Initial attempt at adding support for gRPC

client/client.go

@@ -1,33 +1,15 @@
 package client
 
+type RequestFunc func(address string) (err error)
+
 type Client interface {
-	NewRequest(string, string, interface{}) Request
-	NewProtoRequest(string, string, interface{}) Request
-	NewJsonRequest(string, string, interface{}) Request
-	Call(interface{}, interface{}) error
-	CallRemote(string, string, interface{}, interface{}) error
+	NewRequest(service string, f RequestFunc) error
 }
 
 var (
-	client = NewRpcClient()
+	client = NewGRPCClient()
 )
 
-func Call(request Request, response interface{}) error {
-	return client.Call(request, response)
-}
-
-func CallRemote(address, path string, request Request, response interface{}) error {
-	return client.CallRemote(address, path, request, response)
-}
-
-func NewRequest(service, method string, request interface{}) Request {
-	return client.NewRequest(service, method, request)
-}
-
-func NewProtoRequest(service, method string, request interface{}) Request {
-	return client.NewProtoRequest(service, method, request)
-}
-
-func NewJsonRequest(service, method string, request interface{}) Request {
-	return client.NewJsonRequest(service, method, request)
+func NewRequest(service string, f RequestFunc) error {
+	return client.NewRequest(service, f)
 }

client/grpc_client.go

@@ -0,0 +1,56 @@
+package client
+
+import (
+	"fmt"
+	"github.com/asim/go-micro/registry"
+	"math/rand"
+	"net/http"
+	"time"
+
+	"github.com/asim/go-micro/errors"
+	"google.golang.org/grpc"
+)
+
+type headerRoundTripper struct {
+	r http.RoundTripper
+}
+
+type GRPCClient struct{}
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+func (r *GRPCClient) NewRequest(serviceName string, f RequestFunc) error {
+	service, err := registry.GetService(serviceName)
+	if err != nil {
+		return errors.InternalServerError("go.micro.client", err.Error())
+	}
+
+	if len(service.Nodes()) == 0 {
+		return errors.NotFound("go.micro.client", "Service not found")
+	}
+
+	n := rand.Int() % len(service.Nodes())
+	node := service.Nodes()[n]
+	address := fmt.Sprintf("%s:%d", node.Address(), node.Port())
+
+	return f(address)
+}
+
+func NewGRPCClient() *GRPCClient {
+	return &GRPCClient{}
+}
+
+func GRPCRequest(f func(cc *grpc.ClientConn) error) RequestFunc {
+	return func(address string) error {
+		fmt.Println(address)
+		cc, err := grpc.Dial(address)
+		if err != nil {
+			return err
+		}
+		defer cc.Close()
+
+		return f(cc)
+	}
+}

examples/greeter-client/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"os"
+
+	"github.com/asim/go-micro/client"
+	log "github.com/golang/glog"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+
+	pb "github.com/asim/go-micro/examples/greeter-service/proto"
+)
+
+const (
+	defaultName = "world"
+)
+
+func main() {
+	name := defaultName
+	if len(os.Args) > 1 {
+		name = os.Args[1]
+	}
+
+	// Create new request to service go.micro.service.go-template
+	var r *pb.HelloReply
+	err := client.NewRequest("go.micro.service.greeter", client.GRPCRequest(func(cc *grpc.ClientConn) (err error) {
+		c := pb.NewGreeterClient(cc)
+		r, err = c.SayHello(context.Background(), &pb.HelloRequest{Name: name})
+		return
+	}))
+	if err != nil {
+		log.Fatalf("could not greet: %v", err)
+	}
+
+	log.Infof("Greeting: %s", r.Message)
+
+}

examples/greeter-service/Dockerfile

@@ -0,0 +1,3 @@
+FROM scratch
+ADD template /
+ENTRYPOINT [ "/template" ]

examples/greeter-service/README.md

@@ -0,0 +1,30 @@
+# Template Service
+
+An example Go service running with go-micro
+
+### Prerequisites
+
+Install Consul
+[https://www.consul.io/intro/getting-started/install.html](https://www.consul.io/intro/getting-started/install.html)
+
+Run Consul
+```
+$ consul agent -server -bootstrap-expect 1 -data-dir /tmp/consul
+```
+
+Run Service
+```
+$ go run main.go
+
+1416690099281057746 [Debug] Rpc handler /_rpc
+1416690099281092588 [Debug] Starting server go.micro.service.template id go.micro.service.template-c0bfcb44-728a-11e4-b099-68a86d0d36b6
+1416690099281192941 [Debug] Listening on [::]:58264
+1416690099281215346 [Debug] Registering go.micro.service.template-c0bfcb44-728a-11e4-b099-68a86d0d36b6
+```
+
+Test Service
+```
+$ go run go-micro/examples/service_client.go
+
+go.micro.service.template-c0bfcb44-728a-11e4-b099-68a86d0d36b6: Hello John
+```