Update imports to elastic-agent-libs/file where needed

[kvch]

What does this PR do?

This PR removes some parts of libbeat/common/file package that was moved to elastic-agent-libs.

Why is it important?

We avoid maintaining the same code twice in different repositories.

Checklist

• My code follows the style guidelines of this project
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have made corresponding changes to the documentation
  - [ ] I have made corresponding change to the default configuration files
  - [ ] I have added tests that prove my fix is effective or that my feature works
  - [ ] I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[elasticmachine]

💔 Build Failed

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2022-04-29T11:01:15.610+0000

• Duration: 81 min 15 sec

Test stats 🧪

Test	Results
Failed	0
Passed	22251
Skipped	1934
Total	24185

Steps errors

Expand to view the steps failures

filebeat-goIntegTest - mage goIntegTest

• Took 5 min 15 sec . View more details here
• Description: mage goIntegTest

filebeat-goIntegTest - mage goIntegTest

• Took 2 min 28 sec . View more details here
• Description: mage goIntegTest

filebeat-packaging-linux - mage package

• Took 6 min 29 sec . View more details here
• Description: mage package

filebeat-packaging-arm-arm - mage package

• Took 2 min 26 sec . View more details here
• Description: mage package

Error signal

• Took 0 min 0 sec . View more details here
• Description: Error 'hudson.AbortException: script returned exit code 1'

💚 Flaky test report

Tests succeeded.

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

• /package : Generate the packages and run the E2E tests.

• /beats-tester : Run the installation tests with beats-tester.

• run elasticsearch-ci/docs : Re-trigger the docs validation. (use unformatted text in the comment!)

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b use-file-from-libs upstream/use-file-from-libs
git merge upstream/main
git push upstream use-file-from-libs

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b use-file-from-libs upstream/use-file-from-libs
git merge upstream/main
git push upstream use-file-from-libs

[rdner]

Can we at least return these errors, I know it was not there before but should we suppress them in this function? This does not feel write, I think it was a bug.

[kvch]

f.Sync errors are not returned on purpose. Those might fail sometimes, but it is not an error from Beats point of view. Also, if the write calls return an error it is not an issue, because Beat saves the files constantly, so we are not losing data/information.

Unfortunately, when we touch the disk things can go wrong more times than we think. So we have resilience at strategically important file writes (see. SafeFileRotate). But not all Write call has to be checked.

[kvch]

Also, if we happened to expose a non-error "error" I do not want to track down what changed... I would rather focus on the actual goal of my project: moving stuff out of libbeat. The scope of this PR is already too big thanks to the linter.

[rdner]

@kvch could you please turn your reply into a comment before those suppressed errors? otherwise it looks strange that everyone is fine with it.