trafficpolicy: Adopt policy IR pattern, define Equals methods, etc

[timflannagan]

Description

Follow-up to the re-organization trafficpolicy plugin PR

Further standardizes the per-policy-IR pattern and ensures that each policy type define it's own IR, Equals, handleX methods, etc

Make all sub IR types unexported for consistency

Change Type

/kind cleanup

Changelog

NONE

Additional Notes

[timflannagan]

TODO: handleAI method. Wanted to double check the state of CI after this change since it's invasive first.

[Copilot]

Pull Request Overview

This PR standardizes the policy IR pattern by introducing unexported IR types with custom Equals methods and refactoring the translation logic for various policy components. Key changes include the introduction of transformationIR, rustformationIR, aiPolicyIR, extprocIR and corresponding updates in rate limiting and ext auth components.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/kgateway/extensions2/plugins/trafficpolicy/transformation_plugin.go	Refactored transformation and rustformation translation with new IR types and Equals methods.
internal/kgateway/extensions2/plugins/trafficpolicy/traffic_policy_plugin.go	Updated references to new IR names and method calls for AI, transformation, ext proc, rate limit, and CORS.
internal/kgateway/extensions2/plugins/trafficpolicy/local_rate_limit_plugin.go	Updated local rate limit translation to use new IR.
internal/kgateway/extensions2/plugins/trafficpolicy/global_rate_limit_plugin.go	Updated global rate limit translation with new IR type and error handling.
internal/kgateway/extensions2/plugins/trafficpolicy/extproc_policy.go	Refactored ExtProc IR and translation logic under new naming conventions.
internal/kgateway/extensions2/plugins/trafficpolicy/extauth_policy.go	Updated ExtAuth translation to use new naming conventions.
internal/kgateway/extensions2/plugins/trafficpolicy/cors_policy.go	Adjusted CORS policy translation consistent with other policy IR changes.
internal/kgateway/extensions2/plugins/trafficpolicy/builder.go	Updated overall builder logic to integrate new IR methods for different policies.
internal/kgateway/extensions2/plugins/trafficpolicy/ai_policy.go	Renamed and updated AI policy translation and Equals method.

Comments suppressed due to low confidence (2)

internal/kgateway/extensions2/plugins/trafficpolicy/global_rate_limit_plugin.go:75

• The error check for the global rate limit extension compares against v1alpha1.GatewayExtensionTypeExtAuth instead of the expected GatewayExtensionTypeRateLimit. Please update the expected type for clarity.

return pluginutils.ErrInvalidExtensionType(v1alpha1.GatewayExtensionTypeExtAuth, gwExtIR.ExtType)

internal/kgateway/extensions2/plugins/trafficpolicy/extproc_policy.go:55

• The extproc translation error check is using v1alpha1.GatewayExtensionTypeExtAuth as the expected type instead of the appropriate GatewayExtensionTypeExtProc. Please update this to reflect the correct extension type.

return pluginutils.ErrInvalidExtensionType(v1alpha1.GatewayExtensionTypeExtAuth, gatewayExtension.ExtType)

[nfuden]

nit: transformationIR.transformation seems clunky.
is there a world where it could/should be policy or something else?

[nfuden]

This is a pretty brutal set of opinions on text formatting.
If we are going do it can we find or make a linter for this? Otherwise someone else is going come around and revert this and also add tons of lines.