NATS
介绍
NATS是一个开源、轻量级、高性能的分布式消息中间件，实现了高可伸缩性和优雅的Publish/Subscribe模型，使用Golang语言开发。NATS的开发哲学认为高质量的QoS应该在客户端构建，故只建立了Request-Reply，不提供 1.持久化 2.事务处理 3.增强的交付模式 4.企业级队列。
NATS消息传递模型
NATS支持各种消息传递模型，包括：
发布订阅（Publish Subscribe）
请求回复（Request Reply）
队列订阅（Queue Subscribers )
提供的功能：
纯粹的发布订阅模型（Pure pub-sub）
服务器集群（Cluster mode server）
自动精简订阅者（Auto-pruning of subscribers)
基于文本协议（Text-based protocol）
多服务质量保证（Multiple qualities of service - QoS）
发布订阅（Publish Subscribe）
NATS将publish/subscribe消息分发模型实现为一对多通信，发布者在Subject上发送消息，并且监听该Subject在任何活动的订阅者都会收到该消息
整合go-micro
consumer:
package main
import (
"fmt"
"github.com/micro/go-micro/broker"
"github.com/micro/go-plugins/broker/nats"
nat "github.com/nats-io/nats.go"
"log"
)
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.Event) 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.Event) error {
fmt.Println("[sub] received message:", string(p.Message().Body), "header", p.Message().Header)
return nil
})
if err != nil {
fmt.Println(err)
}
}
func main() {
na := nats.NewBroker(nats.Options(nat.GetDefaultOptions()))
if err := na.Init(); err != nil {
log.Fatalf("Broker Init error: %v", err)
}
if err := na.Connect(); err != nil {
log.Fatalf("Broker Connect error: %v", err)
}
sub()
select {}
}
producer:
package main
import (
"fmt"
"log"
"time"
"github.com/micro/go-micro/broker"
"github.com/micro/go-plugins/broker/nats"
nat "github.com/nats-io/nats.go"
)
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() {
na := nats.NewBroker(nats.Options(nat.GetDefaultOptions()))
if err := na.Init(); err != nil {
log.Fatalf("Broker Init error: %v", err)
}
if err := na.Connect(); err != nil {
log.Fatalf("Broker Connect error: %v", err)
}
pub()
}NATS Streaming
介绍
NATS由于不能保证消息的投递正确性和存在其他的缺点,NATS Streaming就孕育而生.他是一个由NATS提供支持的数据流系统,采用Go语言编写,NATS Streaming与核心NATS平台无缝嵌入，扩展和互操作.除了核心NATS平台的功能外,他还提供了以下功能:
NATS Streaming特征
增强消息协议(Enhanced message protocol)
消息/事件持久化(Message/event persistence)
至少一次数据传输(At-least-once-delivery)
Publisher限速(Publisher rate limiting)
Subscriber速率匹配(Rate matching/limiting per subscriber)
按主题重发消息(Historical message replay by subject)
持续订阅(Durable subscriptions)
整合go-micro
consumer:
package main
import (
"fmt"
"github.com/micro/go-micro/broker"
"github.com/micro/go-plugins/broker/stan"
stancf "github.com/nats-io/stan.go"
"log"
)
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.Event) 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.Event) error {
fmt.Println("[sub] received message:", string(p.Message().Body), "header", p.Message().Header)
return nil
})
if err != nil {
fmt.Println(err)
}
}
func main() {
na := stan.NewBroker(stan.ClusterID("test-cluster"), stan.Options(stancf.GetDefaultOptions()))
if err := na.Init(); err != nil {
log.Fatalf("Broker Init error: %v", err)
}
if err := na.Connect(); err != nil {
log.Fatalf("Broker Connect error: %v", err)
}
sub()
select {}
}
producer：
package main
import (
"fmt"
"log"
"time"
"github.com/micro/go-micro/broker"
"github.com/micro/go-plugins/broker/stan"
stancf "github.com/nats-io/stan.go"
)
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() {
na := stan.NewBroker(stan.ClusterID("test-cluster"), stan.Options(stancf.GetDefaultOptions()))
if err := na.Init(); err != nil {
log.Fatalf("Broker Init error: %v", err)
}
if err := na.Connect(); err != nil {
log.Fatalf("Broker Connect error: %v", err)
}
pub()
}
命令行选择mq
package main
import (
"fmt"
"log"
"time"
"github.com/micro/go-micro/broker"
"github.com/micro/go-micro/config/cmd"
_ "github.com/micro/go-plugins/broker/nats" //导入该包，
)
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.Event) 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)
}启动时添加：--broker=启动的mq名称 --broker_address=ip地址
总结：
基本上只需要更改插件既可切换 mq，可以在github.com/micro/go-plugins/broker包下找到自己需要的mq，导入使用既可
"github.com/micro/go-plugins/broker/stan"有疑问加站长微信联系（非本文作者）
