NSQ是目前比較流行的一個分布式的訊息佇列，本文主要介紹了NSQ及Go語言如何操作NSQ，

NSQ

NSQ介紹

NSQ是Go語言撰寫的一個開源的實時分布式記憶體訊息佇列，其性能十分優異， NSQ的優勢有以下優勢：

NSQ提倡分布式和分散的拓撲，沒有單點故障，支持容錯和高可用性，并提供可靠的訊息交付保證
NSQ支持橫向擴展，沒有任何集中式代理，
NSQ易于配置和部署，并且內置了管理界面，

NSQ的應用場景

通常來說，訊息佇列都適用以下場景，

異步處理

參照下圖利用訊息佇列把業務流程中的非關鍵流程異步化，從而顯著降低業務請求的回應時間，

應用解耦

通過使用訊息佇列將不同的業務邏輯解耦，降低系統間的耦合，提高系統的健壯性，后續有其他業務要使用訂單資料可直接訂閱訊息佇列，提高系統的靈活性，

流量削峰

類似秒殺（大秒）等場景下，某一時間可能會產生大量的請求，使用訊息佇列能夠為后端處理請求提供一定的緩沖區，保證后端服務的穩定性，

安裝

官方下載頁面根據自己的平臺下載并解壓即可，

NSQ組件

nsqd

nsqd是一個守護行程，它接收、排隊并向客戶端發送訊息，

啟動nsqd，指定-broadcast-address=127.0.0.1來配置廣播地址

./nsqd -broadcast-address=127.0.0.1

如果是在搭配nsqlookupd使用的模式下需要還指定nsqlookupd地址:

./nsqd -broadcast-address=127.0.0.1 -lookupd-tcp-address=127.0.0.1:4160

如果是部署了多個nsqlookupd節點的集群，那還可以指定多個-lookupd-tcp-address，

nsqdq相關配置項如下：

-auth-http-address value
    <addr>:<port> to query auth server (may be given multiple times)
-broadcast-address string
    address that will be registered with lookupd (defaults to the OS hostname) (default "PROSNAKES.local")
-config string
    path to config file
-data-path string
    path to store disk-backed messages
-deflate
    enable deflate feature negotiation (client compression) (default true)
-e2e-processing-latency-percentile value
    message processing time percentiles (as float (0, 1.0]) to track (can be specified multiple times or comma separated '1.0,0.99,0.95', default none)
-e2e-processing-latency-window-time duration
    calculate end to end latency quantiles for this duration of time (ie: 60s would only show quantile calculations from the past 60 seconds) (default 10m0s)
-http-address string
    <addr>:<port> to listen on for HTTP clients (default "0.0.0.0:4151")
-http-client-connect-timeout duration
    timeout for HTTP connect (default 2s)
-http-client-request-timeout duration
    timeout for HTTP request (default 5s)
-https-address string
    <addr>:<port> to listen on for HTTPS clients (default "0.0.0.0:4152")
-log-prefix string
    log message prefix (default "[nsqd] ")
-lookupd-tcp-address value
    lookupd TCP address (may be given multiple times)
-max-body-size int
    maximum size of a single command body (default 5242880)
-max-bytes-per-file int
    number of bytes per diskqueue file before rolling (default 104857600)
-max-deflate-level int
    max deflate compression level a client can negotiate (> values == > nsqd CPU usage) (default 6)
-max-heartbeat-interval duration
    maximum client configurable duration of time between client heartbeats (default 1m0s)
-max-msg-size int
    maximum size of a single message in bytes (default 1048576)
-max-msg-timeout duration
    maximum duration before a message will timeout (default 15m0s)
-max-output-buffer-size int
    maximum client configurable size (in bytes) for a client output buffer (default 65536)
-max-output-buffer-timeout duration
    maximum client configurable duration of time between flushing to a client (default 1s)
-max-rdy-count int
    maximum RDY count for a client (default 2500)
-max-req-timeout duration
    maximum requeuing timeout for a message (default 1h0m0s)
-mem-queue-size int
    number of messages to keep in memory (per topic/channel) (default 10000)
-msg-timeout string
    duration to wait before auto-requeing a message (default "1m0s")
-node-id int
    unique part for message IDs, (int) in range [0,1024) (default is hash of hostname) (default 616)
-snappy
    enable snappy feature negotiation (client compression) (default true)
-statsd-address string
    UDP <addr>:<port> of a statsd daemon for pushing stats
-statsd-interval string
    duration between pushing to statsd (default "1m0s")
-statsd-mem-stats
    toggle sending memory and GC stats to statsd (default true)
-statsd-prefix string
    prefix used for keys sent to statsd (%s for host replacement) (default "nsq.%s")
-sync-every int
    number of messages per diskqueue fsync (default 2500)
-sync-timeout duration
    duration of time per diskqueue fsync (default 2s)
-tcp-address string
    <addr>:<port> to listen on for TCP clients (default "0.0.0.0:4150")
-tls-cert string
    path to certificate file
-tls-client-auth-policy string
    client certificate auth policy ('require' or 'require-verify')
-tls-key string
    path to key file
-tls-min-version value
    minimum SSL/TLS version acceptable ('ssl3.0', 'tls1.0', 'tls1.1', or 'tls1.2') (default 769)
-tls-required
    require TLS for client connections (true, false, tcp-https)
-tls-root-ca-file string
    path to certificate authority file
-verbose
    enable verbose logging
-version
    print version string
-worker-id
    do NOT use this, use --node-id

