main.js

/* 
GENERAL USAGE:
	start with 'node main.js {hoursDelay} {hoursIntervalHours}'
	where {hoursDelay} is the number of hours to wait before attempting to generate backups.
	after that hoursDelay and the initial backup generation, the tool will wait for {hoursInterval} hours before
	attempting to generate backups again.

	if hourshoursDelay is undefined or 0, the first backup will happen after 10 seconds. if hoursIntervalHours is undefined, 
	default is 24 hours between backups.
	
	i used this setup because the server to which i deployed this app was set to a different time zone than mine.
	setting the backup time relative to current time meant i didnt need to worry about converting times. 

DOCKER USAGE:
	you must mount the directories containing backups at /app/backups and the directory where zips should output
	  at /app/zips
*/


const backup = require('./backupGenerator.js');
const logger = require('./logger.js');

function generateBackups() {


	console.log('attempting backup generation...')
	try {
		backup.updateBackups();
	}
	catch(e) {
		logger.errorLog('error updating backups ' + e.message + '\n' + e.stack);
	}
		
}

// runs backup, then starts setInterval with given hoursInterval delay
function firstBackupAndStartInterval(_hoursInterval) {
	try {
		generateBackups();

		setInterval(generateBackups, _hoursInterval * 60 * 60 * 1000)
	}
	catch(e) {
		let error = 'error in firstBackupAndStartInterval' + '\n' + e.message + '\n' + e.stack;
		console.log(error);
		logger.errorLog(error);
	}

}

try {


	// remove 'node' and 'main.js' from arguments list so that needed arguments
	// will start at [0]
	var args = process.argv.slice(2);

	// defaults
	var hoursDelay = 0.01667; // equivalent to ~60 seconds, gives user chance to abort
	var hoursInterval = 24;

	// case where user provides no arguments
	if (args.length == 0) {
		
		//defaults
		console.log('defaulting to immediate backup and 24 hour hoursInterval');
	}

	// case where user only provides delay argument
	else if (args.length == 1) {
		if (isNaN(args[0])) {
			console.log('you didnt enter a number for the hoursDelay, defaulting to generate backups after 10 seconds');
		}
		else {
			hoursDelay = parseInt(args[0]);
		}

	}

	// case where user provides delay and hoursinterval argument
	else if (args.length > 1) {
		
		if (isNaN(args[0])) {
			console.log('you didnt enter a number for the hoursDelay, defaulting to generate backups after 10 seconds');
		}
		else {
			hoursDelay = parseInt(args[0]);
		}

		if (isNaN(args[1])) {
			console.log('you didnt enter a number for hoursInterval, defaulting to 24');
		}
		else {
			hoursInterval = parseInt(args[1]);
		}
	}

	console.log('starting setTimeout with ' + hoursDelay + 
		' hours of delay and a ' + hoursInterval + ' hour interval between successive backups');

	setTimeout( firstBackupAndStartInterval.bind(null, hoursInterval) , hoursDelay * 60 * 60 * 1000); 

}

catch(e) {

	let error = 'error starting or error within main event loop. attempting to write to error log' + 
		e.message + '\n' + e.stack;
	console.log(error);

	logger.errorLog(error);
}