rebootify/lib/rebootify.js

A Faster and lightweight alertnative to nodemon to monitor your Node Application

const spawn = require('child_process').spawn;
const chokidar = require('chokidar');
const path = require('path');
const Utility = require('../util/utility');
const logger = require('./logger');

class Rebootify {
    constructor() {
        this.__init__();
    }

    __init__ = () => {
        this.args = process.argv;
        this.fileName = this.args[2];
        this.cwd = process.cwd();

        // Watch only the server.js file for changes, update to match your use case
        this.watchPaths = [path.join(this.cwd, 'server.js')]; // Watch the specific file `server.js`
        this.ignoredPaths = "**/node_modules/*";

        this.logInit();
        this.reload();  // Start initial process
        this.startWatching();  // Start file watching
        this.listeningEvents(); // Listen for CLI input
    }

    reload = () => {
        logger('debug', `Starting ${this.fileName}`);
        if (this.nodeServer) this.killNodeProcess(); // Kill previous process before spawning a new one
    
        const nodeArgs = this.args.slice(3); // Capture any additional arguments
        logger('debug', `Spawning new process for ${this.fileName}`);
        this.nodeServer = spawn('node', [this.fileName, ...nodeArgs], { stdio: 'inherit' });

        this.nodeServer.on('close', (code) => {
            if (code !== 0) {
                logger('error', `${this.fileName} crashed. Restarting on changes...`);
            }
        });

        this.nodeServer.on('spawn', () => {
            logger('debug', `${this.fileName} spawned successfully`);
        });
    };

    startWatching = () => {
        const watcher = chokidar.watch(this.watchPaths, {
            ignored: this.ignoredPaths,
            ignoreInitial: true,
        });

        watcher.on('ready', () => {
            logger('info', 'Watcher is ready. Monitoring changes...');
        }).on('change', (filePath) => {
            logger('debug', `File changed: ${filePath}`);
            Utility.debounce(() => {
                logger('debug', 'Debounced reload triggered.');
                this.reload();  // Restart the process when file changes
            }, 500)();
        });
    };

    listeningEvents = () => {
        // Listening for CLI input (e.g., 'rs' to restart)
        process.stdin.on("data", (chunk) => {
            let cliInput = chunk.toString().trim(); // Trim extra spaces/newlines
            if (cliInput === 'rs') {
                this.reload();
            }
        });
    };

    logInit = () => {
        logger('info', 'Rebootify v1.0.0');
        logger('info', 'To restart at any time, enter `rs`');
    };

    killNodeProcess = () => {
        if (this.nodeServer) {
            logger('info', 'Killing the previous Node.js process...');
            this.nodeServer.kill('SIGTERM'); // Send the signal to gracefully stop the process
            this.nodeServer = null;
        } else {
            logger('warn', 'No process to kill.');
        }
    };
}

// Graceful shutdown: Ensure subprocess is killed when exiting
process.on('SIGINT', () => {
    logger('info', 'Shutting down gracefully...');
    if (this.nodeServer) this.killNodeProcess();
    process.exit();
});

process.on('SIGTERM', () => {
    logger('info', 'Received SIGTERM. Shutting down...');
    if (this.nodeServer) this.killNodeProcess();
    process.exit();
});

module.exports = new Rebootify();