Add example binary for testing the example service

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

example/cmd/main.go

@@ -0,0 +1,135 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package main
+
+import (
+	context "context"
+	"encoding/json"
+	"errors"
+	"log"
+	"net"
+	"os"
+
+	ttrpc "github.com/containerd/ttrpc"
+	"github.com/containerd/ttrpc/example"
+	"github.com/gogo/protobuf/types"
+)
+
+const socket = "example-ttrpc-server"
+
+func main() {
+	if err := handle(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func handle() error {
+	command := os.Args[1]
+	switch command {
+	case "server":
+		return server()
+	case "client":
+		return client()
+	default:
+		return errors.New("invalid command")
+	}
+}
+
+func serverIntercept(ctx context.Context, um ttrpc.Unmarshaler, i *ttrpc.UnaryServerInfo, m ttrpc.Method) (interface{}, error) {
+	log.Println("server interceptor")
+	dumpMetadata(ctx)
+	return m(ctx, um)
+}
+
+func clientIntercept(ctx context.Context, req *ttrpc.Request, resp *ttrpc.Response, i *ttrpc.UnaryClientInfo, invoker ttrpc.Invoker) error {
+	log.Println("client interceptor")
+	dumpMetadata(ctx)
+	return invoker(ctx, req, resp)
+}
+
+func dumpMetadata(ctx context.Context) {
+	md, ok := ttrpc.GetMetadata(ctx)
+	if !ok {
+		panic("no metadata")
+	}
+	if err := json.NewEncoder(os.Stdout).Encode(md); err != nil {
+		panic(err)
+	}
+}
+
+func server() error {
+	s, err := ttrpc.NewServer(
+		ttrpc.WithServerHandshaker(ttrpc.UnixSocketRequireSameUser()),
+		ttrpc.WithUnaryServerInterceptor(serverIntercept),
+	)
+	if err != nil {
+		return err
+	}
+	defer s.Close()
+	example.RegisterExampleService(s, &exampleServer{})
+
+	l, err := net.Listen("unix", socket)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		l.Close()
+		os.Remove(socket)
+	}()
+	return s.Serve(context.Background(), l)
+}
+
+func client() error {
+	conn, err := net.Dial("unix", socket)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	tc := ttrpc.NewClient(conn, ttrpc.WithUnaryClientInterceptor(clientIntercept))
+	client := example.NewExampleClient(tc)
+
+	r := &example.Method1Request{
+		Foo: os.Args[2],
+		Bar: os.Args[3],
+	}
+
+	ctx := context.Background()
+	md := ttrpc.Metadata{}
+	md.Set("name", "koye")
+	ctx = ttrpc.WithMetadata(ctx, md)
+
+	resp, err := client.Method1(ctx, r)
+	if err != nil {
+		return err
+	}
+	return json.NewEncoder(os.Stdout).Encode(resp)
+}
+
+type exampleServer struct {
+}
+
+func (s *exampleServer) Method1(ctx context.Context, r *example.Method1Request) (*example.Method1Response, error) {
+	return &example.Method1Response{
+		Foo: r.Foo,
+		Bar: r.Bar,
+	}, nil
+}
+
+func (s *exampleServer) Method2(ctx context.Context, r *example.Method1Request) (*types.Empty, error) {
+	return &types.Empty{}, nil
+}