add commandline flags to set GC interval and metrics TTL

Signed-off-by: Harman Singh <iamgrewal7@gmail.com>

pkg/provider/hpa.go

@@ -62,6 +62,7 @@ type HPAProvider struct {
 	recorder                  kube_record.EventRecorder
 	logger                    *log.Entry
 	disregardIncompatibleHPAs bool
+	gcInterval                time.Duration
 }
 
 // metricCollection is a container for sending collected metrics across a
@@ -72,7 +73,7 @@ type metricCollection struct {
 }
 
 // NewHPAProvider initializes a new HPAProvider.
-func NewHPAProvider(client kubernetes.Interface, interval, collectorInterval time.Duration, collectorFactory *collector.CollectorFactory, disregardIncompatibleHPAs bool) *HPAProvider {
+func NewHPAProvider(client kubernetes.Interface, interval, collectorInterval time.Duration, collectorFactory *collector.CollectorFactory, disregardIncompatibleHPAs bool, metricsTTL time.Duration, gcInterval time.Duration) *HPAProvider {
 	metricsc := make(chan metricCollection)
 
 	return &HPAProvider{
@@ -81,12 +82,13 @@ func NewHPAProvider(client kubernetes.Interface, interval, collectorInterval tim
 		collectorInterval: collectorInterval,
 		metricSink:        metricsc,
 		metricStore: NewMetricStore(func() time.Time {
-			return time.Now().UTC().Add(15 * time.Minute)
+			return time.Now().UTC().Add(metricsTTL)
 		}),
 		collectorFactory:          collectorFactory,
 		recorder:                  recorder.CreateEventRecorder(client),
 		logger:                    log.WithFields(log.Fields{"provider": "hpa"}),
 		disregardIncompatibleHPAs: disregardIncompatibleHPAs,
+		gcInterval:                gcInterval,
 	}
 }
 
@@ -218,7 +220,7 @@ func (p *HPAProvider) collectMetrics(ctx context.Context) {
 	go func(ctx context.Context) {
 		for {
 			select {
-			case <-time.After(10 * time.Minute):
+			case <-time.After(p.gcInterval):
 				p.metricStore.RemoveExpired()
 			case <-ctx.Done():
 				p.logger.Info("Stopped metrics store garbage collection.")

pkg/provider/hpa_test.go

@@ -106,7 +106,7 @@ func TestUpdateHPAs(t *testing.T) {
 	err = collectorFactory.RegisterPodsCollector("", mockCollectorPlugin{})
 	require.NoError(t, err)
 
-	provider := NewHPAProvider(fakeClient, 1*time.Second, 1*time.Second, collectorFactory, false)
+	provider := NewHPAProvider(fakeClient, 1*time.Second, 1*time.Second, collectorFactory, false, 1*time.Second, 1*time.Second)
 	provider.collectorScheduler = NewCollectorScheduler(context.Background(), provider.metricSink)
 
 	err = provider.updateHPAs()
@@ -171,7 +171,7 @@ func TestUpdateHPAsDisregardingIncompatibleHPA(t *testing.T) {
 	require.NoError(t, err)
 
 	eventRecorder := &mockEventRecorder{}
-	provider := NewHPAProvider(fakeClient, 1*time.Second, 1*time.Second, collectorFactory, true)
+	provider := NewHPAProvider(fakeClient, 1*time.Second, 1*time.Second, collectorFactory, true, 1*time.Second, 1*time.Second)
 	provider.recorder = eventRecorder
 	provider.collectorScheduler = NewCollectorScheduler(context.Background(), provider.metricSink)
 
@@ -183,7 +183,7 @@ func TestUpdateHPAsDisregardingIncompatibleHPA(t *testing.T) {
 
 	// check for events when disregardIncompatibleHPAs=false
 	eventRecorder = &mockEventRecorder{}
-	provider = NewHPAProvider(fakeClient, 1*time.Second, 1*time.Second, collectorFactory, false)
+	provider = NewHPAProvider(fakeClient, 1*time.Second, 1*time.Second, collectorFactory, false, 1*time.Second, 1*time.Second)
 	provider.recorder = eventRecorder
 	provider.collectorScheduler = NewCollectorScheduler(context.Background(), provider.metricSink)
 

pkg/server/start.go

@@ -116,6 +116,8 @@ func NewCommandStartAdapterServer(stopCh <-chan struct{}) *cobra.Command {
 	flags.StringVar(&o.MetricsAddress, "metrics-address", o.MetricsAddress, "The address where to serve prometheus metrics")
 	flags.BoolVar(&o.DisregardIncompatibleHPAs, "disregard-incompatible-hpas", o.DisregardIncompatibleHPAs, ""+
 		"disregard failing to create collectors for incompatible HPAs")
+	flags.DurationVar(&o.MetricsTTL, "metrics-ttl", 15*time.Minute, "TTL for metrics that are stored in in-memory cache.")
+	flags.DurationVar(&o.GCInterval, "garbage-collector-interval", 10*time.Minute, "Interval to clean up metrics that are stored in in-memory cache.")
 	return cmd
 }
 
@@ -243,7 +245,7 @@ func (o AdapterServerOptions) RunCustomMetricsAdapterServer(stopCh <-chan struct
 		collectorFactory.RegisterExternalCollector([]string{collector.AWSSQSQueueLengthMetric}, collector.NewAWSCollectorPlugin(awsSessions))
 	}
 
-	hpaProvider := provider.NewHPAProvider(client, 30*time.Second, 1*time.Minute, collectorFactory, o.DisregardIncompatibleHPAs)
+	hpaProvider := provider.NewHPAProvider(client, 30*time.Second, 1*time.Minute, collectorFactory, o.DisregardIncompatibleHPAs, o.MetricsTTL, o.GCInterval)
 
 	go hpaProvider.Run(ctx)
 
@@ -350,4 +352,8 @@ type AdapterServerOptions struct {
 	// Whether to disregard failing to create collectors for incompatible HPAs - such as when using
 	// kube-metrics-adapter beside another Metrics Provider
 	DisregardIncompatibleHPAs bool
+	// TTL for metrics that are stored in in-memory cache
+	MetricsTTL time.Duration
+	// Interval to clean up metrics that are stored in in-memory cache
+	GCInterval time.Duration
 }