在日常开发中，可能会遇到需要实时监控服务器运行信息，用来监控服务器运行情况，是否需要进行服务器的改配等操作。虽然服务器提供平台会有一系列监控数据，但是运营人员不可能频繁的登录控制台来查看服务器运行情况，所以需要在管理系统上展示出服务器的基本运行情况。如：CPU的占用率、内存的占用率、磁盘使用率、系统负载、运行时长等一系列信息。

获取CPU的占用情况

const getCPU = async () => {function cpuAverage() {// Initialise sum of idle and time of cores and fetch CPU infovar totalIdle = 0, totalTick = 0;var cpus = os.cpus();// Loop through CPU coresfor(var i = 0, len = cpus.length; i < len; i++) {// Select CPU corevar cpu = cpus[i];// Total up the time in the cores tickfor(const type in cpu.times) {totalTick += cpu.times[type];}     // Total up the idle time of the coretotalIdle += cpu.times.idle;}// Return the average Idle and Tick timesreturn { idle: totalIdle / cpus.length,  total: totalTick / cpus.length };}const startMeasure = cpuAverage();return new Promise((resolve) => {setTimeout(function() { // Grab second Measurevar endMeasure = cpuAverage(); // Calculate the difference in idle and total time between the measuresvar idleDifference = endMeasure.idle - startMeasure.idle;var totalDifference = endMeasure.total - startMeasure.total;// Calculate the average percentage CPU usagevar percentageCPU = 100 - ~~(100 * idleDifference / totalDifference);// Output the resultresolve({ used: percentageCPU, name: os.cpus()[0].model, threadNumber: os.cpus().length });}, 100);});
}

获取内存占用情况

在多次测试中发现Node提供的内存API所计算的内存占用数据存在较大的偏差，所以此处使用系统命令来获取相应的数据。（但是在windows与macOS上目前没有找到好的解决方案，所以此处使用Node提供的API来处理）

const getMem = async () => {return new Promise(async (resolve) => {// 初始化内存总量、空闲总量、使用总量与占用率let totalmem = 0,freemem = 0,usedmem = 0,usageRate = 0;// 判断操作系统if (os.type() === 'Linux') {// 执行系统命令，命令输出结果如下图const { stdout } = await exec('free -m');// 获取到输出数据后截取计算所需要的信息let str = stdout.split('\n')[1].split(' ').filter(item => item != '');totalmem = str[1];freemem = str[1] - str[2];usedmem = str[2];// 计算占用率usageRate = (usedmem / totalmem * 100).toFixed(2);} else {totalmem = (os.totalmem() / 1024 / 1024 / 1024).toFixed(2);freemem = (os.freemem() / 1024 / 1024 / 1024).toFixed(2);usedmem = ((os.totalmem() - os.freemem()) / 1024 / 1024 / 1024).toFixed(2);usageRate = parseInt(usedmem / totalmem * 100);}// 返回计算结果resolve({ totalmem, freemem, usedmem, usageRate });})
}

获取服务器基本信息

sys = async () => {let date = '',sys = '';// 获取系统运行时间const time = os.uptime();const day = Math.floor(time / 86400);const hour = Math.floor((time - day * 86400) / 3600);const minute = Math.floor((time - day * 86400 - hour * 3600) / 60);const second = Math.floor(time - day * 86400 - hour * 3600 - minute * 60);// 时间格式化date = formatStr('{0}天{1}时{2}分{3}秒', day, hour, minute, second);// 获取系统版本if (os.type() === 'Linux') {// 调用系统命令来获取系统的版本信息const { stdout } = await exec('cat /etc/redhat-release');sys = stdout.trim();} else if (os.type() === 'Darwin') {const { stdout } = await exec('sw_vers');stdout.split('\n').forEach(item => {sys += item.split(':')[1] ? item.split(':')[1] : '';})sys = sys.trim();} else if (os.type() === 'Windows_NT') {const { stdout } = await exec('ver');sys = stdout.trim();}// 获取系统负载const loadavg = os.loadavg();// 1分钟负载const loadavg1m = loadavg[0].toFixed(2);// 5分钟负载const loadavg5m = loadavg[1].toFixed(2);// 10分钟负载const loadavg12m = loadavg[2].toFixed(2);// 返回基本信息数据return Promise.resolve({ date, sys, loadavg1m, loadavg5m, loadavg12m });
}

获取磁盘使用情况

与内存一样，通过调用系统的命令来获取到总数据，并通过截取来获取具体值。（目前只能获取Linux（挂在盘未进行获取）系统的使用情况）

const getDisk = async () => {let total = 0,available = 0,used = 0,usageRate = 0;if (os.type() === 'Linux') {let { stdout } = await exec('df -hl /');stdout = stdout.split('\n')[1].split(' ').filter(item => item != '');total = stdout[1];available = stdout[3];used = parseFloat(stdout[1]) * (parseFloat(stdout[4]) / 100);usageRate = parseFloat(stdout[4]);}return Promise.resolve({ total, available, used, usageRate });
}

当然也有一些开源工具包可以用来获取相应的数据，笔者只是做一个记录