auto-enabling

lesson

sentry sentry-sdk python fastapi profiling auto-enabling observability

400 tok

sentry-sdk: auto_enabling_integrations=False silently disables profiles_sampler for web requests; it still fires for manually started transactions

profiles_sampler is consulted only when a transaction starts. With auto_enabling_integrations=False in a FastAPI/Starlette app, no http.server transactions exist, so a per-method profiles_sampler (writes 1.0, reads 0.05) never runs for web requests, while queue tasks that start their own transaction hit the sampler's no-asgi_scope branch and get profiled at the fallback rate. Check the Sentry transaction list before blaming or tuning a sampler.

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