litellm/tests/e2e/mcp/mcp_client.py
Yuneng Jiang 09a98f5505
test(e2e): settle control-plane writes across every replica, not just one
The suite already waits for a new model or agent to become servable before
handing it back, but that wait returns on the first successful read. Every
request opens a fresh connection (e2e_http calls requests.* with no Session), so
a load-balanced Service routes each one independently: one successful read proves
one replica converged, and the caller's next request re-rolls and can land on a
replica that has not reloaded yet.

At replicaCount: 2 this surfaced as 30 failures on a SHA that is green at 1
replica -- 400 "Invalid model name passed", 404 "Guardrail not found", "no
healthy deployments for this model", and a /model/info listing that contained
one of two models created moments apart.

Add PROPAGATION_TIMEOUT (default 15s, override E2E_PROPAGATION_TIMEOUT) and
settle_propagation(), sized off the proxy's proxy_config_reload_interval_seconds
(30s by default, 7s on the e2e stack) plus margin, and settle after every
control-plane create whose object the suite then uses:

- ProxyClient.create_model and A2AClient.register_agent, after their existing
  polls -- the poll still fails loudly if the object never appears at all
- GuardrailsClient.register, which had no barrier; create_content_filter_guardrail
  and create_bedrock_guardrail now route through it instead of POSTing directly
- the guardrail creates in mcp_client and logging_client
- the vertex passthrough model, whose body cannot go through create_model

Left alone: the /model/new calls that assert a 403 or read back a status code,
since they never use the model.
2026-08-07 19:36:30 -07:00

