scriptoriumadmin/litellm
1
0
Fork 0
mirror of https://github.com/BerriAI/litellm.git synced 2026-10-12 03:48:56 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 57
litellm/tests/integration/caching/test_response_cache_chaos.py
devin-ai-integration[bot] abd3af422d
fix(caching): never store or serve a chat completion with no choices (#44709) 
* fix(caching): never store or serve a chat completion with no choices

A provider response with empty choices was written to the response cache and served on every identical request until the TTL ended, with no provider call in between. The cache now skips storing such a response and treats an already stored one as a miss, so the next request goes back to the provider and its answer replaces the entry.

* fix(caching): skip responses with no output on the Responses API and Anthropic Messages too

* fix(caching): skip streams and stored entries that carry no output

A chat or text completion stream whose chunks carried no choice is closed
by the stream wrapper with one empty choice of its own, so the assembled
response passed the choices check and was cached. The assembled stream is
now judged on its content: a stream with no text, tool call, or other
output in any choice is never stored, on the async and sync writers alike.
The Responses API stream writer and the Anthropic Messages stream writer
apply the same no-output check before storing.

A stored entry with no output read through the worker memory tier is now
evicted from that tier on the miss, so the next read reaches Redis where
the refill lands; the text completion and messages writers only write to
Redis, and the memory copy otherwise kept missing until its own TTL.

* test(integration): response cache cells for answers without output

Deterministic cells for the response cache on every unified endpoint,
streamed and not, through the OpenAI and Anthropic SDKs and raw httpx,
plus the sync SDK paths, stale entries, malformed answers, per-request
TTLs, cache delete, and chaos (Redis stopped or paused mid burst, a
worker killed, in-memory cache mode). The scripted upstream counts only
POSTs as deployment calls, since the proxy's boot-time GET /v1/models
discovery of a config deployment is not one.

* test(caching): pin the stored entry timestamp in the worker-copy test

* test(integration): drop the restating comments from the chaos cells

* test(integration): close the breaker on the first call after the Redis restart

---------

Co-authored-by: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
2026-10-06 20:07:30 +00:00

