feat:implement ServeGRPCAndHTTP supporting generic HTTP Handlers and …

…refactor ServeGRPCAndMetrics to use it (#7)

* feat:implement ServeGRPCAndHTTP supporting generic HTTP Handlers and refactor ServeGRPCAndMetrics to use it

* feat(auth):add support for authentification when creating a new gRPC service

* chore(go.mod):trigger go mod tidy sum update

* refactor: use default interceptors and pass extra extra-interceptors as arguments

* readme:add plain readme

* fix:fix lint issue

* chore(go.mod):add missing deps

* chore(go.mod):fix spurious pkg version

README.md

@@ -0,0 +1,11 @@
+# Optable Package Lib
+
+`optable-pkglib` is a set of useful packages for serving and maintaing gRPC services.
+
+## Install
+
+```sh
+
+go get github.com/optable/optable-pkglib
+
+```

lifecycle/serve.go

@@ -70,10 +70,10 @@ func ServeWithGracefulShutdown(ctx context.Context, listen net.Listener, server
 	return shutdownCompleted
 }
 
-// ServeGrpcAndMetrics behaves like ServeWithGracefulShutdown excepts that it
-// also starts a prometheus HTTP1 service on the same Listener to expose
+// ServeGRPCAndHTTP behaves like ServeWithGracefulShutdown excepts that it
+// also starts an HTTP1 service on the same Listener to expose
 // metrics.
-func ServeGrpcAndMetrics(ctx context.Context, l net.Listener, server *grpc.Server, shutdownTimeout time.Duration) <-chan error {
+func ServeGRPCAndHTTP(ctx context.Context, l net.Listener, handler http.Handler, server *grpc.Server, shutdownTimeout time.Duration) <-chan error {
 	errs := make(chan error, 1)
 
 	go func() {
@@ -101,7 +101,7 @@ func ServeGrpcAndMetrics(ctx context.Context, l net.Listener, server *grpc.Serve
 		// Serve requests for the prometheus HTTP metric handler.
 		group.Go(func() error {
 			httpServer := &http.Server{
-				Handler: promhttp.Handler(),
+				Handler: handler,
 			}
 			if err := httpServer.Serve(httpL); err != nil && !isClosedErr(err) {
 				return fmt.Errorf("Failed serving http: %w", err)
@@ -130,6 +130,13 @@ func ServeGrpcAndMetrics(ctx context.Context, l net.Listener, server *grpc.Serve
 	return errs
 }
 
+// ServeGRPCAndMetrics behaves like ServeWithGracefulShutdown excepts that it
+// also starts a prometheus HTTP1 service on the same Listener to expose
+// metrics.
+func ServeGRPCAndMetrics(ctx context.Context, l net.Listener, server *grpc.Server, shutdownTimeout time.Duration) <-chan error {
+	return ServeGRPCAndHTTP(ctx, l, promhttp.Handler(), server, shutdownTimeout)
+}
+
 func isClosedErr(err error) bool {
 	return errors.Is(err, net.ErrClosed) || errors.Is(err, cmux.ErrServerClosed)
 }

service/server.go

@@ -14,14 +14,13 @@ import (
 	"google.golang.org/grpc"
 )
 
-// NewGrpcService creates a grpc service with various defaults middlewares.
+// NewGRPCService creates a grpc service with various defaults middlewares.
 // Notably, the logging and metrics are automatically registered for sane
 // defaults of observability.
-func NewGrpcService(ctx context.Context, service interface{}, descriptors []*grpc.ServiceDesc) (*grpc.Server, error) {
+func NewGRPCService(ctx context.Context, service interface{}, descriptors []*grpc.ServiceDesc, unaryIntercepts []grpc.UnaryServerInterceptor, streamIntercepts []grpc.StreamServerInterceptor) (*grpc.Server, error) {
 	if len(descriptors) == 0 {
 		return nil, errors.New("Missing descriptors")
 	}
-
 	// By using prometheus.DefaultRegister we benefits from the go runtime
 	// defaults metrics and Linux processes metrics.
 	registry := prometheus.DefaultRegisterer
@@ -34,19 +33,21 @@ func NewGrpcService(ctx context.Context, service interface{}, descriptors []*grp
 	}
 
 	logger := zerolog.Ctx(ctx)
+	defaultStreamInterceptors := []grpc.StreamServerInterceptor{
+		logging.StreamServerInterceptor(grpczerolog.InterceptorLogger(*logger)),
+		metrics.StreamServerInterceptor(m),
+		recovery.StreamServerInterceptor(),
+	}
+	defaultUnaryInterceptors := []grpc.UnaryServerInterceptor{
+		logging.UnaryServerInterceptor(grpczerolog.InterceptorLogger(*logger)),
+		metrics.UnaryServerInterceptor(m),
+		recovery.UnaryServerInterceptor(),
+	}
+
+	defaultUnaryInterceptors = append(defaultUnaryInterceptors, unaryIntercepts...)
+	defaultStreamInterceptors = append(defaultStreamInterceptors, streamIntercepts...)
 
-	server := grpc.NewServer(
-		grpc.ChainStreamInterceptor(
-			logging.StreamServerInterceptor(grpczerolog.InterceptorLogger(*logger)),
-			metrics.StreamServerInterceptor(m),
-			recovery.StreamServerInterceptor(),
-		),
-		grpc.ChainUnaryInterceptor(
-			logging.UnaryServerInterceptor(grpczerolog.InterceptorLogger(*logger)),
-			metrics.UnaryServerInterceptor(m),
-			recovery.UnaryServerInterceptor(),
-		),
-	)
+	server := grpc.NewServer(grpc.ChainStreamInterceptor(defaultStreamInterceptors...), grpc.ChainUnaryInterceptor(defaultUnaryInterceptors...))
 
 	for _, desc := range descriptors {
 		logger.Info().Msgf("Registering grpc service: %s", desc.ServiceName)