[8.19] (backport #8215) fix(diagnostics): handle log rotation races #8228
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Handle a race condition that can occur in Agent diagnostics if log rotation happens while logs are being zipped. There is a time window between when `filepath.WalkDir` reads the directory contents and when log files are opened for reading. During this time window, log rotation can happen, resulting in files that no longer exist and cannot be added to the diagnostic archive. To handle this, `fs.ErrNotExist` errors are ignored when attempting to add log files. Also, address and unrelated linter warning by using fmt.Fprintf. (cherry picked from commit 751acc1)
mergify bot requested review from michel-laterman and pchila and removed request for a team 8 tasks
github-actions bot added bug 
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pkoutsovasilis approved these changes May 26, 2025
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What does this PR do?
Handle a race condition that can occur in Agent diagnostics if log rotation happens while logs are being zipped. There is a time window between when
filepath.WalkDirreads the directory contents and when log files are opened for reading. During this time window, log rotation can happen, resulting in files that no longer exist and cannot be added to the diagnostic archive.To handle this,
fs.ErrNotExisterrors are ignored when attempting to add log files.Why is it important?
This race can happen at any time, so any user could be affected. The problem is worse if debug logging is enabled and logs are being rotated quickly.
Checklist
./changelog/fragmentsusing the changelog toolScreenshots
This is the user reported error:
via OCR, it says:
Disruptive User Impact
How to test this PR locally
Related issues
Questions to ask yourself
This is an automatic backport of pull request #8215 done by [Mergify](https://mergify.com).