503 lines
22 KiB
Python
Raw Blame History

"""Chaos rows for the response cache on an owned two-worker proxy.
Each owned proxy carries its own deployments pointed at scripted upstream scenarios, so both workers know
them from boot. A 24-request burst (chat, text completions, Responses and Anthropic Messages, two of each
streamed at 500 ms per frame so they are still in flight when the outage lands) runs while the cache store
is stopped (C1), paused (C2) or while one worker has just been SIGKILLed (C3): every request answers 200
with content and lands exactly once in the spend log. After recovery an upstream answer with no choices
still reaches the upstream again on the next identical request. C4 runs the in-memory cache mode, where
each worker keeps its own store and the cached object is read back without a JSON round trip.
"""
from __future__ import annotations
import os
import threading
import uuid
from collections.abc import Callable, Iterator, Sequence
from concurrent.futures import Future, ThreadPoolExecutor
from dataclasses import dataclass
from hashlib import sha256
from pathlib import Path
from typing import Final
import httpx
import psutil
import pytest
import yaml
from pydantic import JsonValue
from redis import Redis
from tests.integration._support.client import JSON_OBJECT, Gateway, Scenario, eventually, string_value
from tests.integration._support.database import read_rows
from tests.integration._support.process import owned_proxy_process
from tests.integration._support.redis_process import owned_redis
from tests.integration._support.upstream import ScenarioHandle
from tests.integration.cost_calculation.cost_tracking_case import JsonResponse, SseResponse
from tests.integration.caching.response_cache_case import (
CHAT,
CHAT_MODEL,
CHAT_STREAM,
MESSAGE,
MESSAGE_STREAM,
MESSAGES_MODEL,
PROVIDER_KEY,
RESPONSE,
RESPONSE_STREAM,
TEXT,
TEXT_MODEL,
TEXT_STREAM,
Upstream,
chat_body,
choices,
content_of_first_choice,
emptied,
json_response,
message_body,
prompt,
rescript,
response_id,
scripted,
slowed,
)
RecordProperty = Callable[[str, object], None]
WORKERS: Final = 2
REMOVE_FROM_ENVIRONMENT: Final = ("DATABASE_URL_READ_REPLICA",)
BURST_TIMEOUT_SECONDS: Final = 60
CHAOS_AFTER_ANSWERS: Final = 4
STREAM_FRAME_DELAY_MS: Final = 500
PER_ENDPOINT: Final = 6
STREAMS_PER_ENDPOINT: Final = 2
LOCAL_BATCH: Final = 20
SPEND_SQL: Final = 'SELECT request_id FROM "LiteLLM_SpendLogs" WHERE api_key = %s'
@dataclass(frozen=True, slots=True)
class Deployment:
name: str
litellm_model: str
handle: ScenarioHandle
def entry(self) -> dict[str, JsonValue]:
return {
"model_name": self.name,
"litellm_params": {
"model": self.litellm_model,
"api_base": self.handle.api_base(),
"api_key": PROVIDER_KEY,
},
}
@dataclass(frozen=True, slots=True)
class Fleet:
chat: Deployment
chat_stream: Deployment
text: Deployment
text_stream: Deployment
responses: Deployment
responses_stream: Deployment
messages: Deployment
messages_stream: Deployment
flip: Deployment
def burst_members(self) -> tuple[Deployment, ...]:
return (
self.chat,
self.chat_stream,
self.text,
self.text_stream,
self.responses,
self.responses_stream,
self.messages,
self.messages_stream,
)
def entries(self) -> list[dict[str, JsonValue]]:
return [deployment.entry() for deployment in (*self.burst_members(), self.flip)]
@dataclass(frozen=True, slots=True)
class Call:
label: str
path: str
body: dict[str, JsonValue]
@property
def streamed(self) -> bool:
return self.label.startswith("stream-")
@dataclass(frozen=True, slots=True)
class Answer:
call: Call
status: int | None
text: str
@property
def has_content(self) -> bool:
marker: Final = "streamed" if self.call.streamed else "scripted"
return self.status == 200 and marker in self.text
def describe(self) -> str:
return f"{self.call.label}: {self.status} {self.text[:160]!r}"
