feat: Add health check endpoint

[o-kopysov]

Pull Request

Description

This PR introduces a new health check API endpoint (/health). The endpoint allows monitoring the service's status by providing the current length of the processing queue, which is retrieved directly from the database. This enhancement is crucial for operational health checks, load monitoring, and ensuring the service is functioning as expected.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code cleanup/refactoring
• Documentation update
• This change requires a documentation update
• CI system update
• Test Coverage update
• Version update (release)

Testing

curl --location 'http://127.0.0.1:7896/health'

{
    "queueLength": 0
}

Checklist:

• My code follows the style guidelines of this project
• My code meets the required code coverage for lines (90% and above)
• My code meets the required code coverage for branches (80% and above)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.58%. Comparing base (3ea64d5) to head (7843883).

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #776      +/-   ##
============================================
+ Coverage     93.55%   93.58%   +0.03%     
- Complexity      411      414       +3     
============================================
  Files            29       30       +1     
  Lines          1752     1761       +9     
  Branches        225      225              
============================================
+ Hits           1639     1648       +9     
  Misses           49       49              
  Partials         64       64              

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[t-naumenko]

Good job!

[tdrozdovsky]

LGTM!