Locust spawns N virtual users (default 1000), all from 127.0.0.1 as
admin. /auth/login is rate-limited 10/5min per-IP AND per-username, so
the 11th on_start() got 429 and a RuntimeError. A @task(2) login in
the task weights turned the whole run into a 429 factory even after
ramp-up. And _login_with_retry treated 429 as non-retryable, so there
was no graceful degradation path.
Three changes, one root cause:
- decnet/web/limiter.py: read DECNET_LIMITER_ENABLED (default true).
When false, slowapi's Limiter(enabled=False) makes @limiter.limit a
no-op. Default ships unchanged; nobody should ever release with this
off.
- tests/stress/conftest.py: set DECNET_LIMITER_ENABLED=false in the
uvicorn subprocess env. Stress tests measure throughput, not rate
limiting.
- tests/stress/locustfile.py: drop the @task(2) login — it added zero
coverage (every user already logs in at on_start) and only generated
contention. Teach _login_with_retry to honour 429 + Retry-After so a
Locust pointed at a limiter-enabled server degrades gracefully
instead of crashing on_start.