在很多系统中，会有展示服务器信息的页面。

比如 CPU、内存、磁盘等：

这是怎么实现的呢？

其实通过 node 的原生 api 就可以做到。

我们还是用 Nest 写个接口来返回这些信息：

nest new server-status

在 AppController 加个接口，用 os.cpus 拿到 cpu 的信息：

import { Controller, Get } from "@nestjs/common";
import { AppService } from "./app.service";
import * as os from "os";

@Controller()
export class AppController {
    constructor(private readonly appService: AppService) {}

    @Get()
    getHello(): string {
        return this.appService.getHello();
    }

    @Get("status")
    status() {
        return os.cpus();
    }
}

把服务跑起来：

npm run start:dev

浏览器访问下：

返回的数组元素个数就是 cpu 数。

那具体的属性是什么意思呢？

可以看到，times.user、times.sys、times.idle 分别代表用户代码占用的 cpu 时间、系统代码占用的 cpu 时间，空闲的 cpu 时间：

基于这些就能算出 cpu 的使用率、空置率来。

@Get('status')
status() {
    const cpus = os.cpus();
    const cpuInfo = cpus.reduce(
      (info, cpu) => {
        info.cpuNum += 1;
        info.user += cpu.times.user;
        info.sys += cpu.times.sys;
        info.idle += cpu.times.idle;
        info.total += cpu.times.user + cpu.times.sys + cpu.times.idle;
        return info;
      },
      { user: 0, sys: 0, idle: 0, total: 0, cpuNum: 0 },
    );
    const cpu = {
      cpuNum: cpuInfo.cpuNum,
      sys: ((cpuInfo.sys / cpuInfo.total) * 100).toFixed(2),
      used: ((cpuInfo.user / cpuInfo.total) * 100).toFixed(2),
      free: ((cpuInfo.idle / cpuInfo.total) * 100).toFixed(2),
    };
    return cpu;
}

用 reduce 方法累加 cpu 的数量、user、sys、idle 以及总的 cpu 时间。

然后 cpu 的系统使用率就是 sys/total，用户使用率是 user/total 而空置率就是 idle/total。

对应的就是这部分信息：

然后继续拿内存信息：

import { Controller, Get } from "@nestjs/common";
import { AppService } from "./app.service";
import * as os from "os";

@Controller()
export class AppController {
    constructor(private readonly appService: AppService) {}

    @Get()
    getHello(): string {
        return this.appService.getHello();
    }

    @Get("status")
    status() {
        return {
            cpu: this.getCpuInfo(),
            mem: this.getMemInfo(),
        };
    }

    getMemInfo() {
        const totalMemory = os.totalmem();
        const freeMemory = os.freemem();
        const usedMemory = totalMemory - freeMemory;
        const memoryUsagePercentage = (
            ((totalMemory - freeMemory) / totalMemory) *
            100
        ).toFixed(2);
        const mem = {
            total: totalMemory,
            used: usedMemory,
            free: freeMemory,
            usage: memoryUsagePercentage,
        };
        return mem;
    }

    getCpuInfo() {
        const cpus = os.cpus();
        const cpuInfo = cpus.reduce(
            (info, cpu) => {
                info.cpuNum += 1;
                info.user += cpu.times.user;
                info.sys += cpu.times.sys;
                info.idle += cpu.times.idle;
                info.total += cpu.times.user + cpu.times.sys + cpu.times.idle;
                return info;
            },
            { user: 0, sys: 0, idle: 0, total: 0, cpuNum: 0 }
        );
        const cpu = {
            cpuNum: cpuInfo.cpuNum,
            sys: ((cpuInfo.sys / cpuInfo.total) * 100).toFixed(2),
            used: ((cpuInfo.user / cpuInfo.total) * 100).toFixed(2),
            free: ((cpuInfo.idle / cpuInfo.total) * 100).toFixed(2),
        };
        return cpu;
    }
}

os.totalmem 是总内存，os.freemem 是空闲内存，那差值就是已使用的内存。

这样也可以求出内存使用率。

我们把它转成 GB 单位的数值返回：

bytesToGB(bytes) {
    const gb = bytes / (1024 * 1024 * 1024);
    return gb.toFixed(2);
}

getMemInfo() {
    const totalMemory = os.totalmem();
    const freeMemory = os.freemem();
    const usedMemory = totalMemory - freeMemory;
    const memoryUsagePercentage = (((totalMemory - freeMemory) / totalMemory) * 100).toFixed(2);
    const mem = {
      total: this.bytesToGB(totalMemory),
      used: this.bytesToGB(usedMemory),
      free: this.bytesToGB(freeMemory),
      usage: memoryUsagePercentage,
    };
    return mem;
}

