Not possible to use both otelmetrichttp and otelmetricgrpc

[pellared]

Not possible to use both otelmetrichttp and otelmetricgrpc

[MrAlias]

Please coordinate with @XSAM who is working on #5250

[pellared]

Most probably we will have to revert these two PRs:

• #5222
• #5216

@gregoryfranklin, thanks for reporting the issue ❤️

[pellared]

This has be double-check before making a new release as it can be a blocker.

[XSAM]

I have checked the protobuf codes regarding this behavior. The implementation prevents importing go.opentelemetry.io/proto/otlp and go.opentelemetry.io/proto/slim at the same time.

https://github.com/protocolbuffers/protobuf-go/blob/e4ad8f9dfc8bc3184ebb70c296bd63955343e903/reflect/protoregistry/registry.go#L126-L133

Though we could use go build -ldflags "-X google.golang.org/protobuf/reflect/protoregistry.conflictPolicy=warn" to change the conflict policy and probably pass this check, it requires our end-users to do this, which is not acceptable.

Plan for the release

Rollback these two PRs:

• #5222
• #5216

After the release

We might need to deprecate package go.opentelemetry.io/proto/slim, as it is not compatible with go.opentelemetry.io/proto/otlp, which provides grpc support. And it makes the package somewhat unusable.