litellm/tests/e2e/test_e2e_http.py
yuneng-jiang e64536c425
test(e2e): retry provider-transient statuses at the transport with bounded backoff (#35824)
* test(e2e): retry provider-transient statuses at the transport with bounded backoff

The Anthropic passthrough cost test failed a full-suite run on a real 529
overloaded_error. Passthrough routes forward provider responses verbatim
and bypass the router's num_retries, so provider blips reach the harness
only on those paths. Following standard practice, the retry is scoped to
the dependency boundary instead of rerunning tests: only the enumerated
transient statuses (500/502/503/504/529, the set production SDKs retry by
default) are retried, with bounded exponential backoff and a printed line
per retry so flakiness stays visible in run logs.

429 is deliberately excluded: the quota suites assert the proxy's own
rate-limit and budget 429s, and a transport that absorbed them would break
those tests. Network errors and timeouts are not retried either, so a hang
surfaces as a hang. request_with_retry takes injected callables, and the
new harness tests pin the contract with protocol fakes, no monkeypatching

* test(e2e): narrow the transport retry to 529, the one status the proxy cannot emit

Greptile's review is right that status-only classification could absorb an
intermittently failing proxy: at the transport a 500/502/503/504 from the
proxy is indistinguishable from one it relayed, and the proxy is the system
under test. 529 is the only status litellm provably never originates
(Anthropic's overload signal, forwarded verbatim on passthrough) and the
only transient observed across the full-suite runs, so the set shrinks to
exactly that. The canary tests now also pin 500/502/503/504 as never
retried
2026-08-04 14:57:42 -07:00

82 lines
3.1 KiB
Python

"""Harness coverage for the transport's transient-retry policy.
No proxy needed and no ``e2e`` marker: this pins the retry CONTRACT, which is
load-bearing for the whole suite. Only statuses the proxy itself cannot emit
may ever be retried (today exactly 529, Anthropic's overload signal): 429 must
stay unretried because the quota suites assert the proxy's own rate-limit and
budget 429s, and proxy-capable 5xx must stay unretried or an intermittently
failing proxy would slip through green. The fakes satisfy the
RetryableResponse protocol directly, so nothing here imports requests or
monkeypatches anything.
"""
from __future__ import annotations
from collections.abc import Callable, Sequence
from dataclasses import dataclass, field
import pytest
from e2e_http import RETRY_ATTEMPTS, TRANSIENT_STATUSES, request_with_retry
@dataclass
class FakeResponse:
status_code: int
close_calls: int = 0
def close(self) -> None:
self.close_calls += 1
@dataclass
class SleepRecorder:
delays: list[float] = field(default_factory=list)
def __call__(self, seconds: float) -> None:
self.delays.append(seconds)
def _issue_from(responses: Sequence[FakeResponse]) -> Callable[[], FakeResponse]:
it = iter(responses)
return lambda: next(it)
class TestTransientRetryPolicy:
def test_transient_set_is_only_statuses_the_proxy_cannot_emit(self) -> None:
assert TRANSIENT_STATUSES == frozenset({529})
assert 429 not in TRANSIENT_STATUSES
@pytest.mark.parametrize("status", [200, 201, 400, 401, 404, 422, 500, 502, 503, 504])
def test_non_transient_status_returns_immediately(self, status: int) -> None:
responses = (FakeResponse(status), FakeResponse(200))
sleep = SleepRecorder()
result = request_with_retry(_issue_from(responses), sleep=sleep)
assert result is responses[0]
assert sleep.delays == []
assert responses[0].close_calls == 0
def test_429_is_never_retried(self) -> None:
responses = (FakeResponse(429), FakeResponse(200))
sleep = SleepRecorder()
result = request_with_retry(_issue_from(responses), sleep=sleep)
assert result is responses[0]
assert sleep.delays == []
assert responses[0].close_calls == 0
def test_overloaded_529_retries_with_backoff_then_returns_the_success(self) -> None:
responses = (FakeResponse(529), FakeResponse(200))
sleep = SleepRecorder()
result = request_with_retry(_issue_from(responses), sleep=sleep)
assert result is responses[1]
assert sleep.delays == [0.5]
assert responses[0].close_calls == 1
assert responses[1].close_calls == 0
def test_persistent_transient_is_bounded_and_returns_the_last_response(self) -> None:
responses = tuple(FakeResponse(529) for _ in range(RETRY_ATTEMPTS + 1))
sleep = SleepRecorder()
result = request_with_retry(_issue_from(responses), sleep=sleep)
assert result is responses[RETRY_ATTEMPTS - 1]
assert sleep.delays == [0.5, 1.0]
assert [r.close_calls for r in responses] == [1, 1, 0, 0]