"home",
"http 1.4.2",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-named-pipe",
"hyper-rustls 0.27.9",
"hyper-util",
@ -2255,7 +2255,7 @@ dependencies = [
"chrono",
"http 1.4.2",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-rustls 0.27.9",
"hyper-util",
"ring",
@ -2391,7 +2391,7 @@ dependencies = [
"http 1.4.2",
"http-body 1.1.0",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"lazy_static",
"opentelemetry",
"opentelemetry-semantic-conventions",
@ -2833,9 +2833,9 @@ dependencies = [
[[package]]
name = "hyper"
version = "1.10.1"
version = "1.12.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "55281c53a1894c864990125767da440a4e630446785086f52523b20033b74498"
checksum = "2c3e324da4c95177d6291d4c8730197c0d1822f8a9766814a4a44fa5ab797c9c"
dependencies = [
"atomic-waker",
"bytes",
@ -2860,7 +2860,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "fab3637d6b04a8037af8a266fdf6cf92ea957e8c53981a2bf6136572531025bf"
dependencies = [
"hex",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-util",
"pin-project-lite",
"tokio",
@ -2889,7 +2889,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "33ca68d021ef39cf6463ab54c1d0f5daf03377b70561305bb89a8f83aab66e0f"
dependencies = [
"http 1.4.2",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-util",
"rustls 0.23.42",
"rustls-native-certs",
@ -2904,7 +2904,7 @@ version = "0.5.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "2b90d566bffbce6a75bd8b09a05aa8c2cb1fabb6cb348f8840c9e4c90a0d83b0"
dependencies = [
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-util",
"pin-project-lite",
"tokio",
@ -2923,7 +2923,7 @@ dependencies = [
"futures-util",
"http 1.4.2",
"http-body 1.1.0",
"hyper 1.10.1",
"hyper 1.12.0",
"ipnet",
"libc",
"percent-encoding",
@ -2942,7 +2942,7 @@ checksum = "986c5ce3b994526b3cd75578e62554abd09f0899d6206de48b3e96ab34ccc8c7"
dependencies = [
"hex",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-util",
"pin-project-lite",
"tokio",
@ -3769,6 +3769,7 @@ dependencies = [
"litellm-config",
"litellm-error",
"litellm-gateway-auth",
"litellm-gateway-forward",
"litellm-gateway-inference",
"litellm-gateway-mcp",
"litellm-gateway-ui",
@ -3815,6 +3816,29 @@ dependencies = [
"veil",
]
[[package]]
name = "litellm-gateway-forward"
version = "0.1.0"
dependencies = [
"axum",
"bytes",
"envy",
"futures-util",
"http-body-util",
"httparse",
"hyper 1.12.0",
"hyper-util",
"proptest",
"rstest",
"serde",
"thiserror 2.0.19",
"tokio",
"tokio-tungstenite",
"tokio-util",
"tower-service",
"tracing",
]
[[package]]
name = "litellm-gateway-inference"
version = "0.1.0"
@ -6031,7 +6055,7 @@ dependencies = [
"http 1.4.2",
"http-body 1.1.0",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-rustls 0.27.9",
"hyper-util",
"js-sys",
@ -7512,6 +7536,7 @@ dependencies = [
"bytes",
"futures-core",
"futures-sink",
"futures-util",
"pin-project-lite",
"tokio",
]
@ -7591,7 +7616,7 @@ dependencies = [
"http 1.4.2",
"http-body 1.1.0",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-timeout",
"hyper-util",
"percent-encoding",
@ -8167,9 +8192,9 @@ dependencies = [
[[package]]
name = "want"
version = "0.3.1"
version = "0.3.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "bfa7760aed19e106de2c7c0b581b509f2f25d3dacaf737cb82ac61bc6d760b0e"
checksum = "ec4cdd0dd910afe868b7ef477227d8d538b46b3075031afee8a9f2acb0a2ed0b"
dependencies = [
"try-lock",
]
@ -8551,7 +8576,7 @@ dependencies = [
"futures",
"http 1.4.2",
"http-body-util",
"hyper 1.10.1",
"hyper 1.12.0",
"hyper-util",
"log",
"once_cell",

1
litellm-rust/Cargo.toml
View file

@ -26,6 +26,7 @@ litellm-inference-ocr = { path = "crates/inference-ocr" }
litellm-inference-testing = { path = "crates/inference-testing" }
litellm-gateway-mcp = { path = "crates/gateway-mcp" }
litellm-gateway = { path = "crates/gateway" }
litellm-gateway-forward = { path = "crates/gateway-forward" }
litellm-gateway-inference = { path = "crates/gateway-inference" }
litellm-gateway-auth = { path = "crates/gateway-auth" }
litellm-gateway-management = { path = "crates/gateway-management" }

37
litellm-rust/crates/gateway-forward/AGENTS.md Normal file
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@ -0,0 +1,37 @@
# Forwarding gateway
`Forward` is a reverse proxy in front of the Python proxy on loopback. Python must see each request as if the client had connected to it directly, because every Python route (inference, MCP, pass-through, UI, WebSocket) is served behind it without Rust knowing which one it is
- Serve HTTP/1.1 only, as uvicorn does. The supervisor never puts Rust in front of a Python server that speaks HTTP/2
- Never branch on a route or path. A behavior one endpoint needs is a protocol behavior every endpoint gets
- Forward the method, request target, headers, and body byte for byte within the [URL contract](FORWARDING.md#url-fragments-and-literal-hashes). An unescaped `#` starts a fragment and is omitted with everything after it, while `%23` is preserved. Only drop hop-by-hop headers (RFC 9110 section 7.6.1) and set `x-litellm-rust-peer`, which replaces any client copy
- Stream both bodies. Never buffer, cap, or time out a body, since uploads and provider streams have no upper bound
- A client disconnect closes the upstream connection at every stage, because that is how Python learns to stop a provider stream
- An upstream that dies mid-response fails the client body. Never end it cleanly, or SSE clients treat a truncated stream as complete
- Never invent a Host. Python builds absolute URLs from it, so a missing one must never become the private upstream address
- A request Python could not have received unchanged (HTTP/1.1 without Host, a transfer coding other than chunked, a target without a path) gets the status uvicorn would have given, from Rust
- Pooled upstream connections are retired well before Python's keep-alive timeout, so a request never lands on a connection Python is closing
- Idle client connections close after Python's keep-alive timeout, as uvicorn closed them, so a client that vanishes cannot hold a socket forever. Only the wait for the next request is timed, never an exchange in progress
- WebSocket is the one protocol switch Python serves. Upgrades are relayed as raw bytes after the 101 and drained on shutdown
## Layout
Every forwarding decision has one home. `rewrite.rs` owns what Python and the client receive, as pure functions over requests and responses. `Rejection` in `error.rs` is the only place that picks a status for a request Rust answers itself. `settings.rs` parses the environment into typed values, so an `Upstream` is a loopback origin by construction. `server.rs` accepts client connections and owns their timeouts, since `axum::serve` exposes none, and `connections.rs` tracks every connection and relay for shutdown. `forward.rs` and `websocket.rs` only move requests, bodies and upgraded connections and never touch a header themselves. `connector.rs` keeps hyper reading Python's answer after Python stops reading the request
## Environment
`Settings` reads only these variables, and only when `LITELLM_FORWARD_UPSTREAM` is set. The Python supervisor in `litellm/proxy/rust_forward/` sets every one of them from the values Python actually runs with, so all of them are required and a missing or invalid one fails startup naming it. The crate never reads Python's own settings (`HOST`, `PORT`, `KEEPALIVE_TIMEOUT`, `GRACEFUL_SHUTDOWN_TIMEOUT`) and keeps no copy of Python's defaults, since Python can get those values from CLI flags the environment never shows
| Variable | Meaning |
|---|---|
| `LITELLM_FORWARD_UPSTREAM` | Python's loopback origin, e.g. `http://127.0.0.1:53211` |
| `LITELLM_FORWARD_HOST` | public bind host |
| `LITELLM_FORWARD_PORT` | public bind port |
| `LITELLM_FORWARD_UPSTREAM_KEEPALIVE` | seconds uvicorn keeps an idle connection open. Pooled connections are retired at half of it, and idle client connections are closed after it |
| `LITELLM_FORWARD_SHUTDOWN_DRAIN` | seconds to drain on shutdown, already including Python's graceful timeout and teardown headroom |
## Tests
Test through real sockets with `tests/support`, never `oneshot`. `Gateway` runs the forwarder on a listener like production, `recording` is a well-behaved upstream that captures what Python would receive, and `raw_upstream` and `Raw` drive bytes by hand for framing, timing and disconnects a real server would not produce. Waits measured in minutes use paused tokio time instead of real sleeps
The forwarder sees HTTP/1.1 messages, not routes, so the tests are split into one file per traffic shape uvicorn can emit: `exchange` (plain request and response), `framing` (requests whose framing a parser could read two ways), `slow_head` (minutes before response headers), `stream` (incremental response bodies), `idle_stream` (long-lived streams that go quiet), `upload`, `download`, `websocket`, `client_identity`, `lifecycle` (disconnects, pooling, idle timeouts, shutdown) and `roundtrip` (the forwarding invariant for generated messages). A new route never gets its own test. Add its behavior to the shape it already has, and when it needs a wire behavior none of the files covers, add a new shape file for it

30
litellm-rust/crates/gateway-forward/Cargo.toml Normal file
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@ -0,0 +1,30 @@
[package]
name = "litellm-gateway-forward"
version = "0.1.0"
edition.workspace = true
rust-version.workspace = true
license.workspace = true
repository.workspace = true
[dependencies]
axum.workspace = true
envy = "0.4.2"
hyper = { version = "1.12.0", features = ["http1", "server"] }
hyper-util = { workspace = true, features = ["client-legacy", "http1", "tokio"] }
serde.workspace = true
thiserror.workspace = true
tokio = { workspace = true, features = ["io-util"] }
tokio-util = { version = "0.7", features = ["rt"] }
tower-service = "0.3.3"
tracing.workspace = true
[dev-dependencies]
bytes.workspace = true
futures-util.workspace = true
http-body-util = "0.1"
httparse = "1"
hyper = { version = "1.12.0", features = ["client"] }
proptest.workspace = true
rstest.workspace = true
tokio = { workspace = true, features = ["io-util", "sync", "test-util"] }
tokio-tungstenite.workspace = true

31
litellm-rust/crates/gateway-forward/FORWARDING.md Normal file
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@ -0,0 +1,31 @@
# Python forwarding compatibility
The opt-in forwarding gateway serves HTTP/1.1 and WebSockets in front of Python. Python still owns every route and policy. Its protocol contract and environment settings are in [AGENTS.md](AGENTS.md)
## URL fragments and literal hashes
The gateway follows Hyper's `http::Uri` parsing. If a raw client sends an unescaped `#` in the request target, only the path and query before the first `#` reach Python. For example, `/v1/files?purpose=batch#retry&limit=1` becomes `/v1/files?purpose=batch`, and `/gemini/v1beta/files/a#b?key=k` becomes `/gemini/v1beta/files/a`
This is accepted behavior because `#` starts a URL fragment, which is separated before dereferencing ([RFC 3986 section 3.5](https://www.rfc-editor.org/rfc/rfc3986.html#section-3.5)). HTTP origin-form contains only the path and optional query, not a fragment ([RFC 9112 section 3.2.1](https://www.rfc-editor.org/rfc/rfc9112.html#section-3.2.1)). Browsers and URL-based clients omit the fragment before sending the request, so UI hash routing is unaffected
A literal hash in path or query data must be encoded as `%23`, which the gateway forwards unchanged. Direct Python with h11 also accepts unescaped hashes as data, but that permissive raw-target behavior is outside this URL contract. Active socket tests cover both [fragment omission](tests/exchange.rs) and [encoded-hash preservation](tests/exchange.rs)
## Known differences from uvicorn with h11
These cases remain executable as ignored socket tests. They are not passing parity checks
| Input | Direct Python | Through Rust | Regression test |
|---|---|---|---|
| Header after a removed hop-by-hop field | Keeps the remaining header order | `HeaderMap::remove` can move a later header | [dropping_a_hop_by_hop_header_keeps_the_others_in_order](tests/exchange.rs) |
| Repeated header names interleaved with other names | Keeps the interleaving | Groups values by name, keeping their order within that name | [interleaved_repeated_headers_reach_python_interleaved](tests/exchange.rs) |
| Obsolete folded header, such as `x-a: b\r\n c` | Unfolds to `b c` | Rejects with 400 | [a_folded_header_reaches_python_unfolded](tests/exchange.rs) |
| Identical Content-Length list, such as `7, 7` | Accepts length 7 | Rejects with 400 | [a_content_length_list_of_one_value_reaches_python](tests/framing.rs) |
| HTTP/1.0 request with chunked transfer coding | Decodes the body | Rejects with 400 | [an_http10_chunked_upload_reaches_python](tests/framing.rs) |
Clients can avoid the parser rejections by sending unfolded headers, one Content-Length value, and HTTP/1.1 for chunked uploads. Integrations must not depend on header ordering across different field names
Run `cargo test -p litellm-gateway-forward --test exchange --test framing -- --ignored` from this directory to reproduce the differences
## Connection header handling
The gateway strips standard hop-by-hop fields and fields named by Connection, except routing, representation, credential, forwarding, and WebSocket handshake headers. A client cannot nominate those end-to-end fields for removal. The private `x-litellm-rust-peer` always replaces any client-supplied copy

58
litellm-rust/crates/gateway-forward/src/connections.rs Normal file
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@ -0,0 +1,58 @@
use tokio_util::{
sync::{CancellationToken, DropGuard},
task::TaskTracker,
};
/// Every client connection and WebSocket relay the gateway runs, so shutdown can wait for them
/// and then close whatever outlives the drain.
#[derive(Clone, Default)]
pub(crate) struct Connections {
tasks: TaskTracker,
draining: CancellationToken,
closed: CancellationToken,
}
impl Connections {
/// Runs `work` until it finishes or the gateway closes every connection.
pub fn spawn(&self, work: impl Future<Output = ()> + Send + 'static) {
let closed = self.closed.clone();
self.tasks.spawn(async move {
tokio::select! {
() = closed.cancelled() => {}
() = work => {}
}
});
}
pub fn begin_shutdown(&self) {
self.draining.cancel();
}
pub async fn draining(&self) {
self.draining.cancelled().await;
}
pub fn is_draining(&self) -> bool {
self.draining.is_cancelled()
}
pub async fn until_closed<T>(&self, future: impl Future<Output = T>) -> Option<T> {
tokio::select! {
() = self.closed.cancelled() => None,
output = future => Some(output),
}
}
pub fn close(&self) {
self.closed.cancel();
}
pub fn close_on_drop(&self) -> DropGuard {
self.closed.clone().drop_guard()
}
pub async fn wait(&self) {
self.tasks.close();
self.tasks.wait().await;
}
}

122
litellm-rust/crates/gateway-forward/src/connector.rs Normal file
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@ -0,0 +1,122 @@
use std::{
io::{self, IoSlice},
pin::Pin,
task::{Context, Poll, ready},
};
use axum::http::Uri;
use hyper::rt::{Read, ReadBufCursor, Write};
use hyper_util::{
client::legacy::connect::{Connected, Connection, HttpConnector},
rt::TokioIo,
};
use tokio::net::TcpStream;
/// Connects to Python like `HttpConnector`, but keeps hyper reading Python's answer after Python
/// stops reading the request. uvicorn rejects an upload (413, 401) as soon as it reads the head
/// and closes with the body unread, so writing the rest fails, and hyper would fail the request
/// and drop the answer it already received. Like curl and httpcore, the forwarder discards the
/// rest of the request instead and reads on. A connection that never answered still fails, on the
/// read, and no request is ever sent twice.
#[derive(Clone)]
pub(crate) struct Connector(pub HttpConnector);
impl tower_service::Service<Uri> for Connector {
type Response = AnswerAfterRefusal;
type Error = <HttpConnector as tower_service::Service<Uri>>::Error;
type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;
fn poll_ready(&mut self, context: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.0.poll_ready(context)
}
fn call(&mut self, uri: Uri) -> Self::Future {
let connecting = self.0.call(uri);
Box::pin(async move {
Ok(AnswerAfterRefusal {
stream: connecting.await?,
refused: false,
})
})
}
}
pub(crate) struct AnswerAfterRefusal {
stream: TokioIo<TcpStream>,
refused: bool,
}
impl AnswerAfterRefusal {
fn written(&mut self, written: io::Result<usize>, length: usize) -> io::Result<usize> {
match written {
Err(error)
if matches!(
error.kind(),
io::ErrorKind::BrokenPipe | io::ErrorKind::ConnectionReset
) =>
{
self.refused = true;
Ok(length)
}
written => written,
}
}
}
impl Read for AnswerAfterRefusal {
fn poll_read(
mut self: Pin<&mut Self>,
context: &mut Context<'_>,
buffer: ReadBufCursor<'_>,
) -> Poll<io::Result<()>> {
Pin::new(&mut self.stream).poll_read(context, buffer)
}
}
impl Write for AnswerAfterRefusal {
fn poll_write(
mut self: Pin<&mut Self>,
context: &mut Context<'_>,
buffer: &[u8],
) -> Poll<io::Result<usize>> {
if self.refused {
return Poll::Ready(Ok(buffer.len()));
}
let written = ready!(Pin::new(&mut self.stream).poll_write(context, buffer));
Poll::Ready(self.written(written, buffer.len()))
}
fn poll_write_vectored(
mut self: Pin<&mut Self>,
context: &mut Context<'_>,
buffers: &[IoSlice<'_>],
) -> Poll<io::Result<usize>> {
let length = buffers.iter().map(|buffer| buffer.len()).sum();
if self.refused {
return Poll::Ready(Ok(length));
}
let written = ready!(Pin::new(&mut self.stream).poll_write_vectored(context, buffers));
Poll::Ready(self.written(written, length))
}
fn is_write_vectored(&self) -> bool {
self.stream.is_write_vectored()
}
fn poll_flush(mut self: Pin<&mut Self>, context: &mut Context<'_>) -> Poll<io::Result<()>> {
if self.refused {
return Poll::Ready(Ok(()));
}
Pin::new(&mut self.stream).poll_flush(context)
}
fn poll_shutdown(mut self: Pin<&mut Self>, context: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.stream).poll_shutdown(context)
}
}
impl Connection for AnswerAfterRefusal {
fn connected(&self) -> Connected {
self.stream.connected()
}
}

91
litellm-rust/crates/gateway-forward/src/error.rs Normal file
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@ -0,0 +1,91 @@
use axum::{
http::StatusCode,
response::{IntoResponse, Response},
};
#[derive(Debug, thiserror::Error)]
pub enum Error {
#[error("invalid forwarding upstream URI")]
UpstreamUri(#[source] axum::http::uri::InvalidUri),
#[error(
"LITELLM_FORWARD_UPSTREAM must be a loopback IPv4 http origin without a path, query or credentials"
)]
Upstream,
#[error("{0} must be set in forward mode")]
MissingSetting(String),
#[error("invalid forwarding setting: {0}")]
InvalidSetting(String),
#[error("forwarding gateway I/O failed: {0}")]
Io(#[from] std::io::Error),
}
/// Why a request got an answer from Rust instead of from Python.
#[derive(Debug, thiserror::Error)]
pub(crate) enum Rejection {
#[error("HTTP/1.1 request without a Host header")]
MissingHost,
#[error("request target has no path to forward")]
NoPath,
#[error("request uses a transfer coding other than chunked")]
UnsupportedTransferCoding,
#[error("client request body failed: {0}")]
ClientBody(#[source] hyper_util::client::legacy::Error),
#[error("python proxy unreachable: {0}")]
Unreachable(#[source] hyper_util::client::legacy::Error),
#[error("python proxy switched protocols without being asked to")]
UnrequestedUpgrade,
#[error("python proxy websocket upgrade failed: {0}")]
UpgradeFailed(#[source] hyper::Error),
#[error("forwarding gateway is shutting down")]
ShuttingDown,
#[error("could not build the request for the python proxy")]
Internal,
}
impl Rejection {
/// A client body that ends early or breaks its framing fails the upstream request too, but
/// the fault is the client's, not Python's.
pub fn from_upstream(error: hyper_util::client::legacy::Error) -> Self {
let client_body = std::error::Error::source(&error)
.and_then(|source| source.downcast_ref::<hyper::Error>())
.is_some_and(hyper::Error::is_user);
match client_body {
true => Self::ClientBody(error),
false => Self::Unreachable(error),
}
}
fn status(&self) -> StatusCode {
match self {
Self::MissingHost
| Self::NoPath
| Self::UnsupportedTransferCoding
| Self::ClientBody(_) => StatusCode::BAD_REQUEST,
Self::Unreachable(_) | Self::UnrequestedUpgrade | Self::UpgradeFailed(_) => {
StatusCode::BAD_GATEWAY
}
Self::ShuttingDown => StatusCode::SERVICE_UNAVAILABLE,
Self::Internal => StatusCode::INTERNAL_SERVER_ERROR,
}
}
fn is_gateway_fault(&self) -> bool {
matches!(
self,
Self::Unreachable(_)
| Self::UnrequestedUpgrade
| Self::UpgradeFailed(_)
| Self::Internal
)
}
}
impl IntoResponse for Rejection {
fn into_response(self) -> Response {
match self.is_gateway_fault() {
true => tracing::warn!(error = %self, "request not forwarded"),
false => tracing::debug!(error = %self, "request not forwarded"),
}
self.status().into_response()
}
}

