Track go fm package usage and version by env var (#52)

* get env to track go fm package usage and version

* update Go FM env var

* update

Author: linglingye001

azureappconfiguration/azureappconfiguration.go

@@ -821,6 +821,7 @@ func configureTracingOptions(options *Options) tracing.Options {
 	}
 
 	tracingOption.Host = tracing.GetHostType()
+	tracingOption.FMVersion = tracing.GetFeatureManagementVersion()
 
 	if !(options.KeyVaultOptions.SecretResolver == nil && options.KeyVaultOptions.Credential == nil) {
 		tracingOption.KeyVaultConfigured = true

azureappconfiguration/internal/tracing/tracing.go

@@ -45,6 +45,8 @@ const (
 	LoadBalancingEnabledTag          = "LB"
 
 	// Feature flag usage tracing
+	FMGoVerEnv        = "MS_FEATURE_MANAGEMENT_GO_VERSION"
+	FMGoVerKey         = "FMGoVer"
 	FeatureFilterTypeKey = "Filter"
 	CustomFilterKey      = "CSTM"
 	TimeWindowFilterKey  = "TIME"
@@ -76,6 +78,7 @@ type Options struct {
 	ReplicaCount                     int
 	IsLoadBalancingEnabled           bool
 	FeatureFlagTracing               *FeatureFlagTracing
+	FMVersion                        string
 }
 
 func GetHostType() HostType {
@@ -93,6 +96,10 @@ func GetHostType() HostType {
 	return ""
 }
 
+func GetFeatureManagementVersion() string {
+	return os.Getenv(FMGoVerEnv)
+}
+
 func CreateCorrelationContextHeader(ctx context.Context, options Options) http.Header {
 	header := http.Header{}
 	output := make([]string, 0)
@@ -141,6 +148,10 @@ func CreateCorrelationContextHeader(ctx context.Context, options Options) http.H
 		output = append(output, featureStr)
 	}
 
+	if options.FMVersion != "" {
+		output = append(output, FMGoVerKey+"="+options.FMVersion)
+	}
+
 	if options.FeatureFlagTracing != nil {
 		if options.FeatureFlagTracing.UsesAnyFeatureFilter() {
 			output = append(output, FeatureFilterTypeKey+"="+options.FeatureFlagTracing.CreateFeatureFiltersString())