GitHub Actions
Let's dissect this workflow file and understand what each line is doing.
name: ci
on:
pull_request:
branches: [main]
jobs:
tests:
name: Tests
runs-on: ubuntu-latest
steps:
- name: Check out code
uses: actions/checkout@v4
- name: Set up Go
uses: actions/setup-go@v5
with:
go-version: "1.25.1"
- name: Echo Go version
run: go version
Workflow Name
name: ci
The first line simply assigns a human-readable name to the workflow.
Triggering the Workflow
on:
pull_request:
branches: [main]
The on key specifies when the workflow should run. In our case, we want to run the workflow when a pull request is opened to the main branch.
Jobs
jobs:
tests:
name: Tests
runs-on: ubuntu-latest
The jobs key is a list of jobs that make up the workflow. In our case, we only have one job called tests.
Each job has a few pieces of metadata associated with it. The name key assigns a human-readable name to the job. The runs-on key specifies the type of runner to use. In our case, we want to use the latest version of Ubuntu/Linux.
Job Steps
- name: Check out code
uses: actions/checkout@v4
Each job has a list of steps that make up the job. In our case, we have three steps. The first step checks out the code by using the pre-built checkout action to clone the repository into the runner. You'll almost always want to include this step in your workflows. The uses key specifies the action to use, and the with key specifies the inputs to the action.
An action is a reusable custom application that helps reduce the complexity of creating workflows. The checkout action is a publicly available action that checks-out your repository so your workflow can access it.
- name: Set up Go
uses: actions/setup-go@v5
with:
go-version: '1.25.1'
The second step sets up Go by using the pre-built setup-go action to configure a Go environment for use in workflows.
- name: Echo Go version
run: go version
The third step runs the go version command to print the version of Go installed in the runner. The run key specifies the command to run. The run key is used to run arbitrary command-line commands in the runner.
Which is the correct hierarchy? (from top to bottom)