Add recover in grpc service handler (#1727)

* 🐛 bug(grpc): add missing recover in grpc unkonwn service handler

* Add grpc handler recover testcases

* improve test case

Co-authored-by: ben-toogood <bentoogood@gmail.com>
Co-authored-by: Asim Aslam <asim@aslam.me>

server/grpc/grpc.go

@@ -183,7 +183,17 @@ func (g *grpcServer) getListener() net.Listener {
 	return nil
 }
 
-func (g *grpcServer) handler(srv interface{}, stream grpc.ServerStream) error {
+func (g *grpcServer) handler(srv interface{}, stream grpc.ServerStream) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
+				logger.Error("panic recovered: ", r)
+				logger.Error(string(debug.Stack()))
+			}
+			err = errors.InternalServerError("go.micro.server", "panic recovered: %v", r)
+		}
+	}()
+
 	if g.wg != nil {
 		g.wg.Add(1)
 		defer g.wg.Done()
@@ -367,15 +377,6 @@ func (g *grpcServer) processRequest(stream grpc.ServerStream, service *service,
 
 		// define the handler func
 		fn := func(ctx context.Context, req server.Request, rsp interface{}) (err error) {
-			defer func() {
-				if r := recover(); r != nil {
-					if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
-						logger.Error("panic recovered: ", r)
-						logger.Error(string(debug.Stack()))
-					}
-					err = errors.InternalServerError("go.micro.server", "panic recovered: %v", r)
-				}
-			}()
 			returnValues = function.Call([]reflect.Value{service.rcvr, mtype.prepareContext(ctx), reflect.ValueOf(argv.Interface()), reflect.ValueOf(rsp)})
 
 			// The return value for the method is an error.

server/grpc/grpc_test.go

@@ -60,6 +60,11 @@ func (s *testServer) Call(ctx context.Context, req *pb.Request, rsp *pb.Response
 		return &errors.Error{Id: "1", Code: 99, Detail: "detail"}
 	}
 
+	if req.Name == "Panic" {
+		// make it panic
+		panic("handler panic")
+	}
+
 	rsp.Msg = "Hello " + req.Name
 	return nil
 }
@@ -205,3 +210,101 @@ func TestGRPCServer(t *testing.T) {
 		}
 	}
 }
+
+// TestGRPCServerWithPanicWrapper test grpc server with panic wrapper
+// gRPC server should not crash when wrapper crashed
+func TestGRPCServerWithPanicWrapper(t *testing.T) {
+	r := rmemory.NewRegistry()
+	b := bmemory.NewBroker()
+	tr := tgrpc.NewTransport()
+	s := gsrv.NewServer(
+		server.Broker(b),
+		server.Name("foo"),
+		server.Registry(r),
+		server.Transport(tr),
+		server.WrapHandler(func(hf server.HandlerFunc) server.HandlerFunc {
+			return func(ctx context.Context, req server.Request, rsp interface{}) error {
+				// make it panic
+				panic("wrapper panic")
+			}
+		}),
+	)
+
+	h := &testServer{}
+	pb.RegisterTestHandler(s, h)
+
+	if err := s.Start(); err != nil {
+		t.Fatalf("failed to start: %v", err)
+	}
+
+	// check registration
+	services, err := r.GetService("foo")
+	if err != nil || len(services) == 0 {
+		t.Fatalf("failed to get service: %v # %d", err, len(services))
+	}
+
+	defer func() {
+		if err := s.Stop(); err != nil {
+			t.Fatalf("failed to stop: %v", err)
+		}
+	}()
+
+	cc, err := grpc.Dial(s.Options().Address, grpc.WithInsecure())
+	if err != nil {
+		t.Fatalf("failed to dial server: %v", err)
+	}
+
+	rsp := pb.Response{}
+	if err := cc.Invoke(context.Background(), "/test.Test/Call", &pb.Request{Name: "John"}, &rsp); err == nil {
+		t.Fatal("this must return error, as wrapper should be panic")
+	}
+
+	// both wrapper and handler should panic
+	rsp = pb.Response{}
+	if err := cc.Invoke(context.Background(), "/test.Test/Call", &pb.Request{Name: "Panic"}, &rsp); err == nil {
+		t.Fatal("this must return error, as wrapper and handler should be panic")
+	}
+}
+
+// TestGRPCServerWithPanicWrapper test grpc server with panic handler
+// gRPC server should not crash when handler crashed
+func TestGRPCServerWithPanicHandler(t *testing.T) {
+	r := rmemory.NewRegistry()
+	b := bmemory.NewBroker()
+	tr := tgrpc.NewTransport()
+	s := gsrv.NewServer(
+		server.Broker(b),
+		server.Name("foo"),
+		server.Registry(r),
+		server.Transport(tr),
+	)
+
+	h := &testServer{}
+	pb.RegisterTestHandler(s, h)
+
+	if err := s.Start(); err != nil {
+		t.Fatalf("failed to start: %v", err)
+	}
+
+	// check registration
+	services, err := r.GetService("foo")
+	if err != nil || len(services) == 0 {
+		t.Fatalf("failed to get service: %v # %d", err, len(services))
+	}
+
+	defer func() {
+		if err := s.Stop(); err != nil {
+			t.Fatalf("failed to stop: %v", err)
+		}
+	}()
+
+	cc, err := grpc.Dial(s.Options().Address, grpc.WithInsecure())
+	if err != nil {
+		t.Fatalf("failed to dial server: %v", err)
+	}
+
+	rsp := pb.Response{}
+	if err := cc.Invoke(context.Background(), "/test.Test/Call", &pb.Request{Name: "Panic"}, &rsp); err == nil {
+		t.Fatal("this must return error, as handler should be panic")
+	}
+}