Building GitHub Actions

Now that you’ve learned how to author workflows and already used some actions from the marketplace, it is time to fully understand what actions are and how they work. In this chapter, I will explain the different types of actions and we will cover the following recipes so that you know how to write actions yourself:

• Creating a Docker container action
• Adding output parameters and using job summaries
• Creating a TypeScript action
• Creating a composite action
• Sharing actions to the marketplace
• Best practices for developing custom actions

You will learn how to pass in parameters to actions and use output parameters in subsequent workflow steps. You will also learn how to write to the workflow log and annotate changes in files from within the action and how to create rich job summaries.