Extract grpc-status from responseContent when not in headers/trailers

[sallylyen]

Motivation

When a client cancels a gRPC request (e.g., via RST_STREAM), the grpc-status may not be present in response headers or trailers, causing metrics to be recorded with UNKNOWN status.

Resolves #6606

Modifications

• Added fallback in GrpcMeterIdPrefixFunction to extract grpc-status from responseContent using Status.fromThrowable()
• Added integration test for client cancellation scenario

Result

• gRPC metrics now correctly record the status when client cancels
• Closes grpc-status not recorded in RequestLog when client cancels (RST_STREAM) #6606

[CLAassistant]

All committers have signed the CLA.

[coderabbitai]

📝 Walkthrough

Walkthrough

Added a fallback in GrpcMeterIdPrefixFunction that inspects RequestLog.responseContent() for an RpcResponse and, when headers/trailers lack grpc-status, derives and sets the grpc.status from the RPC response cause (e.g., client cancellation). Tests added to exercise the cancellation path.

Changes

Cohort / File(s)	Summary
Fallback Status Extraction grpc/src/main/java/.../GrpcMeterIdPrefixFunction.java	Added logic to check RequestLog.responseContent() for an RpcResponse when grpc-status is not present in headers/trailers; if the RPC completed exceptionally, derive a gRPC status from the cause, set the grpc.status tag, and return early.
Test Coverage & Helpers grpc/src/test/java/.../GrpcMeterIdPrefixFunctionTest.java	Added grpcStatusFromResponseContent_clientCancellation test that simulates client cancellation via a low-level ClientCall and asserts grpc.status=CANCELLED; added helper to find client meters with configurable http.status and a delayed server method to enable cancellation testing.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I hopped through logs where trailers hid,
I peered at response content when headers slid.
A cancelled call, a cause made plain,
I tag the status, trace the strain.
Metrics smile — no longer in vain. 🥕

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% 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 and specifically describes the main change: extracting grpc-status from responseContent when not in headers/trailers.
Description check	✅ Passed	The description accurately explains the motivation, modifications, and expected outcome of the pull request.
Linked Issues check	✅ Passed	The pull request directly addresses issue #6606 by implementing the fallback mechanism to extract grpc-status from responseContent and adding an integration test.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to resolving issue #6606: the fallback logic in GrpcMeterIdPrefixFunction and supporting test infrastructure.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[github-actions]

🔍 Build Scan® (commit: 5a79d3f)

Job name	Status	Build Scan®
build-ubicloud-standard-16-jdk-8	✅	https://ge.armeria.dev/s/qg2ypcwcdpy54
build-ubicloud-standard-16-jdk-25	✅	https://ge.armeria.dev/s/aab57dpaisjtg
build-ubicloud-standard-16-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/vvipl55pi5npe
build-ubicloud-standard-16-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/icvypwp5hip6w
build-ubicloud-standard-16-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/ium2v6zoqz3ng
build-ubicloud-standard-16-jdk-17-leak	❌ (failure)	https://ge.armeria.dev/s/nv3zjquojzqhk
build-ubicloud-standard-16-jdk-11	✅	https://ge.armeria.dev/s/7g647chkpv3kw
build-macos-latest-jdk-25	✅	https://ge.armeria.dev/s/k3zvkeibms4gq

[jrhee17]

Changes look good once CI passes

[jrhee17]

This unfortunately fails due to how shadedTest works in our codebase at the moment.
You may need to either:

• Avoid using *FutureStub in tests
• Or move the added test to a module without the relocate flag (i.e. :it:grpc:java)

[ikhoon]

LGTM once @jrhee17's comments are addressed

[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In
`@grpc/src/test/java/com/linecorp/armeria/common/grpc/GrpcMeterIdPrefixFunctionTest.java`:
- Around line 279-289: In unaryCallWithAllDifferentParameterTypes (in
GrpcMeterIdPrefixFunctionTest) stop processing when the Thread.sleep is
interrupted: in the catch block for InterruptedException, after re-setting the
interrupt flag (Thread.currentThread().interrupt()), return immediately so you
do not call responseObserver.onNext/onCompleted after an interruption (which can
race with cancellation/stream closure).

[jrhee17]

👍 👍