共计 9855 个字符,预计需要花费 25 分钟才能阅读完成。
网上看了好多,都是抄个官网 README,很多重要的货色不说分明。只好本人钻研了一下。
自己博客,关键词 Less-Bug.com,欢送关注。
NSQ 的全家桶介绍
- nsqd:守护过程,客户端通信。默认端口
4150
(TCP)4151
(HTTP) - nsqlookupd:相当于一个路由器。客户端能够经由它发现生产者、nsqd 播送的话题。 一个 nsqlookupd 可能治理一群 nsqd。 默认端口:
:4160
(TCP),:4161
(HTTP) - nsqadmin:在线面板,可能通过浏览器间接拜访。默认端口
:4171
从命令行启动
能够间接下载二进制文件。开三个终端,别离执行:
nsqlookupd
nsqd --lookupd-tcp-address=127.0.0.1:4160 --broadcast-address=127.0.0.1
nsqadmin --lookupd-http-address=127.0.0.1:4161
go-nsq 的应用
我封装了一个包:
package mq
import (
"encoding/json"
"fmt"
"time"
"github.com/nsqio/go-nsq"
"go.uber.org/zap"
)
type MessageQueueConfig struct {
NsqAddr string
NsqLookupdAddr string
SupportedTopics []string}
type MessageQueue struct {
config MessageQueueConfig
producer *nsq.Producer
consumers map[string]*nsq.Consumer
}
func NewMessageQueue(config MessageQueueConfig) (mq *MessageQueue, err error) {zap.L().Debug("New message queue")
producer, err := initProducer(config.NsqAddr)
if err != nil {return nil, err}
consumers := make(map[string]*nsq.Consumer)
for _, topic := range config.SupportedTopics {nsq.Register(topic,"default")
consumers[topic], err = initConsumer(topic, "default", config.NsqAddr)
if err != nil {return}
}
return &MessageQueue{
config: config,
producer: producer,
consumers: consumers,
}, nil
}
func (mq *MessageQueue) Run() {
for name, c := range mq.consumers {zap.L().Info("Run consumer for" + name)
// c.ConnectToNSQLookupd(mq.config.NsqLookupdAddr)
c.ConnectToNSQD(mq.config.NsqAddr)
}
}
func initProducer(addr string) (producer *nsq.Producer, err error) {zap.L().Debug("initProducer to" + addr)
config := nsq.NewConfig()
producer, err = nsq.NewProducer(addr, config)
return
}
func initConsumer(topic string, channel string, address string) (c *nsq.Consumer, err error) {zap.L().Debug("initConsumer to" + topic + "/" + channel)
config := nsq.NewConfig()
config.LookupdPollInterval = 15 * time.Second
c, err = nsq.NewConsumer(topic, channel, config)
return
}
func (mq *MessageQueue) Pub(name string, data interface{}) (err error) {body, err := json.Marshal(data)
if err != nil {return}
zap.L().Info("Pub" + name + "to mq. data =" + string(body))
return mq.producer.Publish(name, body)
}
type Messagehandler func(v []byte)
func (mq *MessageQueue) Sub(name string, handler Messagehandler) (err error) {zap.L().Info("Subscribe" + name)
