fix(tracing): establish tracing capture context early enough - #3057
Draft
Conversation
solnic
changed the title
![github-advanced-security[bot]](https://avatars.githubusercontent.com/in/57789?s=60&v=4){kind=small}
Rails::Rack::Logger's "Started ..." line (and anything logged before CaptureExceptions runs) got an unrelated trace_id, since CaptureExceptions runs after ActionDispatch::ShowExceptions. Add Sentry::Rails::CaptureContext, a minimal middleware unshifted to the front of the stack that establishes the propagation context early. CaptureExceptions now consumes and reuses it instead of regenerating a new trace_id/span_id. Co-Authored-By: GitHub Copilot <noreply@example.com>
This fixes the issue while ensuring we're not adding Sentry overhead to static file-serving routes, which is why the middleware was moved historically.
The established flag lived in the request-scoped env but certified a thread-local hub, so any middleware doing `@app.call` on another thread lost the incoming trace. The env now carries the context itself, trusted only while it is still the current scope's.
solnic
force-pushed
the
3015-railsrackloggers-started-log-line-and-anything-else-logged-before-sentryrailscaptureexceptions-gets-an-unrelated-trace_idspan_id
branch
from
September 2, 2026 14:25
029569e to
01910dc
Compare
The example stubs Sentry.initialized? to false, and RSpec tears mocks down after the suite's after hooks run. The sentry-rails hook only clears captured events and detaches the structured logging subscribers when Sentry reports itself initialized, so the stub made it skip both. The subscribers stayed attached and later examples inherited log events they never emitted, failing whenever the order put them after this one. Scoping the stub to the call under test lets the hook see the real state. Co-Authored-By: Claude Opus 5 <noreply@anthropic.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
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.
This is based on #3016
This adds a new
Sentry::Rails::CaptureContextmiddleware establishes the propagation context once, early.CaptureExceptionsreuses it instead of generating its own, and a transaction with no incoming trace continues the established one rather than fabricating a newtrace_id.It sits
insert_after ActionDispatch::Executor- aboveRails::Rack::Loggerso the fix covers the logging, below the file-serving middlewares so static requests never touch Sentry.Fixes #3015