ExpressJS / Heroku Application Error

Question

I am attempting to deploy a test express app on Heroku.

My package.json looks like this -

{
  "name": "heroku-test-app",
  "version": "1.0.0",
  "description": "",
  "main": "dist",
  "scripts": {
    "test": "cross-env NODE_ENV=test nodemon --exec mocha ./**/*.spec.js --compilers js:babel-core/register --require babel-polyfill",
    "dev": "nodemon -w src --exec \"babel-node src --presets es2015,stage-0\"",
    "build": "babel src -s -D -d dist --presets es2015,stage-0",
    "start": "cross-env node dist",
    "prestart": "npm run -s build",
    "clean": "rimraf dist/"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "babel-cli": "^6.26.0",
    "babel-core": "^6.26.0",
    "babel-eslint": "^7.2.3",
    "babel-polyfill": "^6.26.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-stage-0": "^6.24.1",
    "body-parser": "^1.17.2",
    "cross-env": "^5.0.5",
    "dotenv": "^4.0.0",
    "express": "^4.15.4",
    "morgan": "^1.8.2"
  },
  "devDependencies": {
    "chai": "^4.1.1",
    "mocha": "^3.5.0",
    "nodemon": "^1.11.0",
    "rimraf": "^2.6.1",
    "supertest": "^3.0.0"
  }
}

My Procfile looks like this -

web: npm start

and my test app is as so -

import express from 'express';
import morgan from 'morgan';
import bodyParser from 'body-parser';

const app = express();

const postBodyLimit = '100kb';
const port = 3000;

app.use(
  morgan('combined', {
    skip: (req, res) => res.statusCode < 400
  })
);

app.use(bodyParser.json({ limit: postBodyLimit }));
app.use(bodyParser.urlencoded({ extended: false }));

app.get('/', (req, res) => res.status(200).json({ message: 'No unicorns here.' }));

// catch 404's and pass to our global error handler
app.all('*', (req, res, next) => {
  const err = new Error('Not Found');
  err.status = 404;
  next(err);
});

app.use((err, req, res, next) => {
  res.status(err.status || 500).json({
    message: err.message,
    error: app.get('env') === 'development' ? err : null
  });
});

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

export default app;

When running my app locally, it starts and works perfectly. When running heroku local web, it also works as expected.

When I deploy to heroku however, I get the application error page. However on streaming my logs, there is nothing to suggest it has crashed.

I have just deployed again now, this is the current log file

2017-08-28T06:38:40.000000+00:00 app[api]: Build succeeded
2017-08-28T06:39:03.959631+00:00 app[web.1]: 
2017-08-28T06:39:03.959649+00:00 app[web.1]: > heroic-test-app@1.0.0 prestart /app
2017-08-28T06:39:03.959650+00:00 app[web.1]: > npm run -s build
2017-08-28T06:39:03.959651+00:00 app[web.1]: 
2017-08-28T06:39:05.856118+00:00 app[web.1]: src/index.js -> dist/index.js
2017-08-28T06:39:05.898228+00:00 app[web.1]: 
2017-08-28T06:39:05.898232+00:00 app[web.1]: > heroic-test-app@1.0.0 start /app
2017-08-28T06:39:05.898234+00:00 app[web.1]: > cross-env node dist
2017-08-28T06:39:05.898234+00:00 app[web.1]: 
2017-08-28T06:39:06.654100+00:00 app[web.1]: listening on port 3000
2017-08-28T06:44:40.078283+00:00 app[web.1]: 
2017-08-28T06:44:40.078319+00:00 app[web.1]: > heroic-test-app@1.0.0 prestart /app
2017-08-28T06:44:40.078320+00:00 app[web.1]: > npm run -s build
2017-08-28T06:44:40.078321+00:00 app[web.1]: 
2017-08-28T06:44:42.379605+00:00 app[web.1]: src/index.js -> dist/index.js
2017-08-28T06:44:42.434704+00:00 app[web.1]: 
2017-08-28T06:44:42.434707+00:00 app[web.1]: > heroic-test-app@1.0.0 start /app
2017-08-28T06:44:42.434708+00:00 app[web.1]: > cross-env node dist
2017-08-28T06:44:42.434709+00:00 app[web.1]: 
2017-08-28T06:44:43.156940+00:00 app[web.1]: listening on port 3000
2017-08-28T06:45:39.332668+00:00 app[web.1]: Error waiting for process to terminate: No child processes

I am at a loss how to proceed at this point.

Answer 1

you shouldn't set the port of http server as 3000 , you should use the port of process.env , heroku will set an PORT in process.env .

So you should use app.listen(process.env.PORT, () => {}) .

and there is an err code about the heroku application, if you can provide that, it would be better.