Enhanced feature flags by linglingye001 · Pull Request #73 · Azure/AppConfiguration-GoProvider

linglingye001 · 2026-08-05T11:10:42Z

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Pull request overview

This PR introduces enhanced feature flags support by loading feature flags from both classic key-value settings and the dedicated feature-flag endpoint, then merging them into the Microsoft Feature Management schema. It also updates client abstractions to support both settings and feature-flag operations and extends refresh/tracing behavior accordingly.

Changes:

Add enhanced feature flag loading + merging logic (classic KV feature flags + enhanced endpoint flags).
Introduce an appConfigClient abstraction (appConfigurationClient) to unify settings/snapshot/feature-flag operations.
Extend refresh + tracing to detect/enumerate enhanced feature flag usage and changes (via page ETags), and update tests.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
azureappconfiguration/snapshot_test.go	Updates snapshot tests to pass an enhanced feature-flag client stub.
azureappconfiguration/settings_client.go	Adds enhanced feature-flag loader + ETag-change monitor; switches clients to `appConfigClient`.
azureappconfiguration/refresh_test.go	Extends refresh tests to include enhanced feature-flag loader/monitor fields.
azureappconfiguration/internal/tracing/tracing.go	Adds correlation-context tags/options for enhanced feature flags.
azureappconfiguration/feature_flag.go	New: feature-flag merge + schema conversion + telemetry metadata helpers.
azureappconfiguration/feature_flag_test.go	New: unit tests for conversion/merge/dedup/ETag helpers and merged loading.
azureappconfiguration/failover_test.go	Updates failover tests to use `appConfigClient` wrappers/types.
azureappconfiguration/constants.go	Adds schema key constants needed by enhanced feature-flag conversion.
azureappconfiguration/client_manager.go	Refactors client manager/wrapper types to `appConfigClient` abstraction and new constructors.
azureappconfiguration/azureappconfiguration.go	Wires enhanced feature-flag loading/refresh into provider lifecycle and replaces old single-source FF loading.
azureappconfiguration/azureappconfiguration_test.go	Adds `newEmptyEnhancedFFClient()` test helper and updates FF load tests for new signature/types.
azureappconfiguration/app_configuration_client.go	New: concrete `appConfigClient` implementation backed by azappconfig clients.

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Yuan Qu (yuanqu72) · 2026-08-14T23:28:52Z

 	}

-	if !eTagChanged {
+	if !ffChanged {


I am wondering if the refresh logic here is an intentional decision: it currently reloads both flags when either is changed, which means more network calls if only one flag is changed. If the flag merge logic is correct, we should not need to reload both flags every time?

It's intentional, I remember it was discussed before that we always make call for both flags.

Yuan Qu (@yuanqu72)

I am wondering if the refresh logic here is an intentional decision: it currently reloads both flags when either is changed, which means more network calls if only one flag is changed.

If we detect that some classic feature flags are missing or have been deleted, it could mean that the customer has adopted or migrated to the new enhanced feature flags. Therefore, we should reload both types of feature flags.

Yuan Qu (yuanqu72) · 2026-08-14T23:36:17Z

 }

-func rotateClientsToNextEndpoint(clients []*configurationClientWrapper, lastSuccessfulEndpoint string) {
+func rotateClientsToNextEndpoint(clients []*appConfigClientWrapper, lastSuccessfulEndpoint string) {


A note for future consideration: this file is very long and contains all the core logic for setup/load/refresh + helper methods. Maybe some helper methods can be separated out and only leave the high level orchestration logic in this file.

Yuan Qu (yuanqu72) · 2026-08-15T01:02:31Z

+		}
+
+		azappcfg.updateFeatureFlagTracing(ff)
+		populateTelemetryMetadata(ff, setting.ETag, generateFeatureFlagReference(clientEndpoint, "kv", *setting.Key, setting.Label))


Suggested change

populateTelemetryMetadata(ff, setting.ETag, generateFeatureFlagReference(clientEndpoint, "kv", *setting.Key, setting.Label))

populateTelemetryMetadata(ff, setting.ETag, generateFeatureFlagReference(clientEndpoint, "ff", *setting.Key, setting.Label))

we use kv path for flags loaded from key-value endpoint, and ff for enhanced flags

I find this confusing -> if the official name is ff for kv based ff and enhanced ff for the new one, we should stick to it everywhere. In this specific case, I think kv is OK, but using ff to indicate enhanced ff is very confusing.

Yuan Qu (yuanqu72) · 2026-08-15T01:05:37Z

+
+		ff := convertToMicrosoftSchema(flag)
+		azappcfg.updateFeatureFlagTracing(ff)
+		populateTelemetryMetadata(ff, flag.ETag, generateFeatureFlagReference(clientEndpoint, "ff", *flag.Name, flag.Label))


Suggested change

populateTelemetryMetadata(ff, flag.ETag, generateFeatureFlagReference(clientEndpoint, "ff", *flag.Name, flag.Label))

populateTelemetryMetadata(ff, flag.ETag, generateFeatureFlagReference(clientEndpoint, "enhancedFF", *flag.Name, flag.Label))

Yuan Qu (yuanqu72) · 2026-08-16T21:41:31Z

Did we run any integration tests/live tests that does the real network call and interact with the enhanced feature flag endpoint?
Please check the copilot suggestions, some of them seem reasonable.

linglingye001 · 2026-08-17T08:17:33Z

Did we run any integration tests/live tests that does the real network call and interact with the enhanced feature flag endpoint?

