Understanding the Basics of GitHub Actions
Understand Github Actions and the details of it's components.
We'll cover the following...
GitHub Actions are event-driven automation tasks that live within a GitHub repository. An event like a pull request can trigger a set of tasks to be executed. An example is a pull request triggering a set of tasks to clone the Git repository and execute go test to run Go tests.
GitHub Actions is extremely flexible, enabling developers to author a wide variety of automation, even some that we might not normally associate with a traditional continuous integration/release pipeline. Actions are also composable, enabling groups of tasks to be packaged together as a published action and used in workflows together with other actions.
In this lesson, we will learn about the components of a GitHub Action: workflows, events, context and expressions, jobs, steps, and actions. After we have been introduced to these components, we'll build and trigger our first GitHub Action.
Exploring the components of a GitHub Action
Understanding the components of a GitHub Action, their relationships, and how they interact is the key to understanding how to compose our own automation. Let's get started with exploring the components of an action.
Workflows
A workflow is an automation file written in YAML that lives in a GitHub repository in the ./github/workflows/ folder. A workflow consists of one or more jobs and can be scheduled or triggered by an event. A workflow is the highest-level component of a GitHub Action.
Workflow syntax
Workflows require a developer to specify the events that will trigger automation via the on key and the jobs that automation will execute when it is triggered by the jobs key. Often, a name is also specified by the name keyword. Otherwise, the workflow will take the short name of the file that contains the workflow YAML. For example, the workflow defined in ./github/workflows/foo.yaml will have the default name of foo.
The following is an example of a named workflow with the minimum set of keys defined. However, this is not a valid workflow, as we have not yet defined any events to trigger the workflow nor any jobs to be executed once triggered:
name: my-workflow # (optional) The name of your workflow; defaults to the file name.on: # Events that will trigger the workflowjobs: # Jobs to run when the event is triggered
Next, let's discuss how to trigger workflows.
Events
An event is a trigger that causes a workflow to start ...