v, ok := mq.consumers[name]
if !ok {err = fmt.Errorf("No such topic:" + name)
return
}
v.AddHandler(nsq.HandlerFunc(func(message *nsq.Message) error {handler(message.Body)
return nil
}))
return
}
应用示例:
m, err := mq.NewMessageQueue(mq.MessageQueueConfig{
NsqAddr: "127.0.0.1:4150",
NsqLookupdAddr: "127.0.0.1:4161",
SupportedTopics: []string{"hello"},
})
if err != nil {zap.L().Fatal("Message queue error:" + err.Error())
}
m.Sub("hello", func(resp []byte) {zap.L().Info("S1 Got:" + string(resp))
})
m.Sub("hello", func(resp []byte) {zap.L().Info("S2 Got:" + string(resp))
})
m.Run()
err = m.Pub("hello", "world")
if err != nil {zap.L().Fatal("Message queue error:" + err.Error())
}
err = m.Pub("hello", "tom")
if err != nil {zap.L().Fatal("Message queue error:" + err.Error())
}
sigChan := make(chan os.Signal, 1)
signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
<-sigChan
os.Exit(0);
次要是进行解耦合,这样万一咱们换成 Kalfa 之类的队列,就能够不必动业务代码。
输入后果:
2021-11-07T19:13:41.886+0800 DEBUG mq/mq.go:29 New message queue
2021-11-07T19:13:41.886+0800 DEBUG mq/mq.go:58 initProducer to 127.0.0.1:4150
2021-11-07T19:13:41.887+0800 DEBUG mq/mq.go:65 initConsumer to hello/default
2021-11-07T19:13:41.887+0800 INFO mq/mq.go:84 Subscribe hello
2021-11-07T19:13:41.887+0800 INFO mq/mq.go:84 Subscribe hello
2021-11-07T19:13:41.887+0800 INFO mq/mq.go:51 Run consumer for hello
2021/11/07 19:13:41 INF 2 [hello/default] (127.0.0.1:4150) connecting to nsqd
2021-11-07T19:13:41.887+0800 INFO mq/mq.go:77 Pub hello to mq. data = "world"
2021/11/07 19:13:41 INF 1 (127.0.0.1:4150) connecting to nsqd
2021-11-07T19:13:41.888+0800 INFO mq/mq.go:77 Pub hello to mq. data = "tom"
2021-11-07T19:13:41.888+0800 INFO buqi-admin-backend/main.go:60 S1 Got: "world"
2021-11-07T19:13:41.888+0800 INFO buqi-admin-backend/main.go:63 S2 Got: "tom"
从输入后果咱们能够确认一个事实,就是对于订阅了同一个 topic,同一个 channel 的不同消费者,当音讯涌入时,将会负载平衡—— 每个 Handler 只会收到一个音讯 。
遇到的问题
TOPIC_NOT_FOUND
遇到两个起因。
其一是大小写,Topic 名是大小写敏感的,因而 Hello
和 hello
是两个不同的 topic,写代码时应该标准操作:抽取常量,并保护一个所有 Topic 的列表。
其二是 Topic 未创立。第一次 pub 之后,对应的 topic/channel 能力创立。倡议写个脚本调用 /topic/create
接口一次性创立好,不然前面第二次重试订阅的时候能力收到音讯,造成不可意料的提早。
发现客户端轮询 HTTP
这是因为 NsqLookupd 自身是一个中介,能够治理一堆不同 IP 的 nsqd,那么咱们就不可能永远只连贯一个 nsq,所以就要轮询来确认有哪些客户端。
对于小我的项目,能够绕过 NsqLookupd:
// c.ConnectToNSQLookupd(mq.config.NsqLookupdAddr)
c.ConnectToNSQD(mq.config.NsqAddr)
如何让多个消费者生产同一个 topic?
