don't fail when chown to postgres fails

[evgeni]

• add prepare directory tests
• move chown postgres inside unless preserve
• only chown to postgres group for online backups with local DB
• don't fail when chown to postgres fails

[evgeni]

# foreman-maintain backup online /mnt/online-new-1
Starting backup: 2024-06-25 09:11:30 +0000
…
--------------------------------------------------------------------------------
Prepare backup Directory: 
Creating backup folder /mnt/online-new-1/katello-backup-2024-06-25-09-11-30
                                                                      [WARNING]
/mnt/online-new-1/katello-backup-2024-06-25-09-11-30 could not be made readable by the 'postgres' user.
This won't affect the backup procedure, but you have to ensure that
the 'postgres' user can read the data during restore.

--------------------------------------------------------------------------------
…
--------------------------------------------------------------------------------
Scenario [Backup] failed.

The following steps ended up in warning state:

  [backup-prepare-directory]

The steps in warning state itself might not mean there is an error,
but it should be reviewed to ensure the behavior is expected


Done with backup: 2024-06-25 09:11:39 +0000
**** BACKUP Complete, contents can be found in: /mnt/online-new-1/katello-backup-2024-06-25-09-11-30 ****

# echo $?
78

[ekohl]

Should this be in the else part of unless @preserve_dir?

[evgeni]

Maybe. But honestly I didn't want to touch too much of the code, just the parts that I actually wanted to change.

Also, I am not really sure why this is guarded by if @preserve_dir anyway.
As when it's false, the @backup_dir will be fresh and empty and the .glob will just return [].

[ekohl]

I think this would actually make a lot more sense, but I can understand why you don't want to touch those too much

Suggested change

	puts "Creating backup folder #{@backup_dir}"
	unless @preserve_dir
	if @preserve_dir
	FileUtils.rm(Dir.glob(File.join(@backup_dir, '.*.snar')))
	else
	puts "Creating backup folder #{@backup_dir}"

[evgeni]

(moved the puts, but not the rm)

I think what my brain tries to fight is the fact that "not preserve_dir" is the primary mode of operation of this code, so it should come first vs the else branch that is, well, "else" ;-)