FR: the Backup database engine to work with ON CLUSTER backups

Company or project name

No response

Use case

The Backup database engine is a great feature that allows to look into a backup without restoring it. https://clickhouse.com/docs/engines/database-engines/backup Unfortunately the Backup engine does not see backups created with the ON CLUSTER clause. It is possible to point a Backup database to a directory with an ON CLUSTER backup, but it will be empty.

Here is the file structure for single backups:

-rw-r----- 1 clickhouse clickhouse 2634 Nov  3 16:07 .backup
drwxr-x--- 3 clickhouse clickhouse 4096 Nov  3 16:07 data
drwxr-x--- 3 clickhouse clickhouse 4096 Nov  3 16:07 metadata

Here is the file structure for ON CLUSTER backups:

-rw-r-----   1 clickhouse clickhouse 12790981 Nov  3 11:13 .backup
drwxr-x---   5 clickhouse clickhouse     4096 Nov  3 11:00 shards

# ls -l shards/1/replicas/1
total 16
drwxr-x--- 3 clickhouse clickhouse 4096 Nov  3 11:00 data
drwxr-x--- 3 clickhouse clickhouse 4096 Nov  3 11:00 metadata

Describe the solution you'd like

I would like the Backup engine to be able to find objects from a particular shard and/or replica.

Describe alternatives you've considered

No response

Additional context

No response