Heroku Application error: An error occurred in the application and your page could not be served

user_10538095 0
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I'm building an app and I've gotten to the point where deployment to HEROKU was successful. On opening app(https://odm-mobile.herokuapp.com/), I get APPLICATION ERROR, I checked log with CLI command and this is what I get: 

2018-10-22T09:06:32.000000+00:00 app[api]: Build started by user aailoje@gmail.com

2018-10-22T09:06:45.572183+00:00 app[api]: Deploy 7bc663ae by user aailoje@gmail.com

2018-10-22T09:06:45.572183+00:00 app[api]: Release v24 created by user aailoje@gmail.com

2018-10-22T09:06:45.826688+00:00 heroku[web.1]: State changed from crashed to starting

2018-10-22T09:06:47.000000+00:00 app[api]: Build succeeded

2018-10-22T09:06:49.116924+00:00 heroku[web.1]: Starting process with command `npm start`

2018-10-22T09:06:53.099327+00:00 app[web.1]:

2018-10-22T09:06:53.099345+00:00 app[web.1]: > odm-mobile@1.0.0 start /app

2018-10-22T09:06:53.099347+00:00 app[web.1]: > node index.js

2018-10-22T09:06:53.099349+00:00 app[web.1]:

2018-10-22T09:06:53.840102+00:00 heroku[web.1]: Process exited with status 0

2018-10-22T09:06:53.856482+00:00 heroku[web.1]: State changed from starting to crashed

2018-10-22T09:06:53.858384+00:00 heroku[web.1]: State changed from crashed to starting

2018-10-22T09:06:57.152906+00:00 heroku[web.1]: Starting process with command `npm start`

2018-10-22T09:07:00.298331+00:00 app[web.1]:

2018-10-22T09:07:00.298348+00:00 app[web.1]: > odm-mobile@1.0.0 start /app

2018-10-22T09:07:00.298350+00:00 app[web.1]: > node index.js

2018-10-22T09:07:00.298351+00:00 app[web.1]:

2018-10-22T09:07:00.979144+00:00 heroku[web.1]: Process exited with status 0

2018-10-22T09:07:00.997278+00:00 heroku[web.1]: State changed from starting to crashed

2018-10-22T09:07:20.183091+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=odm-mobile.herokuapp.com request_id=c9a8b164-2f61-459b-87da-56518ce4dc81 fwd="154.120.97.254" dyno= connect= service= status=503 bytes= protocol=https

2018-10-22T09:07:22.293716+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=odm-mobile.herokuapp.com request_id=6870b281-7607-4882-8bac-e97c38169e26 fwd="154.120.97.254" dyno= connect= service= status=503 bytes= protocol=https

2018-10-22T09:25:14.164205+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=odm-mobile.herokuapp.com request_id=af0d9ab3-8a64-494e-8b2e-4b5e0a46f7fd fwd="154.120.97.254" dyno= connect= service= status=503 bytes= protocol=https

2018-10-22T09:25:15.783603+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=odm-mobile.herokuapp.com request_id=dcd6cc6f-0959-4ca7-b4d4-43143e952b8c fwd="154.120.97.254" dyno= connect= service= status=503 bytes= protocol=https`

The following are the files that I'm working with on dreamweaver

  1. index.js 

    var port = Number(process.env.PORT|| 5000);
var express = require('express'),
    moment = require('moment');

var exports = module.exports = function(dir, options) {
    var modules = {};
    options = merge(options || {}, {
        lazy: true
    });

    fs.readdirSync(dir).forEach(function(filename) {
        // filter index and dotfiles
        if (filename !== 'index.js' && filename[0] !== '.') {
            var moduleName = path.basename(filename, path.extname(filename));
            var modulePath = path.join(dir, moduleName);
            // lazy load
            if (options.lazy) {
                Object.defineProperty(modules, moduleName, {
                    get: function() {
                        return require(modulePath);
                    }
                });
            } else {
                modules[moduleName] = require(modulePath);
            }
        }
    });

    return modules;
};

  2. package.json 

    {
  "name": "odm-mobile",
  "version": "1.0.0",
  "description": "odm daily devotional",
  "main": "index.js",
  "scripts": {
    "start": "node index.js"
  },
  "keywords": [],
  "author": "xdoshent <aailoje@gmail.com>",
  "license": "MIT",
  "repository": {
    "type": "git",
    "url": "odm-mobile"
  },
  "dependencies": {
    "@fortawesome/fontawesome-free": "^5.4.1",
    "express": "^4.16.4",
    "index.js": "0.0.3",
    "moment": "^2.22.2",
    "packages": "0.0.8"
  },
  "engines": {
    "node": "8.12.0",
    "engines": {
      "npm": "6.4.1"
    }
  }
}

  3. Procfile 

    web: node index.js

Pls clearly point out the issues I might be having and errors in the files I'm working with as I'm new to all these

dreamweaver heroku html javascript
2 Answers

Heroku isn't a FaaS service, it's a PaaS. I see that you've exported a function, but it ends there. Ensure that you're running a long-running application i.e. daemon. As stated clearly in logs, your application doesn't wait for anything and directly exits with return code 0 which indicates that the program has finished execution successfully. I'm not a Node.js developer but having a look at the Hello World example by ExpressJS will most likely help you understand why things didn't work this time.

https://expressjs.com/en/starter/hello-world.html

app.listen(port, () => console.log(`Example app listening on port ${port}!`))

This line does the work in the code snippet by ExpressJS. It starts listening to incoming connections, so it blocks forever until killed and accepts connections.

user_47925520

Case 1: Procfile
in Procfile there should be no spaces between web: and node index.js.

  • incorrect:
    web: node index.js
  • correct:
    web:node index.js

Case 2: devDependency
There should not be any dev dependencies on the server, as heroku didn't install devDependencies by default. So either change devDependencies to dependencies in your package.json, or run:

heroku config:set NPM_CONFIG_PRODUCTION=false
user_144702950
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