对应的是这部分信息：

然后是磁盘信息：

这里用到 node-disk-info 这个包：

安装下：

npm install --save node-disk-info

调用下：

import { Controller, Get } from "@nestjs/common";
import { AppService } from "./app.service";
import * as os from "os";
import * as nodeDiskInfo from "node-disk-info";

@Controller()
export class AppController {
    constructor(private readonly appService: AppService) {}

    @Get()
    getHello(): string {
        return this.appService.getHello();
    }

    @Get("status")
    async status() {
        return {
            cpu: this.getCpuInfo(),
            mem: this.getMemInfo(),
            dist: await this.getDiskStatus(),
        };
    }

    async getDiskStatus() {
        const disks = await nodeDiskInfo.getDiskInfoSync();

        const sysFiles = disks.map((disk: any) => {
            return {
                dirName: disk._mounted,
                typeName: disk._filesystem,
                total: this.bytesToGB(disk._blocks) + "GB",
                used: this.bytesToGB(disk._used) + "GB",
                free: this.bytesToGB(disk._available) + "GB",
                usage: ((disk._used / disk._blocks || 0) * 100).toFixed(2),
            };
        });
        return sysFiles;
    }

    bytesToGB(bytes) {
        const gb = bytes / (1024 * 1024 * 1024);
        return gb.toFixed(2);
    }

    getMemInfo() {
        const totalMemory = os.totalmem();
        const freeMemory = os.freemem();
        const usedMemory = totalMemory - freeMemory;
        const memoryUsagePercentage = (
            ((totalMemory - freeMemory) / totalMemory) *
            100
        ).toFixed(2);
        const mem = {
            total: this.bytesToGB(totalMemory),
            used: this.bytesToGB(usedMemory),
            free: this.bytesToGB(freeMemory),
            usage: memoryUsagePercentage,
        };
        return mem;
    }

    getCpuInfo() {
        const cpus = os.cpus();
        const cpuInfo = cpus.reduce(
            (info, cpu) => {
                info.cpuNum += 1;
                info.user += cpu.times.user;
                info.sys += cpu.times.sys;
                info.idle += cpu.times.idle;
                info.total += cpu.times.user + cpu.times.sys + cpu.times.idle;
                return info;
            },
            { user: 0, sys: 0, idle: 0, total: 0, cpuNum: 0 }
        );
        const cpu = {
            cpuNum: cpuInfo.cpuNum,
            sys: ((cpuInfo.sys / cpuInfo.total) * 100).toFixed(2),
            used: ((cpuInfo.user / cpuInfo.total) * 100).toFixed(2),
            free: ((cpuInfo.idle / cpuInfo.total) * 100).toFixed(2),
        };
        return cpu;
    }
}

这里拿到的就是本地所有的磁盘信息：

分别是路径、文件系统、总大小、已用大小、可用大小、已用百分比：

最后，我们还要返回其他的服务器信息：

@Get('status')
async status() {
    return {
      cpu: this.getCpuInfo(),
      mem: this.getMemInfo(),
      dist: await this.getDiskStatus(),
      sys: this.getSysInfo()
    }
}

getSysInfo() {
    return {
      computerName: os.hostname(),
      computerIp: this.getServerIP(),
      osName: os.platform(),
      osArch: os.arch(),
    };
}

getServerIP() {
    const nets = os.networkInterfaces();
    for (const name of Object.keys(nets)) {
      for (const net of nets[name]) {
        if (net.family === 'IPv4' && !net.internal) {
          return net.address;
        }
      }
    }
}