Act - GitHub Actions Runner

Act is a powerful open-source tool that allows developers to run GitHub Actions workflows locally on their own machines. By leveraging Docker containers, Act provides a seamless way to test and debug your CI/CD pipelines without the need to push changes to your repository.

How does Act work?

When you run Act, it reads your GitHub Actions workflows from the .github/workflows/ directory in your project. It then determines which actions need to be executed and uses the Docker API to pull or build the necessary images. Act sets up the environment variables and filesystem to match what GitHub provides, ensuring a consistent experience between local and remote runs.

Key features of Act

Act offers several features that make it an essential tool for developers working with GitHub Actions:

• Local execution of workflows
• Support for multiple events (e.g., push, pull_request)
• Ability to run specific jobs or steps
• Secret management for sensitive information
• Customizable runner images

How to install Act

Act can be installed on various operating systems using package managers like Homebrew, Chocolatey, or Scoop. For example, on macOS, you can install Act using the command: brew install act. Windows users can use choco install act-cli or scoop install act.

Running GitHub Actions locally

To run your workflows locally, navigate to your project directory and execute the act command. By default, Act will run the push event, but you can specify different events or jobs using command-line options. For instance, act pull_request will trigger workflows associated with pull requests.

Can Act run all types of GitHub Actions?

While Act supports most GitHub Actions, there may be some limitations when it comes to certain platform-specific actions or those requiring special permissions. However, for the majority of workflows, Act provides an excellent local testing environment that can significantly speed up your development process.

Is Act suitable for large-scale projects?

Act is designed to handle projects of various sizes. For larger projects with complex workflows, Act allows you to selectively run specific jobs or steps, making it easier to focus on particular areas of your CI/CD pipeline. This targeted approach can be especially useful when debugging or optimizing your workflows.

How does Act handle secrets and environment variables?

Act provides several methods for managing secrets and environment variables. You can use a .env file, pass secrets directly through command-line arguments, or use the --secret-file option to load secrets from a dedicated file. This flexibility ensures that you can securely test workflows that depend on sensitive information.

By incorporating Act into your development workflow, you can catch and fix issues earlier in the development cycle, reduce the number of commits needed to get your CI/CD pipeline working correctly, and ultimately streamline your GitHub Actions experience. Whether you're a solo developer or part of a large team, Act offers a valuable tool for enhancing your productivity and ensuring the reliability of your automated workflows.