envoyproxy/envoy

grpc: grpc-status in trailers does not trigger retries

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#17,629 opened on Aug 9, 2021

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area/grpcarea/routerhelp wanted

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Description

I noticed that currently for gRPC:

Envoy's retries will only detect grpc-status in Headers.When the server sets a custom Header, grpc-status will appear in the Trailers, which will cause Envoy's retries to not work: https://github.com/grpc/grpc-go/blob/master/stream.go#L1369

I think we should do something in here: https://github.com/envoyproxy/envoy/blob/main/source/common/router/router.cc#L1392-L1412

I noticed this comment, which makes me think that the developers didn't accidentally overlook the problem, but just put it aside for now: https://github.com/envoyproxy/envoy/blob/main/source/common/router/router.cc#L1238-L1240

So are there any special considerations or difficulties? Will I get support if I submit a PR to fix this issue?

Contributor guide

Research direction
Inspect the retry logic in source/common/router/router.cc, specifically the condition checking grpc status in headers, and extend it to also check trailers when headers are not present.
Tech stack
cpp
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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Half day
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Active
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Clear
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65