Implementing feature flag for otel

config/config.go

@@ -91,6 +91,7 @@ type Config struct {
 	OTExporterOTLPEndpoint               string        `envconfig:"OTEL_EXPORTER_OTLP_ENDPOINT"`
 	OTServiceName                        string        `envconfig:"OTEL_SERVICE_NAME"`
 	OTBatchTimeout                       time.Duration `envconfig:"OTEL_BATCH_TIMEOUT"`
+	OtelEnabled                          bool          `envconfig:"OTEL_ENABLED"`
 	Auth                                 authorisation.Config
 }
 
@@ -179,6 +180,7 @@ func Get() (*Config, error) {
 		OTExporterOTLPEndpoint:               "localhost:4317",
 		OTServiceName:                        "dp-api-router",
 		OTBatchTimeout:                       time.Second * 5,
+		OtelEnabled:                          false,
 	}
 
 	return cfg, envconfig.Process("", cfg)

interceptor/interceptor.go

@@ -2,6 +2,7 @@ package interceptor
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -13,6 +14,7 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/ONSdigital/dp-api-router/config"
 	"github.com/ONSdigital/log.go/v2/log"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 )
@@ -29,7 +31,17 @@ var _ http.RoundTripper = &Transport{}
 
 // NewRoundTripper creates a Transport instance with configured domain
 func NewRoundTripper(domain, contextURL string, rt http.RoundTripper) *Transport {
-	return &Transport{domain, contextURL, otelhttp.NewTransport(rt)}
+	cfg, err := config.Get()
+	if err != nil {
+		log.Error(context.Background(), "Unable to retrieve config'", err)
+	}
+
+	if cfg.OtelEnabled {
+		return &Transport{domain, contextURL, otelhttp.NewTransport(rt)}
+
+	}
+
+	return &Transport{domain, contextURL, rt}
 }
 
 const (

main.go

@@ -48,22 +48,23 @@ func run(ctx context.Context) error {
 		return errors.Wrap(err, "unable to retrieve service configuration")
 	}
 
-	// // Set up OpenTelemetry
-	otelConfig := dpotelgo.Config{
-		OtelServiceName:          cfg.OTServiceName,
-		OtelExporterOtlpEndpoint: cfg.OTExporterOTLPEndpoint,
-		OtelBatchTimeout:         cfg.OTBatchTimeout,
-	}
+	if cfg.OtelEnabled {
+		// // Set up OpenTelemetry
+		otelConfig := dpotelgo.Config{
+			OtelServiceName:          cfg.OTServiceName,
+			OtelExporterOtlpEndpoint: cfg.OTExporterOTLPEndpoint,
+			OtelBatchTimeout:         cfg.OTBatchTimeout,
+		}
 
-	otelShutdown, oErr := dpotelgo.SetupOTelSDK(ctx, otelConfig)
-	if oErr != nil {
-		log.Error(ctx, "error setting up OpenTelemetry - hint: ensure OTEL_EXPORTER_OTLP_ENDPOINT is set", oErr)
+		otelShutdown, oErr := dpotelgo.SetupOTelSDK(ctx, otelConfig)
+		if oErr != nil {
+			log.Error(ctx, "error setting up OpenTelemetry - hint: ensure OTEL_EXPORTER_OTLP_ENDPOINT is set", oErr)
+		}
+		// Handle shutdown properly so nothing leaks.
+		defer func() {
+			err = goerrors.Join(err, otelShutdown(context.Background()))
+		}()
 	}
-	// Handle shutdown properly so nothing leaks.
-	defer func() {
-		err = goerrors.Join(err, otelShutdown(context.Background()))
-	}()
-
 	// Run the service
 	svc, err := service.Run(ctx, cfg, svcList, BuildTime, GitCommit, Version, svcErrors)
 	if err != nil {

service/service.go

@@ -72,8 +72,13 @@ func Run(ctx context.Context, cfg *config.Config, serviceList *ExternalServiceLi
 	r := CreateRouter(ctx, cfg)
 	otelhandler := otelhttp.NewHandler(r, "/")
 	m := svc.CreateMiddleware(cfg, r)
-	r.Use(otelmux.Middleware(cfg.OTServiceName))
-	svc.Server = dphttp.NewServer(cfg.BindAddr, m.Then(otelhandler))
+
+	if cfg.OtelEnabled {
+		r.Use(otelmux.Middleware(cfg.OTServiceName))
+		svc.Server = dphttp.NewServer(cfg.BindAddr, m.Then(otelhandler))
+	} else {
+		svc.Server = dphttp.NewServer(cfg.BindAddr, m.Then(r))
+	}
 
 	svc.Server.DefaultShutdownTimeout = cfg.GracefulShutdown
 	svc.Server.HandleOSSignals = false