Creating a Reusable JavaScript GitHub Action: A Step-by-Step Guide

Introduction: GitHub Actions are a powerful tool for automating workflows and tasks within your software development projects. With Actions, you can build, test, and deploy your code seamlessly. In this blog post, we will walk you through the process of creating a reusable JavaScript GitHub Action, using the “update-github-action-secret” action as an example. By examining the code and structure of the public GitHub repository (https://github.com/NikhilVashistha/update-github-action-secret), you’ll gain a clear understanding of how to create your own custom Actions to streamline your development process.

Prerequisites: Before we dive into creating a JavaScript GitHub Action, make sure you have the following prerequisites:

1. Basic understanding of JavaScript and GitHub Actions.
2. A GitHub account.
3. Familiarity with Git and version control concepts.
4. Node.js and npm (Node Package Manager) installed on your local machine.

Step 1: Setting Up Your Local Environment To get started, create a new directory on your local machine for your GitHub Action project. Open a terminal or command prompt, navigate to the project directory, and initialize a new Node.js project by running the following command:

$ npm init -y

This will generate a package.json file for your project, which will allow you to manage dependencies and scripts.

Step 2: Installing Dependencies Next, we need to install the required dependencies for our GitHub Action. In this example, we will be using the @actions/core package, which provides a set of tools for working with GitHub Actions. Run the following command to install it:

$ npm install @actions/core

Step 3: Cloning the Example Repository To understand the structure and implementation of the “update-github-action-secret” GitHub Action, clone the example repository from GitHub by running the following command in your terminal:

$ git clone https://github.com/NikhilVashistha/update-github-action-secret

This will create a local copy of the repository on your machine.

Step 4: Examining the Action Code Navigate to the cloned repository directory and open the index.js file in your code editor. Take the time to review the code and understand how it works. This will give you valuable insights into building your own GitHub Actions.

Step 5: Understanding the Action Metadata In the repository, you’ll find an action.yml file. Open it in your code editor to examine the metadata for the Action. This YAML file defines the name, description, inputs, outputs, and execution details of the Action. Study it carefully to grasp how the example Action is structured.

Step 6: Modifying and Customizing the Action Now that you have a solid understanding of the example Action, you can modify and customize it according to your specific requirements. Feel free to update the code, metadata, and any other relevant files to align with your desired functionality.

Step 7: Committing and Pushing Your Custom Action Once you have made the necessary modifications to the example Action, it’s time to commit and push your code to a GitHub repository. Create a new repository on GitHub, initialize a new Git repository locally, add the required files, and push the code to your remote repository.

Step 8: Using Your Custom Action in a Workflow To use your newly created Action in a GitHub workflow, navigate to your repository on GitHub and create a new workflow file (e.g., .github/workflows/main.yml). Define the workflow as needed and add a step that references your custom Action. For example:

- name: Update Secret
  uses: your-username/your-repository-name@main
  with:
    secret_value: ${{ secrets.YOUR_SECRET_NAME }}

Replace your-username and your-repository-name with your GitHub username and repository name, respectively. Also, update YOUR_SECRET_NAME with the actual name of the secret you want to update.

Step 9: Commit and Run the Workflow Commit and push the workflow file to your repository. GitHub will automatically trigger the workflow whenever changes are pushed to the repository. You can also manually run the workflow from the Actions tab on your repository.

Conclusion: Congratulations! You have successfully created a reusable JavaScript GitHub Action by examining the example “update-github-action-secret” repository. By understanding the code and structure of an existing Action, you now have the knowledge and confidence to create your own custom Actions to automate and streamline your development processes. GitHub Actions provide limitless possibilities for enhancing your software development workflow, and with your newfound skills, you can make the most of this powerful tool. Happy automating!