otelgrpc: support OTEL_SEMCONV_STABILITY_OPT_IN (#8726)

Signed-off-by: David Ashpole <dashpole@google.com>

Author: dashpole

CHANGELOG.md

@@ -15,6 +15,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Added support for `attribute_count_limit` and `attribute_value_length_limit` in tracer provider configuration in `go.opentelemetry.io/contrib/otelconf`. (#8687)
 - Added support for `attribute_count_limit` and `attribute_value_length_limit` in logger provider configuration in `go.opentelemetry.io/contrib/otelconf`. (#8686)
 - Added support for `server.address` and `server.port` attributes in `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc`. (#8723)
+- Support `OTEL_SEMCONV_STABILITY_OPT_IN` in `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc`. Supported values are `rpc` (default), `rpc/dup` and `rpc/old`. (#8726)
 
 ### Changed
 

instrumentation/google.golang.org/grpc/otelgrpc/config.go

@@ -5,6 +5,8 @@ package otelgrpc // import "go.opentelemetry.io/contrib/instrumentation/google.g
 
 import (
 	"context"
+	"os"
+	"strings"
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
@@ -29,6 +31,14 @@ type InterceptorFilter func(*InterceptorInfo) bool
 // A Filter must return true if the request should be instrumented.
 type Filter func(*stats.RPCTagInfo) bool
 
+type semconvMode int
+
+const (
+	semconvModeNew semconvMode = iota // Default
+	semconvModeOld
+	semconvModeDup
+)
+
 // config is a group of options for this instrumentation.
 type config struct {
 	Filter             Filter
@@ -47,6 +57,8 @@ type config struct {
 
 	ReceivedEvent bool
 	SentEvent     bool
+
+	semconvMode semconvMode
 }
 
 // Option applies an option value for a config.
@@ -66,13 +78,33 @@ func newConfig(opts []Option) *config {
 		Propagators:    otel.GetTextMapPropagator(),
 		TracerProvider: otel.GetTracerProvider(),
 		MeterProvider:  otel.GetMeterProvider(),
+		semconvMode:    parseSemconvMode(),
 	}
 	for _, o := range opts {
 		o.apply(c)
 	}
+
 	return c
 }
 
+func parseSemconvMode() semconvMode {
+	val := os.Getenv("OTEL_SEMCONV_STABILITY_OPT_IN")
+	if val == "" {
+		return semconvModeNew
+	}
+	parts := strings.SplitSeq(val, ",")
+	for p := range parts {
+		p = strings.TrimSpace(p)
+		if p == "rpc/dup" {
+			return semconvModeDup
+		}
+		if p == "rpc/old" {
+			return semconvModeOld
+		}
+	}
+	return semconvModeNew
+}
+
 // WithPublicEndpoint configures the Handler to link the span with an incoming
 // span context. If this option is not provided, then the association is a child
 // association instead of a link.

instrumentation/google.golang.org/grpc/otelgrpc/config_test.go

@@ -0,0 +1,62 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package otelgrpc
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseSemconvMode(t *testing.T) {
+	tests := []struct {
+		name string
+		val  string
+		want semconvMode
+	}{
+		{
+			name: "empty",
+			val:  "",
+			want: semconvModeNew,
+		},
+		{
+			name: "old",
+			val:  "rpc/old",
+			want: semconvModeOld,
+		},
+		{
+			name: "dup",
+			val:  "rpc/dup",
+			want: semconvModeDup,
+		},
+		{
+			name: "unknown",
+			val:  "unknown",
+			want: semconvModeNew,
+		},
+		{
+			name: "multiple with valid",
+			val:  "foo, rpc/dup",
+			want: semconvModeDup,
+		},
+		{
+			name: "multiple with old first",
+			val:  "rpc/old, rpc/dup",
+			want: semconvModeOld,
+		},
+		{
+			name: "spaces",
+			val:  "  rpc/old  ",
+			want: semconvModeOld,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv("OTEL_SEMCONV_STABILITY_OPT_IN", tt.val)
+			got := parseSemconvMode()
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}