Set log level based on HTTP status code, create issues for handled exceptions in FastAPI when the status code is 5xx

[alexmojaki]

• Always set the log level to warning on server spans when the HTTP status code is 4xx. Previously this was only done specifically for a starlette/fastapi HTTPException. This affects for example 404 spans where there's no matching route.
• Similarly set the log level to error based on HTTP status code in other cases (see docs diff), but this usually will already be set so known cases aren't affected
• If an exception is handled by FastAPI (particularly by a custom handler), and the handler returns a 5xx status code, a fingerprint will be set on the span, meaning an alert issue will be created. Previously this only happened for HTTPException.

[cloudflare-workers-and-pages]

Deploying logfire-docs with    Cloudflare Pages

Latest commit:	32d5c56
Status:	✅  Deploy successful!
Preview URL:	https://06666e15.logfire-docs.pages.dev
Branch Preview URL:	https://alex-http-status-log-level.logfire-docs.pages.dev

View logs

[Copilot]

Pull request overview

This PR refactors how log levels are set for HTTP spans, moving from Starlette HTTPException-specific handling to a generic approach based on HTTP status codes and span kinds.

Changes:

• Replaced HTTPException-specific log level handling with generic HTTP status code-based logic
• Updated exception fingerprint handling for FastAPI to conditionally place fingerprints in events vs spans
• Reordered span processor operations to ensure log levels are set before FastAPI-specific tweaks

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/test_logfire.py	Added comprehensive test for HTTP status code-based log level setting across different span kinds
tests/otel_integrations/test_fastapi.py	Updated test expectations to include new log level attributes and exception fingerprints
tests/otel_integrations/test_django.py	Updated test expectations to include log level for 404 responses
tests/conftest.py	Added ANTHROPIC_BASE_URL to environment cleanup (minor unrelated cleanup)
logfire/types.py	Simplified create_issue logic by removing FastAPI-specific exception handling
logfire/_internal/tracer.py	Removed HTTPException-specific handling and updated fingerprint logic for FastAPI exceptions
logfire/_internal/exporters/test.py	Added normalization of exception fingerprints in test output for consistent assertions
logfire/_internal/exporters/processor_wrapper.py	Added generic HTTP status code-based log level setting and reordered processor operations
docs/reference/sql.md	Updated documentation to describe the new HTTP status code-based log level behavior

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.