413 lines
14 KiB
Python

"""Client for the MCP e2e suite: admin server registration plus the api_key tool
surface.
An admin registers an upstream MCP server through the management API
(`/v1/mcp/server`, persisted in the DB) and grants a virtual key access to it via
`object_permission.mcp_servers`. Keys then reach the server through the REST bridge
the proxy exposes for api_key auth (`/mcp-rest/tools/list`, `/mcp-rest/tools/call`),
which `user_api_key_auth` gates the same way the JSON-RPC `/mcp` surface does. The
request/response bodies are co-located here because only this suite speaks MCP.
"""
from __future__ import annotations
import re
import time
from collections.abc import Mapping
from dataclasses import dataclass
from pydantic import BaseModel, ConfigDict, Field, RootModel
from e2e_config import settle_propagation
from e2e_http import Headers, NoBody, Result, Success, UnknownApiError, unwrap
from models import KeyGenerateBody, ObjectPermission
from proxy_client import ProxyClient
McpToolArg = str | int | float | bool | list[str] | dict[str, str]
McpToolArguments = Mapping[str, McpToolArg]
class ApiKeyHeaders(Headers):
x_litellm_api_key: str = Field(serialization_alias="x-litellm-api-key")
class McpServerNewBody(BaseModel):
server_name: str
alias: str
url: str
transport: str = "http"
auth_type: str | None = None
static_headers: dict[str, str] | None = None
allowed_tools: list[str] | None = None
mcp_access_groups: list[str] | None = None
class McpServerNewResponse(BaseModel):
server_id: str
class McpServerRow(BaseModel):
server_id: str
alias: str | None = None
url: str | None = None
class McpServersListResponse(RootModel[list[McpServerRow]]):
pass
class McpToolMcpInfo(BaseModel):
server_id: str | None = None
alias: str | None = None
class McpToolEntry(BaseModel):
name: str
description: str | None = None
mcp_info: McpToolMcpInfo | None = None
class McpToolsListResponse(BaseModel):
tools: list[McpToolEntry] = []
error: str | None = None
message: str | None = None
def tool_names_for_server(self, server_id: str) -> frozenset[str]:
return frozenset(
tool.name
for tool in self.tools
if tool.mcp_info is not None and tool.mcp_info.server_id == server_id
)
def tool_name_containing(self, server_id: str, needle: str) -> str | None:
needle_l = needle.lower()
for tool in self.tools:
if tool.mcp_info is None or tool.mcp_info.server_id != server_id:
continue
if needle_l in tool.name.lower() or tool.name.lower().endswith(needle_l):
return tool.name
return None
class BlockedWordSpec(BaseModel):
keyword: str
action: str = "BLOCK"
class ContentFilterMcpParams(BaseModel):
"""litellm_content_filter params scoped to the MCP tool-call hook. mode is
pre_mcp_call because a pre_call config silently no-ops on the tools/call path
(the event type is rewritten to pre_mcp_call for call_mcp_tool), and default_on
is required there because per-key/request guardrail selection is dropped from
the synthetic MCP request the hook sees."""
guardrail: str = "litellm_content_filter"
mode: str = "pre_mcp_call"
default_on: bool = True
blocked_words: list[BlockedWordSpec]
class GuardrailSpecBody(BaseModel):
guardrail_name: str
litellm_params: ContentFilterMcpParams
class GuardrailCreateBody(BaseModel):
guardrail: GuardrailSpecBody
class GuardrailCreateResponse(BaseModel):
guardrail_id: str
class McpCallToolBody(BaseModel):
name: str
arguments: dict[str, McpToolArg]
server_id: str
class McpCallContent(BaseModel):
type: str | None = None
text: str | None = None
class McpCallToolResponse(BaseModel):
model_config = ConfigDict(populate_by_name=True)
content: list[McpCallContent] = []
is_error: bool | None = Field(default=None, alias="isError")
@property
def first_text(self) -> str | None:
return self.content[0].text if self.content else None
@property
def all_text(self) -> str:
return "\n".join(part.text for part in self.content if part.text)
@dataclass(frozen=True, slots=True)
class McpClient:
proxy: ProxyClient
def register_server(
self,
*,
server_name: str,
alias: str,
url: str,
transport: str = "http",
auth_type: str | None = None,
static_headers: dict[str, str] | None = None,
allowed_tools: list[str] | None = None,
mcp_access_groups: list[str] | None = None,
) -> str:
return unwrap(
self.proxy.transport.post(
"/v1/mcp/server",
headers=self.proxy.transport.master,
json=McpServerNewBody(
server_name=server_name,
alias=alias,
url=url,
transport=transport,
auth_type=auth_type,
static_headers=static_headers,
allowed_tools=allowed_tools,
mcp_access_groups=mcp_access_groups,
),
response_type=McpServerNewResponse,
)
).server_id
def delete_server(self, server_id: str) -> None:
_ = self.proxy.transport.delete(
f"/v1/mcp/server/{server_id}",
headers=self.proxy.transport.master,
json=NoBody(),
response_type=NoBody,
)
def registered_servers(self) -> list[McpServerRow]:
return unwrap(
self.proxy.transport.get(
"/v1/mcp/server",
headers=self.proxy.transport.master,
params=NoBody(),
response_type=McpServersListResponse,
)
).root
def await_registered(self, server_id: str) -> None:
"""Poll /v1/mcp/server until `server_id` is listed. Fails at poll_timeout.
The DB row exists the moment registration returns, but a data-plane pod
answers the listing from a registry it refreshes on a periodic DB sync, so a
pod that joined the load balancer after the write reports the server as
absent until its first sync.
"""
deadline = time.monotonic() + self.proxy.poll_timeout
while True:
registered = frozenset(row.server_id for row in self.registered_servers())
if server_id in registered:
return
if time.monotonic() >= deadline:
raise AssertionError(
f"registered server {server_id} still absent from /v1/mcp/server "
f"{self.proxy.poll_timeout}s after registration (the data plane never synced "
f"the row): {registered}"
)
time.sleep(self.proxy.poll_interval)
def generate_key(
self,
*,
user_id: str,
mcp_servers: list[str] | None,