显然,依据 nsq 的机制,咱们须要让同一个 topic 的消费者应用不同的通道。一种办法是随机化 channel,比方应用一个递增量作为 channel 名。
第二种办法是依据用处定义 channel 名。
第三种办法:据说能够应用 AddConcurrentHandlers,尚未钻研。
第四种办法:咱们把 Handler 中介化,应用一个消费者去生产,然而手动将音讯送入应用层的一个自定义的流水线,让流水线的 filter 去解决音讯。我猜这样还能防止一些临界区问题。
咱们试一下第四种办法。(代码已公布到 GIST,Github 用户名 Pluveto)
实现流水线 Handler
package mq
import (
"encoding/json"
"fmt"
"time"
"github.com/nsqio/go-nsq"
"go.uber.org/zap"
)
type MessageQueueConfig struct {
NsqAddr string
NsqLookupdAddr string
EnableLookupd bool
SupportedTopics []string}
type MessageQueue struct {subscribers map[string]Subscriber
config MessageQueueConfig
producer *nsq.Producer
}
type Messagehandler func(v []byte) bool
// LinkedHandlerNode 第一个节点为头节点,Handler 必须为 nil
type LinkedHandlerNode struct {
Handler *Messagehandler
Index int
NextNode *LinkedHandlerNode
}
type Subscriber struct {
HandlerHeadNode *LinkedHandlerNode
Consumer *nsq.Consumer
Handler nsq.HandlerFunc
}
func createProducer(addr string) (producer *nsq.Producer, err error) {zap.L().Debug("initProducer to" + addr)
config := nsq.NewConfig()
producer, err = nsq.NewProducer(addr, config)
return
}
func createConsumer(topic string, channel string, address string) (c *nsq.Consumer, err error) {zap.L().Debug("initConsumer to" + topic + "/" + channel)
config := nsq.NewConfig()
config.LookupdPollInterval = 15 * time.Second
c, err = nsq.NewConsumer(topic, channel, config)
return
}
func NewMessageQueue(config MessageQueueConfig) (mq *MessageQueue, err error) {zap.L().Debug("New message queue")
producer, err := createProducer(config.NsqAddr)
if err != nil {return nil, err}
subscribers := make(map[string]Subscriber)
for _, topic := range config.SupportedTopics {nsq.Register(topic, "default")
consumer, err := createConsumer(topic, "default", config.NsqAddr)
if err != nil {return nil, err}
// 头节点不参加理论应用,所以 Index = -1
headNode := &LinkedHandlerNode{Index: -1}
hubHandler := nsq.HandlerFunc(func(message *nsq.Message) error {
// 循环链式调用各个 Handler
curNode := headNode.NextNode
// 当不存在任何用户定义的 Handler 时抛出正告
if(nil == curNode){return fmt.Errorf("No handler provided!")
}
for nil != curNode {
msg := message.Body
zap.S().Debugf("handler[%v] for %v is invoked", curNode.Index, topic)
stop := (*curNode.Handler)(msg)
if stop {zap.S().Debugf("the message has stopped spreading")
break
}
curNode = curNode.NextNode
}
return nil
})
consumer.AddHandler(hubHandler)
subscribers[topic] = Subscriber{
Consumer: consumer,
HandlerHeadNode: headNode,
}
}
return &MessageQueue{
config: config,
producer: producer,
subscribers: subscribers,
}, nil
}
func (mq *MessageQueue) Run() {
for name, s := range mq.subscribers {zap.L().Info("Run consumer for" + name)
if mq.config.EnableLookupd {s.Consumer.ConnectToNSQLookupd(mq.config.NsqLookupdAddr)
} else {s.Consumer.ConnectToNSQD(mq.config.NsqAddr)
}
}
}
func (mq *MessageQueue) IsTopicSupported(topic string) bool {
for _, v := range mq.config.SupportedTopics {
if v == topic {return true}
}
return false
}
// Pub 向音讯队列发送一个音讯
func (mq *MessageQueue) Pub(topic string, data interface{}) (err error) {if !mq.IsTopicSupported(topic) {err = fmt.Errorf("unsupported topic name:" + topic)
return
}
body, err := json.Marshal(data)
if err != nil {return}