def _deployment(scenario: Scenario, kind: str, litellm_model: str, response: JsonResponse | SseResponse) -> Deployment:
return Deployment(f"chaos-{kind}-{uuid.uuid4().hex[:8]}", litellm_model, scripted(scenario, response))
def _fleet(scenario: Scenario) -> Fleet:
return Fleet(
chat=_deployment(scenario, "chat", CHAT_MODEL, json_response(CHAT)),
chat_stream=_deployment(scenario, "chat-stream", CHAT_MODEL, slowed(CHAT_STREAM, STREAM_FRAME_DELAY_MS)),
text=_deployment(scenario, "text", TEXT_MODEL, json_response(TEXT)),
text_stream=_deployment(scenario, "text-stream", TEXT_MODEL, slowed(TEXT_STREAM, STREAM_FRAME_DELAY_MS)),
responses=_deployment(scenario, "responses", CHAT_MODEL, json_response(RESPONSE)),
responses_stream=_deployment(
scenario, "responses-stream", CHAT_MODEL, slowed(RESPONSE_STREAM, STREAM_FRAME_DELAY_MS)
),
messages=_deployment(scenario, "messages", MESSAGES_MODEL, json_response(MESSAGE)),
messages_stream=_deployment(
scenario, "messages-stream", MESSAGES_MODEL, slowed(MESSAGE_STREAM, STREAM_FRAME_DELAY_MS)
),
flip=_deployment(scenario, "flip", CHAT_MODEL, json_response(emptied(CHAT, "choices"))),
)
def _config(directory: Path, fleet: Fleet, cache_params: dict[str, JsonValue] | None = None) -> Path:
"""The rig's proxy config with the fleet as its model list and, when given, another response cache."""
rig: Final = yaml.safe_load((Path(__file__).resolve().parents[1] / "proxy_config.yaml").read_text())
assert isinstance(rig, dict)
litellm_settings: Final = rig["litellm_settings"]
assert isinstance(litellm_settings, dict)
config: Final = {
**rig,
"model_list": fleet.entries(),
"litellm_settings": {**litellm_settings, **({"cache_params": cache_params} if cache_params else {})},
}
path: Final = directory / f"proxy_config-{uuid.uuid4().hex[:8]}.yaml"
path.write_text(yaml.safe_dump(config, sort_keys=False))
return path
def _overrides() -> dict[str, str]:
return {"DATABASE_URL": os.environ["DATABASE_URL"]}
def _burst_calls(fleet: Fleet, per_endpoint: int, streams_per_endpoint: int) -> tuple[Call, ...]:
def calls() -> Iterator[Call]:
for index in range(per_endpoint):
streamed: Final = index < streams_per_endpoint
prefix: Final = "stream" if streamed else "plain"
extra: Final[dict[str, JsonValue]] = {"stream": True} if streamed else {}
chat: Final = fleet.chat_stream if streamed else fleet.chat
text: Final = fleet.text_stream if streamed else fleet.text
responses: Final = fleet.responses_stream if streamed else fleet.responses
messages: Final = fleet.messages_stream if streamed else fleet.messages
yield Call(f"{prefix}-chat-{index}", "/v1/chat/completions", chat_body(chat.name, prompt(), **extra))
yield Call(f"{prefix}-text-{index}", "/v1/completions", {"model": text.name, "prompt": prompt(), **extra})
yield Call(
f"{prefix}-responses-{index}", "/v1/responses", {"model": responses.name, "input": prompt(), **extra}
)
yield Call(f"{prefix}-messages-{index}", "/v1/messages", message_body(messages.name, prompt(), **extra))
return tuple(calls())
class Burst:
"""Every call submitted at once against ``target``; ``chaos_point`` is set once ``CHAOS_AFTER_ANSWERS``
have answered (or failed), while the slowed streams are still in flight."""
def __init__(self, target: str, key: str) -> None:
self._target: Final = target
self._key: Final = key
self._lock: Final = threading.Lock()
self._answers = 0 # rebind-ok: counter behind _lock
self._futures: dict[str, Future[Answer]] = {}
self.chaos_point: Final = threading.Event()
def start(self, pool: ThreadPoolExecutor, calls: Sequence[Call]) -> None:
assert not self._futures, "burst already started"
self._futures.update((call.label, pool.submit(self._send, call)) for call in calls)
assert self.chaos_point.wait(BURST_TIMEOUT_SECONDS), (
f"fewer than {CHAOS_AFTER_ANSWERS} requests answered within {BURST_TIMEOUT_SECONDS}s"
