Load feature flags from new endpoint

[linglingye001]

No description provided.

[Copilot]

Pull request overview

This PR adds support for loading “enhanced” feature flags from the dedicated Azure App Configuration feature-flag endpoint, merges them with classic feature flags (with enhanced taking precedence), and propagates the new refresh/ETag tracking through the controller reconciliation flow.

Changes:

• Introduces an AppConfigurationClient abstraction that wraps both key-value and feature-flag endpoint clients.
• Adds enhanced feature-flag loading + ETag change detection, and merges enhanced/classic feature flags into the existing feature management output.
• Extends tracing/telemetry plumbing and controller refresh state to account for enhanced feature flags.

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
internal/loader/settings_client.go	Adds enhanced feature-flag settings + ETag-check clients using the dedicated feature-flag pager.
internal/loader/request_tracing.go	Adds correlation-context telemetry flag for enhanced feature flags.
internal/loader/mocks/mock_configuration_settings_retriever.go	Extends retriever mock with enhanced feature-flag change-check method.
internal/loader/feature_flag_converter.go	Converts enhanced endpoint schema into Microsoft feature management schema (snake_case).
internal/loader/feature_flag_converter_test.go	Adds unit tests for schema conversion and enhanced endpoint paging/ETag behavior.
internal/loader/configuration_setting_loader.go	Loads classic + enhanced feature flags, merges/deduplicates them, and tracks enhanced ETags.
internal/loader/configuration_client_manager.go	Switches client wrapper to use AppConfigurationClient and new constructors.
internal/loader/configuraiton_setting_loader_test.go	Updates tests/mocks to new client wrapper and additional enhanced calls.
internal/loader/app_configuration_client.go	New wrapper that creates/holds both azappconfig.Client and FeatureFlagClient.
internal/controller/suite_test.go	Stubs enhanced change check in controller test suite defaults.
internal/controller/processor.go	Adds refresh-state plumbing for enhanced feature flags during feature-flag refresh.
internal/controller/processor_test.go	Stubs enhanced change check in processor tests.
internal/controller/appconfigurationprovider_controller.go	Extends reconciliation state with enhanced feature-flag ETags.

Files not reviewed (1)

• internal/loader/mocks/mock_configuration_settings_retriever.go: Generated file

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[Yuan Qu (yuanqu72)]

Any reason we use SettingClient for enhanced feature flagchange check instead of directly using &EnhancedFeatureFlagEtagsClient?

[linglingye001]

The interface separates request behavior from failover behavior, lets the loader apply endpoint rotation/backoff uniformly to all request types. Also, in test a mock SettingsClient can be injected to return controlled responses.

In prod, SettingsClient is normally nil so enhanced FF client is created.