improve grpc lifecycle

pkg/app/app.go

@@ -17,8 +17,6 @@ func (a *App) Done() <-chan any {
 func (a *App) MustRun() {
 	if a.cfg != nil {
 		panic(errors.New("already ran app trying to run"))
-	} else if !a.cfg.HTTP.Enabled && !a.cfg.GRPC.Enabled {
-		panic(errors.New("neither http nor grpc enabled, nothing to do"))
 	}
 
 	// Set up app
@@ -28,17 +26,23 @@ func (a *App) MustRun() {
 	a.appDone = make(chan any)
 	a.HTTP.HTTPDone = make(chan any)
 
+	if !a.cfg.HTTPEnabled() && !a.cfg.GRPCEnabled() {
+		panic(errors.New("neither http nor grpc enabled, nothing to do"))
+	}
+
 	if len(a.HTTP.Funcs) < 1 {
 		a.l.Warn().Msg("no http funcs provided, only serving health and metrics")
 	}
 
 	// Start OTEL
+	// Registers a NO-OP provider if not enabled
 	a.initOTEL()
+
 	ctx, initSpan := a.tracer.Start(a.AppContext, "init")
 	defer initSpan.End()
 
 	// Start HTTP (does not block)
-	if a.cfg.HTTP.Enabled {
+	if a.cfg.HTTPEnabled() {
 		if err := a.initHTTP(ctx); err != nil {
 			initSpan.RecordError(err)
 			initSpan.SetStatus(codes.Error, err.Error())
@@ -48,7 +52,7 @@ func (a *App) MustRun() {
 	}
 
 	// Start GRPC (does not block)
-	if a.cfg.GRPC.Enabled {
+	if a.cfg.GRPCEnabled() {
 		if err := a.initGRPC(ctx); err != nil {
 			initSpan.RecordError(err)
 			initSpan.SetStatus(codes.Error, err.Error())

pkg/config/types.go

@@ -22,3 +22,24 @@ type AppConfig struct {
 	OTEL    *OTELConfig `yaml:"otel,omitempty"`
 	GRPC    *GRPCConfig `yaml:"grpc,omitempty"`
 }
+
+func (ac *AppConfig) HTTPEnabled() bool {
+	if ac.HTTP != nil && ac.HTTP.Enabled {
+		return true
+	}
+	return false
+}
+
+func (ac *AppConfig) GRPCEnabled() bool {
+	if ac.GRPC != nil && ac.GRPC.Enabled {
+		return true
+	}
+	return false
+}
+
+func (ac *AppConfig) OTELEnabled() bool {
+	if ac.OTEL != nil && ac.OTEL.Enabled {
+		return true
+	}
+	return false
+}

pkg/otel/otel.go

@@ -44,7 +44,7 @@ func Init(ctx context.Context) (context.Context, func(context.Context) error) {
 	cfg := config.MustFromCtx(ctx)
 
 	// Nothing to do here if not enabled
-	if !cfg.OTEL.Enabled {
+	if !cfg.OTELEnabled() {
 		opentelemetry.SetMeterProvider(noopMetric.NewMeterProvider())
 		opentelemetry.SetTracerProvider(noop.NewTracerProvider())
 		// Won't function with noop providers