I recently needed a way to execute a bash script from a Node application. The premise was simple, to create an authorization protected Node/Express endpoint that could execute a bash script that lives alongside my app. My script does tasks like moving local log files and restarting processes. Node makes this extremely easy to do.
Problem: Run bash script from Node Application
Solution:
By leveraging the child processes in Node I can spawn a new child process to execute the script. Spawning allows separate child processes to run asynchronously. Here I will show an example using a setInterval(), but this can easily be added to any other portion of your Node app, like a JWT protected endpoint.
app.js
'use strict'
const child_process = require("child_process");
setInterval(() => {
const child = child_process.spawn('bash', [__dirname + '/myscript.sh']);
child.on('exit', () => {
console.log('process complete');
});
}, 3000);
This will simply execute myscript.sh every 3 seconds, console logging when the child_process is complete.
To breakdown each line:
const child = child_process.spawn('bash', [__dirname + '/myscript.sh']);
This is creating a new constant variable call child and setting it to a new child_process.spawn(). The spawn will the execute our myscript.sh as a ‘bash’ script.
The child_process.spawn() produces a few different events, here we are listening for the exit event and console.log()‘ing that the process completed.