Deploying Django to Heroku

Step #2 of "Django Getting Started" Series

In the previous Django - Getting Started post, we set up a new Django app, basically creating a fullstack Python Hello World.

In this post, we will deploy this very basic app to Heroku (a free hosting platform which can run a Django server along with other types of web services). There are many ways to deploy Django, but not a single tutorial I've found online actually worked for me as written. Therefor, I've collected the process that finally did the trick and have outlined it below. A lot of the process comes from our bootcamp instructors, with some customization found several layers deep on Stack Overflow and Reddit (and eventually some personal manipulation). Please let me know if this works for you, and comment below if you have any questions!

Deploy Process

Get Ready

  • Load up your terminal and cd into the floor of your Django project. Running the command ls should your requirements.txt, manage.py, main_app folder, and example_project, amongst several others. My example is below (some of these files will be created in the following steps)

Screen Shot of terminal showing example files at floor level

Log In With Heroku CLI

You will need to have a Heroku account for this process. It's free to sign up, and you should also install the CLI (command line interface) from Heroku to complete the following steps:

  • heroku login and press any key to launch a browser window which will allow you to sign in to Heroku

Procfile

This file will tell Heroku what actions to take when it receives a web request:

  • create a blank file with no file extension: touch Procfile

    ensure the capitalization is exact on Procfile; if you accidentally mixed the casing up you can fix it using this method I wrote about

  • open the new Procfile in VSCode, and add this line. If you followed along with part one the project is called example. There should be 3 folders inside your local directory, a .env, a main_app/ that was created most recently that contains your home route/view and a example/ that was created initially and contains a route to your admin, and a settings.py. You want the last one of these.
    web: gunicorn example.wsgi
    

Runtime

This file simply tells Heroku which exact version of Python to use:

  • python3 --version displays your current version of Python locally
  • copy that exact series of numbers; mine is 3.9.2
  • touch runtime.txt and open it in VSCode
  • type python- and then paste (no space in between) the exact version. Mine ends up as python-3.9.2

More Packages

Why re-invent the wheel? Someone already got all this cool stuff working; use it!

  • pip3 install django-on-heroku
  • pip3 install gunicorn
  • pip3 install whitenoise
  • open settings.py
  • add import django_on_heroku near the top of your file under your other import statements
  • scroll the very bottom of settings.py
  • add django_on_heroku.settings(locals())

Update Dependencies

  • pip3 freeze > requirements.txt

Deploy

  • heroku create example --buildpack heroku/python

    This will try and create a Heroku project with the URL example.herokuapp.com. If someone has already taken your preferred name you can change to anything else that you want

  • heroku addons:create heroku-postgresql:hobby-dev - adds a free postgreSQL database to your free Heroku account

Set Heroku Config Vars

In the previous post, we set our app's local config vars in an .env file and read them out dynamically. Please ensure your app is set up properly to use the following commands and allow Heroku to store its own config vars

  • heroku config:set DISABLE_COLLECTSTATIC=1 - prevents one problem, seems to cause some others 🤦‍♂️ (see note at the end for a potential fix)
  • heroku config:set DATABASE_NAME=example-db
  • heroku config:set ENVIRONMENT=production
  • heroku config:set SECRET_KEY=whatever_your_secret_key_is

Push to Production

  • git add .
  • git commit -m "fingers crossed"
  • git push heroku main - this will push your app up to the newly created Heroku project, rather than pushing to GitHub or some other remote as you normally would with git push origin main

    If you are still using master branch instead of main, you'll want to swap that word, and it must be from one of those two named branches that you initiate the push

Fix Deployed Database

Now, you'll tunnel in to the Heroku server with your command line, so you can see what's going on in there and make needed updates to the free database they gave you.

  • heroku run bash
  • once inside, run python3 manage.py makemigrations. As before, there might not be any changes after this step
  • python3 manage.py migrate - this brings your database up to date with the built-in user models that Django provides
  • exit gets you out of Heroku and back on to your local machine

See If It Works!

  • heroku open will launch the site in a browser.

    If you have problems, typing heroku logs --tail will let your terminal log all sorts of difficult to decipher messages, including some that will help you figure out what's wrong. To exit this logging feature, use CTRL+C.

To view even more helpful errors, follow the instructions on this stackoverflow where they explain adding DEBUG_PROPAGATE_EXCEPTIONS = True and a LOGGING = { ... } library to their settings.py. And as Deepak Raj mentioned in the comments, you may also need to run python manage.py collectstatic (or python3 manage.py collectstatic) in your terminal with your project's virtual environment activated before git committing and redeploying. This fixes some of Django's issues finding static files.

Photo by Rodion Kutsaev on Unsplash

Comments (2)

Deepak Raj's photo

It happens sometimes be due to the wrong static folder location. providing the right path will not produce an error or alternatively, you have options as you write.

Try python manage.py collectstatic locally will also solve the problem.

Ben Hammond's photo

awesome, I'll try that. Thanks!