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test(e2e): bound chaos latency and log volume with flat ceilings
A ratio against the healthy phase cannot bound either metric. Once the Redis circuit breaker opens, a request skips Redis instead of waiting on its socket timeout, so the chaos phase can measure cheaper than the baseline it is compared against: local runs came in at 0.61x baseline p90 while a log-bytes ratio read 724x. Splitting Budget into RatioBudget and AbsoluteBudget lets RSS and CPU keep the ratio they need, since both are machine-shaped, while latency and log volume get the wall-clock ceiling a user actually cares about. Co-Authored-By: Claude Code <noreply@anthropic.com>
This commit is contained in:
Kerry Lu
parent
66980bbb87
commit
cc1d2c66c8
4 changed files with 126 additions and 63 deletions
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@ -18,7 +18,7 @@ Each subdirectory under `tests/e2e/` is one suite, scoped to an endpoint family
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- `logging/` - logging-integration delivery (datadog and friends)
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- `security/` - secret handling and log-leak protection
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- `router/` - routing and reliability behavior (fallbacks, cooldowns)
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- `load/` - performance-category tests, kept OUT of the main suite: throughput/load SLO tests are a different testing category from functional e2e (variance-driven, historically flaky) and live outside this suite until re-implemented as their own pipeline (LIT-5163); do not add a live load test that runs in the default collection. What lives here: the weekly session-anomaly test (`test_weekly_session_anomaly_e2e.py`, Claude Code-shaped multi-turn sessions against real providers with ceilings on error rate, cache read/write, turn time, and spend; marked `weekly` and deselected unless `E2E_WEEKLY_ANOMALY` is set, driven by `.github/workflows/weekly_load_anomaly.yml`), the Redis chaos test (`test_redis_chaos_e2e.py`, locust load against mock deployments split round robin over `/chat/completions` and `/v1/messages`, one endpoint per simulated user, with `CLIENT PAUSE ALL` on the proxy's Redis mid-run to simulate it being down outright, asserting zero failed requests on every endpoint and budgeting p50/p90/p99 latency, RSS, CPU-per-request, and log-bytes-per-request as ratios against the same run's healthy phase; needs a proxy booted from `gateway/redis_chaos_ci_config.yml` on the same host with `E2E_PROXY_PID` and `E2E_PROXY_LOG` set, marked `redis_chaos`, deselected unless `E2E_REDIS_CHAOS` is set, driven weekly by `.github/workflows/test-e2e-redis-chaos.yml`), and markerless harness unit tests for the locust, process-usage, and session-anomaly aggregation logic
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- `load/` - performance-category tests, kept OUT of the main suite: throughput/load SLO tests are a different testing category from functional e2e (variance-driven, historically flaky) and live outside this suite until re-implemented as their own pipeline (LIT-5163); do not add a live load test that runs in the default collection. What lives here: the weekly session-anomaly test (`test_weekly_session_anomaly_e2e.py`, Claude Code-shaped multi-turn sessions against real providers with ceilings on error rate, cache read/write, turn time, and spend; marked `weekly` and deselected unless `E2E_WEEKLY_ANOMALY` is set, driven by `.github/workflows/weekly_load_anomaly.yml`), the Redis chaos test (`test_redis_chaos_e2e.py`, locust load against mock deployments split round robin over `/chat/completions` and `/v1/messages`, one endpoint per simulated user, with `CLIENT PAUSE ALL` on the proxy's Redis mid-run to simulate it being down outright, asserting zero failed requests on every endpoint, budgeting RSS and CPU-per-request as ratios against the same run's healthy phase, and holding p50/p90/p99 latency and log-bytes-per-request to flat ceilings (a ratio cannot bound those two: an open breaker skips Redis instead of waiting on it, so the chaos phase can measure cheaper than baseline while still being far slower than a user should see); needs a proxy booted from `gateway/redis_chaos_ci_config.yml` on the same host with `E2E_PROXY_PID` and `E2E_PROXY_LOG` set, marked `redis_chaos`, deselected unless `E2E_REDIS_CHAOS` is set, driven weekly by `.github/workflows/test-e2e-redis-chaos.yml`), and markerless harness unit tests for the locust, process-usage, and session-anomaly aggregation logic
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- `other/` - the holding-pen suite for the `other.*` registry cluster with no home of its own yet: the master-key auth gate and the process-lifecycle health probes (liveness, public readiness, authenticated readiness diagnostics). Promote a cluster out once it is large/stable enough for its own suite
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- `gateway/` - proxy configuration only (`litellm-config.yml`); no tests
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- `claude_code/` - the Claude Code compatibility matrix: drives the real `claude` CLI (and HTTP probes) against a proxy for each feature x provider cell, reporting tagged-union outcomes via the `compat_result` fixture; ships its own driver/builder/publisher plus `_*_unit_tests/` trees. The HTTP probes ride the shared transport (`ProxyClient.count_tokens` / `ProxyClient.messages`); the CLI-driving path stays bespoke
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@ -1,18 +1,27 @@
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"""Comparing one load phase against another, for tests that degrade a dependency mid-run.
