im.doctor/src/doctor/app.armour.js

/**
 * 服务守护脚本。当服务器进程失败时，重启IM服务器。
 *
 * 守护服务不是应用程序的入口，但作为服务的外壳，提供进程信号监听与进程重启，保证服务的连续性。
 */
"use strict";

let cp = require('child_process');
let worker;
require('util');

function startWorker(spawnScript) {
    // 进程守护，开启IPC通道双向通信
    let exeFile = process.platform === "linux" ? "./node" : "node";
    worker = cp.spawn(exeFile, [spawnScript], {stdio: [0, 1, 2, 'ipc']});

    //监视子进程，当其崩溃时重启服务
    worker.on('exit', function (code) {
        if (code !== 0) {
            console.log('IM server is down, restarting...');

            startWorker(spawnScript);
        }
    });

    worker.on('message', function (msg) {
        console.log(msg);
    });
}

function main() {
    console.log('Armour process id: ' + process.pid);

    startWorker('./app.js');

    // 守护进程本身退出时，关闭其启动的服务
    process.on('SIGTERM', function () {
        worker.kill();
        process.exit(0);
    });
}

main();