feat: implement offline kubernetes controller

[shawnh2]

What type of PR is this?

What this PR does / why we need it:

impl offline controller detailed in #3213 (comment) and let file-provider to be able to utilise offline controller.

Which issue(s) this PR fixes:

fix #3213

Release Notes: Yes

[codecov]

Codecov Report

Attention: Patch coverage is 66.81716% with 147 lines in your changes missing coverage. Please review.

Project coverage is 65.40%. Comparing base (6b772d7) to head (6c46dd9).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/provider/file/store.go	45.83%	76 Missing and 28 partials ⚠️
internal/provider/kubernetes/controller_offline.go	81.01%	13 Missing and 2 partials ⚠️
internal/provider/file/status.go	77.77%	9 Missing and 3 partials ⚠️
internal/provider/file/file.go	80.48%	5 Missing and 3 partials ⚠️
internal/provider/kubernetes/indexers.go	93.05%	0 Missing and 5 partials ⚠️
internal/provider/runner/runner.go	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5767      +/-   ##
==========================================
+ Coverage   65.29%   65.40%   +0.11%     
==========================================
  Files         216      217       +1     
  Lines       35907    36061     +154     
==========================================
+ Hits        23445    23586     +141     
+ Misses      11007    10999       -8     
- Partials     1455     1476      +21     

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[zhaohuabing]

Hi @shawnh2 this PR adds the "offline controller," but it doesn’t include an example of how to actually use it. Since it's just a small change, could we also include the file provider modification as part of this PR to verify it works?

Thanks!

[shawnh2]

Hi @shawnh2 this PR adds the "offline controller," but it doesn’t include an example of how to actually use it. Since it's just a small change, could we also include the file provider modification as part of this PR to verify it works?

Thanks!

sure, I was intend to include file provider in next PR. I will add it then.

[shawnh2]

The status works as expected

[arkodg]

LGTM thanks

[arkodg]

@shawnh2 can you rebase ?

[zhaohuabing]

LGTM thanks!

[mathetake]

So this PR has a regression:

https://github.com/envoyproxy/ai-gateway/blob/be2b479b04bc7a219b0c8239143bfbabebdcd615/cmd/aigw/run_test.go#L52

this test runs successfully before this PR and failing after. You can repro by checking out the be2b479b04bc7a219 (a main branch a few days ago), using the latest EG, and run the test. It looks like a Route is not properly reconciled as it seems Envoy starts returning "route not found" after this PR. On the other hand, the standalone tutorial runs successfully even after this PR, so I believe there's some edge case that is not covered by tests in EG.