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A chaos phase's absolute numbers say very little on their own: RSS scales with worker count,
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latency with core count, so a ceiling calibrated on one machine is meaningless on the next.
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What travels is the ratio against a healthy phase measured on the same machine in the same run.
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Two shapes of ceiling, because the metrics divide into two kinds. RSS and CPU are
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machine-shaped: RSS scales with worker count and CPU with core count, so an absolute number
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calibrated on one runner means nothing on the next, and what travels is the ratio against a
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healthy phase measured on the same machine in the same run. Latency and log volume are not:
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a ratio there is actively misleading, because a dependency that fails fast once its breaker
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opens can make the degraded phase look cheaper than the healthy one while still being far
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slower or noisier than a user should ever see. Those get a flat ceiling, which is the promise
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the test is actually making.
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"""
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from __future__ import annotations
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from dataclasses import dataclass
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from typing import Final
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from typing import Final, TypeAlias
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def _rendered(value: float, unit: str, decimals: int) -> str:
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return f"{value:.{decimals}f}{unit}"
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@dataclass(frozen=True, slots=True)
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class Budget:
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class RatioBudget:
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"""One metric's healthy value, its degraded value, and how much growth is allowed."""
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name: str
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@ -27,26 +36,46 @@ class Budget:
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"""How many times the baseline the degraded value is, or None if there is no baseline."""
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return self.degraded / self.baseline if self.baseline > 0 else None
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def _rendered(self, value: float) -> str:
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return f"{value:.{self.decimals}f}{self.unit}"
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def violation(self) -> str | None:
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"""Why this metric fails its budget, or None if it passes."""
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ratio: Final = self.ratio
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if ratio is None:
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return (
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f"{self.name} measured {self._rendered(self.baseline)} in the healthy phase, so there is nothing "
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f"to compare the degraded phase against; the measurement did not happen"
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f"{self.name} measured {_rendered(self.baseline, self.unit, self.decimals)} in the healthy phase, "
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f"so there is nothing to compare the degraded phase against; the measurement did not happen"
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)
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if ratio > self.ratio_ceiling:
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return (
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f"{self.name} went from {self._rendered(self.baseline)} healthy to "
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f"{self._rendered(self.degraded)} degraded, {ratio:.1f}x the baseline and past the "
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f"{self.ratio_ceiling:.1f}x allowed"
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f"{self.name} went from {_rendered(self.baseline, self.unit, self.decimals)} healthy to "
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f"{_rendered(self.degraded, self.unit, self.decimals)} degraded, {ratio:.1f}x the baseline and past "
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f"the {self.ratio_ceiling:.1f}x allowed"
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)
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return None
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@dataclass(frozen=True, slots=True)
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class AbsoluteBudget:
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"""One metric's degraded value against a flat ceiling, for metrics a ratio cannot bound."""
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name: str
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measured: float
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ceiling: float
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unit: str
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decimals: int = 1
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def violation(self) -> str | None:
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"""Why this metric fails its budget, or None if it passes."""
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if self.measured > self.ceiling:
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return (
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f"{self.name} measured {_rendered(self.measured, self.unit, self.decimals)} in the degraded phase, "
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f"past the {_rendered(self.ceiling, self.unit, self.decimals)} allowed"
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)
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return None
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Budget: TypeAlias = RatioBudget | AbsoluteBudget
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def violations(budgets: tuple[Budget, ...]) -> tuple[str, ...]:
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"""Every budget the run blew, so one failure reports all of them instead of the first."""
