Send Cloudwatch Alerts from SNS to slack

cloudwatch-alert-sns-to-slack.js

console.log('[Amazon CloudWatch Notification]');

//Taken from https://raw.githubusercontent.com/ashiina/aws-lambda-cloudwatch-slack/master/handler.js

var ALARM_CONFIG = [
	{
		channel: "#cloudwatch-alerts",
		mention: "<@here> ",
		color: "#F35A00",
		severity: "CRITICAL"
	}
];

var SLACK_CONFIG = {
	path: "https://hooks.slack.com/services/xxxxxxxxxxx/yyyyyyyyyyy/xxxxxxxxxxxxxxxxxxxxx",
};

var http = require ('https');
var querystring = require ('querystring');
exports.handler = function(event, context) {
	// console.log(event.Records[0]);

	// parse information
	var message = event.Records[0].Sns.Message;
	var subject = event.Records[0].Sns.Subject;
	var timestamp = event.Records[0].Sns.Timestamp;

	// vars for final message
	var channel;
	var severity;
	var color;

	// create post message
	var alarmMessage = ""+
	"*Subject: "+subject+"*\n"+
	"Message: "+message+"\n"+
	"Timestamp: "+timestamp;

	// check subject for condition
	for (var i=0; i < ALARM_CONFIG.length; i++) {
		var row = ALARM_CONFIG[i];
		alarmMessage = row.mention+" "+alarmMessage+" ";
		channel = row.channel;
		severity = row.severity;
		color = row.color;
		break;
	}

	if (!channel) {
		context.done('error', "Invalid channel");
	}

	var payloadStr = JSON.stringify({
	"attachments": [
		{
			"fallback": alarmMessage,
			"text": alarmMessage,
			"mrkdwn_in": ["text"],
			"username": "AWS-CloudWatch-Lambda-bot",
			"fields": [
				{
					"title": "Severity",
					"value": severity,
					"short": true
				}
			],
			"color": color
		}
	],
		"channel":channel
	});
	var postData = querystring.stringify({
	  "payload": payloadStr
	});
	console.log(postData);
	var options = {
		hostname: "hooks.slack.com",
		port: 443,
		path: SLACK_CONFIG.path,
		method: 'POST',
		headers: {
			'Content-Type': 'application/x-www-form-urlencoded',
			'Content-Length': postData.length
		}
	};

	var req = http.request(options, function(res) {
		// console.log("Got response: " + res.statusCode);
		res.on("data", function(chunk) {
			// console.log('BODY: '+chunk);
			context.done(null, 'done!');
		});
	}).on('error', function(e) {
		context.done('error', e);
	});
	req.write(postData);
	req.end();
};