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use std::{
pin::Pin,
task::{Context, Poll},
time::Duration,
};
use axum::{
body::Body,
extract::Request,
http::{StatusCode, Uri},
response::{IntoResponse, Response},
};
use hyper::body::{Frame, Incoming, SizeHint};
use hyper_util::{
client::legacy::{Client, connect::HttpConnector},
rt::{TokioExecutor, TokioTimer},
};
use tokio::net::TcpListener;
use crate::{
Rejection, Upstream, connections::Connections, connector::Connector, rewrite, server,
server::ClientSocket, websocket,
};
// h11 counts no headers and only caps a head at 16 KiB, so it accepts as many headers as fit in
// that many shortest lines (`a:\r\n`). Python copies every provider header into its response
// too, so hyper's default of 100 would turn ordinary traffic into 431s and 502s.
pub(crate) const MAX_HEADERS: usize = 16 * 1024 / b"a:\r\n".len();
#[derive(Clone)]
pub struct Forward {
upstream: Uri,
client: Client<Connector, Body>,
connections: Connections,
keepalive: Duration,
}
impl Forward {
/// `upstream_keepalive` is how long the upstream keeps an idle connection open. Pooled
/// connections are dropped well before that, so a request never lands on one it is closing,
/// and idle client connections are closed after it, as uvicorn did.
pub fn new(upstream: &Upstream, upstream_keepalive: Duration) -> Self {
let mut connector = HttpConnector::new();
connector.set_nodelay(true);
let client = Client::builder(TokioExecutor::new())
.http1_max_headers(MAX_HEADERS)
.pool_timer(TokioTimer::new())
.pool_idle_timeout(upstream_keepalive / 2)
.set_host(false)
.build(Connector(connector));
Self {
upstream: upstream.uri().clone(),
client,
connections: Connections::default(),
keepalive: upstream_keepalive,
}
}
/// Serves until `shutdown` resolves, then lets open requests and WebSockets finish for up to
/// `drain` before closing whatever is left. Python shuts down alongside and ends long streams
/// itself, so `drain` only backstops a Python that never does.
pub async fn serve(
self,
listener: TcpListener,
shutdown: impl Future<Output = ()>,
drain: Duration,
) {
server::serve(self, listener, shutdown, drain).await;
}
pub(crate) fn connections(&self) -> &Connections {
&self.connections
}
pub(crate) fn keepalive(&self) -> Duration {
self.keepalive
}
pub(crate) async fn handle(&self, client: ClientSocket, request: Request) -> Response {
self.forward(client, request)
.await
.unwrap_or_else(IntoResponse::into_response)
}
async fn forward(
&self,
client: ClientSocket,
mut request: Request,
) -> Result<Response, Rejection> {
if let Some(downstream) = websocket::take_handshake(&self.connections, &mut request)? {
return self.forward_websocket(client, request, downstream).await;
}
let request = rewrite::upstream_request(request, &self.upstream, client, false)?;
let response = self
.client
.request(request)
.await
.map_err(Rejection::from_upstream)?;
http_response(response)
}
async fn forward_websocket(
&self,
client: ClientSocket,
request: Request,
downstream: hyper::upgrade::OnUpgrade,
) -> Result<Response, Rejection> {
let request = rewrite::upstream_request(request, &self.upstream, client, true)?;
let response = self
.connections
.until_closed(self.client.request(request))
.await
.ok_or(Rejection::ShuttingDown)?
.map_err(Rejection::from_upstream)?;
if response.status() == StatusCode::SWITCHING_PROTOCOLS {
return websocket::switch(&self.connections, downstream, response).await;
}
http_response(response)
}
}
fn http_response(response: Response<Incoming>) -> Result<Response, Rejection> {
if response.status() == StatusCode::SWITCHING_PROTOCOLS {
return Err(Rejection::UnrequestedUpgrade);
}
Ok(
rewrite::downstream_response(response)
.map(|body| Body::new(Relayed { body, failed: None })),
)
}
/// Python's response body on its way to the client.
struct Relayed {
body: Incoming,
failed: Option<hyper::Error>,
}
impl hyper::body::Body for Relayed {
type Data = <Incoming as hyper::body::Body>::Data;
type Error = hyper::Error;
// hyper aborts a client connection whose response body fails without flushing the head it
// buffered, so a head Python sent right before dying would never arrive and SDKs would retry
// a request Python already ran. Holding the error for one poll lets hyper flush the head.
fn poll_frame(
mut self: Pin<&mut Self>,
context: &mut Context<'_>,
) -> Poll<Option<Result<Frame<Self::Data>, Self::Error>>> {
if let Some(error) = self.failed.take() {
return Poll::Ready(Some(Err(error)));
}
match Pin::new(&mut self.body).poll_frame(context) {
Poll::Ready(Some(Err(error))) => {
self.failed = Some(error);
context.waker().wake_by_ref();
Poll::Pending
}
frame => frame,
}
}
fn is_end_stream(&self) -> bool {
self.failed.is_none() && self.body.is_end_stream()
}
fn size_hint(&self) -> SizeHint {
self.body.size_hint()
}
}

29
litellm-rust/crates/gateway-forward/src/lib.rs Normal file
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mod connections;
mod connector;
mod error;
mod forward;
mod rewrite;
mod server;
mod settings;
mod websocket;
pub use error::Error;
pub(crate) use error::Rejection;
pub use forward::Forward;
pub use rewrite::PEER_HEADER;
pub use settings::{Settings, Upstream};
/// Binds the public listener and forwards to Python until `shutdown` resolves, then drains for
/// `settings.shutdown_drain`.
pub async fn run(
settings: Settings,
shutdown: impl Future<Output = ()> + Send + 'static,
) -> Result<(), Error> {
let forward = Forward::new(&settings.upstream, settings.upstream_keepalive);
let listener = tokio::net::TcpListener::bind((settings.host.as_str(), settings.port)).await?;
tracing::info!(address = %listener.local_addr()?, "forwarding gateway listening");
forward
.serve(listener, shutdown, settings.shutdown_drain)
.await;
Ok(())
}

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use axum::{
body::HttpBody,
extract::Request,
http::{HeaderMap, HeaderValue, Response, Uri, Version, header},
};
use crate::{Rejection, server::ClientSocket};
pub const PEER_HEADER: &str = "x-litellm-rust-peer";
/// The request Python receives: the client's method, target, headers and body unchanged, sent to
/// `upstream` over HTTP/1.1 without the client connection's own headers, plus the client's TCP
/// peer in `PEER_HEADER`, which replaces any copy the client sent.
pub(crate) fn upstream_request(
mut request: Request,
upstream: &Uri,
client: ClientSocket,
websocket: bool,
) -> Result<Request, Rejection> {
if !only_chunked(request.headers()) {
return Err(Rejection::UnsupportedTransferCoding);
}
let path_and_query = request
.uri()
.path_and_query()
.cloned()
.ok_or(Rejection::NoPath)?;
if let Some(host) = public_host(&request, client)? {
request.headers_mut().insert(header::HOST, host);
}
let mut uri = upstream.clone().into_parts();
uri.path_and_query = Some(path_and_query);
*request.uri_mut() = Uri::from_parts(uri).map_err(|_| Rejection::Internal)?;
*request.version_mut() = Version::HTTP_11;
let chunked = request.body().size_hint().exact().is_none();
let headers = request.headers_mut();
strip_hop_by_hop(headers);
if chunked {
// hyper sends no body for a GET with an unknown length unless told it is chunked.
headers.insert(
header::TRANSFER_ENCODING,
HeaderValue::from_static("chunked"),
);
}
if websocket {
restore_websocket_handshake(headers);
}
headers.insert(
PEER_HEADER,
HeaderValue::from_str(&client.peer.to_string()).map_err(|_| Rejection::Internal)?,
);
Ok(request)
}
// Python builds absolute URLs from Host and, without a usable one, from the address it listens
// on, which behind Rust is the private loopback port. A client that sent no usable Host gets the
// public address it connected to, which is what Python used before. h11 rejects HTTP/1.1 without
// Host.
fn public_host(request: &Request, client: ClientSocket) -> Result<Option<HeaderValue>, Rejection> {
let host = request.headers().get(header::HOST);
if host.is_some_and(|host| !host.is_empty()) {
return Ok(None);
}
if host.is_none() && request.version() == Version::HTTP_11 {
return Err(Rejection::MissingHost);
}
HeaderValue::from_str(&client.local.to_string())
.map(Some)
.map_err(|_| Rejection::Internal)
}
// hyper only decodes chunked framing, so anything else would reach Python still coded but framed
// as a plain body. uvicorn rejects it with the 400 it sends for every h11 parse error.
fn only_chunked(headers: &HeaderMap) -> bool {
headers
.get_all(header::TRANSFER_ENCODING)
.iter()
.flat_map(|value| value.as_bytes().split(|byte| *byte == b','))
.all(|coding| coding.trim_ascii().eq_ignore_ascii_case(b"chunked"))
}
/// The response the client receives: Python's, without the upstream connection's own headers.
pub(crate) fn downstream_response<B>(mut response: Response<B>) -> Response<B> {
strip_hop_by_hop(response.headers_mut());
response
}
/// Python's 101 as the client receives it, still naming the protocol both sides switch to.
pub(crate) fn switched_response<B>(mut response: Response<B>) -> Response<B> {
strip_hop_by_hop(response.headers_mut());
restore_websocket_handshake(response.headers_mut());
response
}
pub(crate) fn is_websocket_handshake(headers: &HeaderMap) -> bool {
headers
.get(header::UPGRADE)
.is_some_and(|value| value.as_bytes().eq_ignore_ascii_case(b"websocket"))
&& headers
.get_all(header::CONNECTION)
.iter()
.filter_map(|value| value.to_str().ok())
.flat_map(|value| value.split(','))
.any(|token| token.trim().eq_ignore_ascii_case("upgrade"))
}
const HOP_BY_HOP: [&str; 9] = [
"connection",
"keep-alive",
"proxy-authenticate",
"proxy-authorization",
"te",
"trailer",
"transfer-encoding",
"upgrade",
"proxy-connection",
];
// Per-connection headers (RFC 9110 section 7.6.1) describe the client's connection to Rust, not
// Rust's connection to Python, so a proxy must drop them instead of forwarding them.
fn strip_hop_by_hop(headers: &mut HeaderMap) {
let named: Vec<_> = headers
.get_all(header::CONNECTION)
.iter()
.filter_map(|value| value.to_str().ok())
.flat_map(|value| value.split(','))
.filter_map(|name| header::HeaderName::from_bytes(name.trim().as_bytes()).ok())
.filter(|name| !must_forward(name))
.collect();
for name in named {
headers.remove(name);
}
for name in HOP_BY_HOP {
headers.remove(name);
}
}
fn must_forward(name: &header::HeaderName) -> bool {
matches!(
name.as_str(),
"host"
| "authorization"
| "cookie"
| "set-cookie"
| "www-authenticate"
| "authentication-info"
| "api-key"
| "x-api-key"
| "litellm-api-key"
| "forwarded"
| PEER_HEADER
) || name.as_str().starts_with("content-")
|| name.as_str().starts_with("x-forwarded-")
|| name.as_str().starts_with("sec-websocket-")
}
// Stripping drops the handshake's Connection and Upgrade, so each hop gets them back.
fn restore_websocket_handshake(headers: &mut HeaderMap) {
headers.insert(header::CONNECTION, HeaderValue::from_static("upgrade"));
headers.insert(header::UPGRADE, HeaderValue::from_static("websocket"));
}

116
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use std::{convert::Infallible, io, net::SocketAddr, pin::pin, time::Duration};
use axum::{body::Body, extract::Request};
use hyper::{body::Incoming, server::conn::http1, service::service_fn};
use hyper_util::rt::{TokioIo, TokioTimer};
use tokio::net::TcpListener;
use crate::{Forward, forward::MAX_HEADERS};
/// The client's TCP connection to the public listener.
#[derive(Clone, Copy, Debug)]
pub(crate) struct ClientSocket {
pub peer: SocketAddr,
pub local: SocketAddr,
}
/// Serves each public connection with hyper directly, because `axum::serve` cannot configure
/// the connection timeouts uvicorn applied to the same clients.
pub(crate) async fn serve(
forward: Forward,
listener: TcpListener,
shutdown: impl Future<Output = ()>,
drain: Duration,
) {
let connections = forward.connections().clone();
let _close_on_drop = connections.close_on_drop();
let keepalive = forward.keepalive();
let builder = builder(keepalive);
let mut shutdown = pin!(shutdown);
loop {
let (stream, peer) = tokio::select! {
() = &mut shutdown => break,
accepted = listener.accept() => match accepted {
Ok(accepted) => accepted,
Err(error) => {
back_off(error).await;
continue;
}
},
};
let local = match stream.local_addr() {
Ok(local) => local,
Err(error) => {
tracing::debug!(%error, "client connection closed before it was served");
continue;
}
};
if let Err(error) = stream.set_nodelay(true) {
tracing::warn!(%error, "could not disable Nagle on a client connection");
}
let socket = ClientSocket { peer, local };
let forward = forward.clone();
let service = service_fn(move |request: Request<Incoming>| {
let forward = forward.clone();
async move { Ok::<_, Infallible>(forward.handle(socket, request.map(Body::new)).await) }
});
let connection = builder
.serve_connection(TokioIo::new(stream), service)
.with_upgrades();
let draining = connections.clone();
connections.spawn(async move {
let mut connection = pin!(connection);
let ended = tokio::select! {
ended = connection.as_mut() => ended,
() = draining.draining() => {
connection.as_mut().graceful_shutdown();
connection.await
}
};
if let Err(error) = ended {
tracing::debug!(%error, "client connection ended with an error");
}
});
}
drop(listener);
connections.begin_shutdown();
if tokio::time::timeout(drain, connections.wait())
.await
.is_err()
{
tracing::warn!(
?drain,
"closing connections still open after the shutdown drain"
);
}
connections.close();
connections.wait().await;
}
// uvicorn closes a client connection that sits idle for `--keepalive_timeout` between requests.
// Without the same limit, a client that vanishes without closing (NAT expiry, a crashed host)
// would hold its socket for the life of the process until the gateway runs out of descriptors.
// Operators already tune that timeout against their load balancer, so the public side keeps
// Python's value instead of introducing its own. hyper only runs the header timer while a
// connection waits for its next request, so it never cuts a long stream, upload or WebSocket.
fn builder(keepalive: Duration) -> http1::Builder {
let mut builder = http1::Builder::new();
builder
.max_headers(MAX_HEADERS)
.timer(TokioTimer::new())
.header_read_timeout(keepalive);
builder
}
async fn back_off(error: io::Error) {
if matches!(
error.kind(),
io::ErrorKind::ConnectionRefused
| io::ErrorKind::ConnectionAborted
| io::ErrorKind::ConnectionReset
) {
return;
}
tracing::error!(%error, "could not accept a client connection");
tokio::time::sleep(Duration::from_secs(1)).await;
}

113
litellm-rust/crates/gateway-forward/src/settings.rs Normal file
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use std::{ffi::OsString, net::SocketAddr, str::FromStr, time::Duration};
use axum::http::Uri;
use serde::Deserialize;
use crate::Error;
const UPSTREAM: &str = "LITELLM_FORWARD_UPSTREAM";
/// The Python proxy's private origin. Only a loopback IPv4 address parses, so nothing can point
/// the forwarder at another host.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Upstream(Uri);
impl Upstream {
pub(crate) fn uri(&self) -> &Uri {
&self.0
}
}
impl FromStr for Upstream {
type Err = Error;
fn from_str(value: &str) -> Result<Self, Error> {
let uri: Uri = value.parse().map_err(Error::UpstreamUri)?;
let address = uri
.authority()
.filter(|_| uri.scheme_str() == Some("http"))
.filter(|authority| !authority.as_str().contains('@'))
.filter(|_| uri.path() == "/" && uri.query().is_none())
.and_then(|authority| authority.as_str().parse::<SocketAddr>().ok());
match address {
Some(SocketAddr::V4(address)) if address.ip().is_loopback() => Ok(Self(uri)),
_ => Err(Error::Upstream),
}
}
}
#[derive(Deserialize)]
struct Environment {
litellm_forward_upstream: String,
litellm_forward_host: String,
litellm_forward_port: u16,
litellm_forward_upstream_keepalive: f64,
litellm_forward_shutdown_drain: f64,
}
/// Everything forward mode runs with. The Python supervisor resolves each value from the settings
/// Python actually runs with, so none of them is guessed or defaulted here.
/// Setting `LITELLM_FORWARD_UPSTREAM` requires every other `LITELLM_FORWARD_*` setting below.
#[derive(Debug, Clone, PartialEq)]
pub struct Settings {
pub upstream: Upstream,
pub host: String,
pub port: u16,
pub upstream_keepalive: Duration,
pub shutdown_drain: Duration,
}
impl Settings {
/// `None` when `LITELLM_FORWARD_UPSTREAM` is unset, which means the gateway is not forwarding.
pub fn from_env() -> Result<Option<Self>, Error> {
Self::from_vars(std::env::vars_os())
}
pub fn from_vars(
variables: impl IntoIterator<Item = (OsString, OsString)>,
) -> Result<Option<Self>, Error> {
let variables: Vec<(String, String)> = variables
.into_iter()
.filter_map(|(key, value)| Some((key.into_string().ok()?, value.into_string().ok()?)))
.collect();
if !variables.iter().any(|(key, _)| key == UPSTREAM) {
return Ok(None);
}
let environment: Environment = envy::from_iter(variables).map_err(|error| match error {
envy::Error::MissingValue(field) => Error::MissingSetting(field.to_uppercase()),
envy::Error::Custom(message) => Error::InvalidSetting(message),
})?;
Ok(Some(Self {
upstream: environment.litellm_forward_upstream.parse()?,
host: environment.litellm_forward_host,
port: environment.litellm_forward_port,
upstream_keepalive: positive_seconds(
"LITELLM_FORWARD_UPSTREAM_KEEPALIVE",
environment.litellm_forward_upstream_keepalive,
)?,
shutdown_drain: seconds(
"LITELLM_FORWARD_SHUTDOWN_DRAIN",
environment.litellm_forward_shutdown_drain,
)?,
}))
}
}
fn seconds(variable: &str, value: f64) -> Result<Duration, Error> {
Duration::try_from_secs_f64(value).map_err(|_| {
Error::InvalidSetting(format!(
"{variable} must be a non-negative number of seconds, got {value}"
))
})
}
/// The keep-alive also bounds the wait for a client's first request, so zero would close every
/// client connection before it could send one.
fn positive_seconds(variable: &str, value: f64) -> Result<Duration, Error> {
match seconds(variable, value)? {
Duration::ZERO => Err(Error::InvalidSetting(format!(
"{variable} must be a positive number of seconds, got {value}"
))),
duration => Ok(duration),
}
}

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litellm-rust/crates/gateway-forward/src/websocket.rs Normal file
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use axum::{
body::Body,
extract::Request,
http::{Method, Version},
response::Response,
};
use hyper::{
body::Incoming,
upgrade::{OnUpgrade, Upgraded},
};
use hyper_util::rt::TokioIo;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use crate::{Rejection, connections::Connections, rewrite};
pub(crate) fn take_handshake(
connections: &Connections,
request: &mut Request,
) -> Result<Option<OnUpgrade>, Rejection> {
if request.method() != Method::GET
|| request.version() != Version::HTTP_11
|| !rewrite::is_websocket_handshake(request.headers())
{
return Ok(None);
}
if connections.is_draining() {
return Err(Rejection::ShuttingDown);
}
Ok(Some(hyper::upgrade::on(request)))
}
pub(crate) async fn switch(
connections: &Connections,
downstream: OnUpgrade,
mut response: Response<Incoming>,
) -> Result<Response, Rejection> {
if !rewrite::is_websocket_handshake(response.headers()) {
return Err(Rejection::UnrequestedUpgrade);
}
let upstream = connections
.until_closed(hyper::upgrade::on(&mut response))
.await
.ok_or(Rejection::ShuttingDown)?
.map_err(Rejection::UpgradeFailed)?;
connections.spawn(async move {
match downstream.await {
Ok(downstream) => relay(downstream, upstream).await,
Err(_) => tracing::debug!("websocket upgrade did not complete"),
}
});
Ok(rewrite::switched_response(response).map(|_| Body::empty()))
}
// uvicorn never half-closes a WebSocket, so Python's EOF means the socket is gone and the relay
// ends. Only a client that is gone ends it from the other side: the client's EOF just half-closes
// Python's side, and a write Python refuses means it closed with its last frames still in flight
// to the client.
async fn relay(downstream: Upgraded, upstream: Upgraded) {
let (mut client_read, mut client_write) = tokio::io::split(TokioIo::new(downstream));
let (mut python_read, mut python_write) = tokio::io::split(TokioIo::new(upstream));
let to_python = async {
let mut buffer = vec![0; 8192];
loop {
let read = match client_read.read(&mut buffer).await {
Ok(0) => break,
Ok(read) => read,
Err(_) => return,
};
if python_write.write_all(&buffer[..read]).await.is_err() {
return std::future::pending().await;
}
}
python_write.shutdown().await.ok();
std::future::pending().await
};
let to_client = async {
tokio::io::copy(&mut python_read, &mut client_write)
.await
.ok();
client_write.shutdown().await.ok();
};
tokio::select! {
() = to_python => tracing::debug!("websocket client disconnected"),
() = to_client => {}
}
}

