removal of ERROR backups

[sanstepan]

It would be great to have Instead of
for BKP in $(pg_probackup show -B /var/lib/pgpro/std-10/probackup -D /var/lib/pgpro/std-10/data --instance banana |grep ERROR|awk '{print $3}') ; do pg_probackup delete -B /var/lib/pgpro/std-10/probackup -D /var/lib/pgpro/std-10/data --instance banana --backup-id $BKP ; done
something like
pg_probackup delete -B /var/lib/pgpro/std-10/probackup -D /var/lib/pgpro/std-10/data --instance banana --error-state

[gsmolk]

Hello!
We have an issue for exactly the same problem with slightly different approach of solving it.
#57

Which approach is preferable from your POV?
Personally, I think that both solutions are sound, have their uses, so both should be implemented.

[rzharkov]

It might be a very helpful option.

[gsmolk]

@VictorSpirin, please, in future tag commit messages with issue ID. Example:
1102e57

[VictorSpirin]

@gsmol issue_120 gitlab branch

[gsmolk]

There are some thoughts about your patch:

1. Instead of using flag --error-state, lets use option --status with status as an argument, so it should be possible to delete all backups of any status:

pg_probackup delete -B backup_dir --instance node --status=ok

2. instance_name variable must be used as an argument in function do_delete_error

[VictorSpirin]

Updated issue_120 gitlab branch

[gsmolk]

Inspected your patch. Please consider the following steps to improve your patch:

1. Consider --dry-run flag.
2. Update --help output.
3. Documentation must contain warning, that deleting by status do not take established retention policies into account.
4. Update documentation synopsis, command-line reference and options sections