Fix job services localhost example in workflow-syntax-for-github-actions.md

[piotrekkr]

Why:

Because job services localhost example is wrong and misleading.

What's being changed (if available, include any code snippets, screenshots, or gifs):

Current example states that :

When you specify the Docker host port but not the container port, the container port is randomly assigned to a free port. GitHub sets the assigned container port in the ${{job.services.<service_name>.ports}} context. In this example, you can access the service container ports using the ${{ job.services.nginx.ports['8080'] }} and ${{ job.services.redis.ports['6379'] }} contexts.

Which is not true because you either specify container port only and then GitHub Actions will choose random free port on host, or you specify both, host and container port.

To access host port you should use container port as a key. In nginx example it should be ${{ job.services.nginx.ports['80'] }} and not 8080.

Updated job services yaml example to show more clearly how to access those services.

I tested all this using this yaml

jobs:
  job-a:
    runs-on: ubuntu-latest
    services:
      nginx:
        image: nginx
        # Map port 8080 on the Docker host to port 80 on the nginx container
        ports:
          - 8080:80
      redis:
        image: redis
        # Map TCP port 6379 on Docker host to a random free port on the Redis container
        ports:
          - 6379/tcp
    steps:
      - run: docker ps
      - run: echo '${{ toJSON(job.services) }}'
      - run: |
          echo "Redis available on 127.0.0.1:${{ job.services.redis.ports['6379'] }}"
          echo "Nginx available on 127.0.0.1:${{ job.services.nginx.ports['80'] }}"
      - name: Check Redis
        run: |
          echo -e '*1\r\n$4\r\nPING\r\n' | netcat -w1 127.0.0.1 ${{ job.services.redis.ports['6379'] }}

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[github-actions]

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Source	Preview	Production	What Changed
actions/writing-workflows/workflow-syntax-for-github-actions.md	fpt ghec ghes@ 3.14 3.13 3.12 3.11 3.10	fpt ghec ghes@ 3.14 3.13 3.12 3.11 3.10

---

fpt: Free, Pro, Team
ghec: GitHub Enterprise Cloud
ghes: GitHub Enterprise Server

[nguyenalex836]

@piotrekkr Thanks so much for opening a PR! I'll get this triaged for review ✨

[github-actions]

Thanks for opening a pull request! We've triaged this issue for technical review by a subject matter expert 👀

[github-actions]

This is a gentle bump for the docs team that this PR is waiting for technical review.

[github-actions]

A stale label has been added to this pull request because it has been open 7 days with no activity. To keep this PR open, add a comment or push a commit within 3 days.

[github-actions]

A stale label has been added to this pull request because it has been open 7 days with no activity. To keep this PR open, add a comment or push a commit within 3 days.

[github-actions]

A stale label has been added to this pull request because it has been open 7 days with no activity. To keep this PR open, add a comment or push a commit within 3 days.

[nguyenalex836]

@piotrekkr Thank you so much for your patience while our SME team reviewed! 💛 They have approved of your changes after testing your example ✨

Once you are able to resolve the conflicts with this branch, we are happy to get this merged! If submitting a new PR is easier for you, we're happy to merge that instead 🙇

[piotrekkr]

@nguyenalex836 I've rebased my branch on latest code. There is no conflicts any more.

[nguyenalex836]

@piotrekkr Thank you! 💛 Getting this merged now!

[github-actions]

Thanks very much for contributing! Your pull request has been merged 🎉 You should see your changes appear on the site in approximately 24 hours. If you're looking for your next contribution, check out our help wanted issues ⚡