223
litellm-rust/crates/gateway-forward/tests/client_identity.rs Normal file
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mod support;
use std::sync::{
Arc,
atomic::{AtomicUsize, Ordering},
};
use axum::{body::Body, http::StatusCode, response::Response};
use litellm_gateway_forward::{Forward, PEER_HEADER};
use rstest::rstest;
use support::{DRAIN, Gateway, Raw, UVICORN_KEEPALIVE, raw_upstream, recording, within};
use tokio::net::{TcpListener, TcpStream};
fn ok() -> Response {
Response::new(Body::from("ok"))
}
#[rstest]
#[case::ordinary("")]
#[case::connection_nominated(
"connection: X-Forwarded-For, X-Forwarded-Proto, Forwarded, X-Litellm-Rust-Peer\r\n"
)]
#[tokio::test]
async fn python_sees_forwarding_headers_untouched_and_the_tcp_peer_rust_saw(
#[case] connection: &str,
) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"GET /sso/callback HTTP/1.1\r\n\
host: public.example\r\n\
x-forwarded-for: 192.0.2.1\r\n\
x-forwarded-for: 192.0.2.2\r\n\
x-forwarded-proto: https\r\n\
forwarded: for=192.0.2.1;proto=https\r\n\
x-litellm-rust-peer: 10.1.2.3:1\r\n{connection}\r\n",
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
let forwarded_for: Vec<_> = request.headers.get_all("x-forwarded-for").iter().collect();
assert_eq!(forwarded_for, ["192.0.2.1", "192.0.2.2"]);
assert_eq!(request.headers["x-forwarded-proto"], "https");
assert_eq!(request.headers["forwarded"], "for=192.0.2.1;proto=https");
let peers: Vec<_> = request.headers.get_all(PEER_HEADER).iter().collect();
assert_eq!(peers, [raw.local_address().to_string().as_str()]);
}
/// Python builds redirects and OAuth metadata from Host, and without one from the address it
/// listens on, which behind Rust is its private loopback port. So a request without a usable Host
/// carries the public address the client connected to, except HTTP/1.1, which h11 rejects.
#[rstest]
#[case::http11_without_host("HTTP/1.1", "", false)]
#[case::http10_without_host("HTTP/1.0", "", true)]
#[case::http11_with_an_empty_host("HTTP/1.1", "host:\r\n", true)]
#[tokio::test]
async fn a_request_without_a_usable_host_never_names_the_private_upstream(
#[case] version: &str,
#[case] host: &str,
#[case] forwarded: bool,
) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!("GET /sso/key/generate {version}\r\n{host}\r\n"))
.await;
let status = within(raw.response_head()).await.unwrap().status;
let hosts = received.try_recv().ok().map(|request| {
request
.headers
.get_all("host")
.iter()
.map(|value| value.to_str().unwrap().to_owned())
.collect::<Vec<_>>()
});
let expected = if forwarded {
(StatusCode::OK, Some(vec![gateway.address.to_string()]))
} else {
(StatusCode::BAD_REQUEST, None)
};
assert_eq!((status, hosts), expected);
}
#[rstest]
#[case::uppercase_with_port("PUBLIC.Example:4000")]
#[case::ipv6_literal("[::1]:4000")]
#[case::ipv4_with_port("192.0.2.10:8443")]
#[tokio::test]
async fn python_sees_the_host_header_byte_for_byte(#[case] host: &str) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!("GET /ui HTTP/1.1\r\nHost: {host}\r\n\r\n"))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
let hosts: Vec<_> = request.headers.get_all("host").iter().collect();
assert_eq!(hosts, [host]);
}
/// Python's IP allowlists and rate limits read the peer exactly as uvicorn would have seen it on
/// the public socket, so a dual-stack listener reports IPv4 clients in their mapped form.
#[rstest]
#[case::ipv6("[::1]:0", "[::1]", "[::1]")]
#[case::ipv4_on_a_dual_stack_listener("[::]:0", "127.0.0.1", "[::ffff:127.0.0.1]")]
#[tokio::test]
async fn ipv6_listeners_report_the_peer_bracketed_with_its_port(
#[case] bind: &str,
#[case] connect: &str,
#[case] peer_ip: &str,
) {
let (upstream, mut received) = recording(ok).await;
let forward = Forward::new(
&format!("http://{upstream}").parse().unwrap(),
UVICORN_KEEPALIVE,
);
let public = TcpListener::bind(bind).await.unwrap();
let port = public.local_addr().unwrap().port();
tokio::spawn(forward.serve(public, std::future::pending(), DRAIN));
let mut raw = Raw::new(
TcpStream::connect(format!("{connect}:{port}"))
.await
.unwrap(),
);
raw.send("GET / HTTP/1.1\r\nhost: public.example\r\n\r\n")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(
received.recv().await.unwrap().headers[PEER_HEADER],
format!("{peer_ip}:{}", raw.local_address().port()).as_str()
);
}
/// Without the peer header Python would take Rust's loopback hop as the client, which allowlists
/// often trust, so no spelling, repetition or Connection token may remove or replace it.
#[rstest]
#[case::named_as_hop_by_hop(
"connection: x-litellm-rust-peer\r\nx-litellm-rust-peer: 127.0.0.1:1\r\n"
)]
#[case::mixed_case_copies(
"X-LiteLLM-Rust-Peer: 127.0.0.1:1\r\nx-litellm-rust-peer: 192.0.2.7:2\r\n"
)]
#[case::comma_joined("x-litellm-rust-peer: 127.0.0.1:1, 192.0.2.7:2\r\n")]
#[tokio::test]
async fn a_client_can_neither_strip_nor_spoof_the_peer(#[case] spoof: &str) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"GET /key/info HTTP/1.1\r\nhost: public.example\r\n{spoof}\r\n"
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
let peers: Vec<_> = request.headers.get_all(PEER_HEADER).iter().collect();
assert_eq!(peers, [raw.local_address().to_string().as_str()]);
}
/// Pooled upstream connections carry requests from many clients in turn, so the peer belongs to
/// each request and never to the connection it travels on.
#[rstest]
#[tokio::test]
async fn each_request_carries_its_own_peer_over_a_shared_upstream_connection() {
let connections = Arc::new(AtomicUsize::new(0));
let accepted = connections.clone();
let upstream = raw_upstream(move |mut python| {
accepted.fetch_add(1, Ordering::SeqCst);
async move {
while let Some(head) = python.request_head().await {
let peer = head.header(PEER_HEADER).unwrap().to_vec();
python
.send(
[
format!("HTTP/1.1 200 OK\r\ncontent-length: {}\r\n\r\n", peer.len())
.as_bytes(),
&peer,
]
.concat(),
)
.await;
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut clients = [
gateway.connect().await,
gateway.connect().await,
gateway.connect().await,
];
for index in [0, 1, 2, 2, 1, 0] {
let raw = &mut clients[index];
raw.send("GET /v1/models HTTP/1.1\r\nhost: public.example\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
let peer = raw.body(head.content_length().unwrap()).await;
assert_eq!(peer, raw.local_address().to_string().into_bytes());
}
assert_eq!(connections.load(Ordering::SeqCst), 1);
}

192
litellm-rust/crates/gateway-forward/tests/download.rs Normal file
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@ -0,0 +1,192 @@
mod support;
use std::{
sync::{
Arc,
atomic::{AtomicUsize, Ordering},
},
time::Duration,
};
use axum::{body::Body, extract::Request, http::StatusCode, response::Response};
use http_body_util::BodyExt;
use rstest::rstest;
use support::{Gateway, client, raw_upstream, recording, within};
use tokio::sync::{Notify, mpsc};
#[rstest]
#[tokio::test]
async fn streams_a_body_without_a_content_length_as_python_produces_it() {
let first: &[u8] = &[0xff, 0xfb, 0x90, 0x64, 0x00, 0x0d, 0x0a];
let rest = vec![0xa5; 64 * 1024];
let finish = Arc::new(Notify::new());
let finished = finish.clone();
let tail = rest.clone();
let upstream = raw_upstream(move |mut python| {
let finished = finished.clone();
let tail = tail.clone();
async move {
python.request_head().await.unwrap();
python
.send([&b"HTTP/1.1 200 OK\r\ncontent-type: audio/mpeg\r\ntransfer-encoding: chunked\r\n\r\n7\r\n"[..], first, b"\r\n"].concat())
.await;
finished.notified().await;
python
.send([format!("{:x}\r\n", tail.len()).as_bytes(), &tail, b"\r\n0\r\n\r\n"].concat())
.await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut response = within(
client().request(
Request::post(gateway.url("/v1/audio/speech"))
.body(Body::empty())
.unwrap(),
),
)
.await
.unwrap();
assert!(!response.headers().contains_key("content-length"));
let frame = within(response.body_mut().frame()).await.unwrap().unwrap();
assert_eq!(frame.into_data().unwrap(), first);
finish.notify_one();
let body = within(response.into_body().collect())
.await
.unwrap()
.to_bytes();
assert_eq!(body, rest);
}
#[rstest]
#[tokio::test]
async fn range_requests_and_partial_content_pass_unchanged() {
let (upstream, mut received) = recording(|| -> Response {
Response::builder()
.status(StatusCode::PARTIAL_CONTENT)
.header("content-range", "bytes 2-5/10")
.header("accept-ranges", "bytes")
.body(Body::from("2345"))
.unwrap()
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /v1/videos/video_1/content HTTP/1.1\r\nhost: x\r\nrange: bytes=2-5\r\nif-range: \"v1\"\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::PARTIAL_CONTENT);
assert_eq!(head.header("content-range"), Some(&b"bytes 2-5/10"[..]));
assert_eq!(raw.body(head.content_length().unwrap()).await, b"2345");
let request = received.recv().await.unwrap();
assert_eq!(request.headers["range"], "bytes=2-5");
assert_eq!(request.headers["if-range"], "\"v1\"");
}
#[rstest]
#[tokio::test]
async fn a_large_download_is_paced_by_the_client_and_keeps_its_content_length() {
const LENGTH: usize = 128 * 1024 * 1024;
let written = Arc::new(AtomicUsize::new(0));
let writing = written.clone();
let upstream = raw_upstream(move |mut python| {
let writing = writing.clone();
async move {
python.request_head().await.unwrap();
python
.send(format!("HTTP/1.1 200 OK\r\ncontent-type: application/octet-stream\r\ncontent-length: {LENGTH}\r\n\r\n"))
.await;
let chunk = [0xa5; 64 * 1024];
while writing.load(Ordering::SeqCst) < LENGTH {
python.send(chunk).await;
writing.fetch_add(chunk.len(), Ordering::SeqCst);
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /v1/files/file-1/content HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.content_length(), Some(LENGTH));
assert_eq!(head.header("transfer-encoding"), None);
tokio::time::sleep(Duration::from_secs(1)).await;
assert!(
written.load(Ordering::SeqCst) < LENGTH / 4,
"the forwarder buffered a download the client was not reading"
);
let mut remaining = LENGTH;
while remaining > 0 {
remaining -= within(raw.body(remaining.min(1 << 20))).await.len();
}
}
/// The UI revalidates its static assets, and a 304 must carry exactly the validators Python sent,
/// with no length invented for a body it never has.
#[rstest]
#[tokio::test]
async fn a_conditional_request_gets_python_304_with_its_validators_only() {
let (event, mut events) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python| {
let event = event.clone();
async move {
while let Some(head) = python.request_head().await {
event
.send(head.header("if-none-match").map(<[u8]>::to_vec))
.unwrap();
python
.send("HTTP/1.1 304 Not Modified\r\netag: \"5f1-abc\"\r\ncache-control: no-cache\r\nvary: Accept-Encoding\r\ndate: Tue, 03 Nov 2026 10:00:00 GMT\r\n\r\n")
.await;
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
for _ in 0..2 {
raw.send("GET /ui/_next/static/chunks/main.js HTTP/1.1\r\nhost: x\r\nif-none-match: \"5f1-abc\"\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::NOT_MODIFIED);
let mut names: Vec<_> = head.headers.iter().map(|(name, _)| name.as_str()).collect();
names.sort_unstable();
assert_eq!(names, ["cache-control", "date", "etag", "vary"]);
assert_eq!(head.header("etag"), Some(&b"\"5f1-abc\""[..]));
assert_eq!(
head.header("date"),
Some(&b"Tue, 03 Nov 2026 10:00:00 GMT"[..])
);
assert_eq!(
within(events.recv()).await.unwrap().as_deref(),
Some(&b"\"5f1-abc\""[..])
);
}
}
/// A client knows a download was cut short only because fewer bytes than the Content-Length
/// arrived before the connection closed, so the length must survive and the connection must end.
#[rstest]
#[tokio::test]
async fn a_download_python_cuts_short_closes_the_client_connection_before_its_length() {
let upstream = raw_upstream(|mut python| async move {
python.request_head().await.unwrap();
python
.send([&b"HTTP/1.1 200 OK\r\ncontent-type: application/octet-stream\r\ncontent-length: 1000\r\n\r\n"[..], &[0xa5; 500]].concat())
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /v1/files/file-1/content HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::OK);
assert_eq!(head.content_length(), Some(1000));
assert_eq!(within(raw.until_closed()).await, [0xa5; 500]);
}

