Issue with terminating node.js application on AWS

Question

I have a node.js application that pings a url and then sends a Slack message if it receives an error code. It works great for two days, but then it just stops working. I use Screen to make it work, but it still seems to stop. Any help would be greatly appreciated.

Code below:

var request = require("request") var Hapi = require('hapi'); var Slack = require('slack-node'); var h = 0; var s = 0; var e = 0; function onlineBooking(){ request({ url: "http://example.com", json: true }, function (error, response, body) { if (!error && response.statusCode === 200) { // 'if/else' checks that it receives an up respsose four times in a row // the variable e is increased by .25 for every 200(ok response) until e reaches 1 // it will then send a message that the server is up if(e < 1 && response.statusCode === 200){ setTimeout(function () { console.log(response.statusCode) // Print the response code e =e+0.25; }, 6000); // 6 seconds delay between each response } else { while(h == 0){ console.log(response.statusCode) // Print the response code console.log("********************") slackReviewBot("Website :robot_face: ", response.statusCode + " - OK", "http://example.com", ""); h++; s = 0; } }// end of else }// end of if else { console.log(response.statusCode) // Print the response code e = 0; setTimeout(function () { while(s == 0){ console.log(response.statusCode) // Print the response code console.log("********************") slackReviewBot("Website :robot_face: ", response.statusCode, "http://example.com", ""); s++; h=0; }}, 3000); } // end of else }) } // sets the loop for checking every 7 seconds setInterval(function(){ onlineBooking(); }, 7000); // this function sends server name, a message and url to slack function slackReviewBot(servername, body, urls, bod) { var time = require('time'); // Create a new Date instance var now = new time.Date(); now.setTimezone("Europe/London"); var bo = body; var bod = bod; var urls = urls; var sname = servername; // you'll need to replace the slack webhook below // you'll find info on webhooks here https://api.slack.com/incoming-webhooks var webhook_url = 'https://hooks.slack.com/services/xxxxxxxxxxxxxxxxxxxxxx'; slack = new Slack(); slack.setWebhook(webhook_url); slack.webhook({ channel: "#server-uptime", username: "Server:", icon_emoji: "http://4.bp.blogspot.com/-mYCTaPOu-60/VK98X5CJEyI/AAAAAAAAApM/0oplbclvnUY/s1600/unnamed.png", text: " " + "\n" + "*" + sname + " * " + "\n" + "Status: " + bo + "\n" + now + "\n" + "Check the status here: " + urls + "\n" }, function(err, response) { console.log(response); }); } // below is so you can send a test json object to the server // http POST localhost:1337/jsonpost test=Test // you'll get a slack message letting you know the server is running var server = new Hapi.Server(); server.connection({ port: 1337 }); exports.add = function(i, j) { return i + j; }; // Slack function for sending the test reply function slackReviewBot2(testserver) { testserver = testserver; // you'll need to replace the slack webhook below // you'll find info on webhooks here https://api.slack.com/incoming-webhooks var webhook_url = 'https://hooks.slack.com/services/xxxxxxxxxxxxxxxxxxxxxxxxxx'; slack2 = new Slack(); slack2.setWebhook(webhook_url); slack.webhook({ channel: "#server-uptime", username: "Server-Test-Reply:", icon_emoji: "http://www.wonderfulwebsites.ie/phorest-logo.png", text: ":star: :star: :star: :star: :star:" + "\n" + "\n" + "Sever is up and running!!!" }, function(err, response) { console.log(response); }); } // take the json object for testing server.route({ method: 'POST' , path: '/jsonpost', handler: function(req, reply) { var review = { userName: req.payload.userName } //passes the review to the slackbot function slackReviewBot2(review.userName); reply("Received"); } }); // prints a server running message server.start(function(){ console.log('server running at: ', server.info.url); }); 

You can find a post explaining how this works below http://codingyoda.com/slack-pinging-tool.php

Answer 1

I do not know why this is happening, but you can fix it using forever , it will restart the process if it becomes inactive or replaces the screen with an emergency).

Answer 2

The magazine will certainly help us deal with the main reason here - please check your magazines and post here. Like the other answers, any production environment that I would recommend using forever or PM2 to restart the application if it dies. Since @sebastian offers to fix the problem, if not the reason, by automatically restarting the application. Another advantage is that these applications will write your console messages to a file - which will give you (and us) a better idea of ​​what is going on.

Another thought: you can deal with involuntary exception. If you think this is happening, you can add some code to catch, report, and even turn off gracefully. George Ornbo wrote a wonderful article about this here , which I would recommend you read, considering what to do with these exceptions.

Here's a too simplified version of the code to catch uncaught exceptions that should fix the error and, more importantly, a stack trace that you will need to track where the problem occurred (provided that you write these logs):

 //catches uncaught exceptions process.on('uncaughtException', function (err) { console.trace("Uncaught Exception", err); gracefulShutdown(err); }); // implementation beyond the scope of this question. function gracefulShutdown(error) { process.exit(error); } 

I hope this helps!