[Rohithmatham12]

What this changes

• Routes gRPC package-level logs through the configured Cortex go-kit logger so transport errors respect server.log_format.
• Replaces the side-effect automaxprocs import with explicit maxprocs.Set(...) after Cortex initializes logging, so maxprocs messages also use the configured format.
• Preserves gRPC default severity behavior: errors only unless GRPC_GO_LOG_SEVERITY_LEVEL asks for warning/info.
• Adds focused tests for gRPC and automaxprocs log output through the configured JSON logger.

Fixes #7697.

Testing

• GOCACHE=/private/tmp/cortex-go-cache GOMODCACHE=/private/tmp/cortex-go-mod-cache go test ./pkg/util/log
• GOCACHE=/private/tmp/cortex-go-cache GOMODCACHE=/private/tmp/cortex-go-mod-cache go test ./cmd/cortex

[friedrichg]

I am not sure the automaxprocs package is needed after 1.26.
There is conflicting information uber-go/automaxprocs#98 (comment)

we can decide later after some testing

---

@Rohithmatham12 good work though

[sandy2008]

LGTM, this fixes both lines from #7697. I checked it end to end: with -log.format=json, a grpclog.Component("transport").Errorf(...) now comes out as {"level":"error","msg":"[transport] Client received GoAway ..."}. gRPC info/warning logs stay hidden unless GRPC_GO_LOG_SEVERITY_LEVEL asks for them, and the maxprocs: line goes through the same logger at info. Nit: a CHANGELOG entry under ## master / unreleased ending with #7699 would be good, and it could mention that gRPC errors now go through the Cortex logger, so they also count toward log_messages_total{level="error"}.

[Rohithmatham12]

Added the unreleased CHANGELOG entry, including that gRPC errors count toward log_messages_total{level="error"}, in aea07bff3a. go test ./pkg/util/log ./cmd/cortex passes.