Test and deploy a Python application with GitLab CI/CD

This example will guide you how to run tests in your Python application and deploy it automatically as Heroku application.

You can also view or fork the complete example source.

Configure project

This is what the .gitlab-ci.yml file looks like for this project: 

stages:
  - test
  - deploy

test:
  stage: test
  script:
    # this configures Django application to use attached postgres database that is run on `postgres` host
    - export DATABASE_URL=postgres://postgres:@postgres:5432/python-test-app
    - apt-get update -qy
    - apt-get install -y python-dev python-pip
    - pip install -r requirements.txt
    - python manage.py test

staging:
  stage: deploy
  script:
    - apt-get update -qy
    - apt-get install -y ruby-dev
    - gem install dpl
    - dpl --provider=heroku --app=gitlab-ci-python-test-staging --api-key=$HEROKU_STAGING_API_KEY
  only:
    - master

production:
  stage: deploy
  script:
    - apt-get update -qy
    - apt-get install -y ruby-dev
    - gem install dpl
    - dpl --provider=heroku --app=gitlab-ci-python-test-prod --api-key=$HEROKU_PRODUCTION_API_KEY
  only:
    - tags

This project has three jobs:

  • test - used to test Django application.
  • staging - used to automatically deploy staging environment every push to master branch.
  • production - used to automatically deploy production environment for every created tag.

Store API keys

You’ll need to create two variables in Settings > CI/CD > Environment variables in your GitLab project:

  • HEROKU_STAGING_API_KEY - Heroku API key used to deploy staging app.
  • HEROKU_PRODUCTION_API_KEY - Heroku API key used to deploy production app.

Find your Heroku API key in Manage Account.

Create Heroku application

For each of your environments, you’ll need to create a new Heroku application. You can do this through the Dashboard.

Create Runner

First install Docker Engine.

To build this project you also need to have GitLab Runner. You can use public runners available on gitlab.com or you can register your own: 

cat > /tmp/test-config.template.toml << EOF
[[runners]]
[runners.docker]
[[runners.docker.services]]
name = "postgres:latest"
EOF

gitlab-runner register \
  --non-interactive \
  --url "https://gitlab.com/" \
  --registration-token "PROJECT_REGISTRATION_TOKEN" \
  --description "python-3.5" \
  --executor "docker" \
  --template-config /tmp/test-config.template.toml \
  --docker-image python:3.5

With the command above, you create a runner that uses the python:3.5 image and uses a PostgreSQL database.

To access the PostgreSQL database, connect to host: postgres as user postgres with no password.