hotfix for healthcheck access rights check

[adameat]

Changelog entry

fixes access check restrictions, introduced in #22513
allows for prometheus metrics to be collected without access check.
closes #28021

Changelog category

• Bugfix

Description for reviewers

...

[github-actions]

🟢 2025-11-11 06:27:47 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-11-11 06:28:03 UTC Pre-commit check linux-x86_64-release-asan for 9178853 has started.
⚪ 2025-11-11 06:28:21 UTC Artifacts will be uploaded here
⚪ 2025-11-11 06:30:38 UTC ya make is running...
🟡 2025-11-11 08:33:58 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
15239	14724	0	182	304	29

🟢 2025-11-11 08:34:07 UTC Build successful.
🟢 2025-11-11 08:34:34 UTC ydbd size 3.8 GiB changed* by -11.9 KiB, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 4fd8389	merge: 9178853	diff	diff %
ydbd size	4 081 241 880 Bytes	4 081 229 744 Bytes	-11.9 KiB	-0.000%
ydbd stripped size	1 515 019 848 Bytes	1 515 014 600 Bytes	-5.1 KiB	-0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-11-11 06:28:40 UTC Pre-commit check linux-x86_64-relwithdebinfo for 9178853 has started.
⚪ 2025-11-11 06:28:46 UTC Artifacts will be uploaded here
⚪ 2025-11-11 06:31:00 UTC ya make is running...
🟡 2025-11-11 07:50:53 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
31395	29969	0	3	1385	38

⚪ 2025-11-11 07:51:04 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-11-11 07:59:51 UTC Tests successful.

Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
72 (only retried tests)	56	0	0	0	16

🟢 2025-11-11 07:59:58 UTC Build successful.
🟢 2025-11-11 08:00:18 UTC ydbd size 2.3 GiB changed* by -5.9 KiB, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 4fd8389	merge: 9178853	diff	diff %
ydbd size	2 437 872 424 Bytes	2 437 866 344 Bytes	-5.9 KiB	-0.000%
ydbd stripped size	518 656 912 Bytes	518 656 528 Bytes	-384 Bytes	-0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[Copilot]

Pull Request Overview

This PR fixes access check restrictions for the healthcheck endpoint that were introduced in #22513. The main purpose is to allow Prometheus metrics collection without requiring authentication while maintaining access checks for other types of requests.

Key changes:

• Moved authentication check from the HTTP handler registration to inside the healthcheck handler
• Added conditional access check that bypasses authentication for Prometheus format requests
• Refactored code to use base class members (Params, Timeout, JsonSettings, Proto2JsonConfig) instead of local/duplicate variables

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
ydb/core/viewer/viewer.cpp	Disabled auth at handler registration level with comment indicating auth is now checked inside the handler
ydb/core/viewer/viewer_healthcheck.h	Removed duplicate member variables, added conditional access check for non-Prometheus requests, refactored to use base class functionality for parameter parsing and JSON configuration

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