[App] Fix AutoScaler trying to replicate multiple works in a single machine

[akihironitta]

What does this PR do?

See the title and error below that this PR fixes.

$ lightning run app examples/app_server_with_auto_scaler/app.py
Your Lightning App is starting. This won't take long.
ERROR: Found an exception when loading your application from examples/app_server_with_auto_scaler/app.py. Please, resolve it to run your app.

Traceback (most recent call last):
  File "examples/app_server_with_auto_scaler/app.py", line 75, in <module>
    MyAutoScaler(
  File "/home/aki/work/github.com/Lightning-AI/lightning/src/lightning/app/components/auto_scaler.py", line 444, in __init__
    self.add_work(work)
  File "/home/aki/work/github.com/Lightning-AI/lightning/src/lightning/app/components/auto_scaler.py", line 464, in add_work
    setattr(self, work_attribute, work)
  File "/home/aki/work/github.com/Lightning-AI/lightning/src/lightning/app/core/flow.py", line 171, in __setattr__
    value._register_cloud_compute()
  File "/home/aki/work/github.com/Lightning-AI/lightning/src/lightning/app/core/work.py", line 617, in _register_cloud_compute
    _CLOUD_COMPUTE_STORE[internal_id].add_component_name(self.name)
  File "/home/aki/work/github.com/Lightning-AI/lightning/src/lightning/app/utilities/packaging/cloud_compute.py", line 31, in add_component_name
    raise Exception(
Exception: A Cloud Compute can be assigned only to a single Work. Attached to root.worker_0_a7d14e1db8fc4e0380de041c7b5016ab

Does your PR introduce any breaking changes? If yes, please list them.

None

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• Was this discussed/approved via a GitHub issue? (not for typos and docs)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• Did you make sure to update the documentation with your changes? (if necessary)
• Did you write any new necessary tests? (not for typos and docs)
• Did you verify new and existing tests pass locally with your changes?
• Did you list all the breaking changes introduced by this pull request?
• Did you update the CHANGELOG? (not for typos, docs, test updates, or minor internal changes/refactors)

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Anyone in the community is welcome to review the PR.
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Make sure you had fun coding 🙃

cc @Borda

[github-actions]

⚡ Required checks status: All passing 🟢

Groups summary

🟢 lightning_app: Tests workflow

Check ID	Status
app-pytest (macOS-11, app, 3.8, latest)	success	✅
app-pytest (macOS-11, app, 3.8, oldest)	success	✅
app-pytest (macOS-11, lightning, 3.9, latest)	success	✅
app-pytest (ubuntu-20.04, app, 3.8, latest)	success	✅
app-pytest (ubuntu-20.04, app, 3.8, oldest)	success	✅
app-pytest (ubuntu-20.04, lightning, 3.9, latest)	success	✅
app-pytest (windows-2022, app, 3.8, latest)	success	✅
app-pytest (windows-2022, app, 3.8, oldest)	success	✅
app-pytest (windows-2022, lightning, 3.8, latest)	success	✅

These checks are required after the changes to src/lightning_app/components/auto_scaler.py, tests/tests_app/components/test_auto_scaler.py.

🟢 lightning_app: Examples

Check ID	Status
app-examples (macOS-11, app, 3.9, latest)	success	✅
app-examples (macOS-11, app, 3.9, oldest)	success	✅
app-examples (macOS-11, lightning, 3.9, latest)	success	✅
app-examples (ubuntu-20.04, app, 3.9, latest)	success	✅
app-examples (ubuntu-20.04, app, 3.9, oldest)	success	✅
app-examples (ubuntu-20.04, lightning, 3.9, latest)	success	✅
app-examples (windows-2022, app, 3.9, latest)	success	✅
app-examples (windows-2022, app, 3.9, oldest)	success	✅
app-examples (windows-2022, lightning, 3.9, latest)	success	✅

These checks are required after the changes to src/lightning_app/components/auto_scaler.py.

🟢 lightning_app: Azure

Check ID	Status
App.cloud-e2e	success	✅

These checks are required after the changes to src/lightning_app/components/auto_scaler.py.

🟢 lightning_app: Docs

Check ID	Status
make-doctest (app)	success	✅
make-html (app)	success	✅

These checks are required after the changes to src/lightning_app/components/auto_scaler.py.

🟢 mypy

Check ID	Status
mypy	success	✅

These checks are required after the changes to src/lightning_app/components/auto_scaler.py.

🟢 install

Check ID	Status
install-pkg (ubuntu-22.04, app, 3.7)	success	✅
install-pkg (ubuntu-22.04, app, 3.10)	success	✅
install-pkg (ubuntu-22.04, lite, 3.7)	success	✅
install-pkg (ubuntu-22.04, lite, 3.10)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.7)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.10)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.7)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.10)	success	✅
install-pkg (macOS-12, app, 3.7)	success	✅
install-pkg (macOS-12, app, 3.10)	success	✅
install-pkg (macOS-12, lite, 3.7)	success	✅
install-pkg (macOS-12, lite, 3.10)	success	✅
install-pkg (macOS-12, pytorch, 3.7)	success	✅
install-pkg (macOS-12, pytorch, 3.10)	success	✅
install-pkg (macOS-12, lightning, 3.7)	success	✅
install-pkg (macOS-12, lightning, 3.10)	success	✅
install-pkg (windows-2022, app, 3.7)	success	✅
install-pkg (windows-2022, app, 3.10)	success	✅
install-pkg (windows-2022, lite, 3.7)	success	✅
install-pkg (windows-2022, lite, 3.10)	success	✅
install-pkg (windows-2022, pytorch, 3.7)	success	✅
install-pkg (windows-2022, pytorch, 3.10)	success	✅
install-pkg (windows-2022, lightning, 3.7)	success	✅
install-pkg (windows-2022, lightning, 3.10)	success	✅

These checks are required after the changes to src/lightning_app/components/auto_scaler.py.

---

Thank you for your contribution! 💜

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[awaelchli]

You could add a simple test that asserts the contents of self._work_kwargs by calling create_work.

[lantiga]

Approved pending Adrian's suggestion on the test to add