This section describes micro message subscription and publishing content
Before reading this article you might need the following knowledge base
- golang distributed micro-services framework go-micro introductory note 1: Building the go-micro environment,
- golang go-micro Micro Services Framework 2.1 micro micro api introductory notes of tools
- golang micro-services framework go-micro entry notes of 2.2 micro micro web tool
broker proxy
Need to pass messages between the micro broker services through, go-micro supports http / nats / memory three kinds of broker, which is the default http broker.
Meanwhile, go-micro with a strong form of plug-ins provide several common broker as follows.
$ls
gocloud/ googlepubsub/ grpc/ kafka/ mqtt/ nats/ nsq/ proxy/ rabbitmq/ redis/ snssqs/ sqs/ stan/ stomp/
http
HTTP HTTP is based on asynchronous Broker Broker, source code github.com\micro\[email protected]\broker\broker.go, the default is http DefaultBroker
var (
DefaultBroker Broker = newHttpBroker()
)
httpbroker is actually a structure
type httpBroker struct {
id string //微服务ID
address string //主机地址
opts Options //一些配置
mux *http.ServeMux //通过这个监听其他端发送的http请求
c *http.Client //通过这个发送请求到其他端
r registry.Registry
sync.RWMutex
subscribers map[string][]*httpSubscriber //订阅
running bool
exit chan chan error
// offline message inbox
mtx sync.RWMutex
inbox map[string][][]byte //数据缓存
}
By http.Clientsending a request, by the http.ServeMuxrealization request listening, by inboxstoring the data
repeat
following initialization code redis
//main.go
//初始化URL格式redis://密码@主机:端口/
b := redis.NewBroker(
broker.Addrs("redis://user:secret@localhost:6379/"),
)
//初始化
b.Init()
//连接
b.Connect()
// 新建service
service := grpc.NewService(
micro.Name("go.micro.web.config"),
micro.Version("latest"),
micro.Broker(b),
)
//初始化service
service.Init()
//启动,运行,监听
service.Run()
Start the application need to specify the broker to redis
go run main.go --broker=redis
grpc initialization
Initialization process is as follows
//main.go
import (
"github.com/micro/go-plugins/broker/grpc"
)
// 建立连接
b := grpc.NewBroker()
b.Init()
b.Connect()
// 订阅事件
sub, _ := b.Subscribe("events")
defer sub.Unsubscribe()
// 发布事件
b.Publish("events", &broker.Message{
Headers: map[string]string{"type": "event"},
Body: []byte(`an event`),
})
Start the application need to specify the broker to grpc
go run main.go --broker=grpc
rabbitmq initialization
Initialization process is as follows
//main.go
import (
"github.com/micro/go-plugins/broker/grpc"
)
b := rabbitmq.NewBroker(
broker.Addrs("amqp://用户名:密码@主机host:端口port"),
)
b.Init()
b.Connect()
Start the application need to specify the broker to rabbitmq
go run main.go plugin.go --broker=rabbitmq
mqtt
Initialization process is as follows
//main.go
import (
"github.com/micro/go-micro"
"github.com/micro/go-plugins/broker/mqtt"
)
func main() {
service := micro.NewService(
micro.Name("my.service"),
micro.Broker(mqtt.NewBroker()),
)
//...
}
Start the application need to specify the broker to mqtt
go run main.go plugin.go --broker=mqtt
other
Other codes can be read
$GOPATH/src/github.com/micro/go-plugins/broker
Publish and subscribe messaging
Subscribe to implement the message through micro.RegisterSubscriber
The main message subscription API interface as the first parameter identifies the subject of a message, the second parameter indicates that the service instance.
// Register Struct as Subscriber
micro.RegisterSubscriber("go.micro.srv.testsrv", service.Server(), new(subscriber.Testsrv))
// Register Function as Subscriber
micro.RegisterSubscriber("go.micro.srv.testsrv", service.Server(), subscriber.Handler)
Important to note that the third parameter, the third parameter is the handler can be a function, it can be achieved
func Handler(ctx context.Context, msg *testsrv.Message) errorThe method of the structure, the internal micro automatically adapted according to the type of parameter. Structure may be implemented in a plurality of func Handler(ctx context.Context, msg *testsrv.Message) errortypes of methods
Subscribe achieved by broker.Subscribe
Broker provides the following interfaces
type Broker interface {
Init(...Option) error
Options() Options
Address() string
Connect() error
Disconnect() error
Publish(topic string, m *Message, opts ...PublishOption) error
Subscribe(topic string, h Handler, opts ...SubscribeOption) (Subscriber, error)
String() string
}
Subscribe Subscribe to the event, topic behalf of the subject, h event handler
Publish publishing events
Handler defined message handler
In the above relates to the handler handler, explained as follows
type Handler func(Event) error
// Event is given to a subscription handler for processing
type Event interface {
Topic() string
Message() *Message
Ack() error
}
type Message struct {
Header map[string]string
Body []byte
}
Published achieved by broker.Publish
For example as follows
// 建立连接
b := grpc.NewBroker()
b.Init()
b.Connect()
// 订阅事件
sub, _ := b.Subscribe("events")
defer sub.Unsubscribe()
// 发布事件
b.Publish("events", &broker.Message{
Headers: map[string]string{"type": "event"},
Body: []byte(`an event`),
})
Posted micro publish implemented by
For example as follows
micro publish "go.micro.web.config" "hello"
Combat and code
effect
Download the code broker.zipto extract techidea8.com/microapp/brokerthe next run, the effect of FIG nervous
- Note announced json format string
micro publish go.micro.srv.broker "{\"say\":\"这是测试消息\"}"Get Code
No reply to public attention micro-brokercan be obtained
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