Implement appendCallerID feature in vtgate executor

[corbantek]

Description

• Added a new boolean flag appendCallerID to control the appending of CallerId username to queries.
• Updated the NewExecutor function to accept the appendCallerID parameter.
• Modified the newExecute method to conditionally append CallerId to the SQL query if the flag is enabled.

Related Issue(s)

• https://github.com/vitessio/vitess/issues/18636

Checklist

• [X] "Backport to:" labels have been added if this change should be back-ported to release branches
• [X] If this change is to be back-ported to previous releases, a justification is included in the PR description
• [X] Tests were added or are not required
• [X] Did the new or modified tests pass consistently locally and on CI?
• [x] Documentation was added or is not required

Deployment Notes

[vitess-bot[bot]]

Review Checklist

Hello reviewers! :wave: Please follow this checklist when reviewing this Pull Request.

General

• [ ] Ensure that the Pull Request has a descriptive title.
• [ ] Ensure there is a link to an issue (except for internal cleanup and flaky test fixes), new features should have an RFC that documents use cases and test cases.

Tests

• [ ] Bug fixes should have at least one unit or end-to-end test, enhancement and new features should have a sufficient number of tests.

Documentation

• [ ] Apply the release notes (needs details) label if users need to know about this change.
• [ ] New features should be documented.
• [ ] There should be some code comments as to why things are implemented the way they are.
• [ ] There should be a comment at the top of each new or modified test to explain what the test does.

New flags

• [ ] Is this flag really necessary?
• [ ] Flag names must be clear and intuitive, use dashes (-), and have a clear help text.

If a workflow is added or modified:

• [ ] Each item in Jobs should be named in order to mark it as required.
• [ ] If the workflow needs to be marked as required, the maintainer team must be notified.

Backward compatibility

• [ ] Protobuf changes should be wire-compatible.
• [ ] Changes to _vt tables and RPCs need to be backward compatible.
• [ ] RPC changes should be compatible with vitess-operator
• [ ] If a flag is removed, then it should also be removed from vitess-operator and arewefastyet, if used there.
• [ ] vtctl command output order should be stable and awk-able.

[codecov[bot]]

Codecov Report

:x: Patch coverage is 66.66667% with 3 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 67.48%. Comparing base (58f753c) to head (5c6dea2). :warning: Report is 140 commits behind head on main.

Files with missing lines	Patch %	Lines
go/vt/vtgate/plan_execute.go	50.00%	2 Missing :warning:
go/vt/vtgate/vtgate.go	0.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18635      +/-   ##
==========================================
- Coverage   67.50%   67.48%   -0.02%     
==========================================
  Files        1607     1608       +1     
  Lines      263527   263535       +8     
==========================================
- Hits       177890   177858      -32     
- Misses      85637    85677      +40     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• :package: JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[sam-k3nny]

Is there a way of nudging this forward please? Etsy are also very interested in this change.

[harshit-gangal]

Have you looked at the vttablet flag queryserver-config-annotate-queries that enables writing caller ID as comments to the sql query before executing it on MySQL

[corbantek]

Have you looked at the vttablet flag queryserver-config-annotate-queries that enables writing caller ID as comments to the sql query before executing it on MySQL

My apologies on the delayed response, let me go investigate if this has equal parity with this PR...

[sam-k3nny]

The advantage of this approach, IIUC, is that is not based on an honour system. We can't always guarantee the caller will have added Caller ID to the comments. More often than not, when we want to identify the caller, it is because of unexpected requests. This approach ensures we have the caller if there are rogue requests.

Let me know if I've misunderstood anything though.

[github-actions[bot]]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.