Introduction to GitHub Script
The GitHub Script middleware presents a seamless way for users to write custom scripts that interact with the GitHub API within workflows. It's crafted with simplicity in mind, empowering developers to automate processes and extend capabilities within their CI/CD pipelines using synchronous JavaScript functions.
Core Functionality
To utilize GitHub Script in a workflow, developers inject a JavaScript function via the script input. This function gains effortless access to several key elements:
github: A pre-configured, authenticated Octokit client, complete with pagination features for expansive data retrieval.context: Details regarding the execution context of the workflow, offering insights into the current event and environment.core,glob,io,exec: Tools from GitHub Actions' toolkit aiding in filesystem operations, command executions, and more.require: An encapsulated variant of Node.js’srequire, enabling local dependencies and npm modules to be integrated without hassle.
Important Version Changes
- Version 7 shifted the runtime to Node 20, affecting script execution by leveraging the latest Node features and syntax.
- Version 6 & 5 made major updates to lessen dependency on older Node versions, enhancing security and capabilities. It also restructured how REST methods are called in the plugin.
Writing and Retrieving Results
Scripts can return values, which get stored in the action's outputs under a "result" key. Developers can specify encoding preferences, with options like JSON or string encoding.
Retry Configuration
The middleware supports configuring retry attempts for any API requests made using the github client. It includes features for handling specific HTTP status codes that should be excluded from retry attempts.
Practical Examples
- Viewing Context Attributes: A simple script can be used to log contextual attributes of any running workflow, providing visibility into the execution environment.
- Automating Issue Comments/Labels: Enable automatic comments or labels based on issue events, which can significantly streamline workflows for issue triaging or contributor recognition.
- GraphQL Queries: GitHub Script allows custom GraphQL queries to be executed, tapping into GitHub's vast data API more flexibly than traditional REST calls.
- External JavaScript Modules: Developers can write and store scripts externally to keep workflows clean and organized, injecting them as needed.
External Dependencies and Environment
GitHub Script supports the incorporation of npm packages and ESM modules, broadening its capabilities significantly. It can also leverage environment variables and alternate GitHub tokens for enhanced security and flexibility.
Conclusion
GitHub Script enhances automation possibilities within GitHub Actions, allowing developers to seamlessly incorporate the GitHub API into workflows. It's tailored for both novice developers seeking to streamline basic tasks and seasoned engineers aiming to integrate sophisticated automation scripts into their CI/CD pipelines.