Build your first workflow.

Create a tiny repository

In GitHub, create a repository named first-actions-workflow. A private repository is fine. Add a README file so the workflow has a file to check. Open the repository’s Actions tab; you will return there to inspect each run.

Add the workflow file

Use Add file → Create new file. Name it .github/workflows/first.yml. The folders are part of the required path; GitHub only discovers workflow files inside .github/workflows.

Paste this complete example, then commit it to the repository’s default branch:

name: First workflow

on:
  push:
  pull_request:

permissions:
  contents: read

jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6

      - name: Confirm the README is present
        run: test -f README.md

      - name: Create a tiny build output
        run: |
          mkdir -p site
          printf '%s\n' '<h1>Built by GitHub Actions</h1>' > site/index.html

      - uses: actions/upload-artifact@v7
        with:
          name: sample-site
          path: site/
          if-no-files-found: error

on lists the events that start the workflow. GitHub gives the job an Ubuntu runner. The checkout action copies repository files onto it; the test then confirms the README arrived. The last action saves the generated site/ folder as a downloadable artifact.

Read the run before trusting the green mark

Open Actions → First workflow and select the latest run. Open the check job and expand each step. Confirm that checkout ran before the README check, and that the artifact step completed.

Open the run’s summary and download sample-site. The ZIP contains index.html. The artifact belongs to this workflow run; it is how another job can receive the same built files later.

Break checkout, then diagnose the message

Edit first.yml and temporarily remove the step that uses actions/checkout. Commit the change. Open the new run and read the failure from Confirm the README is present.

The command reports that README.md is missing because a fresh runner does not automatically contain your repository. The test did not cause the problem; it revealed that the workflow skipped the step that supplies the source files.

Restore the required step

Put actions/checkout@v6 back before the README check and commit again. Confirm that the new run succeeds and that its artifact downloads. You have now seen both the failure and the exact fix.

• Events start workflow runs.
• A job runs on a runner; its steps execute in order.
• Checkout puts repository files on the runner.
• An artifact carries output beyond the job that created it.

Classes 39e–39h · Check and promote the same artifact

Keep the disposable repository from this lab. Download the complete continuation workflow and save it as .github/workflows/artifact-gate.yml. It runs only when started manually. It creates a text file, records its SHA-256, checks the downloaded artifact, and passes those same bytes to a release rehearsal. It does not deploy to Azure.

1. Commit the workflow, open Actions → Artifact gate practice, and select Run workflow. Expect build, check and release-rehearsal to succeed. Read each log and compare the artifact name and checksum.
2. Break only the grep expectation: change Campux catalogue in the check job to Wrong catalogue. Run again. Expect check to fail and release-rehearsal to be skipped. This demonstrates a gate, not application coverage.
3. Restore the correct expectation and rerun. Expect the checksum and content checks to succeed. Changing a check is a code change requiring review in real work.
4. For Class 39f, open Settings → Environments → training-release. If your repository plan and visibility support required reviewers, add a reviewer and prevent self-review. Rerun: expect the rehearsal to wait before its steps execute. Have the designated reviewer approve. If the controls are unavailable, record that limitation; a named environment alone is not an approval gate.
5. Record the artifact digest, failed run, skipped job and any observed approval pause. Delete the practice repository or workflow/environment when finished; retention and Actions usage depend on your account.