fix: New cleanup when using --cleanup flag (#1406)

[dadurex]

Fixes #1406

Description

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Reviewer Notes

• The code flow looks good.
• Unit tests and or integration tests added.

** Notes**

Flag cleanup does not clean kaniko root directory (default /kaniko). As a result, when building more than one image on same kaniko container we can face the problem of leftovers directories like /kaniko/0/... which are stage-dependent files (https://github.com/GoogleContainerTools/kaniko/blob/v1.16.0/pkg/executor/build.go#L807) saved by kaniko.

New function CleanupFilesystem() first calls DeleteFilesystem() and then removes all files and directories from kaniko root directory with names are digits. Those files are directories that store stage-dependent files and snapshots.

This fix can be also achieved in different way. All snapshot can be placed in kanikoDir/snapshots and layers dependent files in kanikoDir/layers and then CleanupFilesystem() could simply call os.RemoveAll() on those directories instead of this logic with regex.

Described also in issue #1406

I'm open to discussion.

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[aaron-prindle]

@dadurex thanks for the PR here! Not sure why the CI tests didn't run for your submission, can you resubmit your PR to kickoff the CI tests? The PR itself looks good, need the CI to be green and then we should be able to merge

[dadurex]

@dadurex thanks for the PR here! Not sure why the CI tests didn't run for your submission, can you resubmit your PR to kickoff the CI tests? The PR itself looks good, need the CI to be green and then we should be able to merge

@aaron-prindle Do you mean close and create new PR?

[aaron-prindle]

@dadurex you should be able to re-push the PR here as is (resubmitting is also fine)

Something like the following should work:

git commit --amend --no-edit
git push -f origin HEAD

That will resubmit the PR here and kick-off the CI tests

[cmorty]

Your alternative solution sounds much better. But I'm happy if this works at all. ;)

[aaron-prindle]

@dadurex can you re-push the PR here? For some reason our CI/CD tests weren't run for your PR submission initially

[aaron-prindle]

Closing, changes made are now tracked in #3130