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return tuple(violation for budget in budgets if (violation := budget.violation()) is not None)
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@ -2,14 +2,16 @@ from __future__ import annotations
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from typing import Final
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from phase_budget import Budget, violations
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from phase_budget import AbsoluteBudget, RatioBudget, violations
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def _budget(*, baseline: float, degraded: float, ceiling: float = 2.0) -> Budget:
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return Budget(name="p99 RSS", baseline=baseline, degraded=degraded, ratio_ceiling=ceiling, unit=" MB", decimals=0)
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def _budget(*, baseline: float, degraded: float, ceiling: float = 2.0) -> RatioBudget:
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return RatioBudget(
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name="p99 RSS", baseline=baseline, degraded=degraded, ratio_ceiling=ceiling, unit=" MB", decimals=0
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)
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class TestBudget:
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class TestRatioBudget:
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def test_growth_within_the_ceiling_is_not_a_violation(self) -> None:
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assert _budget(baseline=100, degraded=199).violation() is None
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@ -37,7 +39,7 @@ class TestBudget:
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assert "nothing to compare" in violation
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def test_the_unit_and_decimals_carry_into_the_message(self) -> None:
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violation: Final = Budget(
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violation: Final = RatioBudget(
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name="p99 latency", baseline=0.16, degraded=9.5, ratio_ceiling=8.0, unit="s", decimals=3
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).violation()
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@ -46,13 +48,40 @@ class TestBudget:
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assert "9.500s" in violation
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class TestAbsoluteBudget:
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def test_a_value_under_the_ceiling_is_not_a_violation(self) -> None:
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assert AbsoluteBudget(name="p99 latency", measured=1.2, ceiling=5.0, unit="s", decimals=3).violation() is None
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def test_a_value_exactly_at_the_ceiling_is_allowed(self) -> None:
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assert AbsoluteBudget(name="p99 latency", measured=5.0, ceiling=5.0, unit="s", decimals=3).violation() is None
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def test_a_value_past_the_ceiling_reports_the_measurement_and_the_ceiling(self) -> None:
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violation: Final = AbsoluteBudget(
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name="p99 latency", measured=9.5, ceiling=5.0, unit="s", decimals=3
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).violation()
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assert violation is not None
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assert "9.500s" in violation
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assert "5.000s allowed" in violation
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def test_a_flat_ceiling_fails_a_degraded_phase_that_is_cheaper_than_its_baseline(self) -> None:
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# The whole reason this shape exists: once the breaker opens, requests skip Redis instead
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# of waiting on its socket timeout, so the chaos phase can measure faster than the healthy
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# one. A ratio against that baseline passes; the user still waited 9.5s.
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assert _budget(baseline=20.0, degraded=9.5, ceiling=2.0).violation() is None
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assert AbsoluteBudget(name="p99 latency", measured=9.5, ceiling=5.0, unit="s").violation() is not None
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def test_a_zero_measurement_is_not_a_violation(self) -> None:
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assert AbsoluteBudget(name="log bytes per request", measured=0, ceiling=12_000, unit=" B").violation() is None
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class TestViolations:
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def test_every_blown_budget_is_reported_not_just_the_first(self) -> None:
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blown: Final = violations(
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(
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_budget(baseline=100, degraded=500),
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_budget(baseline=100, degraded=120),
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Budget(name="CPU per request", baseline=10, degraded=90, ratio_ceiling=6.0, unit=" ms"),
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RatioBudget(name="CPU per request", baseline=10, degraded=90, ratio_ceiling=6.0, unit=" ms"),
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)
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)
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@ -60,5 +89,17 @@ class TestViolations:
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assert blown[0].startswith("p99 RSS")
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assert blown[1].startswith("CPU per request")
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def test_both_budget_shapes_report_together(self) -> None:
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blown: Final = violations(
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(
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_budget(baseline=100, degraded=500),
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AbsoluteBudget(name="p99 latency", measured=9.5, ceiling=5.0, unit="s", decimals=3),
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)
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)
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assert len(blown) == 2
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assert blown[0].startswith("p99 RSS")
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assert blown[1].startswith("p99 latency")
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def test_a_run_inside_every_budget_reports_nothing(self) -> None:
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assert violations((_budget(baseline=100, degraded=150),)) == ()
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@ -50,7 +50,7 @@ from lifecycle import ResourceManager
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from load_client import LoadClient
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from locust_load import LoadResult, run_gateway_load
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from models import KeyGenerateBody, LiteLLMParamsBody
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from phase_budget import Budget, violations
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from phase_budget import AbsoluteBudget, Budget, RatioBudget, violations
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from proxy_client import ProxyClient
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from proxy_usage import ProxyUsageSampler, UsageWindow
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@ -70,23 +70,25 @@ BASELINE_SECONDS: Final = 60.0
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CHAOS_SECONDS: Final = 90.0
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REDIS_PAUSE_MS: Final = int(CHAOS_SECONDS * 1000)
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# Chaos-phase ceilings, as a multiple of the same metric in the baseline phase. Ratios rather
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# than absolutes because every absolute here is machine-shaped: RSS scales with worker count
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# and latency with core count, so a number calibrated on one runner means nothing on another.