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@ -0,0 +1,855 @@
mod support;
use std::{
convert::Infallible,
sync::{
Arc,
atomic::{AtomicUsize, Ordering},
},
};
use axum::{
Router,
body::{Body, Bytes},
extract::Request,
http::{HeaderValue, StatusCode},
response::Response,
};
use litellm_gateway_forward::PEER_HEADER;
use rstest::rstest;
use support::{Gateway, Head, client, raw_upstream, recording, serve, within};
use tokio::{
io::{AsyncReadExt, AsyncWriteExt},
sync::mpsc,
};
fn ok() -> Response {
Response::new(Body::from("ok"))
}
/// An upstream that reports each bodiless request head exactly as it arrived on the wire.
async fn heads() -> (std::net::SocketAddr, mpsc::UnboundedReceiver<Head>) {
let (sender, receiver) = mpsc::unbounded_channel();
let address = raw_upstream(move |mut python| {
let sender = sender.clone();
async move {
while let Some(head) = python.request_head().await {
sender.send(head).unwrap();
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 2\r\n\r\nok")
.await;
}
}
})
.await;
(address, receiver)
}
#[rstest]
#[tokio::test]
async fn forwards_the_request_as_the_client_sent_it_minus_hop_headers() {
let (upstream, mut received) = recording(|| {
Response::builder()
.status(StatusCode::UNAUTHORIZED)
.header("connection", "x-upstream-hop")
.header("x-upstream-hop", "remove")
.header("x-response", "keep")
.body(Body::from("python error"))
.unwrap()
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(
"PATCH /v1/messages?x=a%2Fb&x=c HTTP/1.1\r\n\
host: public.example\r\n\
authorization: Bearer test\r\n\
connection: x-remove, keep-alive\r\n\
x-remove: remove\r\n\
proxy-authorization: remove\r\n\
te: trailers\r\n\
content-length: 7\r\n\r\npayload",
)
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::UNAUTHORIZED);
assert_eq!(head.header("x-response"), Some(&b"keep"[..]));
assert_eq!(head.header("x-upstream-hop"), None);
let body = raw.body(head.content_length().unwrap()).await;
assert_eq!(body, b"python error");
let request = received.recv().await.unwrap();
assert_eq!(request.method, "PATCH");
assert_eq!(request.uri, "/v1/messages?x=a%2Fb&x=c");
assert_eq!(request.headers["host"], "public.example");
assert_eq!(request.headers["authorization"], "Bearer test");
assert!(!request.headers.contains_key("x-remove"));
assert!(!request.headers.contains_key("proxy-authorization"));
assert!(!request.headers.contains_key("te"));
assert!(!request.headers.contains_key("connection"));
assert_eq!(request.body, "payload");
}
#[rstest]
#[case::host("HoSt", "public.example")]
#[case::length("Content-Length", "7")]
#[case::authorization("AUTHORIZATION", "Bearer test")]
#[case::cookie("Cookie", "session=test")]
#[case::api_key("X-Api-Key", "test")]
#[case::azure_key("Api-Key", "test")]
#[case::litellm_key("Litellm-Api-Key", "test")]
#[case::forwarded("Forwarded", "for=192.0.2.1;proto=https")]
#[case::forwarded_for("X-Forwarded-For", "192.0.2.1")]
#[case::forwarded_proto("X-Forwarded-Proto", "https")]
#[case::forwarded_host("X-Forwarded-Host", "public.example")]
#[case::content_type("Content-Type", "application/octet-stream")]
#[case::content_encoding("Content-Encoding", "identity")]
#[tokio::test]
async fn connection_cannot_remove_end_to_end_headers(#[case] name: &str, #[case] value: &str) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
let host = if name.eq_ignore_ascii_case("host") {
""
} else {
"host: public.example\r\n"
};
let length = if name.eq_ignore_ascii_case("content-length") {
""
} else {
"content-length: 7\r\n"
};
raw.send(format!(
"POST / HTTP/1.1\r\n{host}{length}{name}: {value}\r\nconnection: x-remove\r\nconnection: {name}, keep-alive\r\nx-remove: remove\r\n\r\npayload"
)).await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = within(received.recv()).await.unwrap();
assert_eq!(request.headers[name], value);
assert_eq!(request.body, "payload");
assert!(!request.headers.contains_key("connection"));
assert!(!request.headers.contains_key("x-remove"));
}
#[rstest]
#[tokio::test]
async fn connection_cannot_remove_response_credentials_or_representation_metadata() {
let (upstream, _received) = recording(|| {
Response::builder()
.status(StatusCode::UNAUTHORIZED)
.header("connection", "Content-Length, Set-Cookie, WWW-Authenticate, Authentication-Info, Content-Type, Content-Encoding, x-remove")
.header("content-length", "2")
.header("set-cookie", "session=; Max-Age=0")
.header("www-authenticate", "Bearer")
.header("authentication-info", "nextnonce=test")
.header("content-type", "text/plain")
.header("content-encoding", "identity")
.header("x-remove", "remove")
.body(Body::from("ok"))
.unwrap()
}).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET / HTTP/1.1\r\nhost: x\r\n\r\n").await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::UNAUTHORIZED);
assert_eq!(head.content_length(), Some(2));
assert_eq!(head.header("set-cookie"), Some(&b"session=; Max-Age=0"[..]));
assert_eq!(head.header("www-authenticate"), Some(&b"Bearer"[..]));
assert_eq!(
head.header("authentication-info"),
Some(&b"nextnonce=test"[..])
);
assert_eq!(head.header("content-type"), Some(&b"text/plain"[..]));
assert_eq!(head.header("content-encoding"), Some(&b"identity"[..]));
assert_eq!(head.header("x-remove"), None);
assert_eq!(raw.body(2).await, b"ok");
}
#[rstest]
#[case::get("GET")]
#[case::post("POST")]
#[case::put("PUT")]
#[case::delete("DELETE")]
#[case::options("OPTIONS")]
#[case::extension("PURGE")]
#[case::webdav("PROPFIND")]
#[case::lowercase("get")]
#[case::punctuated("M-SEARCH")]
#[tokio::test]
async fn forwards_every_method(#[case] method: &str) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let response = client()
.request(
Request::builder()
.method(method)
.uri(gateway.url("/mcp"))
.body(Body::from("body"))
.unwrap(),
)
.await
.unwrap();
assert_eq!(response.status(), StatusCode::OK);
let request = received.recv().await.unwrap();
assert_eq!(request.method, method);
assert_eq!(request.body, "body");
}
#[rstest]
#[case::double_slash("//v1//models")]
#[case::encoded_slash("/v1/files/a%2Fb/content")]
#[case::encoded_hash_in_query("/v1/files?purpose=batch%23retry&limit=1")]
#[case::encoded_hash_in_path("/v1/files/report%231.pdf/content")]
#[case::encoded_hash_before_query("/gemini/v1beta/files/a%23b?key=k")]
#[case::encoded_query("/v1/models?q=%E2%9C%93&empty=&flag")]
#[case::utf8_bytes_escaped("/mcp/%F0%9F%A6%80")]
#[case::lowercase_encoded_slash("/v1/files/a%2fb/content")]
#[case::dot_segments("/openai/./v1/../v1/models")]
#[case::encoded_dot_segments("/openai/%2e%2e/v1/%2E/models")]
#[case::matrix_params("/langfuse/api;v=1/public;x=y/traces")]
#[case::plus_and_encoded_space("/gemini/v1beta/models?q=a+b&r=a%20b&s=%2B")]
#[case::empty_query("/v1/models?")]
#[case::question_marks_in_query("/v1/models??a=b?c")]
#[case::colons_in_segments(
"/v1/projects/p/locations/l/publishers/google/models/m:streamGenerateContent?alt=sse"
)]
#[case::sub_delims("/~u/@:!$&'()*+,=/x")]
#[case::raw_bytes_browsers_leave_unescaped("/a{b}|c^d\\e\"f?g={}|^`")]
#[case::invalid_percent_escapes("/a%zz%00b?%")]
#[tokio::test]
async fn forwards_the_request_target_byte_for_byte(#[case] target: &str) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!("GET {target} HTTP/1.1\r\nhost: x\r\n\r\n"))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(received.recv().await.unwrap().uri, target);
}
#[rstest]
#[tokio::test]
async fn forwards_a_query_string_as_long_as_uvicorn_accepts() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
let target = format!("/vertex_ai/v1/models?key=%2F{}&end", "a%20b".repeat(3000));
raw.send(format!("GET {target} HTTP/1.1\r\nhost: x\r\n\r\n"))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(received.recv().await.unwrap().uri, target.as_str());
}
#[rstest]
#[case::in_query("/v1/files?purpose=batch#retry&limit=1", "/v1/files?purpose=batch")]
#[case::in_path("/v1/files/report#1.pdf/content", "/v1/files/report")]
#[case::before_query("/gemini/v1beta/files/a#b?key=k", "/gemini/v1beta/files/a")]
#[tokio::test]
async fn forwards_only_the_path_and_query_before_a_fragment(
#[case] target: &str,
#[case] expected: &str,
) {
let (upstream, mut received) = heads().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!("GET {target} HTTP/1.1\r\nhost: x\r\n\r\n"))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(within(received.recv()).await.unwrap().path, expected);
}
#[rstest]
#[tokio::test]
async fn absolute_form_targets_reach_python_as_origin_form() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(
"GET http://elsewhere.example/v1/models?x=1 HTTP/1.1\r\nhost: elsewhere.example\r\n\r\n",
)
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
assert_eq!(request.uri, "/v1/models?x=1");
}
#[rstest]
#[tokio::test]
async fn relays_a_response_with_more_headers_than_hyper_allows_by_default() {
let upstream = serve(axum::Router::new().fallback(|| async {
let headers = (0..150).map(|index| (format!("llm_provider-x-{index}"), "v"));
let mut response = ok();
for (name, value) in headers {
response.headers_mut().insert(
axum::http::HeaderName::from_bytes(name.as_bytes()).unwrap(),
HeaderValue::from_static(value),
);
}
response
}))
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /v1/chat/completions HTTP/1.1\r\nhost: public.example\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::OK);
assert_eq!(head.header("llm_provider-x-149"), Some(&b"v"[..]));
}
/// uvicorn's h11 parser has no header count limit, only a 16 KiB cap on the whole head.
#[rstest]
#[tokio::test]
async fn forwards_a_request_with_as_many_headers_as_uvicorn_accepts() {
let (sender, mut received) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |python| {
let sender = sender.clone();
async move {
let mut stream = python.into_stream();
let mut head = Vec::new();
while !head.ends_with(b"\r\n\r\n") {
head.push(stream.read_u8().await.unwrap());
}
sender.send(head).unwrap();
stream
.write_all(b"HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n")
.await
.unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
let headers: String = (0..1000).map(|index| format!("x-{index}: v\r\n")).collect();
raw.send(format!(
"GET /v1/chat/completions HTTP/1.1\r\nhost: x\r\n{headers}\r\n"
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let head = String::from_utf8(within(received.recv()).await.unwrap()).unwrap();
assert!(head.contains(&headers));
}
async fn header_fields_python_receives(fields: &str) -> Vec<(String, Vec<u8>)> {
let (upstream, mut received) = heads().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"GET /anthropic/v1/messages HTTP/1.1\r\nhost: x\r\n{fields}\r\n"
))
.await;
within(raw.response_head()).await.unwrap();
within(received.recv())
.await
.unwrap()
.headers
.into_iter()
.filter(|(name, _)| name.starts_with("x-") && name != PEER_HEADER)
.collect()
}
fn fields(expected: &[(&str, &str)]) -> Vec<(String, Vec<u8>)> {
expected
.iter()
.map(|(name, value)| ((*name).to_owned(), value.as_bytes().to_vec()))
.collect()
}
/// Python reads `scope["headers"]` as the list the client sent, in that order.
#[rstest]
#[ignore = "divergence: HeaderMap::remove can move the headers after a dropped hop-by-hop one"]
#[tokio::test]
async fn dropping_a_hop_by_hop_header_keeps_the_others_in_order() {
let received = header_fields_python_receives(
"x-a: 1\r\nconnection: keep-alive\r\nx-b: 2\r\nx-c: 3\r\nx-d: 4\r\n",
)
.await;
assert_eq!(
received,
fields(&[("x-a", "1"), ("x-b", "2"), ("x-c", "3"), ("x-d", "4")])
);
}
/// uvicorn speaks only HTTP/1.1, so an HTTP/2 prior-knowledge client never reaches Python through
/// Rust either. hyper closes the connection where h11 answers 400, which no HTTP/2 client reads.
#[rstest]
#[tokio::test]
async fn an_http2_client_never_reaches_python() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(b"PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n\x00\x00\x00\x04\x00\x00\x00\x00\x00")
.await;
assert!(within(raw.until_closed()).await.is_empty());
assert!(received.try_recv().is_err());
}
#[rstest]
#[ignore = "divergence: HeaderMap groups every value of a name at its first position"]
#[tokio::test]
async fn interleaved_repeated_headers_reach_python_interleaved() {
let received = header_fields_python_receives("x-a: 1\r\nx-b: 2\r\nx-a: 3\r\n").await;
assert_eq!(
received,
fields(&[("x-a", "1"), ("x-b", "2"), ("x-a", "3")])
);
}
/// h11 trims optional whitespace around a value and keeps everything inside it, including empty
/// values and names using every token character.
#[rstest]
#[tokio::test]
async fn python_sees_header_values_as_h11_would_parse_them() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET / HTTP/1.1\r\nhost: x\r\nx-empty:\r\nx-blank: \r\nx-inner: a \t b \t\r\nX-Token!#$%&'*+.^_`|~: v\r\nx-empty: second\r\n\r\n")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
let values = |name: &str| -> Vec<&[u8]> {
request
.headers
.get_all(name)
.iter()
.map(HeaderValue::as_bytes)
.collect()
};
assert_eq!(values("x-empty"), [&b""[..], b"second"]);
assert_eq!(values("x-blank"), [&b""[..]]);
assert_eq!(values("x-inner"), [&b"a \t b"[..]]);
assert_eq!(values("x-token!#$%&'*+.^_`|~"), [&b"v"[..]]);
}
/// RFC 9112 section 5.2 lets a server either reject obs-fold or unfold it, and h11 unfolds.
#[rstest]
#[ignore = "divergence: hyper rejects obs-fold with a 400 where uvicorn unfolds it to one space"]
#[tokio::test]
async fn a_folded_header_reaches_python_unfolded() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET / HTTP/1.1\r\nhost: x\r\nx-a: b\r\n c\r\n\r\n")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(received.recv().await.unwrap().headers["x-a"], "b c");
}
#[rstest]
#[tokio::test]
async fn keeps_repeated_response_headers_and_opaque_header_bytes() {
let (upstream, mut received) = recording(|| {
Response::builder()
.header("set-cookie", "a=1; Path=/")
.header("set-cookie", "b=2; HttpOnly")
.header("x-opaque", HeaderValue::from_bytes(b"caf\xe9").unwrap())
.body(Body::empty())
.unwrap()
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(b"GET / HTTP/1.1\r\nhost: x\r\nx-opaque: caf\xe9\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
let cookies: Vec<_> = head
.headers
.iter()
.filter(|(name, _)| name == "set-cookie")
.map(|(_, value)| value.as_slice())
.collect();
assert_eq!(cookies, [&b"a=1; Path=/"[..], b"b=2; HttpOnly"]);
assert_eq!(head.header("x-opaque"), Some(&b"caf\xe9"[..]));
assert_eq!(
received.recv().await.unwrap().headers["x-opaque"].as_bytes(),
b"caf\xe9"
);
}
/// An HTTP/1.0 client cannot decode chunked framing, so a streamed answer reaches it delimited by
/// the connection closing, as uvicorn sends it.
#[rstest]
#[tokio::test]
async fn an_http10_client_gets_a_streamed_answer_unframed_and_python_gets_its_body() {
let (upstream, mut received) = recording(|| {
Response::new(Body::from_stream(futures_util::stream::iter(
["str", "eamed"].map(|piece| Ok::<_, Infallible>(Bytes::from_static(piece.as_bytes()))),
)))
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("POST /v1/completions HTTP/1.0\r\nhost: x\r\ncontent-length: 7\r\n\r\npayload")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::OK);
assert_eq!(head.header("transfer-encoding"), None);
assert_eq!(within(raw.until_closed()).await, b"streamed");
let request = received.recv().await.unwrap();
assert_eq!(request.method, "POST");
assert_eq!(request.body, "payload");
}
#[rstest]
#[tokio::test]
async fn answers_pipelined_requests_in_order() {
let upstream = serve(
Router::new().fallback(|request: Request| async move { request.uri().path().to_owned() }),
)
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /first HTTP/1.1\r\nhost: x\r\n\r\nHEAD /second HTTP/1.1\r\nhost: x\r\n\r\nGET /third HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
let first = within(raw.response_head()).await.unwrap();
assert_eq!(raw.body(first.content_length().unwrap()).await, b"/first");
let second = within(raw.response_head()).await.unwrap();
assert_eq!(second.content_length(), Some(7));
let third = within(raw.response_head()).await.unwrap();
assert_eq!(raw.body(third.content_length().unwrap()).await, b"/third");
}
#[rstest]
#[case::no_content(StatusCode::NO_CONTENT)]
#[case::not_modified(StatusCode::NOT_MODIFIED)]
#[tokio::test]
async fn bodiless_statuses_keep_the_connection_reusable(#[case] status: StatusCode) {
let upstream = serve(Router::new().fallback(move |request: Request| async move {
match request.uri().path() {
"/next" => (StatusCode::OK, "next"),
_ => (status, ""),
}
}))
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /empty HTTP/1.1\r\nhost: x\r\n\r\nGET /next HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
assert_eq!(within(raw.response_head()).await.unwrap().status, status);
let next = within(raw.response_head()).await.unwrap();
assert_eq!(raw.body(next.content_length().unwrap()).await, b"next");
}
#[rstest]
#[tokio::test]
async fn informational_responses_keep_the_connection_reusable() {
let upstream = raw_upstream(|mut python| async move {
while let Some(head) = python.request_head().await {
match head.path.as_str() {
"/hints" => {
python
.send("HTTP/1.1 103 Early Hints\r\nlink: </ui/app.css>; rel=preload\r\n\r\nHTTP/1.1 200 OK\r\ncontent-length: 5\r\n\r\nfinal")
.await
}
_ => {
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 4\r\n\r\nnext")
.await
}
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /hints HTTP/1.1\r\nhost: x\r\n\r\nGET /next HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
let mut hinted = within(raw.response_head()).await.unwrap();
while hinted.status.is_informational() {
hinted = within(raw.response_head()).await.unwrap();
}
assert_eq!(hinted.status, StatusCode::OK);
assert_eq!(raw.body(hinted.content_length().unwrap()).await, b"final");
let next = within(raw.response_head()).await.unwrap();
assert_eq!(raw.body(next.content_length().unwrap()).await, b"next");
}
#[rstest]
#[case::found(
StatusCode::FOUND,
"https://idp.example/authorize?state=a%2Fb&redirect_uri=https%3A%2F%2Fpublic.example%2Fsso%2Fcallback"
)]
#[case::see_other(StatusCode::SEE_OTHER, "/ui/?login=success")]
#[case::temporary(StatusCode::TEMPORARY_REDIRECT, "./mcp/oauth/authorize?client_id=x")]
#[tokio::test]
async fn redirects_reach_the_client_with_location_and_cookies_unchanged(
#[case] status: StatusCode,
#[case] location: &'static str,
) {
let (upstream, _received) = recording(move || {
Response::builder()
.status(status)
.header("location", location)
.header(
"set-cookie",
"token=a%2Fb; Path=/; HttpOnly; Secure; SameSite=Lax",
)
.header("set-cookie", "state=; Max-Age=0")
.header(
"set-cookie",
"session=x; Expires=Wed, 04 Nov 2026 10:00:00 GMT; Path=/",
)
.body(Body::empty())
.unwrap()
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /sso/key/generate HTTP/1.1\r\nhost: public.example\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, status);
assert_eq!(head.header("location"), Some(location.as_bytes()));
let cookies: Vec<_> = head
.headers
.iter()
.filter(|(name, _)| name == "set-cookie")
.map(|(_, value)| value.as_slice())
.collect();
assert_eq!(
cookies,
[
&b"token=a%2Fb; Path=/; HttpOnly; Secure; SameSite=Lax"[..],
b"state=; Max-Age=0",
b"session=x; Expires=Wed, 04 Nov 2026 10:00:00 GMT; Path=/",
]
);
}
#[rstest]
#[tokio::test]
async fn non_websocket_upgrades_reach_python_as_plain_requests() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET / HTTP/1.1\r\nhost: x\r\nconnection: upgrade, http2-settings\r\nupgrade: h2c\r\nhttp2-settings: AAMAAABkAAQAoAAAAAIAAAAA\r\n\r\n")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
assert!(!request.headers.contains_key("upgrade"));
assert!(!request.headers.contains_key("connection"));
assert!(!request.headers.contains_key("http2-settings"));
}
#[rstest]
#[tokio::test]
async fn forwards_an_asterisk_form_options_request() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("OPTIONS * HTTP/1.1\r\nhost: x\r\n\r\n").await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
assert_eq!(request.method, "OPTIONS");
assert_eq!(request.uri, "*");
}
#[rstest]
#[tokio::test]
async fn an_authority_form_target_is_a_400_python_never_sees() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("CONNECT api.example:443 HTTP/1.1\r\nhost: api.example:443\r\n\r\n")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::BAD_REQUEST
);
assert!(received.try_recv().is_err());
}
#[rstest]
#[tokio::test]
async fn a_client_connection_close_ends_only_the_client_connection() {
let connections = Arc::new(AtomicUsize::new(0));
let accepted = connections.clone();
let upstream = raw_upstream(move |mut python| {
accepted.fetch_add(1, Ordering::SeqCst);
async move {
while python.request_head().await.is_some() {
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 2\r\n\r\nok")
.await;
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
for _ in 0..2 {
let mut raw = gateway.connect().await;
raw.send("GET / HTTP/1.1\r\nhost: x\r\nconnection: close\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.header("connection"), Some(&b"close"[..]));
assert_eq!(raw.body(2).await, b"ok");
within(raw.closed()).await;
}
assert_eq!(connections.load(Ordering::SeqCst), 1);
}
#[rstest]
#[tokio::test]
async fn a_python_connection_close_ends_only_the_upstream_connection() {
let connections = Arc::new(AtomicUsize::new(0));
let accepted = connections.clone();
let upstream = raw_upstream(move |mut python| {
accepted.fetch_add(1, Ordering::SeqCst);
async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 500 Internal Server Error\r\ncontent-length: 5\r\nconnection: close\r\n\r\nerror")
.await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
for _ in 0..2 {
raw.send("GET / HTTP/1.1\r\nhost: x\r\n\r\n").await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::INTERNAL_SERVER_ERROR);
assert_eq!(head.header("connection"), None);
assert_eq!(raw.body(5).await, b"error");
}
assert_eq!(connections.load(Ordering::SeqCst), 2);
}
/// uvicorn answers HEAD on a streaming route with chunked framing and no body, so the client
/// must not be told the body is empty, and must not wait for one before its next request.
#[rstest]
#[tokio::test]
async fn head_answered_with_chunked_framing_claims_no_length_and_keeps_the_connection() {
let upstream = raw_upstream(|mut python| async move {
while let Some(head) = python.request_head().await {
match head.path.as_str() {
"/next" => {
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 4\r\n\r\nnext")
.await
}
_ => {
python
.send("HTTP/1.1 200 OK\r\ncontent-type: text/event-stream\r\ntransfer-encoding: chunked\r\n\r\n")
.await
}
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("HEAD /mcp HTTP/1.1\r\nhost: x\r\n\r\nGET /next HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::OK);
assert_eq!(head.content_length(), None);
let next = within(raw.response_head()).await.unwrap();
assert_eq!(raw.body(next.content_length().unwrap()).await, b"next");
}
const GZIP: &[u8] = &[
0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x4b, 0x49, 0x2c, 0x49, 0xb4, 0x52,
0x30, 0xe4, 0xe2, 0x02, 0x00, 0xce, 0xcd, 0x78, 0x54, 0x09, 0x00, 0x00, 0x00,
];
#[rstest]
#[case::fixed_length(false)]
#[case::streamed(true)]
#[tokio::test]
async fn content_codings_cross_unchanged_both_ways(#[case] streamed: bool) {
let (upstream, mut received) = recording(move || {
let body = match streamed {
true => Body::from_stream(futures_util::stream::iter(
GZIP.chunks(5)
.map(|piece| Ok::<_, Infallible>(Bytes::from_static(piece))),
)),
false => Body::from(GZIP),
};
Response::builder()
.header("content-encoding", "gzip")
.header("vary", "Accept-Encoding")
.body(body)
.unwrap()
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(
[
format!(
"POST /v1/chat/completions HTTP/1.1\r\nhost: x\r\ncontent-encoding: gzip\r\naccept-encoding: gzip, br;q=0.5\r\ncontent-length: {}\r\n\r\n",
GZIP.len()
)
.as_bytes(),
GZIP,
]
.concat(),
)
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.header("content-encoding"), Some(&b"gzip"[..]));
assert_eq!(head.header("vary"), Some(&b"Accept-Encoding"[..]));
let body = match head.content_length() {
Some(length) => raw.body(length).await,
None => within(raw.chunked_body()).await,
};
assert_eq!(body, GZIP);
assert_eq!(head.content_length().is_none(), streamed);
let request = received.recv().await.unwrap();
assert_eq!(request.headers["content-encoding"], "gzip");
assert_eq!(request.headers["accept-encoding"], "gzip, br;q=0.5");
assert_eq!(request.body, GZIP);
}
#[rstest]
#[tokio::test]
async fn python_sees_no_accept_encoding_the_client_did_not_send() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /metrics/ HTTP/1.1\r\nhost: x\r\n\r\n").await;
within(raw.response_head()).await.unwrap();
assert!(
!received
.recv()
.await
.unwrap()
.headers
.contains_key("accept-encoding")
);
}

259
litellm-rust/crates/gateway-forward/tests/framing.rs Normal file
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@ -0,0 +1,259 @@
mod support;
use std::{collections::BTreeSet, net::SocketAddr};
use axum::http::StatusCode;
use rstest::rstest;
use support::{Gateway, Head, Raw, raw_upstream, within};
use tokio::sync::mpsc;
struct Captured {
head: Head,
body: Vec<u8>,
}
/// A keep-alive upstream that decodes framing like h11 and reports every request it reads.
async fn capturing() -> (SocketAddr, mpsc::UnboundedReceiver<Captured>) {
let (sender, receiver) = mpsc::unbounded_channel();
let address = raw_upstream(move |mut python: Raw| {
let sender = sender.clone();
async move {
while let Some(head) = python.request_head().await {
let body = match head.header("transfer-encoding") {
Some(_) => python.chunked_body().await,
None => python.body(content_length(&head)).await,
};
sender.send(Captured { head, body }).unwrap();
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 2\r\n\r\nok")
.await;
}
}
})
.await;
(address, receiver)
}
/// The length h11 reads from every Content-Length field, which may repeat one value.
fn content_length(head: &Head) -> usize {
let lengths: BTreeSet<usize> = head
.headers
.iter()
.filter(|(name, _)| name.eq_ignore_ascii_case("content-length"))
.flat_map(|(_, value)| value.split(|byte| *byte == b','))
.map(|length| {
std::str::from_utf8(length.trim_ascii())
.unwrap()
.parse()
.unwrap()
})
.collect();
assert!(
lengths.len() < 2,
"python got conflicting lengths {lengths:?}"
);
lengths.first().copied().unwrap_or(0)
}
/// RFC 9112 section 6.3: Transfer-Encoding overrides Content-Length. Forwarding both would let
/// Python split the stream at a different place than Rust did. Section 6.1 then closes the
/// connection after the response, so a request smuggled behind it never runs.
#[rstest]
#[tokio::test]
async fn a_request_framed_two_ways_reaches_python_framed_by_transfer_encoding_and_closes() {
let (upstream, mut received) = capturing().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("POST /v1/files HTTP/1.1\r\nhost: x\r\ncontent-length: 3\r\ntransfer-encoding: chunked\r\n\r\n5\r\nhello\r\n0\r\n\r\nGET /next HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
raw.body(2).await;
within(raw.until_closed()).await;
let upload = received.recv().await.unwrap();
assert_eq!(upload.head.header("content-length"), None);
assert_eq!(
upload.head.header("transfer-encoding"),
Some(&b"chunked"[..])
);
assert_eq!(upload.body, b"hello");
assert!(
received.try_recv().is_err(),
"python ran the smuggled request"
);
}
#[rstest]
#[case::conflicting_content_lengths("content-length: 4\r\ncontent-length: 40\r\n")]
#[case::content_length_list("content-length: 4, 40\r\n")]
#[case::signed_content_length("content-length: +4\r\n")]
#[case::chunked_not_last("transfer-encoding: chunked, identity\r\ncontent-length: 4\r\n")]
#[case::unknown_coding("transfer-encoding: xchunked\r\ncontent-length: 4\r\n")]
#[case::space_before_colon("transfer-encoding : chunked\r\ncontent-length: 4\r\n")]
#[case::folded_transfer_encoding("transfer-encoding:\r\n chunked\r\ncontent-length: 4\r\n")]
#[case::bare_cr("x-a: b\rx-b: c\r\ncontent-length: 4\r\n")]
#[case::nul_byte("x-a: b\x00c\r\ncontent-length: 4\r\n")]
#[tokio::test]
async fn ambiguous_framing_never_reaches_python(#[case] headers: &str) {
let (upstream, mut received) = capturing().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\n{headers}\r\nbodyGET /smuggled HTTP/1.1\r\nhost: x\r\n\r\n"
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::BAD_REQUEST
);
within(raw.closed()).await;
assert!(received.try_recv().is_err(), "python received a request");
}
#[rstest]
#[case::bare_lf("4\nbody\n0\n\n")]
#[case::invalid_size("zz\r\nbody\r\n0\r\n\r\n")]
#[case::size_overflow("10000000000000004\r\nbody\r\n0\r\n\r\n")]
#[tokio::test]
async fn a_malformed_request_body_is_a_400_not_a_502(#[case] chunks: &str) {
let upstream = raw_upstream(|mut python| async move { python.closed().await }).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\ntransfer-encoding: chunked\r\n\r\n{chunks}"
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::BAD_REQUEST
);
}
/// hyper decodes only the chunked layer, so any other coding would reach Python still coded but
/// framed as a plain body. uvicorn turns every h11 parse error into a 400, ignoring the 501 h11
/// suggests for codings.
#[rstest]
#[case::listed_before_chunked("transfer-encoding: gzip, chunked\r\n")]
#[case::split_across_fields("transfer-encoding: gzip\r\ntransfer-encoding: chunked\r\n")]
#[tokio::test]
async fn a_transfer_coding_other_than_chunked_is_the_400_uvicorn_sends_python_never_sees(
#[case] headers: &str,
) {
let (upstream, mut received) = capturing().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\n{headers}\r\n4\r\nbody\r\n0\r\n\r\n"
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::BAD_REQUEST
);
assert!(
received.try_recv().is_err(),
"python received a still-coded body"
);
}
async fn assert_python_reads_the_body_and_the_next_request(headers: &str) {
let (upstream, mut received) = capturing().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\n{headers}\r\npayloadGET /next HTTP/1.1\r\nhost: x\r\n\r\n"
))
.await;
for _ in 0..2 {
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
raw.body(2).await;
}
assert_eq!(received.recv().await.unwrap().body, b"payload");
assert_eq!(received.recv().await.unwrap().head.path, "/next");
}
#[rstest]
#[case::repeated_fields("content-length: 7\r\ncontent-length: 7\r\n")]
#[case::leading_zeros("content-length: 007\r\n")]
#[tokio::test]
async fn a_content_length_h11_reads_one_way_reaches_python_framed_the_same(#[case] headers: &str) {
assert_python_reads_the_body_and_the_next_request(headers).await;
}
/// h11 accepts a Content-Length list that repeats one value, as RFC 9110 section 8.6 allows.
#[rstest]
#[ignore = "divergence: hyper's server parses each Content-Length field as one number and 400s a list"]
#[tokio::test]
async fn a_content_length_list_of_one_value_reaches_python() {
assert_python_reads_the_body_and_the_next_request("content-length: 7, 7\r\n").await;
}
#[rstest]
#[case::leading_zeros("0004\r\nbody\r\n0\r\n\r\n", "body")]
#[case::uppercase_hex("A\r\nbody\r\nbody\r\n0\r\n\r\n", "body\r\nbody")]
#[case::whitespace_after_size("4 \r\nbody\r\n0\r\n\r\n", "body")]
#[case::extension_and_trailer("4;a=\"b;c\"\r\nbody\r\n0\r\nx-sum: 1\r\n\r\n", "body")]
#[tokio::test]
async fn chunk_framing_h11_accepts_reaches_python_decoded(
#[case] chunks: &str,
#[case] body: &str,
) {
let (upstream, mut received) = capturing().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\ntransfer-encoding: chunked\r\n\r\n{chunks}GET /next HTTP/1.1\r\nhost: x\r\n\r\n"
))
.await;
for _ in 0..2 {
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
raw.body(2).await;
}
assert_eq!(received.recv().await.unwrap().body, body.as_bytes());
assert_eq!(received.recv().await.unwrap().head.path, "/next");
}
/// h11 reads a head whose lines end in a bare LF, so Python gets the same request through Rust.
#[rstest]
#[tokio::test]
async fn a_head_with_bare_lf_line_endings_reaches_python() {
let (upstream, mut received) = capturing().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("POST /v1/files HTTP/1.1\nhost: x\nx-a: b\ncontent-length: 4\n\nbody")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let upload = received.recv().await.unwrap();
assert_eq!(upload.head.header("x-a"), Some(&b"b"[..]));
assert_eq!(upload.body, b"body");
}
/// h11 decodes a chunked body from an HTTP/1.0 client, and RFC 9112 section 6.1 only asks the
/// server to close the connection afterwards.
#[rstest]
#[ignore = "divergence: hyper rejects Transfer-Encoding on HTTP/1.0 with a 400 that uvicorn never sends"]
#[tokio::test]
async fn an_http10_chunked_upload_reaches_python() {
let (upstream, mut received) = capturing().await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("POST /v1/files HTTP/1.0\r\nhost: x\r\ntransfer-encoding: chunked\r\n\r\n4\r\nbody\r\n0\r\n\r\n")
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(received.recv().await.unwrap().body, b"body");
}

