Feature flag tracing

[linglingye001]

No description provided.

[Copilot]

Pull Request Overview

This PR adds feature flag telemetry and tracing support by introducing a FeatureFlagTracing type, updating the correlation context header to include feature flag usage details, and modifying the feature-flag loading logic to populate telemetry metadata and update tracing metrics.

• Introduces FeatureFlagTracing with methods to track filters, feature usage, and variant counts
• Extends CreateCorrelationContextHeader to append feature-flag tracing entries
• Updates loadFeatureFlags to call populateTelemetryMetadata and updateFeatureFlagTracing, and adds tests for the new functionality

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
azureappconfiguration/internal/tracing/tracing.go	Added FeatureFlagTracing to header options and included logic to append its data to the correlation context header
azureappconfiguration/internal/tracing/featureflag_tracing.go	New implementation of FeatureFlagTracing methods
azureappconfiguration/internal/tracing/tracing_test.go	Unit tests for FeatureFlagTracing and header updates
azureappconfiguration/constants.go	Added constants for feature-flag keys and tags
azureappconfiguration/azureappconfiguration.go	Updated feature-flag loading to populate telemetry metadata, update tracing, and generate reference URLs; added endpoint field
azureappconfiguration/azureappconfiguration_test.go	New tests for telemetry-enabled flags and tracing updates

Comments suppressed due to low confidence (4)

azureappconfiguration/internal/tracing/tracing.go:138

• Use header.Set here instead of header.Add to ensure the correlation context header is not duplicated if invoked multiple times.

header.Add(CorrelationContextHeader, strings.Join(output, DelimiterComma))

azureappconfiguration/internal/tracing/featureflag_tracing.go:6

• [nitpick] Add GoDoc comments for FeatureFlagTracing and its exported methods to explain their purpose and usage.

type FeatureFlagTracing struct {

azureappconfiguration/azureappconfiguration.go:809

• [nitpick] Consider adding unit tests for populateTelemetryMetadata to verify that telemetry metadata (ETag and reference URL) is correctly populated when telemetry is enabled.

func populateTelemetryMetadata(featureFlag map[string]interface{}, setting azappconfig.Setting, endpoint string) {

azureappconfiguration/azureappconfiguration.go:761

• The fmt.Sprintf call requires the fmt package but I don't see it imported. Please add import \"fmt\" at the top of the file.

featureFlagReference := fmt.Sprintf("%s/kv/%s", endpoint, *setting.Key)

[RichardChen820]

LGTM