Lab: Environment Variable Scope

Introduction

In this lab, you will learn how to set environment variables at different scopes, including workflow, job, and step levels. You will also learn how to access these environment variables in your workflow.

Estimated Duration: 20-30 minutes

Instructions

Step 1: Create a YAML Workflow File

  1. In your repository, create a directory .github/workflows if it doesn’t exist.

  2. Inside .github/workflows, create a new file named env-var-scope.yml.

  3. Add the following initial content to the file:

    name: Env Var Scope

on:
  workflow_dispatch:
  push:
    paths:
      - '.github/workflows/env-var-scope.yml'

  4. Commit the file to the main branch.

Step 2: Add Environment Variable at Workflow Level

  1. Edit env-var-scope.yml and add a workflow-level environment variable called WORKFLOW_ENV_VAR with the value Workflow Environment Variable:

    env:
  WORKFLOW_ENV_VAR: 'Workflow Environment Variable'

Step 3: Update the Workflow to Access and Print Environment Variables

  1. Add a job named print that runs on ubuntu-latest.
  2. Define a job-level environment variable JOB_ENV_VAR with value Job Environment Variable.
  3. Add a step in the job where you define a step-level environment variable STEP_ENV_VAR with value Step Environment Variable.
  4. Print the values of all three environment variables (WORKFLOW_ENV_VAR, JOB_ENV_VAR, and STEP_ENV_VAR).

The final workflow should look like this:

name: Env Var Scope

on:
  workflow_dispatch:
  push:
    paths:
      - '.github/workflows/env-var-scope.yml'

env:
  WORKFLOW_ENV_VAR: 'Workflow Environment Variable'

jobs:
  print:
    runs-on: ubuntu-latest
    env:
      JOB_ENV_VAR: 'Job Environment Variable'

    steps:
      - name: Display Environment Variables
        env:
          STEP_ENV_VAR: 'Step Environment Variable'
        run: |
          echo "WORKFLOW_ENV_VAR: $WORKFLOW_ENV_VAR"
          echo "JOB_ENV_VAR: $JOB_ENV_VAR"
          echo "STEP_ENV_VAR: $STEP_ENV_VAR"

Step 4: Commit and Run the Workflow

  1. Commit the changes to the main branch.
  2. In GitHub, go to the Actions tab and select the Env Var Scope workflow.
  3. Click Run workflow and choose the main branch.
  4. After the workflow runs, review the logs to see the printed environment variable values.

Summary

Congratulations! You have successfully defined environment variables at different scopes (workflow, job, and step levels) and accessed them in your workflow. You have also learned how to print their values during workflow execution.

Additional Resources