Propagate tags from worker to host #3303
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Pull request overview
This PR adds functionality to propagate Activity tags from the worker to the host through the trace context. Tags from the worker's invocation activity are captured, filtered to exclude known OpenTelemetry attributes, and sent back to the host via the InvocationResponse.
Changes:
- Added trace_context field to InvocationResponse protobuf message
- Implemented tag extraction from Activity and storage in FunctionContext.Items
- Created filtering logic to exclude known OpenTelemetry attributes from propagated tags
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.
| File | Description |
|---|---|
| protos/azure-functions-language-worker-protobuf/src/proto/FunctionRpc.proto | Added trace_context field to InvocationResponse message for tag propagation |
| src/DotNetWorker.Core/Diagnostics/TraceConstants.cs | Added KnownAttributes list and FunctionContextItemsKey constant to support tag filtering |
| src/DotNetWorker.Core/FunctionsApplication.cs | Extracts Activity tags to dictionary and stores in FunctionContext.Items after function execution |
| src/DotNetWorker.Grpc/Handlers/InvocationHandler.cs | Added AddTraceContextTags method to filter and populate trace context in response |
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| RpcTraceContext traceContext = AddTraceContextTags(request, context); | ||
| response.TraceContext = traceContext; |
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The new functionality to propagate trace context tags lacks test coverage. Based on the test patterns observed in InvocationHandlerTests.cs, consider adding a test that verifies the trace context is properly populated in the InvocationResponse when tags are present in the FunctionContext.Items, and another test to verify that known attributes are filtered out correctly.
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
…re-functions-dotnet-worker into satvu/otel-worker-tags
Issue describing the changes in this PR
Related to Azure/azure-functions-host#11574 and the PR resolving it.
Depends on Azure/azure-functions-language-worker-protobuf#98.
Pull request checklist
release_notes.md