Add grpc plugin (#2758)

* Add grpc plugin

* remove stale readmes

client/grpc/grpc_test.go

@@ -0,0 +1,112 @@
+package grpc
+
+import (
+	"context"
+	"net"
+	"testing"
+
+	"go-micro.dev/v5/client"
+	"go-micro.dev/v5/errors"
+	"go-micro.dev/v5/registry"
+	"go-micro.dev/v5/selector"
+	pgrpc "google.golang.org/grpc"
+	pb "google.golang.org/grpc/examples/helloworld/helloworld"
+)
+
+// server is used to implement helloworld.GreeterServer.
+type greeterServer struct {
+	pb.UnimplementedGreeterServer
+}
+
+// SayHello implements helloworld.GreeterServer.
+func (g *greeterServer) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
+	if in.Name == "Error" {
+		return nil, &errors.Error{Id: "1", Code: 99, Detail: "detail"}
+	}
+	return &pb.HelloReply{Message: "Hello " + in.Name}, nil
+}
+
+func TestGRPCClient(t *testing.T) {
+	l, err := net.Listen("tcp", ":0")
+	if err != nil {
+		t.Fatalf("failed to listen: %v", err)
+	}
+	defer l.Close()
+
+	s := pgrpc.NewServer()
+	pb.RegisterGreeterServer(s, &greeterServer{})
+
+	go s.Serve(l)
+	defer s.Stop()
+
+	// create mock registry
+	r := registry.NewMemoryRegistry()
+
+	// register service
+	r.Register(&registry.Service{
+		Name:    "helloworld",
+		Version: "test",
+		Nodes: []*registry.Node{
+			{
+				Id:      "test-1",
+				Address: l.Addr().String(),
+				Metadata: map[string]string{
+					"protocol": "grpc",
+				},
+			},
+		},
+	})
+
+	// create selector
+	se := selector.NewSelector(
+		selector.Registry(r),
+	)
+
+	// create client
+	c := NewClient(
+		client.Registry(r),
+		client.Selector(se),
+	)
+
+	testMethods := []string{
+		"/helloworld.Greeter/SayHello",
+		"Greeter.SayHello",
+	}
+
+	for _, method := range testMethods {
+		req := c.NewRequest("helloworld", method, &pb.HelloRequest{
+			Name: "John",
+		})
+
+		rsp := pb.HelloReply{}
+
+		err = c.Call(context.TODO(), req, &rsp)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if rsp.Message != "Hello John" {
+			t.Fatalf("Got unexpected response %v", rsp.Message)
+		}
+	}
+
+	req := c.NewRequest("helloworld", "/helloworld.Greeter/SayHello", &pb.HelloRequest{
+		Name: "Error",
+	})
+
+	rsp := pb.HelloReply{}
+
+	err = c.Call(context.TODO(), req, &rsp)
+	if err == nil {
+		t.Fatal("nil error received")
+	}
+
+	verr, ok := err.(*errors.Error)
+	if !ok {
+		t.Fatalf("invalid error received %#+v\n", err)
+	}
+
+	if verr.Code != 99 && verr.Id != "1" && verr.Detail != "detail" {
+		t.Fatalf("invalid error received %#+v\n", verr)
+	}
+}