add go-micro examples

README.md

@@ -25,6 +25,11 @@ Use flag `--registry=mdns`
 - [plugins](plugins) - How to use plugins
 - [template](template) - Api, web and srv service templates generated with `micro new`
 
+- [client](client) - Usage of the Client package to call a service.
+- [broker](broker) - A example of using Broker for Publish and Subscribing.
+- [server](server) - Use of the Server package directly to server requests.
+- [service](service) - Example of the top level Service in go-micro.
+
 ## External
 
 - [auth-srv](https://github.com/micro/auth-srv) - An Oauth2 authentication service

broker/README.md

@@ -0,0 +1,7 @@
+# Broker
+
+## Contents
+
+- main.go - demonstrates simple runs pub-sub as two go routines running for 10 seconds.
+- producer - publishes messages to the broker every second
+- consumer - consumes any messages sent by the producer

broker/consumer/consumer.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/micro/go-micro/broker"
+	"github.com/micro/go-micro/cmd"
+	// To enable rabbitmq plugin uncomment
+	//_ "github.com/micro/go-plugins/broker/rabbitmq"
+)
+
+var (
+	topic = "go.micro.topic.foo"
+)
+
+// Example of a shared subscription which receives a subset of messages
+func sharedSub() {
+	_, err := broker.Subscribe(topic, func(p broker.Publication) error {
+		fmt.Println("[sub] received message:", string(p.Message().Body), "header", p.Message().Header)
+		return nil
+	}, broker.Queue("consumer"))
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+// Example of a subscription which receives all the messages
+func sub() {
+	_, err := broker.Subscribe(topic, func(p broker.Publication) error {
+		fmt.Println("[sub] received message:", string(p.Message().Body), "header", p.Message().Header)
+		return nil
+	})
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+func main() {
+	cmd.Init()
+
+	if err := broker.Init(); err != nil {
+		log.Fatalf("Broker Init error: %v", err)
+	}
+	if err := broker.Connect(); err != nil {
+		log.Fatalf("Broker Connect error: %v", err)
+	}
+
+	sub()
+	select {}
+}

broker/main.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/micro/go-micro/broker"
+	"github.com/micro/go-micro/cmd"
+)
+
+var (
+	topic = "go.micro.topic.foo"
+)
+
+func pub() {
+	tick := time.NewTicker(time.Second)
+	i := 0
+	for _ = range tick.C {
+		msg := &broker.Message{
+			Header: map[string]string{
+				"id": fmt.Sprintf("%d", i),
+			},
+			Body: []byte(fmt.Sprintf("%d: %s", i, time.Now().String())),
+		}
+		if err := broker.Publish(topic, msg); err != nil {
+			log.Printf("[pub] failed: %v", err)
+		} else {
+			fmt.Println("[pub] pubbed message:", string(msg.Body))
+		}
+		i++
+	}
+}
+
+func sub() {
+	_, err := broker.Subscribe(topic, func(p broker.Publication) error {
+		fmt.Println("[sub] received message:", string(p.Message().Body), "header", p.Message().Header)
+		return nil
+	})
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+func main() {
+	cmd.Init()
+
+	if err := broker.Init(); err != nil {
+		log.Fatalf("Broker Init error: %v", err)
+	}
+	if err := broker.Connect(); err != nil {
+		log.Fatalf("Broker Connect error: %v", err)
+	}
+
+	go pub()
+	go sub()
+
+	<-time.After(time.Second * 10)
+}

broker/producer/producer.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/micro/go-micro/broker"
+	"github.com/micro/go-micro/cmd"
+	// To enable rabbitmq plugin uncomment
+	//_ "github.com/micro/go-plugins/broker/rabbitmq"
+)
+
+var (
+	topic = "go.micro.topic.foo"
+)
+
+func pub() {
+	tick := time.NewTicker(time.Second)
+	i := 0
+	for _ = range tick.C {
+		msg := &broker.Message{
+			Header: map[string]string{
+				"id": fmt.Sprintf("%d", i),
+			},
+			Body: []byte(fmt.Sprintf("%d: %s", i, time.Now().String())),
+		}
+		if err := broker.Publish(topic, msg); err != nil {
+			log.Printf("[pub] failed: %v", err)
+		} else {
+			fmt.Println("[pub] pubbed message:", string(msg.Body))
+		}
+		i++
+	}
+}
+
+func main() {
+	cmd.Init()
+
+	if err := broker.Init(); err != nil {
+		log.Fatalf("Broker Init error: %v", err)
+	}
+
+	if err := broker.Connect(); err != nil {
+		log.Fatalf("Broker Connect error: %v", err)
+	}
+
+	pub()
+}

