Experiment 6

Now, you add a concurrency group but have not enabled cancel-in-progress, which would automatically cancel any currently running workflows within the same concurrency group.

1. Make sure you are still in the right project folder.

cd path/to/experiment-5-6-7

2. In the .github/workflows/main.yml file,

• Add concurrency group at the workflow level to ensure that only a single workflow using the same concurrency group will run at a time.

• With a group named main, when a workflow is queued, it will be in the pending state if a different workflow using the main group is already in progress. If another workflow enters the queue, any pending workflow in the group will be canceled. This ensures that at any given time, there can be a maximum of one running job and one pending job in the group.

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name: main

on:
  push:
    branches: ["main"]

concurrency:
  group: main

jobs:
  run-test:
    runs-on: ubuntu-latest
    steps:
      - name: Extend the workflow duration by an additional 300 seconds.
        run: sleep 300

3. Modify the README.md file with the following content.

echo "experiment 6: the first workflow execution!" > README.md

4. Make another commit and push to the remote repository.

git add . && git commit -m "experiment 6: the first workflow execution" && git push

5. On your remote repository, click the Actions tab, you should see that a workflow execution has been triggered.

6. On your local repository, update the README.md file with the following content.

echo "experiment 6: the second workflow execution!" > README.md

7. Make another commit and push to the remote repository.

git add . && git commit -m "experiment 6: the second workflow execution" && git push

8. On your remote repository, under the Actions tab, while the first workflow execution is running, you may notice that the second workflow execution is in the Pending state.

9. On your local repository, update the README.md file with the following content.

echo "experiment 6: the third workflow execution!" > README.md

10. Make another commit and push to the remote repository.

git add . && git commit -m "experiment 6: the third workflow execution" && git push

11. On your remote repository, under the Actions tab, as the first workflow runs, you might notice the second workflow gets canceled, while the third goes in a Pending state, waiting for its turn.

A merge group without cancel-in-progress enabled ensures that, at any moment, there can be no more than one running job and one pending job within the group.