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So I'm running through the following:

  • Created a Dockerfile and a docker-compose.yml to develop a django app locally, nothing to do here, everything works just fine.

  • Dockerfile

    FROM python:3
    ENV PYTHONUNBUFFERED 1
    RUN mkdir /code
    WORKDIR /code
    ADD requirements.txt /code/
    RUN pip install -r requirements.txt
    ADD . /code/

  • All it does is fetches python3 image, copies the code from my source folder to the docker image

  • Then I'm trying to deploy this to heroku, so I added postgres add-on on heroku apps, and configured it using dj_database_url, with the following command on my settings.py file : DATABASES = {} DATABASES['default'] = dj_database_url.config()

  • After that I pushed my application to heroku using heroku container:push web and it got pushed to my app no problem at all...

  • The final piece is when I open my application using heroku open it says I got an error: Application error An error occurred in the application and your page could not be served. If you are the application owner, check your logs for details.

  • This is what get printed on the heroku website

  • Now, when I log using heroku logs -t, it says that exited with code 0, then it crashes

What am I missing?

  • Plus: when I run heroku run web python manage.py migrate it migrates the data on the heroku app
  • Plus 2: when I run heroku run web python manage.py runserver it says is running on 127.0.0.1:8000

EDIT 1: If you want to reproduce the problem you can clone all my code in the following git repo: https://github.com/giovanniKleinCampigoto/djangoherokuproblem.git

EDIT 2:

In this official tutorial: https://devcenter.heroku.com/articles/deploying-python , says to use virtualenv, but I'm using docker, so I don't really know how to proceed...

EDIT 3: Also, I noticed that when I push the image to heroku using: heroku container:push web, the server re-deploys, but instead of running whatever is on the procfile it just logs this: Starting process with command python3]

EDIT 4: When running heroku local web, and editing the Procfile to run docker-compose up works just fine, the problem is with the upload to heroku's server...not sure if I should edit the file to just python manage.py runserver...

docker-compose.yml 

version: '2'

services:
  web:
    build: .
    env_file: composeexample/.env
    command: python3 manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - "8000:8000"
Giovanni Klein Campigoto
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  • try to change running server on heroku to `heroku run web python manage.py runserver 0.0.0.0:5000` inside your `ProcFile`. I've some issues running flask and django on heroku, so, this worked for me. – Abe Sep 14 '17 at 18:18
  • Aren't we suposed to listen to the $PORT variable? Wouldn't it be 0.0.0.0:$PORT, plus I don't believe that my procfile get's ever executed... – Giovanni Klein Campigoto Sep 14 '17 at 18:25

3 Answers3

19

Since I did not receive any answers to this I'm answering my own question, so others can use my solution...

Ok so after a lot of testing, coming and goings I have discovered the problem.

So what happened was the following: for local development you should use docker-compose, mount volumes and all that yummy stuff, however when going on production with heroku you need to set a command for server starting. So if you ever plan to setup a project with docker + django + postgres add-on on heroku. Do the following steps.

First off:

DATABASES = {}

DATABASES['default'] = dj_database_url.config(default='DATABASE_URL')

  • This DATABASE_URL is a environment variable that you can get in your heroku app, go to your dashboard on heroku, find your app, go to settings, and Config Variables, click on reveal, and you should get the DATABASE_URL, the default variable is needed to /admin on django work...(This is only a work around, you should find a way to get the DATABASE_URL from a environment var)
  • Modify your Dockerfile to run the command to put the django server up adding to the last line: CMD python3 manage.py runserver 0.0.0.0:$PORT
  • The $PORT variable is the application port provided by heroku, so your application can run
  • Last but not least add your heroku app url to ALLOWED_HOSTS, as our friend Alejandro Sánchez said
  • And you're golden, your application should be running at the heroku app url

EDIT 1:

You don't need gunicorn as a dependency, the only command you should have in your Procfile is: web: python3 manage.py runserver

EDIT 2

As user: https://stackoverflow.com/users/1949328/sam pointed out runserver should not be ran in the PRODUCTION environment, use it at your own risk THIS SHOULD ONLY BE USED TO SETUP SOME SMALL TEST PROJECT.

Giovanni Klein Campigoto
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  • thanks for this. i was in a similar pinch and found this very helpful. – Ryan Skene Feb 11 '18 at 23:25
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    Any chance you used Caddy as the server and can share the configs? Finding it difficult to run for production using heroku's default app domain vs caddy's requirements – Jay Jung Mar 23 '18 at 01:55
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    did you find installing django-heroku to be necessary? The module itself seems to break for me. – Jay Jung Mar 23 '18 at 14:03
  • No, I used docker, I can't answer about caddy, because I don't have any knowledge about it. – Giovanni Klein Campigoto Mar 23 '18 at 14:12
  • I was finally able to only push it thanks to your descriptions. But I'm having trouble with the `CMD python3 ...` line. Heroku logs say `python3: can't open file 'manage.py': [Errno 2] No such file or directory`. Any idea? I wouldve thought with CMD, I'd run gunicorn. I've tried that too, but the following "app.wsgi" "module can't be found".. – Jay Jung Mar 23 '18 at 14:42
  • That's probably because you are not in the right django repository, because your manage.py was not found, you should try to find the django directory that contains manage.py file, and open it's path with CD, before executing CMD python3 – Giovanni Klein Campigoto Mar 23 '18 at 19:14
  • Wait a minute, are you using `runserver` in production?! This is very explicitly frowned upon in the docs. This should not be the accepted answer. https://docs.djangoproject.com/en/3.1/ref/django-admin/#runserver – sam Oct 31 '20 at 16:15
  • Man you really helped me getting this running you the real MVP – Wassaf Shahzad Feb 16 '21 at 11:25
1

Try adding the heroku url to ALLOWED_HOSTS

Reference

Alejandro Sánchez
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0

also Don't forget to add your application domain:"app-name.herokuapp.com" in ALLOWED_HOST = ['app-name.herokuapp.com'] in project settings.py.

Pravin
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