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@ -0,0 +1,102 @@
mod support;
use std::time::Duration;
use axum::{
body::Body,
extract::Request,
http::StatusCode,
response::{IntoResponse, Response},
};
use http_body_util::BodyExt;
use rstest::rstest;
use support::{Gateway, client, raw_upstream, recording, within};
use tokio::{sync::mpsc, time::Instant};
const SSE_HEAD: &str = "HTTP/1.1 200 OK\r\n\
date: Tue, 03 Nov 2026 00:00:00 GMT\r\n\
server: uvicorn\r\n\
cache-control: no-cache, no-transform\r\n\
connection: keep-alive\r\n\
content-type: text/event-stream\r\n\
mcp-session-id: session-1\r\n\
x-accel-buffering: no\r\n\
transfer-encoding: chunked\r\n\r\n";
const PING: &str = ": ping - 2026-11-03 00:20:00.000000+00:00\r\n\r\n";
const MESSAGE: &str = "event: message\r\ndata: {\"jsonrpc\":\"2.0\",\"method\":\"notifications/tools/list_changed\"}\r\n\r\n";
fn chunk(data: &str) -> String {
format!("{:x}\r\n{data}\r\n", data.len())
}
/// An MCP client holds a GET stream open for server-initiated messages, which may not come for
/// many minutes, so neither hop may close a stream for being idle.
#[rstest]
#[tokio::test(start_paused = true)]
async fn an_idle_mcp_stream_stays_open_in_both_directions() {
let idle = Duration::from_secs(20 * 60);
let (session, mut sessions) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python| {
let session = session.clone();
async move {
let head = python.request_head().await.unwrap();
session
.send(head.header("mcp-session-id").map(<[u8]>::to_vec))
.unwrap();
python.send(SSE_HEAD).await;
tokio::time::sleep(idle).await;
python.send(chunk(PING)).await;
python.send(chunk(MESSAGE)).await;
python.send("0\r\n\r\n").await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let started = Instant::now();
let response = client()
.request(
Request::get(gateway.url("/github/mcp"))
.header("accept", "text/event-stream")
.header("mcp-session-id", "session-1")
.body(Body::empty())
.unwrap(),
)
.await
.unwrap();
assert_eq!(response.headers()["mcp-session-id"], "session-1");
assert_eq!(response.headers()["x-accel-buffering"], "no");
assert!(!response.headers().contains_key("connection"));
assert_eq!(
sessions.recv().await.unwrap().as_deref(),
Some(&b"session-1"[..])
);
let body = response.into_body().collect().await.unwrap().to_bytes();
assert_eq!(body, [PING, MESSAGE].concat());
assert!(started.elapsed() >= idle);
}
#[rstest]
#[tokio::test]
async fn ends_a_session_with_a_bodiless_delete() {
let (upstream, mut received) = recording(|| -> Response {
([("mcp-session-id", "session-1")], StatusCode::NO_CONTENT).into_response()
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("DELETE /mcp HTTP/1.1\r\nhost: x\r\nmcp-session-id: session-1\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::NO_CONTENT);
assert_eq!(head.header("mcp-session-id"), Some(&b"session-1"[..]));
let request = received.recv().await.unwrap();
assert_eq!(request.method, "DELETE");
assert_eq!(request.headers["mcp-session-id"], "session-1");
assert!(!request.headers.contains_key("transfer-encoding"));
assert!(request.body.is_empty());
}

473
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@ -0,0 +1,473 @@
mod support;
use std::{
sync::Arc,
time::{Duration, Instant},
};
use axum::{Router, body::Body, extract::Request, http::StatusCode, response::Response};
use http_body_util::BodyExt;
use rstest::rstest;
use support::{
DRAIN, Gateway, Raw, client, raw_upstream, recording, serve, unreachable_upstream, within,
};
use tokio::{
net::{TcpListener, TcpStream},
sync::{Notify, mpsc},
};
fn ok() -> Response {
Response::new(Body::from("ok"))
}
/// Python stops a provider stream when it sees the client go away, so a client disconnect must
/// close Rust's connection to Python at every stage of the exchange.
#[rstest]
#[case::waiting_for_headers(
"POST /v1/chat/completions HTTP/1.1\r\nhost: x\r\ncontent-length: 0\r\n\r\n",
false
)]
#[case::mid_stream(
"POST /v1/chat/completions HTTP/1.1\r\nhost: x\r\ncontent-length: 0\r\n\r\n",
true
)]
#[case::mid_upload(
"POST /v1/files HTTP/1.1\r\nhost: x\r\ncontent-length: 1000000\r\n\r\npartial",
false
)]
#[case::waiting_for_websocket_handshake(
"GET /v1/realtime HTTP/1.1\r\nhost: x\r\nconnection: Upgrade\r\nupgrade: websocket\r\nsec-websocket-version: 13\r\nsec-websocket-key: dGhlIHNhbXBsZSBub25jZQ==\r\n\r\n",
false
)]
#[tokio::test]
async fn client_disconnect_closes_the_upstream_connection(
#[case] request: &'static str,
#[case] headers_sent: bool,
) {
let (event, mut events) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let event = event.clone();
async move {
python.request_head().await.unwrap();
if headers_sent {
python
.send("HTTP/1.1 200 OK\r\ntransfer-encoding: chunked\r\n\r\n6\r\ndata: \r\n")
.await;
}
event.send("received").unwrap();
python.closed().await;
event.send("closed").unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(request).await;
assert_eq!(within(events.recv()).await, Some("received"));
if headers_sent {
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
}
drop(raw);
assert_eq!(within(events.recv()).await, Some("closed"));
}
/// Python treats EOF on its socket as the client leaving, so Rust must not half-close the
/// upstream connection once it has sent the request body.
#[rstest]
#[tokio::test]
async fn python_sees_no_eof_while_its_response_is_pending() {
let (verdict, mut verdicts) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let verdict = verdict.clone();
async move {
let head = python.request_head().await.unwrap();
python.body(head.content_length().unwrap()).await;
let eof = tokio::time::timeout(Duration::from_millis(200), python.closed())
.await
.is_ok();
verdict.send(eof).unwrap();
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 2\r\n\r\nok")
.await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let response = within(
client().request(
Request::post(gateway.url("/mcp"))
.body(Body::from("{}"))
.unwrap(),
),
)
.await
.unwrap();
assert_eq!(response.status(), StatusCode::OK);
assert_eq!(verdicts.recv().await, Some(false));
}
/// uvicorn closes a connection that sat idle past its keep-alive timeout. A request Rust sends on
/// that connection as uvicorn closes it is lost, so Rust must retire idle connections first.
#[rstest]
#[case::reused_while_fresh(Duration::from_millis(0))]
#[case::past_the_pool_timeout(Duration::from_millis(250))]
#[case::past_python_keepalive(Duration::from_millis(450))]
#[tokio::test]
async fn never_reuses_a_connection_python_is_closing_for_idleness(#[case] idle: Duration) {
let keepalive = Duration::from_millis(400);
let upstream = raw_upstream(move |mut python: Raw| async move {
let mut idle_since = None::<Instant>;
while python.request_head().await.is_some() {
if idle_since.is_some_and(|since| since.elapsed() >= keepalive) {
return;
}
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 2\r\n\r\nok")
.await;
idle_since = Some(Instant::now());
}
})
.await;
let gateway = Gateway::with_keepalive(upstream, keepalive).await;
let client = client();
let first = within(client.request(Request::get(gateway.url("/")).body(Body::empty()).unwrap()))
.await
.unwrap();
first.into_body().collect().await.unwrap();
tokio::time::sleep(idle).await;
let second =
within(client.request(Request::get(gateway.url("/")).body(Body::empty()).unwrap()))
.await
.unwrap();
assert_eq!(second.status(), StatusCode::OK);
}
#[rstest]
#[case::health("/health/liveliness")]
#[case::messages("/v1/messages")]
#[tokio::test]
async fn unreachable_python_is_a_502(#[case] path: &str) {
let gateway = Gateway::start(unreachable_upstream()).await;
let response =
within(client().request(Request::get(gateway.url(path)).body(Body::empty()).unwrap()))
.await
.unwrap();
assert_eq!(response.status(), StatusCode::BAD_GATEWAY);
}
#[rstest]
#[case::bad_status_line(b"HTTP/1.1 OK\r\ncontent-length: 0\r\n\r\n".to_vec())]
#[case::header_without_colon(b"HTTP/1.1 200 OK\r\nbroken header\r\ncontent-length: 0\r\n\r\n".to_vec())]
#[case::not_http(b"SSH-2.0-OpenSSH_9.6\r\n".to_vec())]
#[case::conflicting_lengths(
b"HTTP/1.1 200 OK\r\ncontent-length: 2\r\ncontent-length: 3\r\n\r\nok".to_vec()
)]
#[case::oversized_head(
[&b"HTTP/1.1 200 OK\r\nx-big: "[..], &vec![b'a'; 1024 * 1024], b"\r\n\r\n"].concat()
)]
#[case::closed_without_reply(Vec::new())]
#[tokio::test]
async fn an_upstream_that_breaks_http_is_a_502_and_the_client_connection_survives(
#[case] reply: Vec<u8>,
) {
let upstream = raw_upstream(move |mut python: Raw| {
let reply = reply.clone();
async move {
python.request_head().await.unwrap();
if reply.is_empty() {
return;
}
python.send(reply).await;
std::future::pending::<()>().await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
for _ in 0..2 {
raw.send("GET / HTTP/1.1\r\nhost: x\r\n\r\n").await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::BAD_GATEWAY);
assert_eq!(head.content_length(), Some(0));
}
}
#[rstest]
#[tokio::test]
async fn python_restarting_is_a_502_until_it_listens_again() {
let address = unreachable_upstream();
let gateway = Gateway::start(address).await;
let get = || client().request(Request::get(gateway.url("/")).body(Body::empty()).unwrap());
assert_eq!(
within(get()).await.unwrap().status(),
StatusCode::BAD_GATEWAY
);
let listener = TcpListener::bind(address).await.unwrap();
let router = Router::new().fallback(|| async { "up" });
tokio::spawn(async move { axum::serve(listener, router).await });
assert_eq!(within(get()).await.unwrap().status(), StatusCode::OK);
}
/// A request Python already read may have run, so it is answered with a 502 and never replayed.
#[rstest]
#[tokio::test]
async fn a_request_python_read_before_closing_is_a_502_and_never_replayed() {
let (event, mut seen) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let event = event.clone();
async move {
while let Some(head) = python.request_head().await {
python.body(head.content_length().unwrap()).await;
event.send(head.path.clone()).unwrap();
if head.path == "/v1/chat/completions" {
return;
}
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 2\r\n\r\nok")
.await;
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("POST /warm HTTP/1.1\r\nhost: x\r\ncontent-length: 0\r\n\r\n")
.await;
let warm = within(raw.response_head()).await.unwrap();
raw.body(warm.content_length().unwrap()).await;
raw.send("POST /v1/chat/completions HTTP/1.1\r\nhost: x\r\ncontent-length: 2\r\n\r\n{}")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::BAD_GATEWAY);
let paths: Vec<_> = std::iter::from_fn(|| seen.try_recv().ok()).collect();
assert_eq!(paths, ["/warm", "/v1/chat/completions"]);
}
#[rstest]
#[tokio::test]
async fn shutdown_lets_an_in_flight_stream_finish() {
let release = Arc::new(Notify::new());
let released = release.clone();
let upstream = raw_upstream(move |mut python: Raw| {
let released = released.clone();
async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 200 OK\r\ntransfer-encoding: chunked\r\n\r\n5\r\nfirst\r\n")
.await;
released.notified().await;
python.send("4\r\nlast\r\n0\r\n\r\n").await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let response =
within(client().request(Request::get(gateway.url("/")).body(Body::empty()).unwrap()))
.await
.unwrap();
let server = gateway.shutdown();
tokio::time::sleep(Duration::from_millis(100)).await;
assert!(!server.is_finished());
release.notify_one();
let body = within(response.into_body().collect())
.await
.unwrap()
.to_bytes();
assert_eq!(body, "firstlast");
within(server).await.unwrap();
}
#[rstest]
#[tokio::test]
async fn shutdown_stops_waiting_for_a_stream_still_open_after_the_drain() {
let upstream = raw_upstream(|mut python: Raw| async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 200 OK\r\ntransfer-encoding: chunked\r\n\r\n5\r\nfirst\r\n")
.await;
std::future::pending::<()>().await;
})
.await;
let gateway = Gateway::start(upstream).await;
let response =
within(client().request(Request::get(gateway.url("/")).body(Body::empty()).unwrap()))
.await
.unwrap();
let started = std::time::Instant::now();
within(gateway.shutdown()).await.unwrap();
assert!(started.elapsed() >= DRAIN);
drop(response);
}
#[rstest]
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn concurrent_keep_alive_connections_each_get_their_own_responses() {
let upstream = serve(Router::new().fallback(|request: Request| async move {
let index: usize = request.uri().query().unwrap().parse().unwrap();
Response::builder()
.header("etag", format!("\"{index}\""))
.body(Body::from(index.to_string().repeat(1 + index * 1000)))
.unwrap()
}))
.await;
let gateway = Gateway::start(upstream).await;
let connections = 6;
let tasks: Vec<_> = (0..connections)
.map(|first| {
let address = gateway.address;
tokio::spawn(async move {
let mut raw = Raw::new(TcpStream::connect(address).await.unwrap());
for index in (first..50).step_by(connections) {
raw.send(format!(
"GET /ui/chunk.js?{index} HTTP/1.1\r\nhost: x\r\n\r\n"
))
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.header("etag"), Some(format!("\"{index}\"").as_bytes()));
let body = raw.body(head.content_length().unwrap()).await;
assert_eq!(
body,
index.to_string().repeat(1 + index * 1000).into_bytes()
);
}
})
})
.collect();
for task in tasks {
within(task).await.unwrap();
}
}
// Python's `--keepalive_timeout` governed idle client connections before Rust took the public
// port, and operators tune it against their load balancer's idle timeout, so it still does.
// Without it, a client that vanishes without closing its connection holds a socket forever and
// the gateway eventually runs out of file descriptors.
const IDLE: Duration = Duration::from_millis(400);
#[rstest]
#[tokio::test]
async fn closes_a_client_connection_idle_past_python_keepalive() {
let (upstream, _received) = recording(ok).await;
let gateway = Gateway::with_keepalive(upstream, IDLE).await;
let mut raw = gateway.connect().await;
for _ in 0..2 {
tokio::time::sleep(IDLE / 2).await;
raw.send("GET /health/liveliness HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::OK);
raw.body(head.content_length().unwrap()).await;
}
let idle_since = Instant::now();
within(raw.closed()).await;
assert!(idle_since.elapsed() >= IDLE * 3 / 4);
}
/// uvicorn would hold a connection that never sends a request, which lets a client park sockets
/// for free, so the same limit applies before the first request too.
#[rstest]
#[tokio::test]
async fn closes_a_client_connection_that_never_sends_a_request() {
let (upstream, _received) = recording(ok).await;
let gateway = Gateway::with_keepalive(upstream, IDLE).await;
let mut raw = gateway.connect().await;
within(raw.closed()).await;
}
/// The limit only covers the wait for the next request. A response that goes quiet for longer
/// belongs to Python, which decides how long it may take.
#[rstest]
#[tokio::test]
async fn keeps_a_connection_open_while_a_response_goes_quiet() {
let upstream = raw_upstream(|mut python: Raw| async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 200 OK\r\ntransfer-encoding: chunked\r\n\r\n")
.await;
tokio::time::sleep(IDLE * 3).await;
python.send("4\r\ndone\r\n0\r\n\r\n").await;
})
.await;
let gateway = Gateway::with_keepalive(upstream, IDLE).await;
let mut raw = gateway.connect().await;
raw.send("GET /v1/chat/completions HTTP/1.1\r\nhost: x\r\n\r\n")
.await;
within(raw.response_head()).await.unwrap();
assert_eq!(within(raw.chunked_body()).await, b"done");
}
/// Likewise for an upload that pauses longer than the limit before it finishes.
#[rstest]
#[tokio::test]
async fn keeps_a_connection_open_while_an_upload_goes_quiet() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::with_keepalive(upstream, IDLE).await;
let mut raw = gateway.connect().await;
raw.send("POST /v1/files HTTP/1.1\r\nhost: x\r\ncontent-length: 8\r\n\r\nhalf")
.await;
tokio::time::sleep(IDLE * 3).await;
raw.send("done").await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(received.recv().await.unwrap().body, "halfdone");
}
/// uvicorn answers a request it rejects (413, 401) as soon as it reads the head and then closes,
/// leaving the upload unread. The client must get that answer, not a 502 or a reset.
#[rstest]
#[case::sized("content-length: 16777216\r\n", vec![b'x'; 256 * 1024])]
#[case::chunked(
"transfer-encoding: chunked\r\n",
[&b"40000\r\n"[..], &[b'x'; 256 * 1024], b"\r\n"].concat()
)]
#[tokio::test]
async fn python_rejecting_an_upload_unread_and_closing_still_answers_the_client(
#[case] framing: &'static str,
#[case] partial_upload: Vec<u8>,
) {
let upstream = raw_upstream(|mut python: Raw| async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 413 Payload Too Large\r\ncontent-type: application/json\r\ncontent-length: 26\r\nconnection: close\r\n\r\n{\"error\":\"file too large\"}")
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\n{framing}\r\n"
))
.await;
raw.send(partial_upload).await;
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::PAYLOAD_TOO_LARGE);
assert_eq!(
raw.body(head.content_length().unwrap()).await,
b"{\"error\":\"file too large\"}"
);
}

