refactor: use client to retrieve token from context

exporter/sapmexporter/exporter.go

@@ -7,9 +7,11 @@ package sapmexporter // import "github.com/open-telemetry/opentelemetry-collecto
 import (
 	"context"
 	"errors"
+	"fmt"
 
 	"github.com/jaegertracing/jaeger/model"
 	sapmclient "github.com/signalfx/sapm-proto/client"
+	"go.opentelemetry.io/collector/client"
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/consumer/consumererror"
@@ -23,12 +25,23 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/translator/jaeger"
 )
 
-type contextKey string
+type ContextSource struct {
+	Key string
+}
+
+func (ts *ContextSource) Get(ctx context.Context) (string, error) {
+	cl := client.FromContext(ctx)
+	ss := cl.Metadata.Get(ts.Key)
 
-const sapmAccessTokenContextKey contextKey = splunk.SFxAccessTokenHeader
+	if len(ss) == 0 {
+		return "", nil
+	}
+
+	if len(ss) > 1 {
+		return "", fmt.Errorf("%d source keys found in the context, can't determine which one to use", len(ss))
+	}
 
-func (k contextKey) String() string {
-	return string(k)
+	return ss[0], nil
 }
 
 // TODO: Find a place for this to be shared.
@@ -139,8 +152,10 @@ func (se *sapmExporter) retrieveAccessToken(ctx context.Context, md ptrace.Resou
 	}
 
 	var token string
-	if ctxAccessToken, ok := ctx.Value(sapmAccessTokenContextKey).(string); ok {
-		token = ctxAccessToken
+	cl := client.FromContext(ctx)
+	ss := cl.Metadata.Get(splunk.SFxAccessTokenHeader)
+	if len(ss) > 0 {
+		token = ss[0]
 	} else {
 		attrs := md.Resource().Attributes()
 		if accessToken, ok := attrs.Get(splunk.SFxAccessTokenLabel); ok {

exporter/sapmexporter/exporter_test.go

@@ -18,6 +18,7 @@ import (
 	splunksapm "github.com/signalfx/sapm-proto/gen"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/client"
 	"go.opentelemetry.io/collector/exporter/exportertest"
 	"go.opentelemetry.io/collector/pdata/ptrace"
 
@@ -275,7 +276,12 @@ func TestSAPMClientTokenAccess(t *testing.T) {
 
 			ctx := context.Background()
 			if tt.inContext {
-				ctx = context.WithValue(ctx, sapmAccessTokenContextKey, "SplunkAccessToken")
+				ctx = client.NewContext(
+					ctx,
+					client.Info{Metadata: client.NewMetadata(
+						map[string][]string{splunk.SFxAccessTokenHeader: {"SplunkAccessToken"}},
+					)},
+				)
 			}
 			err = se.pushTraceData(ctx, trace)
 			require.NoError(t, err)

exporter/sapmexporter/go.mod

@@ -51,6 +51,7 @@ require (
 	github.com/prometheus/procfs v0.15.1 // indirect
 	go.opencensus.io v0.24.0 // indirect
 	go.opentelemetry.io/collector v0.109.0 // indirect
+	go.opentelemetry.io/collector/client v1.15.0 // indirect
 	go.opentelemetry.io/collector/config/configtelemetry v0.109.0 // indirect
 	go.opentelemetry.io/collector/consumer/consumerprofiles v0.109.0 // indirect
 	go.opentelemetry.io/collector/consumer/consumertest v0.109.0 // indirect