mcp_access_groups: list[str] | None = None,
models: list[str] | None = None,
) -> str:
object_permission = (
ObjectPermission(mcp_servers=mcp_servers, mcp_access_groups=mcp_access_groups)
if mcp_servers is not None or mcp_access_groups is not None
else None
)
return self.proxy.generate_key(
KeyGenerateBody(
models=models if models is not None else [],
user_id=user_id,
object_permission=object_permission,
)
)
def list_tools(self, key: str) -> Result[McpToolsListResponse]:
return self.proxy.transport.get(
"/mcp-rest/tools/list",
headers=ApiKeyHeaders(x_litellm_api_key=key),
params=NoBody(),
response_type=McpToolsListResponse,
)
def await_tool(self, key: str, server_id: str, needle: str) -> str:
"""Poll tools/list until `server_id` serves a tool matching `needle`, and
return its fully-qualified name. Fails at poll_timeout.
/v1/mcp/server returns as soon as the DB row is written, but the gateway
runs the initialize + tools/list handshake against the upstream lazily on
the first request that needs it, and reports a server it has not
discovered yet exactly like a dead one: an empty tool list. Waiting is
what separates the two.
"""
deadline = time.monotonic() + self.proxy.poll_timeout
while True:
result = self.list_tools(key)
if isinstance(result, Success):
tool_name = result.data.tool_name_containing(server_id, needle)
if tool_name is not None:
return tool_name
if time.monotonic() >= deadline:
raise AssertionError(
f"server {server_id} never served a tool matching {needle!r} within "
f"{self.proxy.poll_timeout}s of registration (upstream unreachable, or "
f"the key's grant was not applied); last tools/list: {result}"
)
time.sleep(self.proxy.poll_interval)
def await_call_tool(
self,
key: str,
*,
server_id: str,
name: str,
arguments: McpToolArguments,
) -> McpCallToolResponse:
"""Poll tools/call until the result is not a multi-worker registry miss.
Retries only on the gateway's own cold-worker 500 shapes (Tool <name>
not found / server_not_found). Upstream tool errors and other 500s fail
immediately so non-idempotent calls are not repeated.
"""
deadline = time.monotonic() + self.proxy.poll_timeout
last: Result[McpCallToolResponse] | None = None
while True:
last = self.call_tool(key, server_id=server_id, name=name, arguments=arguments)
if not _is_mcp_not_synced(last, tool_name=name):
return unwrap(last)
if time.monotonic() >= deadline:
raise AssertionError(
f"tools/call for {name!r} on server {server_id} still missing on the "
f"data plane after {self.proxy.poll_timeout}s (multi-worker registry lag); "
f"last result: {last}"
)
time.sleep(self.proxy.poll_interval)
def await_call_tool_denied(
self,
key: str,
*,
server_id: str,
name: str,
arguments: McpToolArguments,
) -> UnknownApiError:
"""Poll tools/call until a cold-worker miss clears and the call is 403 access_denied."""
deadline = time.monotonic() + self.proxy.poll_timeout
last: Result[McpCallToolResponse] | None = None
while True:
last = self.call_tool(key, server_id=server_id, name=name, arguments=arguments)
if isinstance(last, UnknownApiError) and last.status_code == 403:
return last
if not _is_mcp_not_synced(last, tool_name=name):
raise AssertionError(
f"ungranted key's tools/call was not 403 access_denied: {last}"
)
if time.monotonic() >= deadline:
raise AssertionError(
f"ungranted key never got 403 for {name!r} within {self.proxy.poll_timeout}s; "
f"last result: {last}"
)
time.sleep(self.proxy.poll_interval)
def register_mcp_content_filter(self, *, name: str, blocked_keyword: str) -> str:
"""Register a default-on content-filter guardrail that runs on the MCP
tool-call hook (pre_mcp_call) and blocks a single keyword. The keyword is
unique per test, so default_on only ever intercepts this test's own
banned tool call on the shared proxy."""
guardrail_id = unwrap(
self.proxy.transport.post(
"/guardrails",
headers=self.proxy.transport.master,
json=GuardrailCreateBody(
guardrail=GuardrailSpecBody(
guardrail_name=name,
litellm_params=ContentFilterMcpParams(
blocked_words=[BlockedWordSpec(keyword=blocked_keyword)],
),
)
),
response_type=GuardrailCreateResponse,
)
).guardrail_id
settle_propagation(time.monotonic())
return guardrail_id
def delete_guardrail(self, guardrail_id: str) -> None:
_ = self.proxy.transport.delete(
f"/guardrails/{guardrail_id}",
headers=self.proxy.transport.master,
json=NoBody(),
response_type=NoBody,
)
def call_tool(
self,
key: str,
*,
server_id: str,
name: str,
arguments: McpToolArguments,
) -> Result[McpCallToolResponse]:
return self.proxy.transport.post(
"/mcp-rest/tools/call",
headers=ApiKeyHeaders(x_litellm_api_key=key),
json=McpCallToolBody(
name=name, arguments=dict(arguments), server_id=server_id
),
response_type=McpCallToolResponse,
)
def _is_mcp_not_synced(
result: Result[McpCallToolResponse],
*,
tool_name: str | None = None,
) -> bool:
"""True only for gateway multi-worker registry misses, not upstream errors.
Matches the proxy's own shapes:
- ValueError ``Tool <name> not found`` wrapped as HTTP 500 (cold tool map /
unresolved server on this process)
- REST ``server_not_found`` when this worker has not loaded the MCP server row
Does not treat arbitrary 500 bodies that merely mention "tool" and "not found"
(e.g. upstream MCP payload text) as lag, so await_call_tool does not retry
real failures or non-idempotent calls.
"""
if not isinstance(result, UnknownApiError) or result.status_code != 500:
return False
body = result.body
body_l = body.lower()
if "server_not_found" in body_l:
return True
if re.search(r"mcp server ['\"][^'\"]+['\"] was not found", body_l):
return True
# Gateway: "Tool search_datadog_logs not found" (optionally inside a longer message)
if tool_name is not None:
return (
re.search(rf"\btool\s+{re.escape(tool_name)}\s+not found\b", body_l) is not None
)
return re.search(r"\btool\s+\S+\s+not found\b", body_l) is not None
def build_client(proxy: ProxyClient) -> McpClient:
return McpClient(proxy=proxy)