nsqlookupd

nsqlookupd是維護所有nsqd狀態、提供服務發現的守護行程，它能為消費者查找特定topic下的nsqd提供了運行時的自動發現服務，它不維持持久狀態，也不需要與任何其他nsqlookupd實體協調以滿足查詢，因此根據你系統的冗余要求盡可能多地部署nsqlookupd節點，它們小豪的資源很少，可以與其他服務共存，我們的建議是為每個資料中心運行至少3個集群，

nsqlookupd相關配置項如下：

-broadcast-address string
    address of this lookupd node, (default to the OS hostname) (default "PROSNAKES.local")
-config string
    path to config file
-http-address string
    <addr>:<port> to listen on for HTTP clients (default "0.0.0.0:4161")
-inactive-producer-timeout duration
    duration of time a producer will remain in the active list since its last ping (default 5m0s)
-log-prefix string
    log message prefix (default "[nsqlookupd] ")
-tcp-address string
    <addr>:<port> to listen on for TCP clients (default "0.0.0.0:4160")
-tombstone-lifetime duration
    duration of time a producer will remain tombstoned if registration remains (default 45s)
-verbose
    enable verbose logging
-version
    print version string

nsqadmin

一個實時監控集群狀態、執行各種管理任務的Web管理平臺，啟動nsqadmin，指定nsqlookupd地址:

./nsqadmin -lookupd-http-address=127.0.0.1:4161

我們可以使用瀏覽器打開http://127.0.0.1:4171/訪問如下管理界面，

nsqadmin相關的配置項如下：

-allow-config-from-cidr string
    A CIDR from which to allow HTTP requests to the /config endpoint (default "127.0.0.1/8")
-config string
    path to config file
-graphite-url string
    graphite HTTP address
-http-address string
    <addr>:<port> to listen on for HTTP clients (default "0.0.0.0:4171")
-http-client-connect-timeout duration
    timeout for HTTP connect (default 2s)
-http-client-request-timeout duration
    timeout for HTTP request (default 5s)
-http-client-tls-cert string
    path to certificate file for the HTTP client
-http-client-tls-insecure-skip-verify
    configure the HTTP client to skip verification of TLS certificates
-http-client-tls-key string
    path to key file for the HTTP client
-http-client-tls-root-ca-file string
    path to CA file for the HTTP client
-log-prefix string
    log message prefix (default "[nsqadmin] ")
-lookupd-http-address value
    lookupd HTTP address (may be given multiple times)
-notification-http-endpoint string
    HTTP endpoint (fully qualified) to which POST notifications of admin actions will be sent
-nsqd-http-address value
    nsqd HTTP address (may be given multiple times)
-proxy-graphite
    proxy HTTP requests to graphite
-statsd-counter-format string
    The counter stats key formatting applied by the implementation of statsd. If no formatting is desired, set this to an empty string. (default "stats.counters.%s.count")
-statsd-gauge-format string
    The gauge stats key formatting applied by the implementation of statsd. If no formatting is desired, set this to an empty string. (default "stats.gauges.%s")
-statsd-interval duration
    time interval nsqd is configured to push to statsd (must match nsqd) (default 1m0s)
-statsd-prefix string
    prefix used for keys sent to statsd (%s for host replacement, must match nsqd) (default "nsq.%s")
-version
    print version string

NSQ架構

NSQ作業模式

Topic和Channel

每個nsqd實體旨在一次處理多個資料流，這些資料流稱為“topics”，一個topic具有1個或多個“channels”，每個channel都會收到topic所有訊息的副本，實際上下游的服務是通過對應的channel來消費topic訊息，

topic和channel不是預先配置的，topic在首次使用時創建，方法是將其發布到指定topic，或者訂閱指定topic上的channel，channel是通過訂閱指定的channel在第一次使用時創建的，

topic和channel都相互獨立地緩沖資料，防止緩慢的消費者導致其他chennel的積壓（同樣適用于topic級別），

channel可以并且通常會連接多個客戶端，假設所有連接的客戶端都處于準備接收訊息的狀態，則每條訊息將被傳遞到隨機客戶端，例如：

總而言之，訊息是從topic -> channel（每個channel接收該topic的所有訊息的副本）多播的，但是從channel -> consumers均勻分布（每個消費者接收該channel的一部分訊息），

NSQ接收和發送訊息流程

NSQ特性

訊息默認不持久化，可以配置成持久化模式，nsq采用的方式時記憶體+硬碟的模式，當記憶體到達一定程度時就會將資料持久化到硬碟，
- 如果將--mem-queue-size設定為0，所有的訊息將會存盤到磁盤，
- 服務器重啟時也會將當時在記憶體中的訊息持久化，
每條訊息至少傳遞一次，
訊息不保證有序，

