Update log level from error to debug and info to reduce log noise

[electron0zero]

What this PR does / Which issue(s) does the PR fix:

Undo some of the log level changes made in #1461

Fixes #1509

Does this PR introduce a user-facing change?

fix: Update log level from error to debug and info to reduce log noise

Checklist

• Tests updated
• Documentation added
• CHANGELOG added in release-notes section of PR Desc.

[SuperQ]

Shouldn't we make these Warn or maybe Debug?

👓 @tjhop

[electron0zero]

Shouldn't we make these Warn or maybe Debug?

not sure if Warn would address the log noise concerns folks are reporting, I am fine with both Debug or Info. @tjhop what do you say?

[datamuc]

Shouldn't we make these Warn or maybe Debug?

not sure if Warn would address the log noise concerns folks are reporting, I am fine with both Debug or Info. @tjhop what do you say?

I still think it should be debug.

[tjhop]

For these error check cases where we're continuing on, I think going with debug logging makes sense in context here -- we would only really care about them if we needed to troubleshoot the entire flow of the probe. For the error checks where we actually stop and return, I think those should remain at error level, though.

[wat-org]

hello,

I also suggest to switch from 'warn' to 'debug' two logs in the http prober concerning redirection:

• https://github.com/prometheus/blackbox_exporter/blob/master/prober/http.go#L490
• https://github.com/prometheus/blackbox_exporter/blob/master/prober/http.go#L493

nb:
it was switched from 'info' to 'warn' 4 month ago and generates log noise too

regards

[Lusitaniae]

When could we expect to get this released?