feat: use autoprop to set up tracing text map propagators

Signed-off-by: Pablo Aguilar <pablo.aguilar@outlook.com.br>

go.mod

@@ -62,6 +62,7 @@ require (
 	go.flipt.io/flipt/rpc/flipt v1.38.0
 	go.flipt.io/flipt/sdk/go v0.11.0
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.49.0
+	go.opentelemetry.io/contrib/propagators/autoprop v0.50.0
 	go.opentelemetry.io/otel v1.25.0
 	go.opentelemetry.io/otel/exporters/jaeger v1.17.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.25.0
@@ -235,6 +236,10 @@ require (
 	github.com/yusufpapurcu/wmi v1.2.3 // indirect
 	go.opencensus.io v0.24.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
+	go.opentelemetry.io/contrib/propagators/aws v1.25.0 // indirect
+	go.opentelemetry.io/contrib/propagators/b3 v1.25.0 // indirect
+	go.opentelemetry.io/contrib/propagators/jaeger v1.25.0 // indirect
+	go.opentelemetry.io/contrib/propagators/ot v1.25.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.1.0 // indirect
 	go.uber.org/atomic v1.11.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect

go.sum

@@ -723,6 +723,16 @@ go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.4
 go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.49.0/go.mod h1:Mjt1i1INqiaoZOMGR1RIUJN+i3ChKoFRqzrRQhlkbs0=
 go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 h1:jq9TW8u3so/bN+JPT166wjOI6/vQPF6Xe7nMNIltagk=
 go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0/go.mod h1:p8pYQP+m5XfbZm9fxtSKAbM6oIllS7s2AfxrChvc7iw=
+go.opentelemetry.io/contrib/propagators/autoprop v0.50.0 h1:tK1hZrY9rV784YPGAUACvqBjvFCim2rrJZR/09giyrA=
+go.opentelemetry.io/contrib/propagators/autoprop v0.50.0/go.mod h1:oTzb+geTS8mHaeIOYd/1AShfxdovU3AA1/m+IrheAvc=
+go.opentelemetry.io/contrib/propagators/aws v1.25.0 h1:LYKyPhf1q+1ok4UUxcmQ2sERvWcUylg4v8MK+h8nCcA=
+go.opentelemetry.io/contrib/propagators/aws v1.25.0/go.mod h1:HMRyfyD8oIZLpKSXC0zGmZZTuG4qGo6OtZOEu8IQPJc=
+go.opentelemetry.io/contrib/propagators/b3 v1.25.0 h1:QU8UEKyPqgr/8vCC9LlDmkPnfFmiWAUF9GtJdcLz+BU=
+go.opentelemetry.io/contrib/propagators/b3 v1.25.0/go.mod h1:qonC7wyvtX1E6cEpAR+bJmhcGr6IVRGc/f6ZTpvi7jA=
+go.opentelemetry.io/contrib/propagators/jaeger v1.25.0 h1:GPnu8mDgqHlISYc0Ub0EbYlPWCOJE0biicGrE7vcE/M=
+go.opentelemetry.io/contrib/propagators/jaeger v1.25.0/go.mod h1:WWa6gdfrRy23dFALEkiT+ynOI5Ke2g+fUa5Q2v0VGyg=
+go.opentelemetry.io/contrib/propagators/ot v1.25.0 h1:9+54ye9caWA5XplhJoN6E8ECDKGeEsw/mqR4BIuZUfg=
+go.opentelemetry.io/contrib/propagators/ot v1.25.0/go.mod h1:Fn0a9xFTClSSwNLpS1l0l55PkLHzr70RYlu+gUsPhHo=
 go.opentelemetry.io/otel v1.25.0 h1:gldB5FfhRl7OJQbUHt/8s0a7cE8fbsPAtdpRaApKy4k=
 go.opentelemetry.io/otel v1.25.0/go.mod h1:Wa2ds5NOXEMkCmUou1WA7ZBfLTHWIsp034OVD7AO+Vg=
 go.opentelemetry.io/otel/exporters/jaeger v1.17.0 h1:D7UpUy2Xc2wsi1Ras6V40q806WM07rqoCWzXu7Sqy+4=

internal/cmd/grpc.go

@@ -10,6 +10,8 @@ import (
 	"sync"
 	"time"
 
+	"go.opentelemetry.io/contrib/propagators/autoprop"
+
 	sq "github.com/Masterminds/squirrel"
 	"go.flipt.io/flipt/internal/cache"
 	"go.flipt.io/flipt/internal/cache/memory"
@@ -39,7 +41,6 @@ import (
 	"go.flipt.io/flipt/internal/tracing"
 	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 	"go.opentelemetry.io/otel"
-	"go.opentelemetry.io/otel/propagation"
 	tracesdk "go.opentelemetry.io/otel/sdk/trace"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
@@ -373,7 +374,12 @@ func NewGRPCServer(
 	})
 
 	otel.SetTracerProvider(tracingProvider)
-	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
+
+	textMapPropagator, err := autoprop.TextMapPropagator(getStringSlice(cfg.Tracing.Propagators)...)
+	if err != nil {
+		return nil, fmt.Errorf("error constructing tracing text map propagator: %w", err)
+	}
+	otel.SetTextMapPropagator(textMapPropagator)
 
 	grpcOpts := []grpc.ServerOption{
 		grpc.ChainUnaryInterceptor(interceptors...),
@@ -551,3 +557,15 @@ func getDB(ctx context.Context, logger *zap.Logger, cfg *config.Config, forceMig
 
 	return db, builder, driver, dbFunc, dbErr
 }
+
+// getStringSlice receives any slice which the underline member type is "string"
+// and return a new slice with the same members but transformed to "string" type.
+// This is useful when we want to convert an enum slice of strings.
+func getStringSlice[AnyString ~string, Slice []AnyString](slice Slice) []string {
+	strSlice := make([]string, 0, len(slice))
+	for _, anyString := range slice {
+		strSlice = append(strSlice, string(anyString))
+	}
+
+	return strSlice
+}