[receiver/prometheusremotewritereceiver] Fix silent data loss on consumer failure #45151
+145
−5
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
aknuds1
force-pushed
the
arve/prom-remote-write-silent-loss
branch
from
a039576 to
23971f0
Compare
…umer failure The receiver was sending HTTP 204 No Content before calling ConsumeMetrics(), so if the consumer failed, clients incorrectly thought data was delivered. This violates the Prometheus Remote Write spec which states receivers MUST NOT return 2xx if data was not successfully written. Changes: - Move WriteHeader(204) to after ConsumeMetrics() succeeds - Return 400 Bad Request for permanent consumer errors - Return 500 Internal Server Error for retryable errors - Add tests for consumer error handling Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
aknuds1
force-pushed
the
arve/prom-remote-write-silent-loss
branch
from
23971f0 to
85f883a
Compare
aknuds1
requested review from
a team,
ArthurSens and
dashpole
as code owners
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 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Outdated suggestions cannot be applied.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.
Summary
The receiver was sending HTTP 204 No Content before calling
ConsumeMetrics(), so if the consumer failed, clients incorrectly thought data was delivered. This violates the Prometheus Remote Write 2.0 specification which states:Changes
WriteHeader(204)to afterConsumeMetrics()succeedsImpact
Without this fix, when a downstream consumer fails (e.g., backend unavailable, memory limiter rejecting batches, exporter failures), Prometheus clients receive a success response and won't retry, leading to silent data loss.
Testing
Added
TestHandlePRWConsumerResponsewith sub-tests:success returns 204- verifies normal operationretryable error returns 500- verifies temporary failures return 500permanent error returns 400- verifies permanent failures return 400