Create agent database files from template atomically

[vikman90]

Related issue
Closes #22847

This pull request aims to address a fault tolerance issue in wazuh-db, which may result in empty database files if abruptly closed. This scenario can occur in an environment where the service takes longer than a minute to shut down, as it forcibly terminates wazuh-db with SIGKILL.

Proposed solution

The proposed solution entails:

• Creating temporary files and renaming them to the database name once they are filled.
  • If left empty, they will be regenerated upon the next execution.
• Adding a log entry confirming the proper closure of wazuh-db.

Not considered

• Validation of databases once created, or upon each opening.
• Cleanup of potential stray temporary files.

Tests

• Unit tests for the modified function: wdb_create_agent_db2.
• Manual test: abruptly closing wazuh-db while it is creating databases.

Manual test

for i in {1..1000}; do echo "agent $i begin"; done | ~/wazuh-tools/utils/wdb-query.py & (sleep 0.1; pkill -9 wazuh-db)

Before

-rw-r----- 1 wazuh wazuh      0 May  2 09:51 187.db
-rw-r----- 1 wazuh wazuh      0 May  2 09:51 188.db
-rw-r----- 1 wazuh wazuh      0 May  2 09:51 189.db
-rw-r----- 1 wazuh wazuh      0 May  2 09:51 190.db
-rw-r----- 1 wazuh wazuh      0 May  2 09:51 191.db
-rw-r----- 1 wazuh wazuh      0 May  2 09:51 192.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 193.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 194.db
-rw-r----- 1 wazuh wazuh      0 May  2 09:51 195.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 196.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 197.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 198.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 199.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 200.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 201.db
-rw-r----- 1 wazuh wazuh  20480 May  2 09:51 202.db

After

-rw-r----- 1 wazuh wazuh 240K May  2 13:20 076.db
-rw-r----- 1 wazuh wazuh 240K May  2 13:20 077.db
-rw-r----- 1 wazuh wazuh 240K May  2 13:20 078.db
-rw-r----- 1 wazuh wazuh 240K May  2 13:20 080.db
-rw-r----- 1 wazuh wazuh 240K May  2 13:20 081.db
-rw-r----- 1 wazuh wazuh 240K May  2 13:20 082.db
-rw-r----- 1 wazuh wazuh 240K May  2 13:20 083.db
-rw-r----- 1 wazuh wazuh 240K May  2 13:20 086.db
-rw-r--r-- 1 wazuh wazuh    0 May  2 13:20 087.db.new
-rw-r--r-- 1 wazuh wazuh    0 May  2 13:20 090.db.new
-rw-r----- 1 wazuh wazuh 212K May  2 13:20 global.db
srw-rw---- 1 wazuh wazuh    0 May  2 13:20 wdb

[vikman90]

Failing checks

scan-build-macos-agent

• Scan-build test is not running on macOS #23176
• Downgrade macOS image version for scan-build test #23178

[cborla]

LGTM!

[LucioDonda]

It LGTM but in my opionion we could add those little details

[cborla]

LGTM!