client/README.md

@@ -0,0 +1,12 @@
+# Client
+
+## Contents
+
+- main.go - calls each of the go.micro.srv.example handlers and includes the use of the streaming handler
+- codegen - demonstrates how to use code generation to remove boilerplate code
+- dc_filter - shows how to use Select filters inside a call wrapper for filtering to the local DC
+- dc_selector - is the same as dc_filter but as a Selector implementation itself
+- pub - publishes messages using the Publish method. By default encoding in protobuf
+- selector - shows how to write and load your own Selector
+- wrapper - provides examples for how to use client Wrappers (middleware)
+

client/codegen/README.md

@@ -0,0 +1,150 @@
+# Code Generation [Experimental]
+
+We're experimenting with code generation to reduce the amount of boiler plate code written.
+
+## Example
+
+Going from this
+```golang
+req := client.NewRequest("go.micro.srv.example", "Example.Call", &example.Request{
+	Name: "John",
+})
+
+rsp := &example.Response{}
+
+if err := client.Call(context.Background(), req, rsp); err != nil {
+	return err
+}
+```
+
+To
+
+```golang
+rsp, err := cl.Call(context.Background(), &example.Request{Name: "John"})
+if err != nil {
+	return err
+}
+```
+
+## Generation of stub code for the example service
+
+```shell
+go get github.com/micro/protobuf/protoc-gen-go
+cd examples/server/proto/example
+protoc --go_out=plugins=micro:. example.proto
+```
+
+Look at examples/server/proto/example/example.pb.go 
+to see the generated code.
+
+## Guide
+
+### Download the protoc-gen-go code
+
+```shell
+go get github.com/micro/protobuf/protoc-gen-go
+```
+
+### Define your proto service.
+
+hello.proto
+```shell
+syntax = "proto3";
+
+// package name is used as the service name for discovery
+// if service name is not passed in when initialising the 
+// client
+package go.micro.srv.greeter;
+
+service Say {
+	rpc Hello(Request) returns (Response) {}
+}
+
+message Request {
+	optional string name = 1;
+}
+
+message Response {
+	optional string msg = 1;
+}
+```
+
+**Note: Remember to set package name in the proto, it's used to generate 
+the service for discovery.**
+
+### Generate code
+
+```shell
+protoc --go_out=plugins=micro:. hello.proto
+```
+
+### Generated code
+
+```shell
+// Client API for Say service
+
+type SayClient interface {
+        Hello(ctx context.Context, in *Request) (*Response, error)
+}
+
+type sayClient struct {
+        c           client.Client
+        serviceName string
+}
+
+func NewSayClient(serviceName string, c client.Client) SayClient {
+        if c == nil {
+                c = client.NewClient()
+        }
+        if len(serviceName) == 0 {
+                serviceName = "go.micro.srv.greeter"
+        }
+        return &sayClient{
+                c:           c,
+                serviceName: serviceName,
+        }
+}
+
+func (c *sayClient) Hello(ctx context.Context, in *Request) (*Response, error) {
+        req := c.c.NewRequest(c.serviceName, "Say.Hello", in)
+        out := new(Response)
+        err := c.c.Call(ctx, req, out)
+        if err != nil {
+                return nil, err
+        }
+        return out, nil
+}
+
+// Server API for Say service
+
+type SayHandler interface {
+        Hello(context.Context, *Request, *Response) error
+}
+
+func RegisterSayHandler(s server.Server, hdlr SayHandler) {
+        s.Handle(s.NewHandler(hdlr))
+}
+```
+
+### Use the client
+```golang
+
+import (
+	"fmt"
+
+	"golang.org/x/net/context"
+	"github.com/micro/go-micro/client"
+	hello "path/to/hello/proto"
+)
+
+func main() {
+	cl := hello.NewSayClient("go.micro.srv.greeter", client.DefaultClient)
+	// alternative initialisation
+	// cl := hello.NewSayClient("", nil)
+
+	rsp, err := cl.Hello(contex.Background(), &hello.Request{"Name": "John"})
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+```