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# Calibrated from local runs under CLIENT PAUSE ALL that came in around 4x latency at every
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# percentile, 1.03x RSS and 4.4x CPU per request, and deliberately loose: the regression these
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# guard against grew memory by an order of magnitude, so catching it does not need a tight
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# bound, and a tight one would flake on a shared CI runner. Latency gets the most slack because
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# it is the metric a Redis outage is legitimately allowed to move, by its socket timeout on
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# every call a request attempts.
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CHAOS_LATENCY_RATIO_CEILING: Final = 12.0
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# RSS and CPU are budgeted as a multiple of the same metric in the baseline phase, because both
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# are machine-shaped: RSS scales with worker count and CPU with core count, so a number
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# calibrated on one runner means nothing on another. Calibrated from local runs under CLIENT
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# PAUSE ALL that came in around 1.03x RSS and 4.4x CPU per request, and deliberately loose: the
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# regression these guard against grew memory by an order of magnitude, so catching it does not
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# need a tight bound, and a tight one would flake on a shared CI runner.
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CHAOS_RSS_RATIO_CEILING: Final = 1.5
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CHAOS_CPU_PER_REQUEST_RATIO_CEILING: Final = 6.0
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# Uncalibrated: no chaos run has measured this yet, since JSON_LOGS and the padded payload
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# landed after the last run this file's other ceilings were calibrated from. Deliberately loose
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# until a real run tightens it; the failed-tracking alert body that motivates this test already
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# logs the full request metadata per timeout, so a JSON-encoded traceback storm should dwarf this.
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CHAOS_LOG_BYTES_PER_REQUEST_RATIO_CEILING: Final = 20.0
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# Latency and log volume get flat ceilings instead, because a ratio cannot bound either one. Once
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# the breaker opens, a request skips Redis rather than waiting on its socket timeout, so the chaos
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# phase can come in faster than baseline (local runs measured p90 at 0.61x) and a ratio passes on a
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# phase that was never slow. What a user actually cares about is the wall-clock number, which these
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# hold directly. Calibrated from local runs whose worst chaos phase was p50 0.66s, p90 0.74s, p99
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# 1.20s and 3.4 KB of log per request, then left roughly 3x loose for a shared CI runner.
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CHAOS_P50_LATENCY_CEILING_SECONDS: Final = 2.0
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CHAOS_P90_LATENCY_CEILING_SECONDS: Final = 3.0
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CHAOS_P99_LATENCY_CEILING_SECONDS: Final = 5.0
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CHAOS_LOG_BYTES_PER_REQUEST_CEILING: Final = 12_000.0
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DRAIN_TIMEOUT_SECONDS: Final = 30.0
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DRAIN_POLL_SECONDS: Final = 1.0
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@ -289,19 +291,12 @@ def _drive(keys: tuple[str, ...], seconds: float) -> LoadResult:
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)
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def _latency_budget(percentile: str, baseline: float, degraded: float) -> Budget:
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return Budget(
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name=f"{percentile} latency",
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baseline=baseline,
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degraded=degraded,
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ratio_ceiling=CHAOS_LATENCY_RATIO_CEILING,
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unit="s",
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decimals=3,
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)
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def _latency_budget(percentile: str, measured: float, ceiling: float) -> Budget:
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return AbsoluteBudget(name=f"{percentile} latency", measured=measured, ceiling=ceiling, unit="s", decimals=3)
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def _rss_budget(percentile: str, baseline: UsageWindow, degraded: UsageWindow, fraction: float) -> Budget:
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return Budget(
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return RatioBudget(
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name=f"{percentile} RSS",
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baseline=baseline.rss_percentile(fraction) / 2**20,
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degraded=degraded.rss_percentile(fraction) / 2**20,
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@ -312,18 +307,18 @@ def _rss_budget(percentile: str, baseline: UsageWindow, degraded: UsageWindow, f
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def _chaos_budgets(baseline: Phase, chaos: Phase) -> tuple[Budget, ...]:
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"""What a Redis outage is allowed to cost, measured against the same run's healthy phase.
