Codestin Search App

ibbybuilds · 2026-06-28T16:54:52Z

Problem

With ENABLE_PROMETHEUS_METRICS=true and FastAPI >=0.137, every request returns HTTP 500.

FastAPI 0.137 (fastapi/fastapi#15745) changed app.routes to hold _IncludedRouter tree nodes that have no .path. prometheus-fastapi-instrumentator 7.x walks app.routes and reads route.path on a match:

File ".../prometheus_fastapi_instrumentator/routing.py", line 55, in _get_route_name
    route_name = route.path
AttributeError: '_IncludedRouter' object has no attribute 'path'

Aegra mounts all its routers via include_router, so an _IncludedRouter is always present, and the instrumentator middleware raises on every request. The same FastAPI change broke opentelemetry-instrumentation-fastapi (open-telemetry/opentelemetry-python-contrib#4699).

Reported against aegra-api==0.9.21 + FastAPI 0.137.0.

Fix

Bump the floor: prometheus-fastapi-instrumentator>=7.1.0 → >=8.0.2. 8.0.2 handles the new route tree.

Verification

Reproduced the exact AttributeError 500 with 7.1.0 + FastAPI 0.137 on an include_router app, confirmed 8.0.2 returns 200 on both FastAPI 0.138.1 (the broken range) and the older FastAPI we previously resolved. Added an integration regression that drives a templated include_router route under metrics (the prior test used a direct @app.get, which never produces an _IncludedRouter and so could not catch this). Full unit + integration suite green on the bumped resolve (FastAPI 0.138.1 / starlette 1.3.1).

Scope

Confirmed metrics is the only thing affected. The other two places Aegra touches app.routes are safe on 0.137: the custom-route auth walker type-checks (isinstance APIRoute / recurses on .routes) and the root-route check already guards with hasattr(route, "path").

🤖 Generated with Claude Code

Summary by CodeRabbit

Bug Fixes
- Improved Prometheus metrics compatibility with newer FastAPI routing behavior, preventing 500 errors when metrics are enabled on routed endpoints.
- Updated the metrics dependency to a newer version that handles the current router structure more reliably.
Tests
- Added an integration test covering a routed endpoint with metrics enabled to verify successful responses and guard against regressions.

Greptile Summary

This PR updates the Prometheus metrics dependency for newer FastAPI route trees. The main changes are:

Raises prometheus-fastapi-instrumentator to >=8.0.2.
Refreshes the lockfile to FastAPI 0.138.1 and Starlette 1.3.1.
Adds an integration test for metrics on an include_router route.

Confidence Score: 5/5

This looks safe to merge.

No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
libs/aegra-api/pyproject.toml	Updates the Prometheus instrumentator lower bound and documents the FastAPI route-tree compatibility reason.
libs/aegra-api/tests/integration/test_prometheus_metrics.py	Adds an isolated regression test for an instrumented route mounted through `include_router`.
uv.lock	Refreshes locked versions for the metrics and FastAPI/Starlette stack.

_{Reviews (1): Last reviewed commit: "fix(metrics): bump prometheus-fastapi-in..." | Re-trigger Greptile}

Context used:

Context used - CLAUDE.md (source)
Context used - AGENTS.md (source)

…astAPI >=0.137 FastAPI 0.137 changed app.routes to hold _IncludedRouter nodes that have no .path. The instrumentator 7.x walks app.routes and reads route.path on a match, raising AttributeError on every request when metrics are enabled. Aegra mounts all routers via include_router, so this 500'd every request under metrics on FastAPI >=0.137. 8.0.2 handles the new route tree and stays compatible with the older FastAPI we already resolve. Adds an integration regression covering an include_router route under metrics (the prior test used a direct @app.get, which never produced an _IncludedRouter and so could not catch this). Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

coderabbitai · 2026-06-28T16:55:10Z

📝 Walkthrough

Walkthrough

The prometheus-fastapi-instrumentator minimum version is bumped from >=7.1.0 to >=8.0.2 in pyproject.toml, with inline comments explaining the FastAPI router change that caused 500 errors. A new regression integration test verifies that a Prometheus-instrumented app with an APIRouter templated route returns HTTP 200.

Changes

Prometheus instrumentator bump and regression test

Layer / File(s)	Summary
Dependency bump and APIRouter regression test `libs/aegra-api/pyproject.toml`, `libs/aegra-api/tests/integration/test_prometheus_metrics.py`	Version constraint updated to `>=8.0.2` with comments explaining the `route.path` access issue. `APIRouter` imported and a new test asserts `/items/42` returns HTTP 200 with metrics enabled.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~4 minutes

Poem

🐇 A version bump, a test so bright,
No more 500s in the night.
The router's path now found with ease,
Prometheus metrics, if you please!
Hopping forward, all is right. 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: fixing FastAPI 0.137 metrics support by bumping the Prometheus instrumentator.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

✨ Finishing Touches

📝 Generate docstrings

Create stacked PR
Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch fix/prometheus-fastapi-0137

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codecov · 2026-06-28T16:55:34Z

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✅ All modified and coverable lines are covered by tests.

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fix(metrics): support FastAPI >=0.137 (bump prometheus instrumentator to >=8.0.2)#440

fix(metrics): support FastAPI >=0.137 (bump prometheus instrumentator to >=8.0.2)#440
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fix/prometheus-fastapi-0137

ibbybuilds commented Jun 28, 2026 •

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Problem

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Greptile Summary

Confidence Score: 5/5

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ibbybuilds commented Jun 28, 2026 •

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