`otelgrpc` possibly reporting status code in incorrect format

[achew22]

Description

Right now, otelgrpc is reporting rpc.grpc.status_code as defined in semconv as an integer. It's entirely possible I'm holding it wrong though. Would love a pointer if that's the case.

https://github.com/open-telemetry/opentelemetry-go-contrib/blob/instrumentation/google.golang.org/grpc/otelgrpc/v0.53.0/instrumentation/google.golang.org/grpc/otelgrpc/stats_handler.go#L199-L201

As I read the spec on enumerations, they should be converted to the string type before being uploaded.

Values, which belong to a limited enumerated set (e.g. a Java enum), SHOULD be converted to AnyValue’s string_value field with the value of the string set to the symbolic name of the enumeration.

Environment

• OS: Linux
• Architecture: x86-64
• Go Version: 1.21
• go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.49.0

Steps To Reproduce

1. Install the otelgrpc package in your gRPC server
2. Run the service
3. See integers in the metrics for the

Expected behavior

I would expect these to be strings describing the gRPC status codes. Could be wrong in my interpretation of the spec.

[dmathieu]

This isn't the proper spec to look at.

The mapping is needed when OpenTelemetry needs to convert a value produced outside OpenTelemetry into a value that can be exported using an OTLP exporter

We are not producing a value from outside OpenTelemetry into a value that can be used by OTLP. We are within OpenTelemetry, and are producing data for any exporter, not specifically OTLP. This spec would apply in a bridge that would allow transforming data from one format into OTLP.

What applies here is semantic conventions. https://github.com/open-telemetry/semantic-conventions/blob/f79fe6b61438bfa0804df9c254c402fd0d71f42a/docs/rpc/grpc.md#grpc-attributes

And the gRPC status code is indeed an integer (which makes sense, since that's the original data type).