Go操作NSQ

官方提供了Go語言版的客戶端：go-nsq，更多客戶端支持請查看CLIENT LIBRARIES，

安裝

go get -u github.com/nsqio/go-nsq

生產者

一個簡單的生產者示例代碼如下：

// nsq_producer/main.go
package main

import (
	"bufio"
	"fmt"
	"os"
	"strings"

	"github.com/nsqio/go-nsq"
)

// NSQ Producer Demo

var producer *nsq.Producer

// 初始化生產者
func initProducer(str string) (err error) {
	config := nsq.NewConfig()
	producer, err = nsq.NewProducer(str, config)
	if err != nil {
		fmt.Printf("create producer failed, err:%v\n", err)
		return err
	}
	return nil
}

func main() {
	nsqAddress := "127.0.0.1:4150"
	err := initProducer(nsqAddress)
	if err != nil {
		fmt.Printf("init producer failed, err:%v\n", err)
		return
	}

	reader := bufio.NewReader(os.Stdin) // 從標準輸入讀取
	for {
		data, err := reader.ReadString('\n')
		if err != nil {
			fmt.Printf("read string from stdin failed, err:%v\n", err)
			continue
		}
		data = https://www.cnblogs.com/Golanguage/p/strings.TrimSpace(data)
		if strings.ToUpper(data) =="Q" { // 輸入Q退出
			break
		}
		// 向 'topic_demo' publish 資料
		err = producer.Publish("topic_demo", []byte(data))
		if err != nil {
			fmt.Printf("publish msg to nsq failed, err:%v\n", err)
			continue
		}
	}
}

將上面的代碼編譯執行，然后在終端輸入兩條資料123和456：

$ ./nsq_producer 
123
2018/10/22 18:41:20 INF    1 (127.0.0.1:4150) connecting to nsqd
456

使用瀏覽器打開http://127.0.0.1:4171/可以查看到類似下面的頁面：在下面這個頁面能看到當前的topic資訊：

點擊頁面上的topic_demo就能進入一個展示更多詳細資訊的頁面，在這個頁面上我們可以查看和管理topic，同時能夠看到目前在LWZMBP:4151 (127.0.01:4151)這個nsqd上有2條message，又因為沒有消費者接入所以暫時沒有創建channel，

在/nodes這個頁面我們能夠很方便的查看當前接入lookupd的nsqd節點，

這個/counter頁面顯示了處理的訊息數量，因為我們沒有接入消費者，所以處理的訊息數量為0，

在/lookup界面支持創建topic和channel，

消費者

一個簡單的消費者示例代碼如下：

// nsq_consumer/main.go
package main

import (
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/nsqio/go-nsq"
)

// NSQ Consumer Demo

// MyHandler 是一個消費者型別
type MyHandler struct {
	Title string
}

// HandleMessage 是需要實作的處理訊息的方法
func (m *MyHandler) HandleMessage(msg *nsq.Message) (err error) {
	fmt.Printf("%s recv from %v, msg:%v\n", m.Title, msg.NSQDAddress, string(msg.Body))
	return
}

// 初始化消費者
func initConsumer(topic string, channel string, address string) (err error) {
	config := nsq.NewConfig()
	config.LookupdPollInterval = 15 * time.Second
	c, err := nsq.NewConsumer(topic, channel, config)
	if err != nil {
		fmt.Printf("create consumer failed, err:%v\n", err)
		return
	}
	consumer := &MyHandler{
		Title: "沙河1號",
	}
	c.AddHandler(consumer)

	// if err := c.ConnectToNSQD(address); err != nil { // 直接連NSQD
	if err := c.ConnectToNSQLookupd(address); err != nil { // 通過lookupd查詢
		return err
	}
	return nil

}

func main() {
	err := initConsumer("topic_demo", "first", "127.0.0.1:4161")
	if err != nil {
		fmt.Printf("init consumer failed, err:%v\n", err)
		return
	}
	c := make(chan os.Signal)        // 定義一個信號的通道
	signal.Notify(c, syscall.SIGINT) // 轉發鍵盤中斷信號到c
	<-c                              // 阻塞
}

將上面的代碼保存之后編譯執行，就能夠獲取之前我們publish的兩條訊息了：

$ ./nsq_consumer 
2018/10/22 18:49:06 INF    1 [topic_demo/first] querying nsqlookupd http://127.0.0.1:4161/lookup?topic=topic_demo
2018/10/22 18:49:06 INF    1 [topic_demo/first] (127.0.0.1:4150) connecting to nsqd
沙河1號 recv from 127.0.0.1:4150, msg:123
沙河1號 recv from 127.0.0.1:4150, msg:456

同時在nsqadmin的/counter頁面查看到處理的資料數量為2，

關于go-nsq的更多內容請閱讀go-nsq的官方檔案，

轉載自李文周博客

轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/45064.html

標籤：Go

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