)
def _send(self, call: Call) -> Answer:
try:
with httpx.Client(base_url=self._target, timeout=BURST_TIMEOUT_SECONDS, trust_env=False) as client:
response: Final = client.post(
call.path, json=call.body, headers={"Authorization": f"Bearer {self._key}"}
)
answer = Answer(call, response.status_code, response.text)
except httpx.HTTPError as error:
answer = Answer(call, None, f"{type(error).__name__}: {error}"[:200])
with self._lock:
self._answers += 1
if self._answers >= CHAOS_AFTER_ANSWERS:
self.chaos_point.set()
return answer
def answered(self) -> int:
with self._lock:
return self._answers
def pending_streams(self) -> tuple[str, ...]:
return tuple(
label for label, future in self._futures.items() if label.startswith("stream-") and not future.done()
)
def outcomes(self) -> tuple[Answer, ...]:
return tuple(future.result(timeout=BURST_TIMEOUT_SECONDS + 30) for future in self._futures.values())
def _assert_all_answered_with_content(outcomes: Sequence[Answer]) -> None:
failures: Final = tuple(answer.describe() for answer in outcomes if not answer.has_content)
assert not failures, (
f"{len(failures)} of {len(outcomes)} burst requests lack a 200 with content:\n " + "\n ".join(failures)
)
def _plain_ids(outcomes: Sequence[Answer]) -> frozenset[str]:
"""The ids of the non-streamed chat, text and Messages answers, which the spend log records verbatim."""
return frozenset(
string_value(JSON_OBJECT.validate_json(answer.text)["id"])
for answer in outcomes
if not answer.call.streamed and answer.call.path != "/v1/responses"
) # comprehension-ok: one filter over the burst
def _spend_request_ids(key: str) -> frozenset[str]:
return frozenset(
string_value(row["request_id"]) for row in read_rows(SPEND_SQL, (sha256(key.encode()).hexdigest(),))
)
def _assert_every_burst_request_landed_once(key: str, outcomes: Sequence[Answer]) -> None:
rows: Final = eventually(lambda: _spend_request_ids(key), lambda ids: len(ids) >= len(outcomes), seconds=70)
assert len(rows) == len(outcomes), f"{len(rows)} spend rows for {len(outcomes)} burst requests: {sorted(rows)}"
missing: Final = _plain_ids(outcomes) - rows
assert not missing, f"burst answers without a spend row: {sorted(missing)}"
def _chat(target: str, key: str, body: dict[str, JsonValue]) -> httpx.Response:
with httpx.Client(base_url=target, timeout=30, trust_env=False) as client:
return client.post("/v1/chat/completions", json=body, headers={"Authorization": f"Bearer {key}"})
def _assert_empty_answer_reaches_upstream_again(target: str, key: str, upstream: Upstream, flip: Deployment) -> None:
"""Through ``target`` after the outage: the scripted empty answer is never served again once the
upstream answers for real, and the real answer is the one served from the cache afterwards."""
request: Final = chat_body(flip.name, prompt())
empty: Final = _chat(target, key, request)
assert choices(empty) == [], empty.text
assert upstream.calls(flip.handle.scenario_id) == 1
rescript(flip.handle, json_response(CHAT))
refilled: Final = _chat(target, key, request)
assert content_of_first_choice(refilled) == "scripted", f"the empty answer was served: {refilled.text}"
assert upstream.calls(flip.handle.scenario_id) == 2
hit: Final = eventually(lambda: _chat(target, key, request), lambda r: response_id(r) == response_id(refilled))
assert content_of_first_choice(hit) == "scripted", hit.text
assert upstream.calls(flip.handle.scenario_id) >= 2
def _workers(root: psutil.Process) -> tuple[psutil.Process, ...]:
"""uvicorn's worker children of the owned proxy root, spawned through ``multiprocessing.spawn``."""
def spawned() -> Iterator[psutil.Process]:
for child in root.children():
try:
cmdline = child.cmdline()
except (psutil.NoSuchProcess, psutil.AccessDenied):
continue
if any("multiprocessing.spawn" in part for part in cmdline):
