本文使用nodejs作為微服務(wù)API網(wǎng)關(guān)猴凹，從而將消費(fèi)端的請(qǐng)求痒筒，隨機(jī)路由到一個(gè)可用的服務(wù)節(jié)點(diǎn)上宰闰。核心代碼如下：

本文參考了《架構(gòu)探險(xiǎn)》輕量級(jí)服務(wù)架構(gòu)
本文示例代碼：node-zookeeper-demo

var express = require('express');
var zookeeper = require('node-zookeeper-client');
var httpProxy = require('http-proxy');
var cluster = require('cluster');
var os = require('os');
var cache = {};

var CPUS = os.cpus().length;

var PORT = 8084;
var CONNECTION_STRING = '127.0.0.1:2181,127.0.0.1:2182,127.0.0.1:2183';
var REGISTRY_ROOT = '/registry';

var app = express();

if (cluster.isMaster) {
    for (var i = 0; i < CPUS; i++) {
        cluster.fork();
    }
}
else {
    //連接zookeeper
    var zk = zookeeper.createClient(CONNECTION_STRING);
    zk.connect();

    //創(chuàng)建代理服務(wù)器對(duì)象并監(jiān)聽錯(cuò)誤事件
    var proxy = httpProxy.createProxyServer();
    proxy.on('error', function (err, req, res) {
        res.end();//輸出空白響應(yīng)數(shù)據(jù)
    });

    //啟動(dòng)web服務(wù)器
    app.use(express.static('public'));
    app.all('*', function (req, res) {
        //處理圖標(biāo)請(qǐng)求
        if (req.path == '/favicon.ico') {
            res.end();
            return;
        }
        //獲取服務(wù)名稱
        var serviceName = req.get('Service-Name');
        
        console.log('ServiceName:%s', serviceName);
        if (!serviceName) {
            console.log('Service-Name request header is not exist');
            res.end();
            return;
        }
        //獲取服務(wù)路徑
        var servicePath = REGISTRY_ROOT + "/" + serviceName;
        console.log('ServicePath:%s', servicePath);
        console.log('cache[serviceName]:'+JSON.stringify(cache));
        if (cache[serviceName]) {
        //if(false){
            //TODO
            /*zk.exists(servicePath, function (event) {
                if (event.NODE_DELETED) {
                    cache = {};
                }
            }, function (error, stat) {
                if (stat) {

                }
            })*/
            console.log("-----------cache---------------"+cache[serviceName]);
            proxy.web(req, res, {
                target: 'http://' + cache[serviceName] //目標(biāo)地址
            });

        }
        else {

            //獲取服務(wù)路徑下的地址節(jié)點(diǎn)
            zk.getChildren(servicePath, function (error, addressNodes) {
                if (error) {
                    console.log(error.stack);
                    res.end();
                    return;
                }
                var size = addressNodes.length;
                if (size == 0) {
                    console.log('address node is not exist');
                    res.end();
                    return;
                }
                //生成地址容器
                var addressPath = servicePath + "/";
                if (size == 1) {
                    //若只有唯一地址，則獲取該地址
                    addressPath += addressNodes[0];
                } else {
                    //若存在多個(gè)地址簿透，則隨機(jī)獲取一個(gè)地址
                    addressPath += addressNodes[parseInt(Math.random() * size)];
                }
                console.log('addressPath:%s', addressPath);
                //獲取服務(wù)地址
                zk.getData(addressPath, function (err, serviceAddress) {
                    if (error) {
                        console.log(error.stack);
                        res.end();
                        return;
                    }
                    console.log('serviceAddress:%s', serviceAddress);
                    if (!serviceAddress) {
                        console.log('serviceAddress is not exist');
                        res.end();
                        return;
                    }

                    cache[serviceName] = serviceAddress;
                    console.log("cache"+  serviceName+": "+cache[serviceName]);

                    //執(zhí)行反向代理
                    proxy.web(req, res, {
                        target: 'http://' + serviceAddress //目標(biāo)地址
                    });
                });

            });
        }

    });

    app.listen(PORT, function () {
        console.log('server is running at %d', PORT);
    });
}

使用supervisor app-gateway.js啟動(dòng)API網(wǎng)關(guān)后：(supervisor可以定時(shí)監(jiān)聽文件的變化移袍，代碼更新無需重啟)

啟動(dòng)網(wǎng)關(guān)

當(dāng)然也需要啟動(dòng)在上文《基于ZooKeeper的服務(wù)注冊(cè)實(shí)現(xiàn)》提到的兩個(gè)客戶端，讓服務(wù)在ZooKeeper上注冊(cè)老充。

測(cè)試頁(yè)面

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Demo</title>
</head>
<body>
<div id="console"></div>
<div id="container">
    <h1>
        hello world
    </h1>
</div>
<button id="btn" >點(diǎn)我一下調(diào)用服務(wù)</button>

</body>
<script src="js/jquery-2.2.3.min.js"></script>
<script>
    $(function () {
        $("#btn").click(function () {
            //alert("hello world");
            $.ajax({
                method: 'GET',
                url: '/hello',
                headers: {
                    'Service-Name': 'HelloService'
                },
                success: function (data) {
                    $("#console").text(data);
                }
            })
        });

    })
</script>
</html>

點(diǎn)擊測(cè)試按鈕葡盗，在界面服務(wù)的顯示運(yùn)行結(jié)果"Hello"

運(yùn)行結(jié)果

AB測(cè)試(Apache Bench)模擬1000個(gè)用戶每次并發(fā)100請(qǐng)求：
注 ：在測(cè)試前，將serviceName設(shè)為固定值：var serviceName='HelloService'

AB測(cè)試

閱讀本文啡浊，請(qǐng)結(jié)合上篇文章《基于ZooKeeper的服務(wù)注冊(cè)實(shí)現(xiàn)》進(jìn)行理解觅够。