A simple pidfile utility. A pidfile holds the current pid of the process running your server. It can be used to detect if your process is already running, and interact with it using signals.

yarn add @jujulego/pid-file

First pid-file will try to create the pidfile with the wx filesystem flag. If the operation succeed, the pidfile didn't exist before, and this process now owns it.

If the file creation failed it means that the pidfile already existed, pid-file will check if the process owning the pidfile is still running. If the other process still runs the creation fails, else pid-file will update the pidfile with it's own pid. While pid-file tries to update the pidfile, this one is locked using proper-lockfile to ensure no other process also try to update it.

Nothing beats an example:

import { PidFile } from '@jujulego/pid-file';

const pidfile = new PidFile('.example.pid');

if (!await pidfile.create()) {
  console.warn('Failed to create .example.pid');
  process.exit(1);
}

// Do your job ;)

// When every thing is finished you should delete the pidfile:
await pidfile.delete();