Fix FastAPI issue with APIRoute subclasses #3681
Merged
+66
−3
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
lannuttia
force-pushed
the
fix/issue-3671
branch
from
090e9c1 to
de946d3
Compare
lannuttia
changed the title
Fixes: open-telemetry#3671 When an APIRoute subclass would overwrite the matches method with an implementation that depended on non-standard fields existing on the HTTP connection scope, this would cause a failure when the OpenTelemetryMiddleware tried to get the default span details for the incoming request. This has been fixed by using the matches implementation on the Route class for any subclass of Route. This should be sufficient since the only information we are trying to get from that method is the path for the request.
This commit adds tests that illustrate the original issue that was being experienced for custom api route implementations when they depended on non-standard fields existing on the ASGI HTTP connection scope. Before the fix was implemented, the inclusion of a custom API route in the FastAPI application would cause an exception to be raised inside the OpenTelemetryMiddleware since the non-standard fields do not exist on the ASGI HTTP connection scope until after the subsequent middleware runs and adds the expected fields.
lannuttia
force-pushed
the
fix/issue-3671
branch
from
299f2de to
8878698
Compare
emdneto
reviewed
Oct 2, 2025
instrumentation/opentelemetry-instrumentation-fastapi/tests/test_fastapi_instrumentation.py
Outdated
Show resolved
Hide resolved
.../opentelemetry-instrumentation-fastapi/src/opentelemetry/instrumentation/fastapi/__init__.py
Show resolved
Hide resolved
lannuttia
force-pushed
the
fix/issue-3671
branch
from
374130c to
fcca86c
Compare
emdneto
approved these changes
Oct 13, 2025
xrmx
approved these changes
Oct 14, 2025
github-project-automation
bot
moved this from Approved PRs
to Done
in @xrmx's Python PR digest
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
When an APIRoute subclass would overwrite the matches method with an implementation that depended on non-standard fields existing on the HTTP connection scope, this would cause a failure when the OpenTelemetryMiddleware tried to get the default span details for the incoming request. This has been fixed by using the matches implementation on the Route class for any subclass of Route. This should be sufficient since the only information we are trying to get from that method is the path for the request.
Fixes #3671
Type of change
Please delete options that are not relevant.
How Has This Been Tested?
This has been validated with automated tests that are included in this pull request.
Does This PR Require a Core Repo Change?
Checklist:
See contributing.md for styleguide, changelog guidelines, and more.