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"""What a Redis outage is allowed to cost.
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Every request still succeeding is the headline assertion, but a proxy can answer every
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request while leaking: the v1.100.0 regression (LIT-6780) served traffic the whole way up
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to a 61 GB worker. These bound the cost of serving it.
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to a 61 GB worker. These bound the cost of serving it. RSS and CPU are bounded against the
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same run's healthy phase, latency and log bytes against a flat ceiling; see phase_budget
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for why the two kinds of metric cannot share one shape.
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Latency and RSS are budgeted at p50, p90 and p99 so a regression that only shows up in the
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tail (or only in the median) cannot hide behind the other. Latency gets the loosest bound
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because a timing-out Redis legitimately adds its socket_timeout to every request that
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touches it, several times over on a retried request. RSS gets the tightest: the failure
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path has no business allocating more per request. CPU and log bytes are each budgeted once,
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as an amount per request rather than per percentile: cores-busy saturates at the worker
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tail (or only in the median) cannot hide behind the other. RSS gets the tightest bound: the
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failure path has no business allocating more per request. CPU and log bytes are each budgeted
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once, as an amount per request rather than per percentile: cores-busy saturates at the worker
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count under load, so its percentiles read the same whether a request costs 10 ms of CPU or
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40, and cannot budget anything; per-request is the figure that actually moves. Log bytes
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isolates the cost of the failed-tracking alert's own noisy error handling from the CPU it
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@ -331,24 +326,23 @@ def _chaos_budgets(baseline: Phase, chaos: Phase) -> tuple[Budget, ...]:
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CPU number.
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"""
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return (
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_latency_budget("p50", baseline.load.p50_seconds, chaos.load.p50_seconds),
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_latency_budget("p90", baseline.load.p90_seconds, chaos.load.p90_seconds),
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_latency_budget("p99", baseline.load.p99_seconds, chaos.load.p99_seconds),
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_latency_budget("p50", chaos.load.p50_seconds, CHAOS_P50_LATENCY_CEILING_SECONDS),
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_latency_budget("p90", chaos.load.p90_seconds, CHAOS_P90_LATENCY_CEILING_SECONDS),
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_latency_budget("p99", chaos.load.p99_seconds, CHAOS_P99_LATENCY_CEILING_SECONDS),
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_rss_budget("p50", baseline.usage, chaos.usage, 0.5),
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_rss_budget("p90", baseline.usage, chaos.usage, 0.9),
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_rss_budget("p99", baseline.usage, chaos.usage, 0.99),
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Budget(
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RatioBudget(
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name="CPU per request",
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baseline=baseline.cpu_seconds_per_request * 1000,
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degraded=chaos.cpu_seconds_per_request * 1000,
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ratio_ceiling=CHAOS_CPU_PER_REQUEST_RATIO_CEILING,
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unit=" ms",
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),
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Budget(
|
||||
AbsoluteBudget(
|
||||
name="log bytes per request",
|
||||
baseline=baseline.log_bytes_per_request,
|
||||
degraded=chaos.log_bytes_per_request,
|
||||
ratio_ceiling=CHAOS_LOG_BYTES_PER_REQUEST_RATIO_CEILING,
|
||||
measured=chaos.log_bytes_per_request,
|
||||
ceiling=CHAOS_LOG_BYTES_PER_REQUEST_CEILING,
|
||||
unit=" B",
|
||||
decimals=0,
|
||||
),
|
||||
|
|
@ -447,8 +441,7 @@ class TestRedisChaos:
|
|||
|
||||
blown: Final = violations(_chaos_budgets(baseline, chaos))
|
||||
assert not blown, (
|
||||
f"pausing Redis cost the proxy more than the socket timeout on the calls it attempts: "
|
||||
f"{'; '.join(blown)}. {report}"
|
||||
f"pausing Redis cost the proxy more than a Redis outage is allowed to: {'; '.join(blown)}. {report}"
|
||||
)
|
||||
|
||||
rows: Final = proxy.poll_logs_for_key(keys[0], min_rows=1)
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue