Setting Up CI/CD Pipelines for FastAPI with GitHub Actions and GitLab CI

Introduction

FastAPI has rapidly gained popularity among Python developers for its speed, simplicity, and ability to build robust web APIs. As modern software development shifts towards automation and continuous delivery, setting up an efficient CI/CD (Continuous Integration and Continuous Deployment) pipeline becomes essential for optimizing workflows, improving code quality, and reducing time-to-market for FastAPI applications.

Why CI/CD for FastAPI?

CI/CD pipelines automate the process of testing, building, and deploying applications. For FastAPI projects, a well-configured pipeline ensures:

• Automated code testing and linting to maintain code quality
• Faster feedback cycles for developers
• Consistent, predictable deployments
• Easy rollback in case of errors

With platforms like GitHub Actions and GitLab CI, setting up such pipelines is more accessible than ever before.

Getting Started with CI/CD: Prerequisites

• A working FastAPI application
• Version control with Git
• Repository hosted on GitHub or GitLab
• Docker (optional, but recommended for containerized deployment)

CI/CD with GitHub Actions

GitHub Actions allows you to automate workflows directly within your GitHub repository. Here’s how you can set up a basic CI/CD pipeline for a FastAPI project:

1. Workflow Configuration: Create a .github/workflows/ci.yml file in your repository. Define jobs for linting, testing, and deploying.
2. Example Workflow:

name: FastAPI CI/CD
on:
  push:
    branches: [main]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: '3.10'
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install -r requirements.txt
      - name: Lint code
        run: |
          pip install flake8
          flake8 .
      - name: Run tests
        run: pytest
      - name: Build Docker Image
        run: docker build -t fastapi-app .
      - name: Deploy
        run: echo "Deploy step here..."

This configuration checks out the code, sets up Python, installs dependencies, lints the code, runs tests, builds a Docker image, and finally triggers a deployment step (which you can customize for your environment).

CI/CD with GitLab CI

GitLab CI/CD is a powerful tool integrated into GitLab repositories. The process is similar to GitHub Actions but uses a .gitlab-ci.yml file:

1. Workflow Configuration: Place the following pipeline definition at the root of your repository.

stages:
  - test
  - build
  - deploy
test:
  image: python:3.10
  script:
    - pip install -r requirements.txt
    - pip install flake8 pytest
    - flake8 .
    - pytest
build:
  image: docker:latest
  services:
    - docker:dind
  script:
    - docker build -t fastapi-app .
deploy:
  script:
    - echo "Deploy step here..."

This pipeline runs code linting and tests, builds the Docker image, and then handles deployment. You can expand the deploy stage to push to a container registry, update your cloud provider, or trigger a more advanced deployment process.

Best Practices for FastAPI CI/CD Pipelines

• Use Environment Variables: Store sensitive data like API keys and secrets in repository secrets or CI/CD variables, never in source code.
• Automate Tests: Run unit and integration tests on every push to catch bugs early.
• Dockerize Your Application: Containerization ensures consistency across dev, test, and prod environments.
• Static Code Analysis: Use tools like flake8 or pylint for code style and quality checks.
• Deploy to Staging First: Before production, deploy to a staging environment to validate changes.

Advanced CI/CD Features

• Parallel Testing: Speed up pipelines by running tests in parallel.
• Cache Dependencies: Use caching to reduce build times.
• Automated Rollbacks: Integrate rollback steps for safer deployments.
• Notifications: Set up Slack, email, or other notifications for pipeline status updates.

Integrating with Cloud Providers

Many FastAPI applications are deployed to cloud platforms such as AWS, Azure, or Google Cloud. Both GitHub Actions and GitLab CI offer direct integrations with these providers, making it simple to:

• Push Docker images to cloud registries
• Trigger serverless deployments (e.g., AWS Lambda, Azure Functions)
• Update infrastructure using Infrastructure as Code (IaC) tools like Terraform

Conclusion

Implementing CI/CD pipelines for FastAPI with GitHub Actions or GitLab CI transforms your development process—boosting quality, reliability, and speed. By automating repetitive tasks, your team can focus on building features while reducing the risk of human error and ensuring your application is always production-ready.

Need help setting up or optimizing your CI/CD pipelines for FastAPI? Contact our experts to get started today!