[DPE-4479][DPE-4625] Make backups behavior correspond to specification

[lucasgameiroborges]

Issue

Two backup components where divergent from their related specification here: list-backups action should output more info than just id, type and status, and create-backup action should raise an error if a type diff/incr is requested but there's no previous (full) backup to reference.

Solution

• Fetch the additional info desired from pgbackrest info command + some context about the bucket and path where the backups are stored. New list-backups action output:

backups: |-
  Storage bucket name: test-bucket
  Backups base path: /test-path/backup/

  backup-id            | type         | status   | reference-backup-id  | LSN start/stop          | start-time           | finish-time          | backup-path
  -----------------------------------------------------------------------------------------------------------------------------------------------------------
  2024-07-01T22:17:07Z | full         | finished | None                 | 0/21000028 / 0/21000100 | 2024-07-01T22:17:07Z | 2024-07-01T22:17:10Z | /dev.patroni-postgresql-k8s/20240701-221707F
  2024-07-01T22:18:53Z | differential | finished | 2024-07-01T22:17:07Z | 0/23000028 / 0/23000100 | 2024-07-01T22:18:53Z | 2024-07-01T22:18:55Z | /dev.patroni-postgresql-k8s/20240701-221707F_20240701-221853D
  2024-07-01T22:23:33Z | incremental  | finished | 2024-07-01T22:18:53Z | 0/25000028 / 0/25000100 | 2024-07-01T22:23:33Z | 2024-07-01T22:23:35Z | /dev.patroni-postgresql-k8s/20240701-221707F_20240701-222333I

• Check if there are any previous backups created before creating a new diff/incr type backup. If not, return fail like below:

Action id 134 failed: Invalid backup type: incremental. No previous full backup to reference.

• Increment unit tests.

[codecov]

Codecov Report

Attention: Patch coverage is 87.50000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 70.25%. Comparing base (ea373d7) to head (8ae0815).
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/backups.py	87.50%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #542      +/-   ##
==========================================
+ Coverage   70.23%   70.25%   +0.02%     
==========================================
  Files          10       10              
  Lines        2785     2797      +12     
  Branches      518      521       +3     
==========================================
+ Hits         1956     1965       +9     
- Misses        731      732       +1     
- Partials       98      100       +2     

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[lucasgameiroborges]

Because pgbackrest returns a list of references, we pick only the most recent one to represent.
For example, if an incremental backup A depends on the previous differential backup B, which depends on a previous full backup C, the reference list for A will be [C, B] --> last one, most recent B will be shown

[marceloneppel]

LGTM!