improve server startup

pkg/app/app.go

@@ -2,6 +2,7 @@ package app
 
 import (
 	"errors"
+	"sync"
 
 	"github.com/rs/zerolog"
 	"go.opentelemetry.io/otel/attribute"
@@ -26,30 +27,52 @@ 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()
 
+	var serverWG sync.WaitGroup
+
 	// Start HTTP (does not block)
-	if err := a.initHTTP(ctx); err != nil {
-		initSpan.RecordError(err)
-		initSpan.SetStatus(codes.Error, err.Error())
+	if a.cfg.HTTPEnabled() {
+		serverWG.Add(1)
+		go func() {
+			defer serverWG.Done()
+			if err := a.initHTTP(ctx); err != nil {
+				initSpan.RecordError(err)
+				initSpan.SetStatus(codes.Error, err.Error())
+			}
+			initSpan.AddEvent("http server started")
+			initSpan.SetAttributes(attribute.Int("http.handlers", len(a.HTTP.Funcs)))
+		}()
 	}
-	initSpan.AddEvent("http server started")
-	initSpan.SetAttributes(attribute.Int("http.handlers", len(a.HTTP.Funcs)))
 
 	// Start GRPC (does not block)
-	if err := a.initGRPC(ctx); err != nil {
-		initSpan.RecordError(err)
-		initSpan.SetStatus(codes.Error, err.Error())
+	if a.cfg.GRPCEnabled() {
+		serverWG.Add(1)
+		go func() {
+			defer serverWG.Done()
+			if err := a.initGRPC(ctx); err != nil {
+				initSpan.RecordError(err)
+				initSpan.SetStatus(codes.Error, err.Error())
+			}
+			initSpan.AddEvent("grpc server started")
+			initSpan.SetAttributes(attribute.Int("grpc.services", len(a.GRPC.Services)))
+		}()
 	}
-	initSpan.AddEvent("grpc server started")
-	initSpan.SetAttributes(attribute.Int("grpc.services", len(a.GRPC.Services)))
+
+	serverWG.Wait()
 
 	// Monitor app lifecycle
 	go a.run()

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

pkg/srv/grpc/grpc.go

@@ -62,6 +62,8 @@ func InitGRPCServer(ctx context.Context, opts *opts.GRPCOpts) (
 		return nil, nil, err
 	}
 
+	appGRPC.logger.Debug().Msg("GRPC Server Started")
+
 	span.SetStatus(codes.Ok, "")
 	return appGRPC.shutdownFunc, appGRPC.doneChan, nil
 }

pkg/srv/grpc/grpc_run.go

@@ -56,8 +56,11 @@ func (a *appGRPCServer) getShutdownFunc() func(context.Context) error {
 
 		select {
 		case <-stoppedChan:
+			a.logger.Warn().Msg("GRPC server shut down gracefully")
 			return nil
 		case <-ctx.Done():
+			a.logger.Warn().Msg("GRPC server shut down hard")
+			a.server.Stop()
 			return ctx.Err()
 		}
 	}