add example

Makefile

@@ -1,8 +1,12 @@
 GO_PLUGIN=bin/protoc-gen-go
 GO_PLUGIN_PKG=github.com/golang/protobuf/protoc-gen-go
+GATEWAY_PLUGIN=bin/protoc-gen-grpc-gateway
+GATEWAY_PLUGIN_PKG=github.com/gengo/grpc-gateway/protoc-gen-grpc-gateway
+GATEWAY_PLUGIN_SRC=protoc-gen-grpc-gateway/main.go protoc-gen-grpc-gateway/generator.go
 OPTIONS_GO=options/options.pb.go
 OPTIONS_PROTO=options/options.proto
 PKGMAP=Mgoogle/protobuf/descriptor.proto=$(GO_PLUGIN_PKG)/descriptor
+EXAMPLES=examples/echo_service.proto
 
 generate: $(OPTIONS_GO)
 
@@ -15,5 +19,12 @@ $(GO_PLUGIN):
 $(OPTIONS_GO): $(OPTIONS_PROTO) $(GO_PLUGIN)
 	protoc -I $(dir $(shell which protoc))/../include -I. --plugin=$(GO_PLUGIN) --go_out=$(PKGMAP):. $(OPTIONS_PROTO)
 
+$(GATEWAY_PLUGIN): $(OPTIONS_GO) $(GATEWAY_PLUGIN_SRC)
+	go build -o $@ $(GATEWAY_PLUGIN_PKG)
+
+test: $(GO_PLUGIN) $(GATEWAY_PLUGIN) $(EXAMPLES)
+	protoc -I $(dir $(shell which protoc))/../include -I. --plugin=$(GO_PLUGIN) --go_out=$(PKGMAP),plugins=grpc:. $(EXAMPLES)
+	protoc -I $(dir $(shell which protoc))/../include -I. --plugin=$(GATEWAY_PLUGIN) --grpc-gateway_out=logtostderr=true:. $(EXAMPLES)
+
 realcelan:
 	rm -f $(OPTIONS_GO)

bin/.gitignore

@@ -1 +1,2 @@
 /protoc-gen-go
+/protoc-gen-grpc-gateway

examples/echo_service.pb.gw.go

@@ -0,0 +1,96 @@
+package examples
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/golang/glog"
+	"github.com/golang/protobuf/proto"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+)
+
+func handle_EchoService_Echo(ctx context.Context, c *EchoServiceClient, req *http.Request) (proto.Message, error) {
+	protoReq := new(SimpleMessage)
+
+	if err = json.NewDecoder(req.Body).Decode(&protoReq); err != nil {
+		return err
+	}
+
+	return c.Echo(ctx, protoReq)
+}
+
+var (
+	endpointEchoService string
+)
+
+func init() {
+
+	flag.StringVar(&endpointEchoService, "echo_service_endpoint", "", "endpoint host:port of EchoService")
+
+}
+
+type handler struct {
+	mux   http.ServeMux
+	conns map[string]*grpc.ClientConn
+}
+
+func (h *handler) Close() error {
+	var err error
+	for svc, conn := range h.conns {
+		cerr := conn.Close()
+		if err == nil {
+			err = cerr
+		}
+		if cerr != nil {
+			glog.Errorf("Failed to close gRPC connection to %s: %v", svc, err)
+		}
+	}
+	return err
+}
+
+func NewHandler(ctx context.Context) (http.Handler, error) {
+	h := &handler{
+		conn: make(map[string]*grpc.ClientConn),
+	}
+	var err error
+	defer func() {
+		if err != nil {
+			h.Close()
+		}
+	}()
+
+	err = func() error {
+		conn, err := grpc.Dial(endpointEchoService)
+		if err != nil {
+			return err
+		}
+		h.conn["EchoService"] = conn
+		client := NewEchoServiceClient(conn)
+
+		mux.HandleFunc("/v1/example/echo", func(w http.ResponseWriter, req *http.Request) {
+			resp, err := handle_EchoService_Echo(ctx, client, req)
+			if err != nil {
+				glog.Errorf("RPC error: %v", err)
+				http.Error(w, err.String(), http.StatusInternalServerError)
+				return
+			}
+			buf, err := proto.Marshal(resp)
+			if err != nil {
+				glog.Errorf("Marshal error: %v", err)
+				http.Error(w, err.String(), http.StatusInternalServerError)
+				return
+			}
+			w.Header().Set("Content-Type", "application/json")
+			if err = w.Write(buf); err != nil {
+				glog.Errorf("Failed to write response: %v", err)
+			}
+		})
+
+	}()
+	if err != nil {
+		return nil, err
+	}
+
+	return h, nil
+}

examples/echo_service.proto

@@ -0,0 +1,18 @@
+syntax = "proto3";
+option go_package = "examples";
+package gengo.grpc.gateway.example;
+
+import "options/options.proto";
+
+message SimpleMessage {
+	string id = 1;
+}
+
+service EchoService {
+	rpc Echo(SimpleMessage) returns (SimpleMessage) {
+		option (gengo.grpc.gateway.ApiMethodOptions.api_options) = {
+			path: "/v1/example/echo"
+			method: "POST"
+		};
+	}
+}