CI/CD pipeline basics in Django

Introduction

A CI/CD pipeline helps developers deliver code changes faster and more reliably by automating testing and deployment.

When you want to automatically test your Django app after every code change.

When you want to deploy your Django app to a server without manual steps.

When multiple developers work on the same Django project and need quick feedback.

When you want to catch bugs early before they reach users.

When you want to save time by automating repetitive tasks like testing and deployment.

Syntax

Django

stages:
  - test
  - deploy

test_job:
  stage: test
  script:
    - python manage.py test

deploy_job:
  stage: deploy
  script:
    - echo "Deploying Django app..."
    - ./deploy_script.sh

This example shows a simple pipeline with two stages: test and deploy.

Each job runs commands under the script section.

Examples

This job runs Django tests using the built-in test command.

Django

test_job:
  script:
    - python manage.py test

This job runs a custom script to deploy the Django app.

Django

deploy_job:
  script:
    - ./deploy_script.sh

You can define multiple stages to organize your pipeline steps.

Django

stages:
  - build
  - test
  - deploy

Sample Program

This pipeline first runs Django tests. If tests pass, it runs the deploy job.

Django

stages:
  - test
  - deploy

test_job:
  stage: test
  script:
    - python manage.py test

deploy_job:
  stage: deploy
  script:
    - echo "Deploying Django app..."
    - ./deploy_script.sh

Important Notes

Make sure your deployment script has execute permission (chmod +x deploy_script.sh).

CI/CD pipelines run automatically on code changes pushed to your repository.

Start simple and add more steps as your project grows.

Summary

CI/CD pipelines automate testing and deployment for faster, safer code delivery.

They run jobs in stages like test and deploy.

Using pipelines helps catch bugs early and saves time.

Practice

1. What is the main purpose of a CI/CD pipeline in a Django project?

easy

A. To automate testing and deployment for faster and safer code delivery

B. To manually review code changes before deployment

C. To write Django models automatically

D. To create database backups

Solution

1. Step 1: Understand CI/CD pipeline purpose

   A CI/CD pipeline automates the process of testing and deploying code changes to reduce errors and speed up delivery.

2. Step 2: Match purpose with options

   To automate testing and deployment for faster and safer code delivery correctly states automation of testing and deployment, which is the core of CI/CD pipelines.

3. Final Answer:

   To automate testing and deployment for faster and safer code delivery -> Option A

4. Quick Check:

   CI/CD automates testing and deployment = D [OK]

Hint: CI/CD means automating tests and deploys [OK]

Common Mistakes:

• Confusing CI/CD with manual code review
• Thinking CI/CD creates Django code automatically
• Assuming CI/CD is for backups

2. Which of the following is the correct syntax to define a job named test in a GitLab CI/CD pipeline YAML file?

easy

A. test:
script:
- python manage.py test

B. job test {
run: python manage.py test
}

C. - job: test
steps:
- script: python manage.py test

D. test => {
script: 'python manage.py test'
}

Solution

1. Step 1: Recall GitLab CI YAML job syntax

   GitLab CI jobs are defined as job_name: followed by script: list with commands.

2. Step 2: Compare options with correct YAML syntax

   test: script: - python manage.py test matches the correct YAML format for a job named test running the Django test command.

3. Final Answer:

   test:\n script:\n - python manage.py test -> Option A

4. Quick Check:

   GitLab CI job syntax uses job_name: and script: list = A [OK]

Hint: GitLab CI jobs use job_name: and script: list [OK]

Common Mistakes:

• Using curly braces or other languages syntax
• Missing the dash before script commands
• Confusing job syntax with other CI tools

3. Given this GitHub Actions workflow snippet for a Django project:

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: '3.12'
      - name: Install dependencies
        run: pip install -r requirements.txt
      - name: Run tests
        run: python manage.py test

What will happen when this workflow runs?

medium

A. The workflow will fail because Python version is not specified

B. The workflow will check out code, set Python 3.12, install dependencies, and run Django tests

C. The workflow will skip installing dependencies

D. The workflow will deploy the Django app automatically

Solution

1. Step 1: Analyze each step in the workflow

   The workflow checks out code, sets up Python 3.12, installs dependencies from requirements.txt, then runs Django tests.

2. Step 2: Confirm expected behavior

   All steps are valid and will run in order, so tests will execute after setup.

3. Final Answer:

   The workflow will check out code, set Python 3.12, install dependencies, and run Django tests -> Option B

4. Quick Check:

   Steps run in order: checkout, setup, install, test = A [OK]

Hint: Read steps top to bottom to predict workflow actions [OK]

Common Mistakes:

• Assuming Python version missing causes failure
• Thinking dependencies are skipped
• Confusing test run with deployment

4. You have this GitLab CI job snippet:

test:
  script:
    - python manage.py test
  only:
    - main
    - develop

But tests are not running on your feature branch pushes. What is the likely problem?

medium

A. The script command is incorrect

B. The pipeline YAML file is missing

C. The job is limited to run only on main and develop branches

D. The tests are skipped because of syntax error in Python code

Solution

1. Step 1: Understand the 'only' keyword in GitLab CI

   The 'only' keyword restricts job execution to specified branches, here main and develop only.

2. Step 2: Analyze why feature branches don't run tests

   Since feature branches are not listed, the job does not run on them.

3. Final Answer:

   The job is limited to run only on main and develop branches -> Option C

4. Quick Check:

   'only' limits branches = B [OK]

Hint: 'only' controls branches where job runs [OK]

Common Mistakes:

• Thinking script command is wrong without checking
• Assuming pipeline file is missing
• Blaming test code syntax without evidence

5. You want to create a CI/CD pipeline for your Django app that runs tests only if code changes affect models.py or views.py. Which GitLab CI configuration snippet correctly implements this?

hard

A. test:
script:
- python manage.py test
only:
refs:
- main
- develop

B. test:
script:
- python manage.py test
except:
changes:
- models.py
- views.py

C. test:
script:
- python manage.py test
when: manual

D. test:
script:
- python manage.py test
only:
changes:
- models.py
- views.py

Solution

1. Step 1: Understand 'only: changes' in GitLab CI

   This setting runs the job only if specified files change in the commit.

2. Step 2: Match requirement with options

   test: script: - python manage.py test only: changes: - models.py - views.py uses 'only: changes' with models.py and views.py, so tests run only if these files change.

3. Final Answer:

   test:\n script:\n - python manage.py test\n only:\n changes:\n - models.py\n - views.py -> Option D

4. Quick Check:

   'only: changes' triggers job on file changes = C [OK]

Hint: 'only: changes' runs job on specific file changes [OK]

Common Mistakes:

• Using 'except' instead of 'only' for changes
• Using branch refs instead of file changes
• Setting job to manual instead of automatic