chronos/lib/chronos/index.js

Log cronjob results to graylog2

var _ = require('underscore')._;
var exec = require('child_process').exec;

var Chronos = module.exports = {};

// some reasonable defaults, can be overwritten by /etc/chronos.json or /usr/local/etc/chronos.json
var defaults = {
	mode: "graylog2",
	amqp: {
		host: '127.0.0.1',
		port: 5672,
		key: 'logging',
		login: 'guest',
		password: 'guest',
		vhost: '/',
	},
	graylog2: {
		host: '127.0.0.1',
		port: 12201,
	},
	stage: false,
};

// nice environment settings formatting
// SOME_VAR: value
function getEnvSettings() {
	return _.map(process.env, function(v, k) { return k + ': ' + v; }).join("\n");
};

// Overwrite default configuration, used by the binary
Chronos.configure = function(opts) {
	defaults = _.extend(defaults, opts);
};

// run a job, cmdArray should contain exactly one element being the actual 
Chronos.run = function(opts) {
	// time in milliseconds the job was started at
	var startTime = (new Date()).getTime();
	
	var jobName = opts.jobname;
	var stage = opts.stage;
	var cmdString = opts.command;
	
	// execute!
	exec(cmdString, function(err, stdout, stderr) {
		// extract exit code of the command
		var exitCode = err === null ? 0 : err.code;
		
		// time in milliseconds the job was finished
		var endTime = (new Date()).getTime();
		
		// construct GELF message
		var message = {
			facility: 'chronos',
			level: exitCode === 0 ? 7 : 3, // success => debug (7), else: error (3)
			short_message: 'Cronjob "' + jobName + '" ' + (exitCode === 0 ? 'was executed' : 'has failed'),
			timestamp: ((new Date()).getTime() / 1000) >> 0,
			_startTime: startTime,
			_endTime: endTime,
			_runTime: (endTime - startTime),
			host: require('os').hostname(),
			_eventType: 'cronjob',
			version: '1.0',
			_jobName: jobName,
			_command: cmdString,
			_exitCode: exitCode,
			
			_user: process.env['USER'],
		};
		
		// more verbose information that may or may not be requested
		stage = stage || defaults.stage;
		if (stage) {
			message._stage = stage;
		}
		
		if (opts.env) {
			message._env = getEnvSettings();
		}
		
		if (opts.stdout) {
			message._stdout = stdout;
		}
		
		if (opts.stderr) {
			message._stderr = stderr;
		}
		
		var rawGELF = JSON.stringify(message);
		
		// connect to AMQP server and publish the message
		if (defaults.mode === 'amqp') {
			var amqp = require('amqp');
			var conn = amqp.createConnection(defaults.amqp);
			conn.on('ready', function() {
				conn.publish(defaults.amqp.key, rawGELF);
				
				// kill connection after 10 milliseconds
				setTimeout(function() {
					conn.end();
				}, 10);
			});
		} else if(defaults.mode === 'graylog2') {
			var buffer = new Buffer(rawGELF);
			require('zlib').deflate(buffer, function(err, compressedGELF) {
				if (err) return;
				
				if (compressedGELF.length > 8192) {
					// TODO: chunked support, see: https://github.com/Graylog2/graylog2-docs/wiki/GELF
					return;
				}
				
				var client = require('dgram').createSocket('udp4');
				client.send(
					compressedGELF,
					0,
					compressedGELF.length,
					defaults.graylog2.port,
					defaults.graylog2.host,
					function(err, byteCount) {
						console.log("Sent directly.");
						client.close();
					}
				);
			});
		}
	});
}