Add slack notification

Chaosfile.json

@@ -9,6 +9,12 @@
   	{
   		"key": "chaos_monkey",
   		"value": "true"
+	}
+  ],
+  "slackWebhook": [
+  	{
+  		"channel": "#random",
+  		"webhookId": "XXXXXXXXX"
   	}
   ]
 }

lambda/index.js

@@ -2,6 +2,8 @@
 // provided under the terms of either of those licenses.
 
 var AWS = require('aws-sdk');
+var https = require('https');
+var util = require('util');
 var llamaConfig = require('./config.json');
 
 AWS.config.region = llamaConfig.region || 'eu-west-1';
@@ -29,6 +31,7 @@ ec2.describeInstances(function(err, data) {
   }
 
   var candidates = [];
+  var asgNames = [];
   data.Reservations.forEach(function(res) {
     res.Instances.forEach(function(inst) {
       inst.Tags.forEach(function(tag) {
@@ -38,11 +41,13 @@ ec2.describeInstances(function(err, data) {
             // this takes precedence - if defined we don't even look at disableForASGs
             if (llamaConfig.enableForASGs.indexOf(tag.Value) !== -1) {
               candidates.push(inst);
+              asgNames.push(tag.Value);
             }
           } else {
             if (llamaConfig.disableForASGs) {
               if (llamaConfig.disableForASGs.indexOf(tag.Value) === -1) {
                 candidates.push(inst);
+                asgNames.push(tag.Value);
               }
             }
           }
@@ -69,9 +74,63 @@ ec2.describeInstances(function(err, data) {
 
   var random = Math.floor(Math.random() * numInstances);
   var target = candidates[random];
+  var asgName = asgNames[random];
 
   console.log('Going to terminate instance with id = %s', target.InstanceId);
 
+  if (llamaConfig.slackWebhook) {
+    llamaConfig.slackWebhook.forEach(function(slack) {
+      if ( (slack.channel === null || typeof slack.channel === 'undefined') || (slack.webhookId === null || typeof slack.webhookId === 'undefined')) {
+        console.log('No channel or webhook specified. Slack message not sent.');
+        return context.done(null);
+      }
+
+      if (slack.username === null || typeof slack.username === 'undefined') {
+        slack.username = "Chaos Lambda";
+      }
+
+      // code taken from https://gist.github.com/stack72/ad97da2df376754e413a
+      var slackMessage = [
+        "*Event*: CHAOS_TERMINATION - ShutdownInstance",
+        "*Description*: Going to terminate instance with id " + target.InstanceId + " (ASG *" + asgName + "*)",
+        "*Cause*: At " + getTimestamp() + " Chaos Lambda struk again!",
+      ].join("\n");
+
+      var postData = {
+        channel: slack.channel,
+        username: slack.username,
+        text: "*Chaos Lambda Termination Notification*",
+        attachments: [{ text: slackMessage, mrkdwn_in: ["text"] }]
+      };
+
+      var options = {
+        method: 'POST',
+        hostname: 'hooks.slack.com',
+        port: 443,
+        path: '/services/' + slack.webhookId
+      };
+
+      var req = https.request(options, function(res) {
+        res.setEncoding('utf8');
+        if (res.statusCode !== "200") {
+          console.log('HTTP status code: %s', res.statusCode);
+          console.log('HTTP headers: %s', res.headers);
+        }
+        res.on('data', function (chunk) {
+          context.done(null);
+        });
+      });
+
+      req.on('error', function(e) {
+        context.fail(e);
+        console.log('request error: ' + e.message);
+      });
+
+      req.write(util.format("%j", postData));
+      req.end();
+    });
+  }
+
   ec2.terminateInstances({InstanceIds:[target.InstanceId]}, function(err, data) {
     if (err) {
       return context.done(err, null);
@@ -83,7 +142,29 @@ ec2.describeInstances(function(err, data) {
 });
 };
 
-function randomIntFromInterval(min,max)
-{
-    return Math.floor(Math.random()*(max-min+1)+min);
+function randomIntFromInterval(min,max) {
+  return Math.floor(Math.random()*(max-min+1)+min);
+}
+
+function getTimestamp() {
+  var date = new Date();
+
+  var hour = date.getHours();
+  hour = (hour < 10 ? "0" : "") + hour;
+
+  var min  = date.getMinutes();
+  min = (min < 10 ? "0" : "") + min;
+
+  var sec  = date.getSeconds();
+  sec = (sec < 10 ? "0" : "") + sec;
+
+  var year = date.getFullYear();
+
+  var month = date.getMonth() + 1;
+  month = (month < 10 ? "0" : "") + month;
+
+  var day  = date.getDate();
+  day = (day < 10 ? "0" : "") + day;
+
+  return year + "-" + month + "-" + day + " " + hour + ":" + min + ":" + sec;
 }