360
litellm-rust/crates/gateway-forward/tests/roundtrip.rs Normal file
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@ -0,0 +1,360 @@
mod support;
use std::{
convert::Infallible,
sync::{Arc, Mutex},
};
use axum::{
body::{Body, Bytes},
http::{HeaderMap, HeaderName, HeaderValue, Method, Request, StatusCode},
response::Response,
};
use http_body_util::BodyExt;
use litellm_gateway_forward::PEER_HEADER;
use proptest::{prelude::*, test_runner::TestRunner};
use support::{Gateway, client, recording, within};
#[derive(Clone, Debug)]
struct Message {
headers: Vec<(String, Vec<Vec<u8>>)>,
body: Vec<u8>,
chunked: bool,
}
#[derive(Clone, Debug)]
struct Exchange {
method: Method,
target: String,
request: Message,
status: StatusCode,
response: Message,
}
/// Any value h11 reads back unchanged: visible ASCII, obs-text and interior whitespace.
fn header_value() -> impl Strategy<Value = Vec<u8>> {
prop::collection::vec(
prop_oneof![8 => 0x21u8..=0x7e, 2 => 0x80u8..=0xff, 1 => Just(b' '), 1 => Just(b'\t')],
0..24,
)
.prop_map(|value| value.trim_ascii().to_vec())
}
fn method() -> impl Strategy<Value = Method> {
prop_oneof![
Just(Method::GET),
Just(Method::POST),
Just(Method::PUT),
Just(Method::PATCH),
Just(Method::DELETE),
Just(Method::OPTIONS),
"[A-Za-z0-9!#$%&'*+.^_`|~-]{1,16}"
.prop_filter("HEAD and CONNECT frame differently", |method| {
!["HEAD", "CONNECT"].contains(&method.as_str())
})
.prop_map(|method| Method::from_bytes(method.as_bytes()).unwrap()),
]
}
fn message() -> impl Strategy<Value = Message> {
(
prop::collection::btree_map(
"x-[a-z0-9!#$%&'*+.^_`|~-]{1,12}",
prop::collection::vec(header_value(), 1..4),
0..12,
),
prop::collection::vec(any::<u8>(), 0..32 * 1024),
any::<bool>(),
)
.prop_map(|(headers, body, chunked)| Message {
headers: headers.into_iter().collect(),
body,
chunked,
})
}
fn target() -> impl Strategy<Value = String> {
let segment = prop_oneof![
"[A-Za-z0-9._~!$&'()*+,;=:@-]{0,8}",
"%[0-9A-Fa-f]{2}",
Just(".".to_owned()),
Just("..".to_owned()),
Just(String::new()),
];
(
prop::collection::vec(segment, 0..6),
prop::option::of("[A-Za-z0-9=&._~%/?:@!$'()*+,;-]{0,40}"),
)
.prop_map(|(segments, query)| {
let path = format!("/{}", segments.join("/"));
match query {
Some(query) => format!("{path}?{query}"),
None => path,
}
})
}
fn exchange() -> impl Strategy<Value = Exchange> {
let status = (200u16..600)
.prop_filter("bodiless status", |code| ![204, 205, 304].contains(code))
.prop_map(|code| StatusCode::from_u16(code).unwrap());
(method(), target(), message(), status, message()).prop_map(
|(method, target, request, status, response)| Exchange {
method,
target,
request,
status,
response,
},
)
}
fn body(message: &Message) -> Body {
if !message.chunked {
return Body::from(message.body.clone());
}
let chunks: Vec<Result<Bytes, Infallible>> = message
.body
.chunks(1000)
.map(|chunk| Ok(Bytes::copy_from_slice(chunk)))
.collect();
Body::from_stream(futures_util::stream::iter(chunks))
}
fn apply(headers: &mut HeaderMap, message: &Message) {
if message.chunked {
headers.insert("transfer-encoding", HeaderValue::from_static("chunked"));
}
for (name, values) in &message.headers {
for value in values {
headers.append(
HeaderName::from_bytes(name.as_bytes()).unwrap(),
HeaderValue::from_bytes(value).unwrap(),
);
}
}
}
fn assert_carried(headers: &HeaderMap, message: &Message, framing_and_hop: &[&str]) {
for (name, values) in &message.headers {
let carried: Vec<&[u8]> = headers
.get_all(name)
.iter()
.map(HeaderValue::as_bytes)
.collect();
let sent: Vec<&[u8]> = values.iter().map(Vec::as_slice).collect();
assert_eq!(carried, sent, "header {name}");
}
for name in headers.keys() {
assert!(
framing_and_hop.contains(&name.as_str())
|| message
.headers
.iter()
.any(|(sent, _)| sent == name.as_str()),
"unexpected header {name}"
);
}
}
/// Any request a client can send and any response Python can give cross the forwarder unchanged,
/// apart from the framing and peer headers the forwarder owns.
#[test]
fn every_exchange_crosses_the_forwarder_unchanged() {
let runtime = tokio::runtime::Runtime::new().unwrap();
let current = Arc::new(Mutex::new(None::<Exchange>));
let responding = current.clone();
let (gateway, received) = runtime.block_on(async {
let (upstream, received) = recording(move || {
let exchange = responding.lock().unwrap().clone().unwrap();
let mut response = Response::new(body(&exchange.response));
*response.status_mut() = exchange.status;
apply(response.headers_mut(), &exchange.response);
response
})
.await;
(
Gateway::start(upstream).await,
tokio::sync::Mutex::new(received),
)
});
let client = client();
TestRunner::new(ProptestConfig::with_cases(256))
.run(&exchange(), |exchange| {
*current.lock().unwrap() = Some(exchange.clone());
runtime.block_on(async {
while received.lock().await.try_recv().is_ok() {}
let mut request = Request::builder()
.method(exchange.method.clone())
.uri(gateway.url(&exchange.target))
.body(body(&exchange.request))
.unwrap();
apply(request.headers_mut(), &exchange.request);
let response = support::within(client.request(request)).await.unwrap();
let python = received.lock().await.recv().await.unwrap();
assert_eq!(python.method, exchange.method);
assert_eq!(python.uri, exchange.target.as_str());
assert_eq!(python.body, exchange.request.body);
assert_carried(
&python.headers,
&exchange.request,
&["host", "content-length", "transfer-encoding", PEER_HEADER],
);
assert_eq!(python.headers.get_all(PEER_HEADER).iter().count(), 1);
assert_eq!(response.status(), exchange.status);
let headers = response.headers().clone();
assert_carried(
&headers,
&exchange.response,
&["date", "content-length", "transfer-encoding"],
);
let body = support::within(response.into_body().collect())
.await
.unwrap();
assert_eq!(body.to_bytes(), exchange.response.body);
});
Ok(())
})
.unwrap();
}
#[derive(Clone, Debug)]
enum Framing {
Unframed,
Length,
Chunked(usize),
}
#[derive(Clone, Debug)]
struct WireRequest {
method: Method,
target: String,
headers: Vec<(String, Vec<u8>)>,
body: Vec<u8>,
framing: Framing,
}
fn wire_request() -> impl Strategy<Value = WireRequest> {
let framing = prop_oneof![
Just(Framing::Unframed),
Just(Framing::Length),
(1usize..2048).prop_map(Framing::Chunked),
];
(
method(),
target(),
prop::collection::vec(
("[xX]-[A-Za-z0-9!#$%&'*+.^_`|~-]{1,12}", header_value()),
0..24,
),
prop::collection::vec(any::<u8>(), 0..8 * 1024),
framing,
)
.prop_map(|(method, target, headers, body, framing)| WireRequest {
method,
target,
headers,
body: match framing {
Framing::Unframed => Vec::new(),
_ => body,
},
framing,
})
}
fn encode(request: &WireRequest) -> Vec<u8> {
let framing = match request.framing {
Framing::Unframed => String::new(),
Framing::Length => format!("Content-Length: {}\r\n", request.body.len()),
Framing::Chunked(_) => "Transfer-Encoding: chunked\r\n".to_owned(),
};
let fields = request
.headers
.iter()
.flat_map(|(name, value)| [name.as_bytes(), b": ", value, b"\r\n"].concat());
let body = match request.framing {
Framing::Chunked(size) => request
.body
.chunks(size)
.flat_map(|chunk| {
[format!("{:x}\r\n", chunk.len()).as_bytes(), chunk, b"\r\n"].concat()
})
.chain(*b"0\r\n\r\n")
.collect(),
_ => request.body.clone(),
};
[
format!(
"{} {} HTTP/1.1\r\nHost: x\r\n",
request.method, request.target
)
.into_bytes(),
fields.collect(),
framing.into_bytes(),
b"\r\n".to_vec(),
body,
]
.concat()
}
fn by_name<'a>(fields: impl Iterator<Item = (&'a str, &'a [u8])>) -> Vec<(String, &'a [u8])> {
let mut fields: Vec<_> = fields
.map(|(name, value)| (name.to_ascii_lowercase(), value))
.collect();
fields.sort_by(|(left, _), (right, _)| left.cmp(right));
fields
}
/// Pipelined requests in any framing, written in arbitrary pieces, reach Python one by one with
/// the bytes h11 would have read from the client directly.
#[test]
fn pipelined_wire_requests_reach_python_as_sent() {
let runtime = tokio::runtime::Runtime::new().unwrap();
let (gateway, received) = runtime.block_on(async {
let (upstream, received) = recording(|| Response::new(Body::from("ok"))).await;
(
Gateway::start(upstream).await,
tokio::sync::Mutex::new(received),
)
});
let requests = (prop::collection::vec(wire_request(), 1..5), 1usize..4096);
TestRunner::new(ProptestConfig::with_cases(256))
.run(&requests, |(requests, piece)| {
runtime.block_on(async {
let mut received = received.lock().await;
while received.try_recv().is_ok() {}
let mut raw = gateway.connect().await;
let wire: Vec<u8> = requests.iter().flat_map(encode).collect();
for bytes in wire.chunks(piece) {
raw.send(bytes).await;
}
for request in &requests {
let head = within(raw.response_head()).await.unwrap();
assert_eq!(head.status, StatusCode::OK, "{request:?}");
assert_eq!(raw.body(2).await, b"ok");
let python = within(received.recv()).await.unwrap();
assert_eq!(python.method, request.method);
assert_eq!(python.uri, request.target.as_str());
assert_eq!(python.body, request.body);
assert_eq!(python.headers["host"], "x");
let forwarded = python.headers.iter().filter(|(name, _)| {
!["host", "content-length", "transfer-encoding", PEER_HEADER]
.contains(&name.as_str())
});
assert_eq!(
by_name(forwarded.map(|(name, value)| (name.as_str(), value.as_bytes()))),
by_name(
request
.headers
.iter()
.map(|(name, value)| (name.as_str(), value.as_slice()))
)
);
}
});
Ok(())
})
.unwrap();
}

110
litellm-rust/crates/gateway-forward/tests/settings.rs Normal file
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@ -0,0 +1,110 @@
use std::{ffi::OsString, time::Duration};
use litellm_gateway_forward::{Error, Settings};
use rstest::rstest;
const COMPLETE: [(&str, &str); 5] = [
("LITELLM_FORWARD_UPSTREAM", "http://127.0.0.1:53211"),
("LITELLM_FORWARD_HOST", "0.0.0.0"),
("LITELLM_FORWARD_PORT", "4000"),
("LITELLM_FORWARD_UPSTREAM_KEEPALIVE", "2"),
("LITELLM_FORWARD_SHUTDOWN_DRAIN", "40"),
];
fn parse(variables: &[(&str, &str)]) -> Result<Option<Settings>, Error> {
Settings::from_vars(
variables
.iter()
.map(|(key, value)| (OsString::from(key), OsString::from(value))),
)
}
fn without(variable: &str) -> Vec<(&'static str, &'static str)> {
COMPLETE
.into_iter()
.filter(|(key, _)| *key != variable)
.collect()
}
fn with<'a>(variable: &'a str, value: &'a str) -> Vec<(&'a str, &'a str)> {
without(variable)
.into_iter()
.chain([(variable, value)])
.collect()
}
#[rstest]
fn reads_every_variable() {
assert_eq!(
parse(&COMPLETE).unwrap(),
Some(Settings {
upstream: "http://127.0.0.1:53211".parse().unwrap(),
host: "0.0.0.0".into(),
port: 4000,
upstream_keepalive: Duration::from_secs(2),
shutdown_drain: Duration::from_secs(40),
})
);
}
#[rstest]
fn without_an_upstream_the_gateway_is_not_forwarding() {
assert_eq!(parse(&without("LITELLM_FORWARD_UPSTREAM")).unwrap(), None);
}
#[rstest]
#[case::host("LITELLM_FORWARD_HOST")]
#[case::port("LITELLM_FORWARD_PORT")]
#[case::upstream_keepalive("LITELLM_FORWARD_UPSTREAM_KEEPALIVE")]
#[case::shutdown_drain("LITELLM_FORWARD_SHUTDOWN_DRAIN")]
fn a_missing_variable_fails_naming_it(#[case] variable: &str) {
let error = parse(&without(variable)).unwrap_err();
assert!(error.to_string().contains(variable), "{error}");
}
#[rstest]
#[case::port_overflow("LITELLM_FORWARD_PORT", "65536")]
#[case::port_text("LITELLM_FORWARD_PORT", "http")]
#[case::keepalive_text("LITELLM_FORWARD_UPSTREAM_KEEPALIVE", "soon")]
#[case::keepalive_negative("LITELLM_FORWARD_UPSTREAM_KEEPALIVE", "-1")]
#[case::keepalive_zero("LITELLM_FORWARD_UPSTREAM_KEEPALIVE", "0")]
#[case::drain_text("LITELLM_FORWARD_SHUTDOWN_DRAIN", "soon")]
#[case::drain_negative("LITELLM_FORWARD_SHUTDOWN_DRAIN", "-1")]
#[case::drain_infinite("LITELLM_FORWARD_SHUTDOWN_DRAIN", "inf")]
fn an_invalid_variable_fails_naming_it(#[case] variable: &str, #[case] value: &str) {
let error = parse(&with(variable, value)).unwrap_err();
assert!(error.to_string().contains(variable), "{error}");
}
#[rstest]
fn fractional_drain_seconds_are_used_as_given() {
let settings = parse(&with("LITELLM_FORWARD_SHUTDOWN_DRAIN", "12.5"))
.unwrap()
.unwrap();
assert_eq!(settings.shutdown_drain, Duration::from_millis(12_500));
}
#[rstest]
#[case::keepalive("KEEPALIVE_TIMEOUT")]
#[case::graceful_shutdown("GRACEFUL_SHUTDOWN_TIMEOUT")]
#[case::host("HOST")]
#[case::port("PORT")]
fn python_settings_are_never_read(#[case] variable: &str) {
let mut variables = COMPLETE.to_vec();
variables.push((variable, "9"));
assert_eq!(parse(&variables).unwrap(), parse(&COMPLETE).unwrap());
}
#[rstest]
fn a_non_loopback_upstream_fails_startup() {
let error = parse(&with("LITELLM_FORWARD_UPSTREAM", "http://192.0.2.1:4000")).unwrap_err();
assert!(
error.to_string().contains("LITELLM_FORWARD_UPSTREAM"),
"{error}"
);
}

41
litellm-rust/crates/gateway-forward/tests/slow_head.rs Normal file
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@ -0,0 +1,41 @@
mod support;
use std::time::Duration;
use axum::{body::Body, extract::Request, http::StatusCode};
use http_body_util::BodyExt;
use rstest::rstest;
use support::{Gateway, client, raw_upstream};
use tokio::time::Instant;
/// Reasoning models with `stream=false`, image and video generation, and model health checks send
/// no response headers until the provider finishes, which can take many minutes.
#[rstest]
#[tokio::test(start_paused = true)]
async fn waits_for_response_headers_as_long_as_python_takes() {
let thinking = Duration::from_secs(30 * 60);
let upstream = raw_upstream(move |mut python| async move {
python.request_head().await.unwrap();
tokio::time::sleep(thinking).await;
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 5\r\n\r\nimage")
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
let started = Instant::now();
let response = client()
.request(
Request::post(gateway.url("/v1/images/generations"))
.body(Body::from("{}"))
.unwrap(),
)
.await
.unwrap();
assert_eq!(response.status(), StatusCode::OK);
assert!(started.elapsed() >= thinking);
let body = response.into_body().collect().await.unwrap().to_bytes();
assert_eq!(body, "image");
}

313
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mod support;
use std::{
sync::{
Arc,
atomic::{AtomicUsize, Ordering},
},
time::Duration,
};
use axum::{body::Body, extract::Request, http::StatusCode};
use http_body_util::BodyExt;
use hyper::body::Incoming;
use rstest::rstest;
use support::{Gateway, client, raw_upstream, within};
use tokio::{
io::AsyncWriteExt,
sync::{Notify, mpsc},
};
fn chunk(bytes: &[u8]) -> Vec<u8> {
[format!("{:x}\r\n", bytes.len()).as_bytes(), bytes, b"\r\n"].concat()
}
const EVENTS: [&str; 3] = ["data: 1\n\n", "data: 2\n\n", "data: [DONE]\n\n"];
#[rstest]
#[tokio::test]
async fn each_event_reaches_the_client_before_python_produces_the_next(
#[values(true, false)] chunked: bool,
) {
let produce = Arc::new(Notify::new());
let next = produce.clone();
let upstream = raw_upstream(move |mut python| {
let next = next.clone();
async move {
python.request_head().await.unwrap();
let framing = match chunked {
true => "transfer-encoding: chunked".to_owned(),
false => format!("content-length: {}", EVENTS.concat().len()),
};
python
.send(format!(
"HTTP/1.1 200 OK\r\ncontent-type: text/event-stream\r\n{framing}\r\n\r\n"
))
.await;
for event in EVENTS {
match chunked {
true => python.send(chunk(event.as_bytes())).await,
false => python.send(event).await,
}
next.notified().await;
}
if chunked {
python.send("0\r\n\r\n").await;
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut response = within(
client().request(
Request::post(gateway.url("/v1/chat/completions"))
.body(Body::from(r#"{"stream":true}"#))
.unwrap(),
),
)
.await
.unwrap();
for event in EVENTS {
let frame = within(response.body_mut().frame()).await.unwrap().unwrap();
assert_eq!(frame.into_data().unwrap(), event);
produce.notify_one();
}
let rest = within(response.into_body().collect()).await.unwrap();
assert!(rest.to_bytes().is_empty());
}
#[rstest]
#[tokio::test]
async fn relays_a_binary_framed_stream_unchanged() {
let message: Vec<u8> = [
&[
0x00, 0x00, 0x00, 0x3d, 0x00, 0x00, 0x00, 0x20, 0x8a, 0x0d, 0x0a, 0xff,
][..],
b"\x0b:event-type\x07\x00\x05chunk\x0d:content-type\x07\x00\x10application/json",
b"0\r\n\r\n{\"bytes\":\"eyJ0eXBlIjoiY29udGVudCJ9\"}",
&[0xc3, 0x28, 0x00, 0x0d],
]
.concat();
let sent = message.clone();
let upstream = raw_upstream(move |mut python| {
let sent = sent.clone();
async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 200 OK\r\ncontent-type: application/vnd.amazon.eventstream\r\ntransfer-encoding: chunked\r\n\r\n")
.await;
for piece in sent.chunks(7) {
python.send(chunk(piece)).await;
}
python.send("0\r\n\r\n").await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let response = within(
client().request(
Request::post(gateway.url("/bedrock/model/m/converse-stream"))
.body(Body::empty())
.unwrap(),
),
)
.await
.unwrap();
assert_eq!(
response.headers()["content-type"],
"application/vnd.amazon.eventstream"
);
let body = within(response.into_body().collect())
.await
.unwrap()
.to_bytes();
assert_eq!(body, message);
}
#[rstest]
#[tokio::test]
async fn relays_a_body_delimited_by_the_upstream_closing() {
let upstream = raw_upstream(|mut python| async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 200 OK\r\nconnection: close\r\n\r\nuntil eof")
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
let response = client().request(Request::get(gateway.url("/")).body(Body::empty()).unwrap());
let body = within(response).await.unwrap().into_body().collect();
assert_eq!(within(body).await.unwrap().to_bytes(), "until eof");
}
async fn drain(mut body: Incoming) -> (Vec<u8>, Result<(), hyper::Error>) {
let mut delivered = Vec::new();
loop {
match within(body.frame()).await {
None => return (delivered, Ok(())),
Some(Err(error)) => return (delivered, Err(error)),
Some(Ok(frame)) => delivered.extend_from_slice(&frame.into_data().unwrap()),
}
}
}
#[rstest]
#[case::after_the_head("transfer-encoding: chunked", "", "")]
#[case::between_events("transfer-encoding: chunked", "6\r\ndata: \r\n", "data: ")]
#[case::mid_event("transfer-encoding: chunked", "a\r\ndata:", "data:")]
#[case::short_of_its_content_length("content-length: 100", "data: 1\n\n", "data: 1\n\n")]
#[tokio::test]
async fn an_upstream_dying_mid_stream_fails_the_client_body_instead_of_ending_it(
#[case] framing: &'static str,
#[case] sent: &'static str,
#[case] delivered: &'static str,
) {
let upstream = raw_upstream(move |mut python| async move {
python.request_head().await.unwrap();
python
.send(format!(
"HTTP/1.1 200 OK\r\ncontent-type: text/event-stream\r\n{framing}\r\n\r\n{sent}"
))
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
let response =
within(client().request(Request::get(gateway.url("/")).body(Body::empty()).unwrap()))
.await
.unwrap();
assert_eq!(response.status(), StatusCode::OK);
let (received, ended) = drain(response.into_body()).await;
assert_eq!(received, delivered.as_bytes());
assert!(ended.is_err());
}
#[rstest]
#[tokio::test]
async fn response_headers_reach_the_client_before_python_sends_any_body() {
let release = Arc::new(Notify::new());
let released = release.clone();
let upstream = raw_upstream(move |mut python| {
let released = released.clone();
async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 200 OK\r\ncontent-type: text/event-stream; charset=utf-8\r\nx-accel-buffering: no\r\nx-litellm-call-id: call-1\r\ntransfer-encoding: chunked\r\n\r\n")
.await;
released.notified().await;
python.send(chunk(b"data: 1\n\n")).await;
python.send("0\r\n\r\n").await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let response =
within(client().request(Request::post(gateway.url("/")).body(Body::empty()).unwrap()))
.await
.unwrap();
assert_eq!(response.headers()["x-litellm-call-id"], "call-1");
assert_eq!(response.headers()["x-accel-buffering"], "no");
release.notify_one();
let body = within(response.into_body().collect())
.await
.unwrap()
.to_bytes();
assert_eq!(body, "data: 1\n\n");
}
/// A connection closed without any response looks retryable to client SDKs, which would re-run a
/// request Python already ran. Python dying right after its head races the relay, hence the loop.
#[rstest]
#[tokio::test]
async fn a_head_python_sent_right_before_dying_still_reaches_the_client() {
let upstream = raw_upstream(|mut python| async move {
python.request_head().await.unwrap();
python
.send("HTTP/1.1 200 OK\r\ncontent-type: text/event-stream\r\ntransfer-encoding: chunked\r\n\r\n")
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
for _ in 0..20 {
let mut raw = gateway.connect().await;
raw.send("POST / HTTP/1.1\r\nhost: x\r\ncontent-length: 0\r\n\r\n")
.await;
let head = within(raw.response_head()).await;
assert_eq!(head.map(|head| head.status), Some(StatusCode::OK));
}
}
#[rstest]
#[tokio::test]
async fn a_client_that_stops_reading_stalls_python_instead_of_being_buffered_for() {
let written = Arc::new(AtomicUsize::new(0));
let counted = written.clone();
let (failed, mut write_failed) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python| {
let counted = counted.clone();
let failed = failed.clone();
async move {
python.request_head().await.unwrap();
let mut python = python.into_stream();
python
.write_all(b"HTTP/1.1 200 OK\r\ntransfer-encoding: chunked\r\n\r\n")
.await
.unwrap();
let piece = chunk(&[0x5a; 64 * 1024]);
while python.write_all(&piece).await.is_ok() {
counted.fetch_add(piece.len(), Ordering::SeqCst);
}
failed.send(()).unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("POST / HTTP/1.1\r\nhost: x\r\ncontent-length: 0\r\n\r\n")
.await;
within(raw.response_head()).await.unwrap();
tokio::time::sleep(Duration::from_secs(1)).await;
let stalled = written.load(Ordering::SeqCst);
tokio::time::sleep(Duration::from_millis(250)).await;
assert_eq!(written.load(Ordering::SeqCst), stalled);
assert!(stalled < 64 * 1024 * 1024, "{stalled} bytes in flight");
drop(raw);
within(write_failed.recv()).await.unwrap();
}
#[rstest]
#[tokio::test]
async fn an_http10_client_receives_a_streamed_body_delimited_by_close() {
let upstream = raw_upstream(|mut python| async move {
python.request_head().await.unwrap();
python
.send([
&b"HTTP/1.1 200 OK\r\ncontent-type: text/event-stream\r\ntransfer-encoding: chunked\r\n\r\n"[..],
&chunk(b"data: 1\n"),
&chunk(b"data: 2\n"),
b"0\r\n\r\n",
]
.concat())
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("GET /v1/stream HTTP/1.0\r\nhost: x\r\n\r\n").await;
let response = String::from_utf8(within(raw.until_closed()).await).unwrap();
let (head, body) = response.split_once("\r\n\r\n").unwrap();
assert!(head.starts_with("HTTP/1.0 200 OK"), "{head}");
assert!(
!head.to_ascii_lowercase().contains("transfer-encoding"),
"{head}"
);
assert_eq!(body, "data: 1\ndata: 2\n");
}