yield child
return tuple(sorted(spawned(), key=lambda process: process.pid))
def _cache_ping(target: str, key: str) -> httpx.Response:
with httpx.Client(base_url=target, timeout=30, trust_env=False) as client:
return client.get("/cache/ping", headers={"Authorization": f"Bearer {key}"})
def _cache_status(response: httpx.Response) -> str:
assert response.status_code == 200, f"/cache/ping: {response.status_code} {response.text}"
return string_value(JSON_OBJECT.validate_json(response.content)["status"])
def _proxy_url(gateway: Gateway) -> str:
return str(gateway.client.base_url).rstrip("/")
@pytest.mark.timeout(300)
def test_redis_stopped_mid_burst_answers_every_request_and_never_pins_an_empty_answer_after(
gateway: Gateway, tmp_path: Path, record_property: RecordProperty
) -> None:
upstream: Final = Upstream(gateway.upstream_url)
with gateway.scenario() as scenario, owned_redis(tmp_path) as store:
fleet: Final = _fleet(scenario)
key: Final = scenario.key(models=[deployment.name for deployment in (*fleet.burst_members(), fleet.flip)])
with (
owned_proxy_process(
gateway,
tmp_path,
{
**_overrides(),
"REDIS_HOST": store.host,
"REDIS_PORT": str(store.port),
"REDIS_CIRCUIT_BREAKER_RECOVERY_TIMEOUT": "0",
},
config=_config(tmp_path, fleet),
remove_environment=REMOVE_FROM_ENVIRONMENT,
workers=WORKERS,
) as owned,
ThreadPoolExecutor(PER_ENDPOINT * 4) as pool,
):
target: Final = _proxy_url(owned.gateway)
assert _cache_status(_cache_ping(target, gateway.key)) == "healthy"
burst: Final = Burst(target, key)
burst.start(pool, _burst_calls(fleet, PER_ENDPOINT, STREAMS_PER_ENDPOINT))
pending: Final = burst.pending_streams()
record_property("answered_before_outage", burst.answered())
assert pending, "no stream was in flight when Redis stopped"
store.stop()
down: Final = _cache_ping(target, gateway.key)
assert down.status_code == 503, f"/cache/ping with Redis stopped: {down.status_code} {down.text}"
assert "Service Unhealthy" in down.text, down.text
outcomes: Final = burst.outcomes()
store.start()
recovered: Final = eventually(
lambda: _cache_ping(target, gateway.key), lambda r: r.status_code == 200, seconds=60
)
assert _cache_status(recovered) == "healthy"
_assert_all_answered_with_content(outcomes)
_assert_every_burst_request_landed_once(key, outcomes)
_assert_empty_answer_reaches_upstream_again(target, key, upstream, fleet.flip)
@pytest.mark.timeout(300)
def test_redis_paused_mid_burst_answers_every_request_and_never_pins_an_empty_answer_after(
gateway: Gateway, tmp_path: Path, record_property: RecordProperty
) -> None:
upstream: Final = Upstream(gateway.upstream_url)
with gateway.scenario() as scenario, owned_redis(tmp_path) as store:
fleet: Final = _fleet(scenario)
key: Final = scenario.key(models=[deployment.name for deployment in (*fleet.burst_members(), fleet.flip)])
with (
owned_proxy_process(
gateway,
tmp_path,
{**_overrides(), "REDIS_HOST": store.host, "REDIS_PORT": str(store.port)},
config=_config(tmp_path, fleet),
remove_environment=REMOVE_FROM_ENVIRONMENT,
workers=WORKERS,
) as owned,
ThreadPoolExecutor(PER_ENDPOINT * 4) as pool,
Redis(host=store.host, port=store.port) as control,
):
target: Final = _proxy_url(owned.gateway)
assert _cache_status(_cache_ping(target, gateway.key)) == "healthy"
burst: Final = Burst(target, key)
burst.start(pool, _burst_calls(fleet, PER_ENDPOINT, STREAMS_PER_ENDPOINT))
pending: Final = burst.pending_streams()
record_property("answered_before_pause", burst.answered())
assert pending, "no stream was in flight when Redis was paused"
assert control.client_pause(2000) is True
outcomes: Final = burst.outcomes()
assert _cache_status(_cache_ping(target, gateway.key)) == "healthy"
_assert_all_answered_with_content(outcomes)
_assert_every_burst_request_landed_once(key, outcomes)
