Integrating GitLab CI/CD, Flask, and Heroku
3 min read
This tutorial assumes you already have a working flask application within a virtual environment and have your code hosted on GitLab. Also ensure you have Gunicorn installed. You can install it from
pip install gunicorn.
pip freeze > requirements.txt to grab all the requirements for running your application.
Procfile file. Inside, place the following code
web: gunicorn <name of the app.py file>:<app-name> where app-name is usually “app”.
Push everything to GitLab.
Create a new Heroku application. Using a short name will make later steps easier.
Create a new file in your app root called
Here is a cookie-cutter example of a GitLab CI/CD config:
[app.py file name]: script: — apt-get update -qy — apt-get install -y python-dev python-pip — pip install -r requirements.txt production: type: deploy script: — apt-get update -qy — apt-get install -y ruby-dev — gem install dpl — dpl — provider=heroku — app=[Heroku App Name] — api-key=$HEROKU_SECRET_KEY only: — master
Now swap out
[app.py file name] with your file name and
[Heroku App Name] with the name of your Heroku app.
To set the HEROKU_SECRET_KEY,
Get your Heroku API key from dashboard.heroku.com/account.
Within GitLab, go to Settings → CI / CD → Secret variables.
Create a new variable and set the Variable key to HEROKU_SECRET_KEY and the Variable Value to your Heroku API Key.
Set the protected switch to ON.
Push the changes to GitLab.
Now that everything is all setup, head over to your Heroku app URL and enjoy the fruits of your labour.