update

index.js

@@ -1 +1 @@
-module.exports = require('./src/middleware-wrapper');
+module.exports = require('./src/Uptime');

package.json

@@ -1,6 +1,6 @@
 {
   "name": "techstar-uptime",
-  "version": "1.0.4",
+  "version": "1.0.5",
   "description": "Uptime monitor",
   "main": "index.js",
   "scripts": {

src/Uptime.js

@@ -0,0 +1,105 @@
+'use strict';
+
+const EventEmitter = require('eventemitter3'),
+      request  = require('request');
+
+class Uptime extends EventEmitter{
+
+    constructor(options) {
+        super();
+        if (!options || (options && (!options.SLACK_WEBHOOK_URL))) {
+          throw new Error("You need to specify an SLACK_WEBHOOK_URL");
+        }
+        this.SLACK_WEBHOOK_URL = options.SLACK_WEBHOOK_URL;
+        this.pingInterval = 1*1000*60
+        this.serviceStatus = {}
+    }
+
+    pingService(url, cb){
+
+      console.log("PING START");
+      request({
+        method: 'GET',
+        uri: url,
+        time: true
+      }, (err, res, body) => {
+        if (!err && res.statusCode == 200) {
+          // we'll use the time from the point we try to establish a connection with
+          // the service until the first byte is received
+          cb(res.timingPhases.firstByte)
+        } else {
+          cb('OUTAGE')
+        }
+      })
+    }
+
+    postToSlack(serviceUrl){
+
+      console.log("POST TO SLACK START");
+      var message = "";
+      if (this.serviceStatus[serviceUrl].status == 'DEGRADED'){
+          message = "`СИСТЕМИЙН АЖИЛЛАГАА УНАСАН !!!` :skull: ";
+      } else if (this.serviceStatus[serviceUrl].status == 'OPERATIONAL') {
+         message = "СИСТЕМИЙН АЖИЛЛАГАА ХЭВИЙН БАЙНА :robot_face:";
+      } else if (this.serviceStatus[serviceUrl].status == 'OUTAGE') {
+         message = "СИСТЕМИЙН АЖИЛЛАГАА ДОГОЛДЛОО :zzz:";
+      }
+      let slackPayload = {
+        text: `*${message}*\n_${serviceUrl}_`
+      }
+
+      request({
+        method: 'POST',
+        uri: this.SLACK_WEBHOOK_URL,
+        body: slackPayload,
+        json: true
+      }, (err, res, body) => {
+        if (err) console.log(`Error posting to Slack: ${err}`)
+      })
+    }
+
+    monitor(websites){
+        console.log("MONITOR START");
+        websites.forEach(service => {
+          this.serviceStatus[service.url] = {
+            status: 'OPERATIONAL', // initialize all services as operational when we start
+            responseTimes: [], // array containing the responses times for last 3 pings
+            timeout: service.timeout // load up the timout from the config
+          }
+
+          setInterval(() => {
+            this.pingService(service.url, (serviceResponse) => {
+              if (serviceResponse === 'OUTAGE' && this.serviceStatus[service.url].status !== 'OUTAGE') {
+                // only update and post to Slack on state change
+                this.serviceStatus[service.url].status = 'OUTAGE'
+                this.postToSlack(service.url)
+              } else {
+                let responseTimes = this.serviceStatus[service.url].responseTimes
+                responseTimes.push(serviceResponse)
+
+                // check degraded performance if we have 3 responses so we can average them
+                if (responseTimes.length > 3) {
+                  // remove the oldest response time (beginning of array)
+                  responseTimes.shift()
+
+                  // compute average of last 3 response times
+                  let avgResTime = responseTimes.reduce((a, b) => a + b, 0) / responseTimes.length
+                  let currService = this.serviceStatus[service.url]
+
+                  if (avgResTime > currService.timeout && currService.status !== 'DEGRADED') {
+                    currService.status = 'DEGRADED'
+                    this.postToSlack(service.url)
+                  } else if (avgResTime < currService.timeout && currService.status !== 'OPERATIONAL') {
+                    currService.status = 'OPERATIONAL'
+                    this.ostToSlack(service.url)
+                  }
+                }
+
+              }
+            })
+          }, this.pingInterval)
+        })
+    }
+}
+
+module.exports = Uptime;