How to get system statistics with node.js

Question

I have a distributed server system.

There are a lot of servers, coordinated through PubSub. All of them are connected to the statistics server. Every minute servers send their stats to the stat server (how many requests was processed, average time etc.).

So... It would be nice to include system status in this stat-messages. I need CPU load (every core) and amount of free memory.

I made a little workaround and decided to call a linux command with "exec", parse answer and form a JSON data for sending.

But how can I get this data from command line?

On Mac OS X I can easily get all I need with geektool scripts, but on linux (debian) they don't work.

For example:

top -l 1 | awk '/PhysMem/ {print "Used: " $8 " Free: " $10}'

On Mac OS X Lion I get:

Used: 3246M Free: 848M

And just an error in debian...

Answer 1

On Linux, you can use /proc. See here for a bunch of command line examples to read the stats.

It would be better to read the files from Node directly though, using fs.readFile()

Update: There is also the OS API which is probably better. Example usage: Convert the output of os.cpus() in Node.js to percentage

Answer 2

IMHO the best option is to use the systeminformation module,

where you can retrieve detailed hardware, system, and OS information with Linux, macOS, partial Windows, and FreeBSD support.

For example to get the CPU information:

const si = require('systeminformation');

// callback style
si.cpu(function(data) {
    console.log('CPU-Information:');
    console.log(data);
});

// promises style - new in version 3
si.cpu()
    .then(data => console.log(data))
    .catch(error => console.error(error));

// full async / await example (node >= 7.6)
async function cpu() {
    try {
        const data = await si.cpu();
        console.log(data)
    } catch (e) {
        console.log(e)
    }
}

This example will result the following:

{ manufacturer: 'Intel®',
    brand: 'Core™ i5-3317U',
    vendor: 'GenuineIntel',
    family: '6',
    model: '58',
    stepping: '9',
    revision: '',
    voltage: '',
    speed: '1.70',
    speedmin: '0.80',
    speedmax: '2.60',
    cores: 4,
    cache: { l1d: 32768, l1i: 32768, l2: 262144, l3: 3145728 } }
CPU-Information:
{ manufacturer: 'Intel®',
    brand: 'Core™ i5-3317U',
    vendor: 'GenuineIntel',
    family: '6',
    model: '58',
    stepping: '9',
    revision: '',
    voltage: '',
    speed: '1.70',
    speedmin: '0.80',
    speedmax: '2.60',
    cores: 4,
    cache: { l1d: 32768, l1i: 32768, l2: 262144, l3: 3145728 } }

Answer 3

You can try os-usage which is a wrapper for top command.

It provides stats like cpu usage and memory usage. Example usage:

var usage = require('os-usage');

// create an instance of CpuMonitor
var cpuMonitor = new usage.CpuMonitor();

// watch cpu usage overview
cpuMonitor.on('cpuUsage', function(data) {
    console.log(data);

    // { user: '9.33', sys: '56.0', idle: '34.66' }
});

// watch processes that use most cpu percentage
cpuMonitor.on('topCpuProcs', function(data) {
    console.log(data);

    // [ { pid: '21749', cpu: '0.0', command: 'top' },
    //  { pid: '21748', cpu: '0.0', command: 'node' },
    //  { pid: '21747', cpu: '0.0', command: 'node' },
    //  { pid: '21710', cpu: '0.0', command: 'com.apple.iCloud' },
    //  { pid: '21670', cpu: '0.0', command: 'LookupViewServic' } ]
});