simplify examples

[Borda]

What does this PR do?

since we do not run tests on examples anyway there is o reason to have them wrap in main especially since there is nothing else than main anyway...

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[codecov]

Codecov Report

Merging #57 (0440d0e) into master (c6725fe) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #57      +/-   ##
==========================================
+ Coverage   80.31%   80.37%   +0.05%     
==========================================
  Files          47       47              
  Lines        1387     1391       +4     
==========================================
+ Hits         1114     1118       +4     
  Misses        273      273              

Flag	Coverage Δ
unittests	80.37% <100.00%> (+0.05%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
flash/core/data/datamodule.py	100.00% <100.00%> (ø)

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[carmocca]

I believe the examples hang with num_workers > 0 on some platforms (namely MacOS) if this is removed

[Borda]

I believe the examples hang with num_workers > 0 on some platforms (namely MacOS) if this is removed

not really, they are not even called anywhere :D
https://github.com/PyTorchLightning/lightning-flash/blob/3c5b535ce26a12fd141acff7e20bc2b18ee56a0a/.github/workflows/ci-testing.yml#L80
and as you can see all test passed :]

[carmocca]

We do test some of them:

https://github.com/PyTorchLightning/lightning-flash/blob/master/tests/examples/test_examples.py

Also num_workers is currently set to 0 by default

https://github.com/PyTorchLightning/lightning-flash/blob/3c5b535ce26a12fd141acff7e20bc2b18ee56a0a/flash/core/data/datamodule.py#L67-L73

So the tests are not checking if it hangs

[Borda]

We do test some of them:

yes but here you test just some of them and the execution is called from tests folder
the wrap in if/main is typical if you want to call test on flash_examples as a folder and skip some code...
which is not the case, right?

[teddykoker]

if/main is needed in order for the dataloaders to function properly (because of multiprocessing)

[Borda]

if/main is needed in order for the dataloaders to function properly (because of multiprocessing)

so the script is called in a subprocess, but it does not have if/main it is empty so when/how it is called?
but here all tests are passing so what test are/were hanging?

[carmocca]

As I said, try uncommenting

https://github.com/PyTorchLightning/lightning-flash/blob/3c5b535ce26a12fd141acff7e20bc2b18ee56a0a/flash/core/data/datamodule.py#L67-L73

And let's see if CI passes

[pep8speaks]

Hello @Borda! Thanks for updating this PR.

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2021-02-03 08:11:10 UTC

[Borda]

As I said, try uncommenting

trying now, but as it is, you preventing the hanging n two fronts - in examples and restricting workers to 0

[Borda]

@carmocca seems to be fine, no hanging...

[carmocca]

The failing MacOS tests seem to show otherwise 😆

[Borda]

As I said, try uncommenting

trying now, but as it is, you preventing the hanging n two fronts - in examples and restricting workers to 0

let's see if the updated nb workers pass on the master - https://github.com/PyTorchLightning/lightning-flash/actions/runs/532388784

[carmocca]

I'm not sure about what are you trying to say.

But you just removed both fronts.

And in any case, we cant fix num_workers 0 forever. So that's why the examples require if __name__: __main__

[Borda]

But you just removed both fronts.

Because you asked for it, so I am returning to workers count 0
so I suggest editing code such that for Linux/win use max nb workers and 0 for mac (anyway there won't be any super multi-core CPU used in Mac machines, right?)