Mysqld: capture mysqlbinlog std error output

[shlomi-noach]

Description

See #15277 for description.
This captures mysqlbinlog executable's stderr just like we do for mysql excutable's, and reports it upon error.

Related Issue(s)

Fixes #15277

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

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[shlomi-noach]

I wonder if we should backport it to release-19.0

[shlomi-noach]

Sample imposed/synthetic error:

$ vtctldclient RestoreFromBackup --restore-to-pos "MySQL56/fe2a00e3-ce42-11ee-aa36-0a43f95f28a3:1-125" zone1-0000000102
...
E0218 12:21:48.917926  911811 main.go:56] rpc error: code = Unknown desc = TabletManager.RestoreFromBackup on zone1-0000000102: Can't restore backup: failed to apply binlog file /tmp/restore-incremental-2351101316/tmp/vtdataroot/vt_0000000102/bin-logs/vt-0000000102-bin.000004: mysqlbinlog command failed: with error output: mysqlbinlog: File 'qqqqqqqqqq' not found (OS errno 2 - No such file or directory)
ERROR: Could not open log file

[codecov]

Codecov Report

Attention: 11 lines in your changes are missing coverage. Please review.

Comparison is base (54c6dfc) 67.44% compared to head (3652f68) 67.45%.

Files	Patch %	Lines
go/vt/mysqlctl/mysqld.go	0.00%	11 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15278   +/-   ##
=======================================
  Coverage   67.44%   67.45%           
=======================================
  Files        1561     1561           
  Lines      193193   193203   +10     
=======================================
+ Hits       130304   130318   +14     
+ Misses      62889    62885    -4     

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[GrahamCampbell]

I wonder if we should backport it to release-19.0

👍 from me, not that my vote counts for much. ;)

[GenLN]

Can this be included in v19 release? I believe it would help a lot in debugging the issue with failing PITR in k8s env...