how to get a child process memory usage in node.js?

Question

I know there is a api process.memoryUsage() to get memory usage in current process.

But if I start a new child process by child_process.spawn(command, [args], [options]) and I get a ChildProcess object, then how can I get the new process memory usage?

Answer 1

The easiest way to get child's memoryUsage is installing pidusage

Link: https://www.npmjs.com/package/pidusage

In the console write this to install it:

In Windows Command: npm i pidusage --save
In Mac Command : sudo npm i pidusage --save

let pidusage = require('pidusage');

const cp = require("child_process");

const child = cp.spawn('ls', ['-lh', '/usr']);

pidusage(child.pid, function (err, stats) {

console.log(stats);

});
/*
Output: 
{
   cpu: 10.0,            // percentage (from 0 to 100*vcore)
   memory: 357306368,    // bytes
   ppid: 312,            // PPID
   pid: 727,             // PID
   ctime: 867000,        // ms user + system time
   elapsed: 6650000,     // ms since the start of the process
   timestamp: 864000000  // ms since epoch
}
*/

If you want to get more than one child's memoryUsage you need to change child.pid for and array [child.pid,child2.pid], function (err, stats) ...