fix: fastapi memory leak only#3688
Merged
xrmx merged 16 commits intoopen-telemetry:mainfrom Aug 23, 2025
Merged
Conversation
…ist to avoid memory leaks
… WeakSet and safe discard
10 tasks
anuraaga
approved these changes
Aug 12, 2025
Contributor
Author
|
Hi @anuraaga, just a gentle reminder — could you take a look at this PR? All checks have passed 👍 |
Contributor
|
Hi @artemziborev - LGTM. I had already approved since was just a comment nit, but I'm not a maintainer so it's a grey check |
emdneto
reviewed
Aug 15, 2025
emdneto
reviewed
Aug 15, 2025
emdneto
approved these changes
Aug 15, 2025
…to fix/fastapi-memory-leak-only
xrmx
reviewed
Aug 22, 2025
xrmx
reviewed
Aug 22, 2025
xrmx
approved these changes
Aug 22, 2025
emdneto
approved these changes
Aug 22, 2025
|
Hi folks, thank you for solving this issue. |
sightseeker
added a commit
to sightseeker/opentelemetry-python-contrib
that referenced
this pull request
Mar 11, 2026
* fix(fastapi-instrumentation): properly remove app from instrumented list to avoid memory leaks * fix(fastapi-instrumentation): fix tests and finalize memory leak fix * docs(changelog): add FastAPI uninstrument memory leak fix with PR references (open-telemetry#3683) * test(fastapi): add GC-based app collection test; refactor tracking to WeakSet and safe discard * docs(changelog): reference FastAPI memory leak fix PR (open-telemetry#3688) * refactor(fastapi): drop __del__ as WeakSet handles cleanup * chore(fastapi): formatting after ruff auto-fix * chore(test-fastapi): ruff import order * Update comment to clarify purpose of removing app from WeakSet * fix: codereview comments * Apply suggestions from code review --------- Co-authored-by: Emídio Neto <9735060+emdneto@users.noreply.github.com> Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 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
Fix FastAPI instrumentation memory leak by tracking instrumented apps with a WeakSet instead of a strong-referenced set. This avoids retaining strong references to
fastapi.FastAPIinstances, allowing them to be garbage-collected even ifuninstrument_app()isn’t called. Also aligns with the approach used in the Starlette instrumentation.Scope minimized to FastAPI only:
_instrumented_fastapi_appsanddiscard()on removaluninstrument_app()test_fastapi_instrumentation.pyFixes # (issue)
Type of change
How Has This Been Tested?
test_fastapi_app_is_collected_after_instrumentintest_fastapi_instrumentation.py, which:gc.collect()Does This PR Require a Core Repo Change?
Checklist: