backup: Migrate backup component from lazy_static to LazyLock

[Lymah123]

What is changed and how it works?

Issue Number: Close #18927

This PR refactors the backup component to replace the lazy_static! macro with std::sync::LazyLock .TiKV uses nightly Rust (1.87-nightly), and the LazyLock API we rely on primarily LazyLock::new is fully stable and available. Using LazyLock removes the need for an external dependency and provides a cleaner, modern initialization pattern.

What's Changed:

-  Replace lazy_static! macro with std::sync::LazyLock
-  Convert static metrics into accessor functions backed by LazyLock
-  Update all metric usages in endpoint.rs, writer.rs, errors.rs, and metrics.rs to use the new accessor functions
- Remove lazy_static dependency from Cargo.toml

Related changes

• [ ] PR to update pingcap/docs/pingcap/docs-cn:
• [ ] Need to cherry-pick to the release branch

Check List

Tests

• [x] Unit test
• [ ] Integration test
• [ ] Manual test (add detailed scripts or steps below)
• [ ] No code

Side effects

• [ ] Performance regression: Consumes more CPU
• [ ] Performance regression: Consumes more Memory
• [ ] Breaking backward compatibility

Release note

   None

[ti-chi-bot[bot]]

Hi @Lymah123. Thanks for your PR.

I'm waiting for a tikv member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[ti-chi-bot[bot]]

Welcome @Lymah123!

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Thank you, and welcome to tikv/tikv. :smiley:

[Lymah123]

@v01dstar, I look forward to your feedback on this PR. Thanks.

[v01dstar]

@v01dstar, I look forward to your feedback on this PR. Thanks.

Please fix the CI first

[Lymah123]

@v01dstar, I look forward to your feedback on this PR. Thanks.

Please fix the CI first

Fixed @v01dstar

[Lymah123]

Hello @v01dstar , I have made requested changes.

[v01dstar]

Please fix the tests

[Lymah123]

Please fix the tests

OK

[Lymah123]

Please fix the tests

Fixed @v01dstar

[v01dstar]

/ok-to-test

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: v01dstar

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[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2025-11-25 19:38:17.538502999 +0000 UTC m=+645261.187697446: :ballot_box_with_check: agreed by v01dstar.

[Lymah123]

Hi @v01dstar , is the PR going to get merged?

[v01dstar]

Hi @v01dstar , is the PR going to get merged?

Please fix the CI first

[Lymah123]

Hi @v01dstar , I tested locally , all the test cases passed.

The failing test (test_raftstore_new_server_cluster) is unrelated to my changes.

My PR only modified the redact_option_key helper function at line 1114 to fix a compilation error in logging code. The function is used at line 1110 to safely log Option<Key> values.

The test failure is:

• A flaky integration test (passed 2 times, failed once)
• A Raft consensus issue peer is not leader for region 1015
• Related to snapshot synchronization, not backup endpoint logging

My changes:

• Fixed a compilation error in redact_option_key
• Code compiles successfully with no errors
• Changes are isolated to logging utilities only

The test should pass on retry. My changes don't affect Raft operations

What do you think I can do to passed the failing test?

[v01dstar]

/test all

[Lymah123]

The test cases have passed @v01dstar

[v01dstar]

Please update your PR title and description to reflect the use of LazyLock instead of OnceLock. Also update the "Release note" section of the PR description to be "None" since it is a refactoring. Meanwhile, I will ping another reviewer to take a look.

[Lymah123]

Please update your PR title and description to reflect the use of LazyLock instead of OnceLock. Also update the "Release note" section of the PR description to be "None" since it is a refactoring. Meanwhile, I will ping another reviewer to take a look.

Done @v01dstar!