Python

Mostly from Project walkthrough doc.

I’ve added empty lines for easy reading.

Samples

CircleCI default

version: 2.1

orbs:
  python: circleci/python@0.2.1

jobs:
  build-and-test:
    executor: python/default
    steps:
      - checkout
      - python/load-cache
      - python/install-deps
      - python/save-cache
      - run:
          command: ./manage.py test
          name: Test

workflows:
  main:
    jobs:
      - build-and-test

Install

Install Python packages.

• main.yml

    version: 2
      
    jobs:
      build:
        docker:
          - image: circleci/python:3.6.2-stretch-browsers
  
        steps:
          - checkout
          - run: pip install -r requirements/dev.txt
  

Services

Add a database - such as for running tests against a staging database.

• main.yml

    version: 2
      
    jobs:
      build:
        docker:
          - image: circleci/python:3.6.2-stretch-browsers
            environment:
              FLASK_CONFIG: testing
              TEST_DATABASE_URL: postgresql://root@localhost/circle_test?sslmode=disable
  
          - image: circleci/postgres:9.6.5-alpine-ram
            environment:
              POSTGRES_USER: root
              POSTGRES_DB: circle_test
              POSTGRES_PASSWORD: ""
  

Combine

Both of the previous sections combined.

• main.yml

    version: 2
    jobs:
      build:
        docker:
          - image: circleci/python:3.6.2-stretch-browsers
            environment:
              FLASK_CONFIG: testing
              TEST_DATABASE_URL: postgresql://ubuntu@localhost/circle_test?sslmode=disable
  
          - image: circleci/postgres:9.6.5-alpine-ram
            environment:
              POSTGRES_USER: ubuntu
              POSTGRES_DB: circle_test
              POSTGRES_PASSWORD: ""
  
      steps:
          - checkout
          - run:
              name: Install Python deps in a venv
              command: |
                python3 -m venv venv
                . venv/bin/activate
                pip install -r requirements/dev.txt
  

Full

The example flow continue including caching of packages and deploying to Heroku.

• main.yml

    workflows:
      version: 2
  
      build-deploy:
        jobs:
          - build
          - deploy:
              requires:
                - build
              filters:
                branches:
                  only: master
  
    version: 2
  
    jobs:
      build:
        docker:
          - image: circleci/python:3.6.2-stretch-browsers
            environment:
              FLASK_CONFIG: testing
              TEST_DATABASE_URL: postgresql://ubuntu@localhost/circle_test?sslmode=disable
  
          - image: circleci/postgres:9.6.5-alpine-ram
            environment:
              POSTGRES_USER: ubuntu
              POSTGRES_DB: circle_test
              POSTGRES_PASSWORD: ""
  
        steps:
          - checkout
  
          - restore_cache:
              key: deps1-{{ .Branch }}-{{ checksum "requirements/dev.txt" }}
  
          - run:
              name: Install Python deps in a venv
              command: |
                python3 -m venv venv
                . venv/bin/activate
                pip install -r requirements/dev.txt
  
          - save_cache:
              key: deps1-{{ .Branch }}-{{ checksum "requirements/dev.txt" }}
              paths:
                - "venv"
  
          - run:
              command: |
                . venv/bin/activate
                python manage.py test
  
          - store_artifacts:
              path: test-reports/
              destination: tr1
  
          - store_test_results:
              path: test-reports/
  
      deploy:
        steps:
          - checkout
          - run:
              name: Deploy Master to Heroku
              command: |
                git push https://heroku:$HEROKU_API_KEY@git.heroku.com/$HEROKU_APP_NAME.git master