进程守护

chapter4/process/app.js

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+const http = require('http');
+
+// console.log(11112222);
+module.exports = http.createServer((req, res) => {
+    res.writeHead(200, {
+        'Content-Type': 'text/plain'
+    });
+    res.end('hello world');
+    while (true) { }
+}).listen(3000, () => {
+    console.log('listened 3000')
+})

chapter4/process/boot.js

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+/**
+ * 简单的进程守护器
+ */
+const cluster = require('cluster');
+
+if (cluster.isMaster) {
+    // console.log(require('os').cpus())
+    for (let i = 0; i < require('os').cpus().length / 2; i++) {
+        createWorker();
+    }
+
+    cluster.on('exit', function () {
+        setTimeout(() => {
+            createWorker()
+        }, 5000)
+    })
+
+    function createWorker() {
+        // 创建子进程并进行心跳监控
+        var worker = cluster.fork();
+
+        var missed = 0;// 没有回应的ping次数
+
+        // 心跳
+        var timer = setInterval(function () {
+
+            // 三次没回应，杀之
+            if (missed == 3) {
+                clearInterval(timer);
+                console.log(worker.process.pid + ' has become a zombie!');
+                process.kill(worker.process.pid);
+                return;
+            }
+            // 开始心跳
+            missed++;
+            worker.send('ping#' + worker.process.pid);
+        }, 10000);
+
+        worker.on('message', function (msg) {
+            // 确认心跳回应。
+            if (msg == 'pong#' + worker.process.pid) {
+                missed--;
+            }
+        });
+
+        // 挂了就没必要再进行心跳了
+        worker.on('exit', function () {
+            clearInterval(timer);
+        });
+    }
+
+} else {
+    // 当进程出现会崩溃的错误
+    process.on('uncaughtException', function (err) {
+        // 这里可以做写日志的操作
+        console.log(err);
+        // 退出进程
+        process.exit(1);
+    });
+
+    // 回应心跳信息
+    process.on('message', function (msg) {
+        if (msg == 'ping#' + process.pid) {
+            process.send('pong#' + process.pid);
+        }
+    });
+
+    // 内存使用过多，自杀
+    if (process.memoryUsage().rss > 734003200) {
+        process.exit(1);
+    }
+
+    require('./app')
+}