zap.L().Info("Pub" + topic + "to mq. data =" + string(body))
return mq.producer.Publish(topic, body)
}
// Sub 从音讯队列订阅一个音讯
func (mq *MessageQueue) Sub(topic string, handler Messagehandler) (err error) {if !mq.IsTopicSupported(topic) {err = fmt.Errorf("unsupported topic name:" + topic)
return
}
zap.L().Info("Subscribe" + topic)
subscriber, ok := mq.subscribers[topic]
if !ok {err = fmt.Errorf("No such topic:" + topic)
return
}
// 到达最初一个无效链表节点
curNode := subscriber.HandlerHeadNode
for nil != curNode.NextNode {curNode = curNode.NextNode}
// 创立节点
curNode.NextNode = &LinkedHandlerNode{
Handler: &handler,
Index: 1 + curNode.Index,
NextNode: nil,
}
return
}
这里的思维是给每个消费者事后创立惟一的 Handler,这个 Handler 会顺次调用链表中的各个具体的 Handler。当用户订阅 Topic 时,将用户提供的 Handler 增加到链表开端。
应用示例:
m, err := mq.NewMessageQueue(mq.MessageQueueConfig{
NsqAddr: "127.0.0.1:4150",
NsqLookupdAddr: "127.0.0.1:4161",
SupportedTopics: []string{"hello"},
EnableLookupd: false,
})
if err != nil {zap.L().Fatal("Message queue error:" + err.Error())
}
m.Sub("hello", func(resp []byte) bool {zap.L().Info("S1 Got:" + string(resp))
return false
})
m.Sub("hello", func(resp []byte) bool {zap.L().Info("S2 Got:" + string(resp))
return true
})
m.Sub("hello", func(resp []byte) bool {zap.L().Info("S3 Got:" + string(resp))
return false
})
m.Run()
err = m.Pub("hello", "world")
if err != nil {zap.L().Fatal("Message queue error:" + err.Error())
}
err = m.Pub("hello", "tom")
if err != nil {zap.L().Fatal("Message queue error:" + err.Error())
}
sigChan := make(chan os.Signal, 1)
signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
<-sigChan
os.Exit(0)
输入:
2021-11-07T20:30:38.448+0800 DEBUG mq/mq.go:40 New message queue
2021-11-07T20:30:38.448+0800 DEBUG mq/mq.go:89 initProducer to 127.0.0.1:4150
2021-11-07T20:30:38.448+0800 DEBUG mq/mq.go:96 initConsumer to hello/default
2021-11-07T20:30:38.448+0800 INFO mq/mq.go:113 Subscribe hello
2021-11-07T20:30:38.448+0800 INFO mq/mq.go:113 Subscribe hello
2021-11-07T20:30:38.448+0800 INFO mq/mq.go:113 Subscribe hello
2021-11-07T20:30:38.448+0800 INFO mq/mq.go:82 Run consumer for hello
2021/11/07 20:30:38 INF 2 [hello/default] (127.0.0.1:4150) connecting to nsqd
2021-11-07T20:30:38.454+0800 INFO mq/mq.go:108 Pub hello to mq. data = "world"
2021/11/07 20:30:38 INF 1 (127.0.0.1:4150) connecting to nsqd
2021-11-07T20:30:38.455+0800 INFO mq/mq.go:108 Pub hello to mq. data = "tom"
2021-11-07T20:30:38.455+0800 DEBUG mq/mq.go:57 handler[0] for hello is invoked
2021-11-07T20:30:38.455+0800 INFO buqi-admin-backend/main.go:60 S1 Got: "world"
2021-11-07T20:30:38.455+0800 DEBUG mq/mq.go:57 handler[1] for hello is invoked
2021-11-07T20:30:38.455+0800 INFO buqi-admin-backend/main.go:64 S2 Got: "world"
2021-11-07T20:30:38.455+0800 DEBUG mq/mq.go:60 the message has stopped spreading
2021-11-07T20:30:38.455+0800 DEBUG mq/mq.go:57 handler[0] for hello is invoked
2021-11-07T20:30:38.455+0800 INFO buqi-admin-backend/main.go:60 S1 Got: "tom"
2021-11-07T20:30:38.455+0800 DEBUG mq/mq.go:57 handler[1] for hello is invoked
2021-11-07T20:30:38.455+0800 INFO buqi-admin-backend/main.go:64 S2 Got: "tom"
2021-11-07T20:30:38.455+0800 DEBUG mq/mq.go:60 the message has stopped spreading
^C
能够看到,Handler 返回 true 时,就能够阻断音讯的流传。