Yes, I did end to end test in my local env.

Please check the copilot suggestions, some of them seem reasonable.

Updated.

Zhiyuan Liang (zhiyuanliang-ms) · 2026-08-17T08:21:51Z

 		eg.Go(func() error {
 			if keyValueRefreshed, err = azappcfg.refreshKeyValues(egCtx, azappcfg.newKeyValueRefreshClient(client)); err != nil {
 				return fmt.Errorf("failed to refresh key values: %w", err)
 			}
 			return nil
 		})

 		eg.Go(func() error {
 			if featureFlagRefreshed, err = azappcfg.refreshFeatureFlags(egCtx, azappcfg.newFeatureFlagRefreshClient(client)); err != nil {
 				return fmt.Errorf("failed to refresh feature flags: %w", err)
 			}
 			return nil
 		})


These two routines write on the same err variable. Will there be any race issue?
For example, the kv routine got an error, but ff routine set the error to nil.

Good catch. FIxed in #74

Zhiyuan Liang (zhiyuanliang-ms) · 2026-08-17T09:30:09Z

+	populateTelemetryMetadata(enabled, &etag, "https://fake.azconfig.io/ff/Beta")
+	metadata := enabled[telemetryKey].(map[string]any)[metadataKey].(map[string]any)
+	assert.Equal(t, "etag-1", metadata[eTagKey])
+	assert.Equal(t, "https://fake.azconfig.io/ff/Beta", metadata[featureFlagReferenceKey])


Did we miss the feature flag prefix?

In dotnet, we have

…Configuration-GoProvider into linglingye/enhanced-ff

Zhiyuan Liang (zhiyuanliang-ms) · 2026-08-18T07:39:30Z

+	return reference
+}
+
+func populateTelemetryMetadata(featureFlag map[string]any, eTag *azcore.ETag, reference string) {


It seems like we don't populate AllocationId in go provider

Zhiyuan Liang (zhiyuanliang-ms) · 2026-08-18T08:54:50Z

+	}
+
+	var parsed any
+	if err := json.Unmarshal([]byte(*raw), &parsed); err == nil {


We should align with the .NET PR where we only parse json when the string value looks like json (e.g. starts with "{")

json.Unmarshal will introduce a subtle difference here. For example , string "42" or "true" will be converted to number and boolean instead of keeping as string. This is different from other language.

Zhiyuan Liang (zhiyuanliang-ms) · 2026-08-18T08:55:18Z

+				variantMap[nameKey] = *variant.Name
+			}
+			if variant.Value != nil {
+				variantMap[configurationValueKey] = parseFeatureFlagValue(variant.Value)


We should respect variant content type

enhanced feature flags

8c499a9

linglingye001 requested a lite review from Copilot August 5, 2026 11:10

Copilot started reviewing on behalf of linglingye001 August 5, 2026 11:11 View session

Copilot AI reviewed Aug 5, 2026

View reviewed changes

Comment thread azureappconfiguration/settings_client.go

Comment thread azureappconfiguration/feature_flag.go Outdated

Comment thread azureappconfiguration/azureappconfiguration.go Outdated

update conditional request

7f638e6

Yuan Qu (yuanqu72) reviewed Aug 15, 2026

View reviewed changes

resolve comments

56bd640

Zhiyuan Liang (zhiyuanliang-ms) reviewed Aug 17, 2026

View reviewed changes

fix race

215ff28

linglingye001 mentioned this pull request Aug 18, 2026

Fix race #74

Merged

Merge branch 'release/v1.7.0-preview' of https://github.com/Azure/App…

6fc4340

…Configuration-GoProvider into linglingye/enhanced-ff

Zhiyuan Liang (zhiyuanliang-ms) reviewed Aug 18, 2026

View reviewed changes

	populateTelemetryMetadata(ff, setting.ETag, generateFeatureFlagReference(clientEndpoint, "kv", *setting.Key, setting.Label))
	populateTelemetryMetadata(ff, setting.ETag, generateFeatureFlagReference(clientEndpoint, "ff", *setting.Key, setting.Label))

	populateTelemetryMetadata(ff, flag.ETag, generateFeatureFlagReference(clientEndpoint, "ff", *flag.Name, flag.Label))
	populateTelemetryMetadata(ff, flag.ETag, generateFeatureFlagReference(clientEndpoint, "enhancedFF", *flag.Name, flag.Label))

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linglingye001 commented Aug 5, 2026

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Yuan Qu (yuanqu72) commented Aug 16, 2026

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linglingye001 commented Aug 17, 2026

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Zhiyuan Liang (zhiyuanliang-ms) Aug 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Zhiyuan Liang (zhiyuanliang-ms) Aug 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Zhiyuan Liang (zhiyuanliang-ms) Aug 18, 2026 •

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