_assert_empty_answer_reaches_upstream_again(target, key, upstream, fleet.flip)
@pytest.mark.timeout(300)
def test_worker_killed_before_burst_leaves_the_survivor_serving_and_never_pins_an_empty_answer(
gateway: Gateway, tmp_path: Path, record_property: RecordProperty
) -> None:
upstream: Final = Upstream(gateway.upstream_url)
with gateway.scenario() as scenario:
fleet: Final = _fleet(scenario)
key: Final = scenario.key(models=[deployment.name for deployment in (*fleet.burst_members(), fleet.flip)])
with (
owned_proxy_process(
gateway,
tmp_path,
_overrides(),
config=_config(tmp_path, fleet),
remove_environment=REMOVE_FROM_ENVIRONMENT,
workers=WORKERS,
) as owned,
ThreadPoolExecutor(PER_ENDPOINT * 4) as pool,
):
target: Final = _proxy_url(owned.gateway)
root: Final = psutil.Process(owned.process.pid)
before: Final = _workers(root)
assert len(before) == WORKERS, [process.pid for process in before]
victim: Final = before[0]
victim.kill()
victim.wait(timeout=10)
with httpx.Client(base_url=target, timeout=15, trust_env=False) as fresh:
readiness: Final = fresh.get("/health/readiness")
assert readiness.status_code == 200, f"/health/readiness with worker {victim.pid} dead: {readiness.text}"
burst: Final = Burst(target, key)
burst.start(pool, _burst_calls(fleet, PER_ENDPOINT // 2, STREAMS_PER_ENDPOINT // 2))
outcomes: Final = burst.outcomes()
respawned: Final = eventually(
lambda: tuple(process.pid for process in _workers(root)),
lambda pids: len(pids) == WORKERS and victim.pid not in pids,
seconds=60,
)
record_property(
"worker_pids", {"before": [process.pid for process in before], "killed": victim.pid, "after": respawned}
)
_assert_all_answered_with_content(outcomes)
_assert_every_burst_request_landed_once(key, outcomes)
_assert_empty_answer_reaches_upstream_again(target, key, upstream, fleet.flip)
def _batch(target: str, key: str, body: dict[str, JsonValue], size: int) -> tuple[httpx.Response, ...]:
"""``size`` identical requests, each on a fresh connection so both workers take traffic."""
return tuple(_chat(target, key, body) for _ in range(size))
@pytest.mark.timeout(300)
def test_in_memory_cache_mode_never_serves_an_empty_answer_from_a_worker_store(
gateway: Gateway, tmp_path: Path
) -> None:
upstream: Final = Upstream(gateway.upstream_url)
with gateway.scenario() as scenario:
fleet: Final = _fleet(scenario)
key: Final = scenario.key(models=[fleet.flip.name])
with owned_proxy_process(
gateway,
tmp_path,
_overrides(),
config=_config(tmp_path, fleet, cache_params={"type": "local"}),
remove_environment=REMOVE_FROM_ENVIRONMENT,
workers=WORKERS,
) as owned:
target: Final = _proxy_url(owned.gateway)
request: Final = chat_body(fleet.flip.name, prompt())
first_batch: Final = _batch(target, key, request, LOCAL_BATCH)
assert all(choices(response) == [] for response in first_batch), [r.text for r in first_batch]
assert upstream.calls(fleet.flip.handle.scenario_id) == LOCAL_BATCH, (
"an empty answer was served from a worker store"
)
rescript(fleet.flip.handle, json_response(CHAT))
second_batch: Final = _batch(target, key, request, LOCAL_BATCH)
served_empty: Final = tuple(response.text for response in second_batch if choices(response) == [])
assert not served_empty, (
f"{len(served_empty)} of {LOCAL_BATCH} answers still empty after the upstream recovered"
)
assert all(content_of_first_choice(response) == "scripted" for response in second_batch)
after_second: Final = upstream.calls(fleet.flip.handle.scenario_id)
assert LOCAL_BATCH < after_second <= 2 * LOCAL_BATCH, after_second
third_batch: Final = _batch(target, key, request, LOCAL_BATCH)
assert all(content_of_first_choice(response) == "scripted" for response in third_batch)
assert upstream.calls(fleet.flip.handle.scenario_id) - after_second <= WORKERS, (
"the real answer is not cached"
)
Reference in a new issue View git blame Copy permalink