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#![allow(
dead_code,
reason = "each test binary uses a different subset of the harness"
)]
use std::{future::Future, net::SocketAddr, time::Duration};
use axum::{
Router,
body::{Body, Bytes},
extract::Request,
http::{HeaderMap, Method, StatusCode, Uri},
};
use http_body_util::BodyExt;
use hyper_util::{
client::legacy::{Client, connect::HttpConnector},
rt::TokioExecutor,
};
use litellm_gateway_forward::Forward;
use tokio::{
io::{AsyncReadExt, AsyncWriteExt},
net::{TcpListener, TcpStream},
sync::{mpsc, oneshot},
task::JoinHandle,
};
pub const WAIT: Duration = Duration::from_secs(5);
pub const UVICORN_KEEPALIVE: Duration = Duration::from_secs(5);
pub const DRAIN: Duration = Duration::from_secs(1);
pub async fn within<T>(future: impl Future<Output = T>) -> T {
tokio::time::timeout(WAIT, future).await.expect("timed out")
}
/// A running forwarder in front of `upstream`, listening on a real socket like production.
pub struct Gateway {
pub address: SocketAddr,
stop: oneshot::Sender<()>,
server: JoinHandle<()>,
}
impl Gateway {
pub async fn start(upstream: SocketAddr) -> Self {
Self::with_keepalive(upstream, UVICORN_KEEPALIVE).await
}
pub async fn with_keepalive(upstream: SocketAddr, keepalive: Duration) -> Self {
let forward = Forward::new(&format!("http://{upstream}").parse().unwrap(), keepalive);
let public = TcpListener::bind("127.0.0.1:0").await.unwrap();
let address = public.local_addr().unwrap();
let (stop, stopped) = oneshot::channel::<()>();
let server = tokio::spawn(forward.serve(
public,
async {
stopped.await.ok();
},
DRAIN,
));
Self {
address,
stop,
server,
}
}
pub fn url(&self, path_and_query: &str) -> Uri {
format!("http://{}{path_and_query}", self.address)
.parse()
.unwrap()
}
pub async fn connect(&self) -> Raw {
Raw::new(TcpStream::connect(self.address).await.unwrap())
}
/// Starts graceful shutdown and returns the server task, which ends once in-flight work drains
/// or `DRAIN` passes.
pub fn shutdown(self) -> JoinHandle<()> {
self.stop.send(()).unwrap();
self.server
}
}
pub fn client() -> Client<HttpConnector, Body> {
Client::builder(TokioExecutor::new()).build_http()
}
/// What the upstream received, after the forwarder rewrote it.
pub struct Received {
pub method: Method,
pub uri: Uri,
pub headers: HeaderMap,
pub body: Bytes,
}
/// An axum upstream that records every request it fully reads and answers with `respond`.
pub async fn recording(
respond: impl Fn() -> axum::response::Response + Clone + Send + Sync + 'static,
) -> (SocketAddr, mpsc::UnboundedReceiver<Received>) {
let (sender, receiver) = mpsc::unbounded_channel();
let address = serve(Router::new().fallback(move |request: Request| {
let sender = sender.clone();
let respond = respond.clone();
async move {
let (parts, body) = request.into_parts();
let body = body.collect().await.unwrap().to_bytes();
sender
.send(Received {
method: parts.method,
uri: parts.uri,
headers: parts.headers,
body,
})
.unwrap();
respond()
}
}))
.await;
(address, receiver)
}
pub async fn serve(router: Router) -> SocketAddr {
let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
let address = listener.local_addr().unwrap();
tokio::spawn(async move { axum::serve(listener, router).await.unwrap() });
address
}
/// An upstream that hands each accepted connection to `handle` as raw bytes, for behavior a
/// well-behaved HTTP server would never produce.
pub async fn raw_upstream<F, Fut>(handle: F) -> SocketAddr
where
F: Fn(Raw) -> Fut + Send + Sync + 'static,
Fut: Future<Output = ()> + Send + 'static,
{
let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
let address = listener.local_addr().unwrap();
tokio::spawn(async move {
loop {
let (stream, _) = listener.accept().await.unwrap();
tokio::spawn(handle(Raw::new(stream)));
}
});
address
}
pub fn unreachable_upstream() -> SocketAddr {
let listener = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
listener.local_addr().unwrap()
}
pub struct Head {
pub status: StatusCode,
pub headers: Vec<(String, Vec<u8>)>,
pub path: String,
}
impl Head {
pub fn header(&self, name: &str) -> Option<&[u8]> {
self.headers
.iter()
.find(|(key, _)| key.eq_ignore_ascii_case(name))
.map(|(_, value)| value.as_slice())
}
pub fn content_length(&self) -> Option<usize> {
self.header("content-length")
.map(|value| std::str::from_utf8(value).unwrap().parse().unwrap())
}
}
/// One TCP connection driven byte by byte, so tests control framing, timing and disconnects.
/// Bytes read past a message head stay buffered for the next read.
pub struct Raw {
stream: TcpStream,
buffer: Vec<u8>,
}
impl Raw {
pub fn new(stream: TcpStream) -> Self {
Self {
stream,
buffer: Vec::new(),
}
}
pub fn into_stream(self) -> TcpStream {
assert!(self.buffer.is_empty(), "buffered bytes would be lost");
self.stream
}
pub fn local_address(&self) -> SocketAddr {
self.stream.local_addr().unwrap()
}
pub async fn send(&mut self, bytes: impl AsRef<[u8]>) {
self.stream.write_all(bytes.as_ref()).await.unwrap();
}
/// Reads one request head, or `None` when the peer closed the connection first.
pub async fn request_head(&mut self) -> Option<Head> {
self.head(|bytes| {
let mut headers = [httparse::EMPTY_HEADER; 256];
let mut request = httparse::Request::new(&mut headers);
let httparse::Status::Complete(length) = request.parse(bytes).unwrap() else {
return None;
};
Some((
length,
Head {
status: StatusCode::OK,
headers: owned(request.headers),
path: request.path.unwrap().to_owned(),
},
))
})
.await
}
pub async fn response_head(&mut self) -> Option<Head> {
self.head(|bytes| {
let mut headers = [httparse::EMPTY_HEADER; 256];
let mut response = httparse::Response::new(&mut headers);
let httparse::Status::Complete(length) = response.parse(bytes).unwrap() else {
return None;
};
Some((
length,
Head {
status: StatusCode::from_u16(response.code.unwrap()).unwrap(),
headers: owned(response.headers),
path: String::new(),
},
))
})
.await
}
async fn head(&mut self, parse: impl Fn(&[u8]) -> Option<(usize, Head)>) -> Option<Head> {
loop {
if let Some((length, head)) = parse(&self.buffer) {
self.buffer.drain(..length);
return Some(head);
}
if self.fill().await == 0 {
return None;
}
}
}
/// Reads exactly `length` body bytes, using what is already buffered first.
pub async fn body(&mut self, length: usize) -> Vec<u8> {
while self.buffer.len() < length {
assert_ne!(self.fill().await, 0, "closed mid-body");
}
self.buffer.drain(..length).collect()
}
/// Reads a whole chunked body and returns its decoded bytes.
pub async fn chunked_body(&mut self) -> Vec<u8> {
let mut decoded = Vec::new();
loop {
let size_line = self.line().await;
let size =
usize::from_str_radix(size_line.split(';').next().unwrap().trim(), 16).unwrap();
if size == 0 {
while !self.line().await.is_empty() {}
return decoded;
}
decoded.extend(self.body(size).await);
assert_eq!(self.body(2).await, b"\r\n");
}
}
async fn line(&mut self) -> String {
loop {
if let Some(end) = self.buffer.windows(2).position(|window| window == b"\r\n") {
let line = String::from_utf8(self.buffer[..end].to_vec()).unwrap();
self.buffer.drain(..end + 2);
return line;
}
assert_ne!(self.fill().await, 0, "closed mid-line");
}
}
async fn fill(&mut self) -> usize {
let mut chunk = [0; 8192];
let read = self.stream.read(&mut chunk).await.unwrap_or(0);
self.buffer.extend_from_slice(&chunk[..read]);
read
}
/// Everything the peer sends until it closes, including bytes already buffered.
pub async fn until_closed(&mut self) -> Vec<u8> {
while self.fill().await != 0 {}
std::mem::take(&mut self.buffer)
}
/// Resolves once the peer closes the connection, discarding anything it still sends.
pub async fn closed(&mut self) {
let mut chunk = [0; 8192];
while self.stream.read(&mut chunk).await.unwrap_or(0) != 0 {}
}
}
fn owned(headers: &[httparse::Header<'_>]) -> Vec<(String, Vec<u8>)> {
headers
.iter()
.map(|header| (header.name.to_owned(), header.value.to_vec()))
.collect()
}

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mod support;
use std::{
convert::Infallible,
sync::{
Arc,
atomic::{AtomicUsize, Ordering},
},
time::Duration,
};
use axum::{
Router,
body::{Body, Bytes},
extract::Request,
http::StatusCode,
response::Response,
};
use http_body_util::BodyExt;
use rstest::rstest;
use support::{Gateway, Raw, client, raw_upstream, recording, serve, within};
use tokio::{
io::AsyncWriteExt,
sync::{Notify, mpsc},
};
fn ok() -> Response {
Response::new(Body::from("ok"))
}
#[rstest]
#[tokio::test]
async fn streams_upload_and_response_incrementally_without_a_body_limit() {
let upstream = serve(
Router::new().fallback(|request: Request| async { Response::new(request.into_body()) }),
)
.await;
let gateway = Gateway::start(upstream).await;
let (sender, receiver) = mpsc::channel::<Result<Bytes, Infallible>>(1);
let stream = futures_util::stream::unfold(receiver, |mut receiver| async {
receiver.recv().await.map(|chunk| (chunk, receiver))
});
sender.send(Ok(Bytes::from_static(b"first"))).await.unwrap();
let mut response = within(
client().request(
Request::post(gateway.url("/v1/files"))
.body(Body::from_stream(stream))
.unwrap(),
),
)
.await
.unwrap();
let frame = within(response.body_mut().frame()).await.unwrap().unwrap();
assert_eq!(frame.into_data().unwrap(), "first");
let large = Bytes::from(vec![b'x'; 8 * 1024 * 1024]);
sender.send(Ok(large.clone())).await.unwrap();
drop(sender);
let rest = within(response.into_body().collect())
.await
.unwrap()
.to_bytes();
assert_eq!(rest, large);
}
/// hyper sends the 100 as soon as the request is forwarded, where uvicorn waits for the app to
/// read the body, so an upload Python rejects on headers alone is still sent in full.
#[rstest]
#[tokio::test]
async fn answers_expect_continue_so_large_uploads_start() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send("POST /v1/audio/transcriptions HTTP/1.1\r\nhost: x\r\nexpect: 100-continue\r\ncontent-length: 4\r\n\r\n")
.await;
let interim = within(raw.response_head()).await.unwrap();
assert_eq!(interim.status, StatusCode::CONTINUE);
raw.send("data").await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(received.recv().await.unwrap().body, "data");
}
/// curl sends `expect: 100-continue` for any body over 1 MiB and waits for the 100 before sending
/// the multipart body, which must reach Python intact even where it looks like framing.
#[rstest]
#[tokio::test]
async fn expect_continue_delivers_a_large_multipart_upload_byte_for_byte() {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let boundary = "------------------------d74496d66958873e";
let audio: Vec<u8> = (0..3 * 1024 * 1024)
.map(|index: u32| (index.wrapping_mul(2_654_435_761) >> 24) as u8)
.chain(*b"\r\n0\r\n\r\nPOST /smuggled HTTP/1.1\r\n\r\n--")
.collect();
let body = [
format!("--{boundary}\r\ncontent-disposition: form-data; name=\"model\"\r\n\r\nwhisper-1\r\n--{boundary}\r\ncontent-disposition: form-data; name=\"file\"; filename=\"a b.wav\"\r\ncontent-type: audio/wav\r\n\r\n").into_bytes(),
audio,
format!("\r\n--{boundary}--\r\n").into_bytes(),
]
.concat();
let content_type = format!("multipart/form-data; boundary={boundary}");
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/audio/transcriptions HTTP/1.1\r\nhost: x\r\ncontent-type: {content_type}\r\nexpect: 100-continue\r\ncontent-length: {}\r\n\r\n",
body.len()
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::CONTINUE
);
raw.send(&body).await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
assert_eq!(request.headers["content-type"], content_type.as_str());
assert_eq!(request.body, body);
}
#[rstest]
#[case::get("GET")]
#[case::delete("DELETE")]
#[case::options("OPTIONS")]
#[case::post("POST")]
#[tokio::test]
async fn forwards_a_chunked_body_on_any_method(#[case] method: &str) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"{method} /v1/search HTTP/1.1\r\nhost: x\r\ntransfer-encoding: chunked\r\n\r\n4\r\nbody\r\n0\r\n\r\n"
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
assert_eq!(received.recv().await.unwrap().body, "body");
}
#[rstest]
#[case::no_framing("", "", &[], "")]
#[case::empty_content_length("content-length: 0\r\n", "", &[("content-length", "0")], "")]
#[case::empty_chunked(
"transfer-encoding: chunked\r\n",
"0\r\n\r\n",
&[("transfer-encoding", "chunked")],
""
)]
#[case::sized(
"content-length: 7\r\n",
"payload",
&[("content-length", "7")],
"payload"
)]
#[case::chunk_extensions_and_trailers(
"transfer-encoding: chunked\r\n",
"4;name=\"v\"\r\nbody\r\n0\r\nx-checksum: 1\r\n\r\n",
&[("transfer-encoding", "chunked")],
"body"
)]
#[tokio::test]
async fn a_body_reaches_python_with_the_framing_the_client_chose(
#[values("POST", "GET")] method: &str,
#[case] framing: &str,
#[case] wire_body: &str,
#[case] python_framing: &[(&str, &str)],
#[case] python_body: &str,
) {
let (upstream, mut received) = recording(ok).await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"{method} /v1/files HTTP/1.1\r\nhost: x\r\n{framing}\r\n{wire_body}"
))
.await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
let request = received.recv().await.unwrap();
let forwarded: Vec<(&str, &str)> = ["content-length", "transfer-encoding"]
.into_iter()
.flat_map(|name| {
request
.headers
.get_all(name)
.iter()
.map(move |value| (name, value.to_str().unwrap()))
})
.collect();
assert_eq!(request.method, method);
assert_eq!(forwarded, python_framing);
assert_eq!(request.body, python_body);
}
#[rstest]
#[tokio::test]
async fn a_large_upload_is_paced_by_python_reading_it() {
const LENGTH: usize = 128 * 1024 * 1024;
let start_reading = Arc::new(Notify::new());
let reading = start_reading.clone();
let upstream = raw_upstream(move |mut python| {
let reading = reading.clone();
async move {
let head = python.request_head().await.unwrap();
reading.notified().await;
let mut remaining = head.content_length().unwrap();
while remaining > 0 {
remaining -= python.body(remaining.min(1 << 20)).await.len();
}
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n")
.await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let (read, mut write) = gateway.connect().await.into_stream().into_split();
let sent = Arc::new(AtomicUsize::new(0));
let sending = sent.clone();
let upload = tokio::spawn(async move {
write
.write_all(
format!("POST /v1/files HTTP/1.1\r\nhost: x\r\ncontent-length: {LENGTH}\r\n\r\n")
.as_bytes(),
)
.await
.unwrap();
let chunk = [0x5a; 64 * 1024];
while sending.load(Ordering::SeqCst) < LENGTH {
write.write_all(&chunk).await.unwrap();
sending.fetch_add(chunk.len(), Ordering::SeqCst);
}
write
});
tokio::time::sleep(Duration::from_secs(1)).await;
assert!(
sent.load(Ordering::SeqCst) < LENGTH / 4,
"the forwarder buffered an upload Python was not reading"
);
start_reading.notify_one();
let write = tokio::time::timeout(Duration::from_secs(60), upload)
.await
.unwrap()
.unwrap();
let mut raw = Raw::new(read.reunite(write).unwrap());
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::OK
);
}
#[rstest]
#[case::between_chunks("5\r\nhello\r\n")]
#[case::mid_chunk("100\r\nhello")]
#[tokio::test]
async fn a_client_abandoning_a_chunked_upload_never_ends_python_body_cleanly(
#[case] sent: &'static str,
) {
let (forwarded, mut received) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python| {
let forwarded = forwarded.clone();
async move {
python.request_head().await.unwrap();
forwarded.send(python.until_closed().await).unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\ntransfer-encoding: chunked\r\n\r\n{sent}"
))
.await;
tokio::time::sleep(Duration::from_millis(100)).await;
drop(raw);
let body = within(received.recv()).await.unwrap();
assert!(body.starts_with(b"5\r\nhello\r\n"));
assert!(
!body.ends_with(b"0\r\n\r\n"),
"python saw a truncated upload end cleanly"
);
}
#[rstest]
#[tokio::test]
async fn an_early_answer_during_an_upload_keeps_both_connections_in_sync() {
let (event, mut events) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python| {
let event = event.clone();
async move {
while let Some(head) = python.request_head().await {
let length = head.content_length();
event.send(head.path.into_bytes()).unwrap();
let Some(length) = length else {
python
.send("HTTP/1.1 200 OK\r\ncontent-length: 4\r\n\r\nnext")
.await;
continue;
};
python
.send("HTTP/1.1 413 Payload Too Large\r\ncontent-length: 2\r\n\r\n{}")
.await;
event.send(python.body(length).await).unwrap();
}
}
})
.await;
let gateway = Gateway::start(upstream).await;
let upload = b"GET /smuggled HTTP/1.1\r\nhost: x\r\n\r\n".repeat(1024);
let (first_half, second_half) = upload.split_at(upload.len() / 2);
let mut raw = gateway.connect().await;
raw.send(format!(
"POST /v1/files HTTP/1.1\r\nhost: x\r\ncontent-length: {}\r\n\r\n",
upload.len()
))
.await;
raw.send(first_half).await;
let rejected = within(raw.response_head()).await.unwrap();
assert_eq!(rejected.status, StatusCode::PAYLOAD_TOO_LARGE);
assert_eq!(raw.body(2).await, b"{}");
raw.send(second_half).await;
raw.send("GET /next HTTP/1.1\r\nhost: x\r\n\r\n").await;
let next = within(raw.response_head()).await.unwrap();
assert_eq!(raw.body(next.content_length().unwrap()).await, b"next");
assert_eq!(within(events.recv()).await.unwrap(), b"/v1/files");
assert_eq!(within(events.recv()).await.unwrap(), upload);
assert_eq!(within(events.recv()).await.unwrap(), b"/next");
}

21
litellm-rust/crates/gateway-forward/tests/upstream.rs Normal file
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@ -0,0 +1,21 @@
use litellm_gateway_forward::Upstream;
use rstest::rstest;
#[rstest]
#[case::https("https://127.0.0.1:4000")]
#[case::public("http://192.0.2.1:4000")]
#[case::hostname("http://localhost:4000")]
#[case::ipv6("http://[::1]:4000")]
#[case::path("http://127.0.0.1:4000/api")]
#[case::query("http://127.0.0.1:4000/?x=y")]
#[case::credentials("http://user@127.0.0.1:4000")]
fn rejects_anything_but_a_loopback_http_origin(#[case] upstream: &str) {
assert!(upstream.parse::<Upstream>().is_err());
}
#[rstest]
#[case::standard("http://127.0.0.1:4000")]
#[case::loopback_range("http://127.0.0.2:4000/")]
fn accepts_a_loopback_http_origin(#[case] upstream: &str) {
assert!(upstream.parse::<Upstream>().is_ok());
}

