Basic GitHub Actions Checkout

Overview
This hands-on lab introduces the fundamentals of GitHub Actions by implementing a basic workflow that demonstrates repository checkout and command execution. You'll learn how to create a workflow file, understand its structure, and execute various commands.

Prerequisites

• GitHub account
• A GitHub repository where you have write access
• Basic understanding of YAML syntax

• Basic knowledge of command line operations
  Learning Objectives
  After completing this lab, you will be able to:

• Create a basic GitHub Actions workflow file

• Understand workflow trigger conditions

• Execute single and multi-line commands

• Use the checkout action

• View and interpret workflow results

Lab Structure

your-repository/
├── .github/
│   └── workflows/
│       └── basic-checkout.yml
└── README.md

Implementation Guide
Step 1: Create Workflow Directory

mkdir -p .github/workflows

Step 2: Create Workflow File
Create .github/workflows/basic-checkout.yml with the following content:

name: Basic Checkout Lab

# Trigger on push to main branch
on:
  push:
    branches:
      - main

# Define jobs and their steps
jobs:
  basic-checkout:
    runs-on: ubuntu-latest
    steps:
      # Step 1: Checkout the repository
      - name: Checkout repository
        uses: actions/checkout@v4

      # Step 2: List repository contents
      - name: List files
        run: ls -la

      # Step 3: Display system information
      - name: Show system info
        run: |
          echo "Repository: $GITHUB_REPOSITORY"
          echo "Operating System: $(uname -a)"
          echo "Current Directory: $(pwd)"

      # Step 4: Check software versions
      - name: Check versions
        run: |
          echo "Node version: $(node --version)"
          echo "Python version: $(python --version)"
          echo "Git version: $(git --version)"

Detailed Explanation
Workflow Trigger
on:
push:
branches:
- main
This section configures the workflow to run whenever code is pushed to the main branch.

Job Configuration
jobs:
basic-checkout:
runs-on: ubuntu-latest
Defines a single job named basic-checkout
Specifies Ubuntu as the runner operating system
Steps Breakdown
`Checkout Step

• name: Checkout repository uses: actions/checkout@v4 Uses the official checkout action Clones your repository into the runner Essential for accessing repository files File Listing
• name: List files run: ls -la Lists all files and directories Includes hidden files Shows file permissions and ownership System Information - name: Show system info run: | echo "Repository: $GITHUB_REPOSITORY" echo "Operating System: $(uname -a)" echo "Current Directory: $(pwd)" Uses multi-line commands Demonstrates environment variable usage Shows system details Version Checks
• name: Check versions run: | echo "Node version: $(node --version)" echo "Python version: $(python --version)" echo "Git version: $(git --version)"` Checks installed software versions Uses command substitution Demonstrates multi-line commands Expected Outputs

File Listing Output
total 24
drwxr-xr-x 4 runner docker 4096 Feb 20 10:00 .
drwxr-xr-x 3 runner docker 4096 Feb 20 10:00 ..
drwxr-xr-x 8 runner docker 4096 Feb 20 10:00 .git
drwxr-xr-x 3 runner docker 4096 Feb 20 10:00 .github
-rw-r--r-- 1 runner docker  654 Feb 20 10:00 README.md

System Information Output

Repository: username/repository-name
Operating System: Linux runner-ubuntu-latest 5.15.0-1047-azure
Current Directory: /home/runner/work/repository-name/repository-name
Version Information Output
Node version: v20.11.0
Python version: Python 3.10.12
Git version: git version 2.42.0

Practice Exercises
Add New Commands Modify the workflow to include:

• Current date and time
• Available disk space
• Memory usage Custom Environment Variables Add environment variables:

env:
CUSTOM_MESSAGE: "Hello from GitHub Actions!"
Conditional Execution Add a conditional step:

- name: Conditional step
if: github.event_name == 'push'
run: echo "This was triggered by a push event"
Troubleshooting
Common Issues and Solutions
Workflow Not Triggering

• Verify branch name matches trigger condition
• Check workflow file syntax
• Ensure Actions are enabled in repository settings
• Checkout Action Fails

Verify Git configuration

git config --global --list

Check permissions

ls -la .git

Command Execution Errors

Check command availability on runner
Verify syntax for multi-line commands
Ensure proper environment variable usage
Debugging Tips
Enable debug logging by setting secret ACTIONS_RUNNER_DEBUG to true
Check workflow run logs in GitHub Actions tab
Use echo statements to debug variables

Additional Resources:

• GitHub Actions Documentation
• Workflow Syntax Reference

• Checkout Action Documentation

• Guide to Actions Checkout