[pkg/stanza] Fix transformer operators logging errors at ERROR level when on_error is set to quiet mode

[paulojmdias]

Description

Fix transformer operators logging errors at ERROR level when on_error is set to quiet mode (send_quiet or drop_quiet)

Link to tracking issue

Fixes #42646

Testing

Updated unit tests and added tests to all operators, which should support on_error configuration.

[iblancasa]

I think you should introduce tests for batch processing with quiet mode, behavior when all entries in a batch fail or a mix.

[paulojmdias]

Thanks for the review @iblancasa, I pushed the changes related to your review, including tests for batch processing with quiet mode 🙏

[andrzej-stencel]

Thank you for this @paulojmdias. This fixes it for many operators, although not for all. I think it would be useful to explicitly list the operators that are fixed and those that still need fixing. This would help guide future contributions.

Ideally the test additions would be contributed in a separate pull request, as those changes are orthogonal to the fix, aren't they? This way, if we have to revert this change for whatever reason, the test additions would not need to be reverted.

[paulojmdias]

@andrzej-stencel, Looking into the operators, I think the ones which missing are recombine, syslog, container and filter. Please let me know if I'm right to move forward with documentation and/or issues/PRs for it 🙏

That's a fair point. I've moved the tests for PR #45688

[paulojmdias]

/rerun

[paulojmdias]

@andrzej-stencel, here are the PRs for the ones that are missing:

• [pkg/stanza] Fix recombine operator logging errors at ERROR level when on_error is set to quiet mode #45703
• [pkg/stanza] Fix container parser operator logging errors at ERROR level when on_error is set to quiet mode #45704
• [pkg/stanza] Fix syslog parser operator logging errors at ERROR level when on_error is set to quiet mode #45705

I'll mark this as ready for merge now 🙏