719
litellm-rust/crates/gateway-forward/tests/websocket.rs Normal file
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@ -0,0 +1,719 @@
mod support;
use std::{
net::SocketAddr,
sync::Arc,
time::{Duration, Instant},
};
use axum::{
Router,
http::{HeaderValue, StatusCode},
response::IntoResponse,
};
use futures_util::{SinkExt, StreamExt, future::join_all};
use litellm_gateway_forward::PEER_HEADER;
use rstest::rstest;
use support::{DRAIN, Gateway, Head, Raw, raw_upstream, serve, within};
use tokio::{
io::{AsyncReadExt, AsyncWriteExt},
net::TcpStream,
sync::{Barrier, mpsc},
};
use tokio_tungstenite::{
WebSocketStream, accept_hdr_async, client_async,
tungstenite::{
Error, Message,
client::IntoClientRequest,
handshake::{
derive_accept_key,
server::{ErrorResponse, Request as Handshake, Response as Accepted},
},
protocol::{CloseFrame, frame::coding::CloseCode},
},
};
const KEY: &str = "dGhlIHNhbXBsZSBub25jZQ==";
async fn connect(
address: SocketAddr,
connection: &'static str,
) -> Result<WebSocketStream<TcpStream>, Box<Error>> {
let mut request = format!("ws://{address}/v1/realtime?model=m")
.into_client_request()
.unwrap();
let headers = request.headers_mut();
headers.insert("authorization", HeaderValue::from_static("Bearer test"));
headers.insert(
"sec-websocket-protocol",
HeaderValue::from_static("realtime"),
);
headers.insert("connection", HeaderValue::from_static(connection));
let stream = TcpStream::connect(address).await.unwrap();
let (socket, response) = client_async(request, stream).await.map_err(Box::new)?;
assert_eq!(response.headers()["sec-websocket-protocol"], "realtime");
Ok(socket)
}
/// Greets, echoes every message, and closes with 4000 when told to "bye".
#[expect(
clippy::result_large_err,
reason = "tungstenite's handshake callback returns ErrorResponse"
)]
async fn echo() -> SocketAddr {
raw_upstream(|python| async move {
let callback = |request: &Handshake, mut response: Accepted| {
assert_eq!(request.uri(), "/v1/realtime?model=m");
assert_eq!(request.headers()["authorization"], "Bearer test");
assert!(request.headers().contains_key(PEER_HEADER));
response.headers_mut().insert(
"sec-websocket-protocol",
HeaderValue::from_static("realtime"),
);
Ok::<_, ErrorResponse>(response)
};
let mut socket = accept_hdr_async(python.into_stream(), callback)
.await
.unwrap();
socket.send(Message::text("greeting")).await.unwrap();
while let Some(Ok(message)) = socket.next().await {
if message == Message::text("bye") {
socket
.close(Some(CloseFrame {
code: CloseCode::Library(4000),
reason: "done".into(),
}))
.await
.unwrap();
continue;
}
if message.is_close() {
break;
}
socket.send(message).await.unwrap();
}
})
.await
}
fn handshake(target: &str, headers: &str) -> String {
format!(
"GET {target} HTTP/1.1\r\nhost: public.example\r\nconnection: Upgrade\r\nupgrade: websocket\r\nsec-websocket-version: 13\r\nsec-websocket-key: {KEY}\r\n{headers}\r\n"
)
}
/// The 101 uvicorn writes for `handshake`, with `headers` added.
fn switching(handshake: &Head, headers: &str) -> String {
let accept = derive_accept_key(handshake.header("sec-websocket-key").unwrap());
format!(
"HTTP/1.1 101 Switching Protocols\r\nupgrade: websocket\r\nconnection: Upgrade\r\nsec-websocket-accept: {accept}\r\n{headers}\r\n"
)
}
fn values(head: &Head, name: &str) -> Vec<String> {
head.headers
.iter()
.filter(|(key, _)| key.eq_ignore_ascii_case(name))
.map(|(_, value)| String::from_utf8(value.clone()).unwrap())
.collect()
}
/// Accepts with `headers` in the 101, hands the handshake head to the test, then echoes bytes.
async fn byte_echo(headers: &'static str) -> (SocketAddr, mpsc::UnboundedReceiver<Head>) {
let (sender, handshakes) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let sender = sender.clone();
async move {
let handshake = python.request_head().await.unwrap();
python.send(switching(&handshake, headers)).await;
sender.send(handshake).unwrap();
echo_bytes(python).await;
}
})
.await;
(upstream, handshakes)
}
async fn echo_bytes(python: Raw) {
let mut stream = python.into_stream();
let (mut read, mut write) = stream.split();
tokio::io::copy(&mut read, &mut write).await.ok();
}
async fn assert_echoes(socket: &mut TcpStream, message: &[u8]) {
socket.write_all(message).await.unwrap();
let mut echoed = vec![0; message.len()];
within(socket.read_exact(&mut echoed)).await.unwrap();
assert_eq!(echoed, message);
}
async fn open(gateway: &Gateway, handshake: String) -> (TcpStream, Head) {
let mut raw = gateway.connect().await;
raw.send(handshake).await;
let switched = within(raw.response_head()).await.unwrap();
assert_eq!(switched.status, StatusCode::SWITCHING_PROTOCOLS);
(raw.into_stream(), switched)
}
#[rstest]
#[tokio::test]
async fn relays_messages_both_ways(
#[values(
"Upgrade",
"keep-alive, Upgrade",
"upgrade",
"Upgrade, Sec-WebSocket-Key, Sec-WebSocket-Version"
)]
connection: &'static str,
#[values(
Message::text("hello"),
Message::binary(vec![0, 1, 2]),
Message::binary(vec![7; 4 * 1024 * 1024])
)]
message: Message,
) {
let gateway = Gateway::start(echo().await).await;
let mut socket = within(connect(gateway.address, connection)).await.unwrap();
assert_eq!(
socket.next().await.unwrap().unwrap(),
Message::text("greeting")
);
socket.send(message.clone()).await.unwrap();
assert_eq!(within(socket.next()).await.unwrap().unwrap(), message);
socket.close(None).await.unwrap();
while socket.next().await.is_some() {}
drop(socket);
within(gateway.shutdown()).await.unwrap();
}
#[rstest]
#[tokio::test]
async fn relays_a_close_python_initiates() {
let gateway = Gateway::start(echo().await).await;
let mut socket = within(connect(gateway.address, "Upgrade")).await.unwrap();
socket.next().await.unwrap().unwrap();
socket.send(Message::text("bye")).await.unwrap();
let Message::Close(Some(frame)) = within(socket.next()).await.unwrap().unwrap() else {
panic!("expected python's close frame");
};
assert_eq!(frame.code, CloseCode::Library(4000));
assert_eq!(frame.reason, "done");
}
#[rstest]
#[tokio::test]
async fn passes_an_upstream_rejection_through() {
let upstream = serve(
Router::new()
.fallback(|| async { (StatusCode::FORBIDDEN, "origin not allowed").into_response() }),
)
.await;
let gateway = Gateway::start(upstream).await;
let error = within(connect(gateway.address, "Upgrade"))
.await
.unwrap_err();
let Error::Http(response) = *error else {
panic!("expected the upstream rejection, got {error}");
};
assert_eq!(response.status(), StatusCode::FORBIDDEN);
assert_eq!(response.body().as_deref(), Some(&b"origin not allowed"[..]));
}
/// The idle timeout only covers a connection waiting for its next HTTP request, and a realtime
/// session may sit silent between turns.
#[rstest]
#[tokio::test]
async fn keeps_a_quiet_socket_open_past_the_keepalive() {
let gateway = Gateway::with_keepalive(echo().await, Duration::from_millis(400)).await;
let mut socket = within(connect(gateway.address, "Upgrade")).await.unwrap();
socket.next().await.unwrap().unwrap();
tokio::time::sleep(Duration::from_millis(1200)).await;
socket.send(Message::text("still here")).await.unwrap();
assert_eq!(
within(socket.next()).await.unwrap().unwrap(),
Message::text("still here")
);
}
/// Browsers carry the API key in a subprotocol, Python accepts with the first one it was offered,
/// and uvicorn negotiates permessage-deflate, so every handshake header must cross unchanged.
#[rstest]
#[tokio::test]
async fn handshake_headers_cross_unchanged_both_ways() {
let (upstream, mut handshakes) = byte_echo(
"sec-websocket-protocol: realtime\r\nsec-websocket-extensions: permessage-deflate; server_max_window_bits=12; client_max_window_bits=12\r\nset-cookie: a=1\r\nset-cookie: b=2\r\nx-litellm-call-id: abc\r\n",
)
.await;
let gateway = Gateway::start(upstream).await;
let target = "/v1/realtime?model=gpt-realtime&api-key=sk%2Fa%2Bb%3D&dup=1&dup=2";
let (_socket, switched) = open(
&gateway,
handshake(
target,
"sec-websocket-protocol: realtime, openai-insecure-api-key.sk-websocket-test, openai-beta.realtime-v1\r\nsec-websocket-protocol: second-line\r\nsec-websocket-extensions: permessage-deflate; client_max_window_bits\r\ncookie: token=abc\r\n",
),
)
.await;
let handshake = within(handshakes.recv()).await.unwrap();
assert_eq!(handshake.path, target);
assert_eq!(
values(&handshake, "sec-websocket-protocol"),
[
"realtime, openai-insecure-api-key.sk-websocket-test, openai-beta.realtime-v1",
"second-line"
]
);
assert_eq!(
values(&handshake, "sec-websocket-extensions"),
["permessage-deflate; client_max_window_bits"]
);
assert_eq!(values(&handshake, "cookie"), ["token=abc"]);
assert_eq!(values(&switched, "sec-websocket-protocol"), ["realtime"]);
assert_eq!(
values(&switched, "sec-websocket-extensions"),
["permessage-deflate; server_max_window_bits=12; client_max_window_bits=12"]
);
assert_eq!(values(&switched, "set-cookie"), ["a=1", "b=2"]);
assert_eq!(values(&switched, "x-litellm-call-id"), ["abc"]);
}
#[rstest]
#[tokio::test]
async fn invents_no_subprotocol_or_extension() {
let (upstream, mut handshakes) = byte_echo("").await;
let gateway = Gateway::start(upstream).await;
let (_socket, switched) = open(&gateway, handshake("/v1/realtime", "")).await;
let handshake = within(handshakes.recv()).await.unwrap();
for name in ["sec-websocket-protocol", "sec-websocket-extensions"] {
assert!(handshake.header(name).is_none());
assert!(switched.header(name).is_none());
}
}
#[rstest]
#[case::capitalized_upgrade("Upgrade: WebSocket\r\nConnection: keep-alive, Upgrade\r\n")]
#[case::uppercase("UPGRADE: WEBSOCKET\r\nCONNECTION: UPGRADE\r\n")]
#[case::split_connection("Upgrade: websocket\r\nConnection: keep-alive\r\nConnection: Upgrade\r\n")]
#[tokio::test]
async fn accepts_any_spelling_of_the_upgrade_headers(#[case] upgrade: &str) {
let (upstream, _handshakes) = byte_echo("").await;
let gateway = Gateway::start(upstream).await;
let (mut socket, _) = open(
&gateway,
format!(
"GET /v1/realtime HTTP/1.1\r\nhost: x\r\n{upgrade}sec-websocket-version: 13\r\nsec-websocket-key: {KEY}\r\n\r\n"
),
)
.await;
socket.write_all(b"ping").await.unwrap();
let mut echoed = [0; 4];
within(socket.read_exact(&mut echoed)).await.unwrap();
assert_eq!(&echoed, b"ping");
}
/// Compressed frames set RSV1 and every client frame is masked, so the socket is relayed as bytes,
/// never re-framed.
#[rstest]
#[tokio::test]
async fn relays_socket_bytes_exactly() {
let (upstream, _handshakes) = byte_echo("").await;
let gateway = Gateway::start(upstream).await;
let (socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
let sent: Vec<u8> = (0..3_000_017u32)
.map(|index| index.wrapping_mul(2_654_435_761).to_be_bytes()[1])
.collect();
let (mut read, mut write) = socket.into_split();
let writing = sent.clone();
let writer = tokio::spawn(async move {
for chunk in writing.chunks(7919) {
write.write_all(chunk).await.unwrap();
}
write
});
let mut echoed = vec![0; sent.len()];
within(read.read_exact(&mut echoed)).await.unwrap();
assert!(echoed == sent);
drop(writer.await.unwrap());
}
/// uvicorn writes the 101, an error event and a close frame back to back and then closes, so they
/// share a segment with the FIN, and a client may send its first frame with the handshake.
#[rstest]
#[tokio::test]
async fn keeps_bytes_that_arrive_with_the_handshake() {
let (early, mut received) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let early = early.clone();
async move {
let handshake = python.request_head().await.unwrap();
let mut segment = switching(&handshake, "").into_bytes();
segment.extend(b"\x81\x05error\x88\x08\x03\xf0denied");
python.send(segment).await;
early.send(within(python.body(6)).await).unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(handshake("/v1/realtime", "") + "early!").await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::SWITCHING_PROTOCOLS
);
assert_eq!(within(received.recv()).await.unwrap(), b"early!");
assert_eq!(
within(raw.until_closed()).await,
b"\x81\x05error\x88\x08\x03\xf0denied"
);
}
/// Python frees a realtime session's budget and parallel slot when its socket closes, so a client
/// that disappears without a close frame must still close Python's socket.
#[rstest]
#[case::fin(false)]
#[case::reset(true)]
#[tokio::test]
async fn a_vanished_client_closes_the_python_socket(#[case] reset: bool) {
let (event, mut events) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let event = event.clone();
async move {
let handshake = python.request_head().await.unwrap();
python.send(switching(&handshake, "")).await;
event.send("open").unwrap();
python.closed().await;
event.send("closed").unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let (socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
assert_eq!(within(events.recv()).await, Some("open"));
if reset {
#[expect(deprecated, reason = "a zero linger is how a test sends a TCP reset")]
socket.set_linger(Some(Duration::ZERO)).unwrap();
}
drop(socket);
assert_eq!(within(events.recv()).await, Some("closed"));
}
#[rstest]
#[case::fin(false)]
#[case::reset(true)]
#[tokio::test]
async fn a_vanished_python_ends_the_client_socket(#[case] reset: bool) {
let upstream = raw_upstream(move |mut python: Raw| async move {
let handshake = python.request_head().await.unwrap();
python.send(switching(&handshake, "")).await;
let socket = python.into_stream();
if reset {
#[expect(deprecated, reason = "a zero linger is how a test sends a TCP reset")]
socket.set_linger(Some(Duration::ZERO)).unwrap();
}
drop(socket);
})
.await;
let gateway = Gateway::start(upstream).await;
let (mut socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
let mut rest = Vec::new();
assert!(matches!(
within(socket.read_to_end(&mut rest)).await,
Ok(0) | Err(_)
));
}
#[rstest]
#[tokio::test]
async fn shutdown_closes_open_sockets_after_drain() {
let gateway = Gateway::start(echo().await).await;
let mut socket = within(connect(gateway.address, "Upgrade")).await.unwrap();
socket.next().await.unwrap().unwrap();
let started = Instant::now();
within(gateway.shutdown()).await.unwrap();
assert!(started.elapsed() >= DRAIN);
assert!(!matches!(socket.next().await, Some(Ok(Message::Text(_)))));
}
#[rstest]
#[tokio::test]
async fn shutdown_relays_the_close_python_sends_while_draining() {
let gateway = Gateway::start(echo().await).await;
let mut socket = within(connect(gateway.address, "Upgrade")).await.unwrap();
socket.next().await.unwrap().unwrap();
let server = gateway.shutdown();
tokio::time::sleep(Duration::from_millis(100)).await;
socket.send(Message::text("bye")).await.unwrap();
let Message::Close(Some(frame)) = within(socket.next()).await.unwrap().unwrap() else {
panic!("expected python's close frame");
};
assert_eq!(frame.code, CloseCode::Library(4000));
while socket.next().await.is_some() {}
drop(socket);
let started = Instant::now();
within(server).await.unwrap();
assert!(started.elapsed() < DRAIN / 2);
}
#[rstest]
#[tokio::test]
async fn refuses_new_sockets_while_draining() {
let gateway = Gateway::start(echo().await).await;
let mut open = within(connect(gateway.address, "Upgrade")).await.unwrap();
open.next().await.unwrap().unwrap();
let address = gateway.address;
let server = gateway.shutdown();
tokio::time::sleep(Duration::from_millis(100)).await;
assert!(
TcpStream::connect(address).await.is_err() || connect(address, "Upgrade").await.is_err()
);
open.send(Message::text("still open")).await.unwrap();
assert_eq!(
within(open.next()).await.unwrap().unwrap(),
Message::text("still open")
);
drop(open);
within(server).await.unwrap();
}
/// uvicorn never half-closes: once Python closes the socket nothing more can cross it, so the
/// relay must end instead of waiting for the client to close its side too.
#[rstest]
#[tokio::test]
async fn relay_ends_when_python_closes_while_the_client_holds_its_socket() {
let upstream = raw_upstream(move |mut python: Raw| async move {
let handshake = python.request_head().await.unwrap();
python.send(switching(&handshake, "")).await;
})
.await;
let gateway = Gateway::start(upstream).await;
let (mut socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
assert_eq!(within(socket.read(&mut [0; 1])).await.unwrap(), 0);
let started = Instant::now();
within(gateway.shutdown()).await.unwrap();
assert!(started.elapsed() < DRAIN / 2);
drop(socket);
}
/// uvicorn answers a handshake Python closes before accepting with a 403, and one Python denies
/// through `websocket.http.response` with any status, headers and body, then drops the socket. The
/// client gets that response whole and keeps a connection that still reaches Python.
#[rstest]
#[case::closed_before_accept("403 Forbidden", None, "")]
#[case::denial_response(
"401 Unauthorized",
Some("Bearer realm=\"litellm\""),
"{\"error\":\"invalid api key\"}"
)]
#[tokio::test]
async fn a_denied_handshake_reaches_the_client_whole(
#[case] status: &'static str,
#[case] authenticate: Option<&'static str>,
#[case] body: &'static str,
) {
let upstream = raw_upstream(move |mut python: Raw| async move {
python.request_head().await.unwrap();
let authenticate = authenticate
.map(|value| format!("www-authenticate: {value}\r\n"))
.unwrap_or_default();
python
.send(format!(
"HTTP/1.1 {status}\r\ndate: Tue, 03 Nov 2026 08:00:00 GMT\r\nconnection: close\r\ncontent-length: {}\r\ncontent-type: text/plain; charset=utf-8\r\n{authenticate}\r\n{body}",
body.len()
))
.await;
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
for _ in 0..2 {
raw.send(handshake("/v1/realtime", "")).await;
let denied = within(raw.response_head()).await.unwrap();
assert_eq!(denied.status.as_str(), &status[..3]);
assert_eq!(
values(&denied, "www-authenticate"),
Vec::from_iter(authenticate.map(String::from))
);
assert!(denied.header("sec-websocket-accept").is_none());
let length = denied.content_length().unwrap();
assert_eq!(within(raw.body(length)).await, body.as_bytes());
}
}
/// Only Python's EOF ends a relay, so a client that half-closes after its close frame still gets
/// everything Python sends before closing its own side.
#[rstest]
#[tokio::test]
async fn a_client_half_close_still_receives_what_python_sends_after_it() {
let upstream = raw_upstream(|mut python: Raw| async move {
let handshake = python.request_head().await.unwrap();
python.send(switching(&handshake, "")).await;
let received = python.until_closed().await;
python.send(received).await;
})
.await;
let gateway = Gateway::start(upstream).await;
let (mut socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
let close = b"\x88\x82\x01\x02\x03\x04\x02\xea";
socket.write_all(close).await.unwrap();
socket.shutdown().await.unwrap();
let mut replied = Vec::new();
within(socket.read_to_end(&mut replied)).await.unwrap();
assert_eq!(replied, close);
}
/// Python authenticates every handshake before accepting it, so sessions opened together must all
/// reach Python before any of them is accepted, and each must stay on its own socket.
#[rstest]
#[tokio::test]
async fn opens_many_sockets_at_once_without_crossing_them() {
const SOCKETS: usize = 64;
let everyone = Arc::new(Barrier::new(SOCKETS));
let upstream = raw_upstream(move |mut python: Raw| {
let everyone = everyone.clone();
async move {
let handshake = python.request_head().await.unwrap();
everyone.wait().await;
python.send(switching(&handshake, "")).await;
echo_bytes(python).await;
}
})
.await;
let gateway = Gateway::start(upstream).await;
let gateway = &gateway;
within(join_all((0..SOCKETS).map(|index| async move {
let (mut socket, _) = open(gateway, handshake("/v1/realtime", "")).await;
assert_echoes(&mut socket, format!("socket {index}").as_bytes()).await;
})))
.await;
}
/// Python resolves the key, budget and model before it accepts, and nothing bounds how long that
/// takes, so the idle timeout must not cut a handshake waiting on its 101.
#[rstest]
#[tokio::test]
async fn waits_for_a_101_slower_than_the_keepalive() {
let upstream = raw_upstream(|mut python: Raw| async move {
let handshake = python.request_head().await.unwrap();
tokio::time::sleep(Duration::from_millis(1200)).await;
python.send(switching(&handshake, "")).await;
echo_bytes(python).await;
})
.await;
let gateway = Gateway::with_keepalive(upstream, Duration::from_millis(400)).await;
let (mut socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
assert_echoes(&mut socket, b"late").await;
}
/// A 101 the client did not ask for, or to a protocol other than the one it asked for, would hand
/// the client a socket it cannot speak, so it is a 502 and Python's socket is closed.
#[rstest]
#[case::plain_request("GET /v1/models HTTP/1.1\r\nhost: x\r\n\r\n".to_owned(), "websocket")]
#[case::other_protocol(handshake("/v1/realtime", ""), "h2c")]
#[tokio::test]
async fn an_unrequested_switch_is_a_502_that_closes_python(
#[case] request: String,
#[case] protocol: &'static str,
) {
let (closed, mut closes) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let closed = closed.clone();
async move {
python.request_head().await.unwrap();
python
.send(format!(
"HTTP/1.1 101 Switching Protocols\r\nconnection: upgrade\r\nupgrade: {protocol}\r\n\r\n"
))
.await;
python.closed().await;
closed.send(()).unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let mut raw = gateway.connect().await;
raw.send(request).await;
assert_eq!(
within(raw.response_head()).await.unwrap().status,
StatusCode::BAD_GATEWAY
);
within(closes.recv()).await.unwrap();
}
/// A realtime session streams audio for as long as the client reads it, so a client that stops
/// reading must stall Python's writes instead of piling them up in the gateway.
#[rstest]
#[tokio::test]
async fn a_client_that_stops_reading_stalls_python() {
let (sent, mut totals) = mpsc::unbounded_channel();
let upstream = raw_upstream(move |mut python: Raw| {
let sent = sent.clone();
async move {
let handshake = python.request_head().await.unwrap();
python.send(switching(&handshake, "")).await;
python.body(2).await;
let mut stream = python.into_stream();
let chunk = vec![0x82; 64 * 1024];
let mut total = 0;
while let Ok(Ok(())) =
tokio::time::timeout(Duration::from_millis(300), stream.write_all(&chunk)).await
{
total += chunk.len();
}
sent.send(total).unwrap();
}
})
.await;
let gateway = Gateway::start(upstream).await;
let (mut socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
socket.write_all(b"go").await.unwrap();
let total = within(totals.recv()).await.unwrap();
assert!(
total < 64 << 20,
"python wrote {total} bytes into a stalled socket"
);
}
/// Python closes a session that is still streaming audio by sending an error event and a close
/// frame and dropping its socket with the client's next frames unread, which resets it. Those last
/// bytes reached the client when it talked to uvicorn directly, so they must reach it through the
/// relay too, even though writing the client's frames to Python now fails.
#[rstest]
#[tokio::test]
async fn python_closing_mid_stream_still_delivers_its_last_frames() {
const LAST: &[u8] = b"\x81\x05error\x88\x02\x03\xf0";
let upstream = raw_upstream(|mut python: Raw| async move {
let handshake = python.request_head().await.unwrap();
python.send(switching(&handshake, "")).await;
python.body(1).await;
tokio::time::sleep(Duration::from_millis(20)).await;
python.send(LAST).await;
})
.await;
let gateway = Gateway::start(upstream).await;
for _ in 0..20 {
let (mut socket, _) = open(&gateway, handshake("/v1/realtime", "")).await;
let (mut read, mut write) = socket.split();
let streaming = async {
while write.write_all(b"\x82\x80\0\0\0\0").await.is_ok() {
tokio::time::sleep(Duration::from_micros(200)).await;
}
std::future::pending().await
};
let mut received = Vec::new();
let receiving = async {
let mut chunk = [0; 4096];
while let Ok(read @ 1..) = read.read(&mut chunk).await {
received.extend_from_slice(&chunk[..read]);
}
};
within(async {
tokio::select! {
() = streaming => {}
() = receiving => {}
}
})
.await;
assert_eq!(received, LAST);
}
}

1
litellm-rust/crates/gateway/Cargo.toml
View file

@ -12,6 +12,7 @@ envy = "0.4.2"
http-body-util = "0.1"
litellm-inference.workspace = true
litellm-gateway-inference.workspace = true
litellm-gateway-forward.workspace = true
litellm-gateway-mcp.workspace = true
tokio-util = "0.7"
thiserror.workspace = true

26
litellm-rust/crates/gateway/src/main.rs
View file

@ -10,7 +10,7 @@ use serde_json::json;
mod settings;
use settings::{Settings, UiSettings};
use settings::{LogSettings, Settings, UiSettings};
struct StderrSink {
level: Level,
@ -41,6 +41,15 @@ impl Sink for StderrSink {
#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
if let Some(forward) = litellm_gateway_forward::Settings::from_env()? {
let log: LogSettings = settings::from_iter(std::env::vars_os())?;
Logger::new(StderrSink {
level: log.log_level(),
})
.install_global()?;
litellm_gateway_forward::run(forward, shutdown_signal()).await?;
return Ok(());
}
let settings: Settings = settings::from_iter(std::env::vars_os())?;
let level = settings.log_level();
Logger::new(StderrSink { level }).install_global()?;
@ -126,7 +135,20 @@ async fn shutdown_signal() {
}
}
}
#[cfg(not(unix))]
// Windows support exists for local CLI runs only, the proxy is never deployed on Windows. The supervisor
// stops the gateway with CTRL_BREAK_EVENT, which has to drain the same way SIGTERM does.
#[cfg(windows)]
{
match tokio::signal::windows::ctrl_break() {
Ok(mut ctrl_break) => {
tokio::select! { _ = tokio::signal::ctrl_c() => (), _ = ctrl_break.recv() => () }
}
Err(_) => {
let _ = tokio::signal::ctrl_c().await;
}
}
}
#[cfg(not(any(unix, windows)))]
{
let _ = tokio::signal::ctrl_c().await;
}

22
litellm-rust/crates/gateway/src/settings.rs
View file

@ -4,6 +4,23 @@ use litellm_secret_value::SecretValue;
use litellm_tracing::Level;
use serde::{Deserialize, de::DeserializeOwned};
#[derive(Deserialize)]
pub(super) struct LogSettings {
rust_log: Option<String>,
}
impl LogSettings {
pub fn log_level(&self) -> Level {
log_level(self.rust_log.as_deref())
}
}
fn log_level(rust_log: Option<&str>) -> Level {
rust_log
.and_then(|value| value.parse().ok())
.unwrap_or(Level::INFO)
}
#[derive(Deserialize)]
#[serde(default)]
pub(super) struct Settings {
@ -26,10 +43,7 @@ impl Default for Settings {
impl Settings {
pub fn log_level(&self) -> Level {
self.rust_log
.as_deref()
.and_then(|value| value.parse().ok())
.unwrap_or(Level::INFO)
log_level(self.rust_log.as_deref())
}
}