Add a separate flag for 'start' parameter

cmd/adapter/adapter.go

@@ -53,6 +53,8 @@ type PrometheusAdapter struct {
 	AdapterConfigFile string
 	// MetricsRelistInterval is the interval at which to relist the set of available metrics
 	MetricsRelistInterval time.Duration
+	// MetricsStartDuration is the period to query available metrics for
+	MetricsStartDuration time.Duration
 
 	metricsConfig *adaptercfg.MetricsDiscoveryConfig
 }
@@ -83,6 +85,8 @@ func (cmd *PrometheusAdapter) addFlags() {
 			"and custom metrics API resources")
 	cmd.Flags().DurationVar(&cmd.MetricsRelistInterval, "metrics-relist-interval", cmd.MetricsRelistInterval, ""+
 		"interval at which to re-list the set of all available metrics from Prometheus")
+	cmd.Flags().DurationVar(&cmd.MetricsStartDuration, "metrics-start-duration", cmd.MetricsStartDuration, ""+
+		"period for which to query the set of available metrics from Prometheus ('start' parameter)")
 }
 
 func (cmd *PrometheusAdapter) loadConfig() error {
@@ -122,7 +126,7 @@ func (cmd *PrometheusAdapter) makeProvider(promClient prom.Client, stopCh <-chan
 	}
 
 	// construct the provider and start it
-	cmProvider, runner := cmprov.NewPrometheusProvider(mapper, dynClient, promClient, namers, cmd.MetricsRelistInterval)
+	cmProvider, runner := cmprov.NewPrometheusProvider(mapper, dynClient, promClient, namers, cmd.MetricsRelistInterval, cmd.MetricsStartDuration)
 	runner.RunUntil(stopCh)
 
 	return cmProvider, nil
@@ -173,6 +177,7 @@ func main() {
 	cmd := &PrometheusAdapter{
 		PrometheusURL:         "https://localhost",
 		MetricsRelistInterval: 10 * time.Minute,
+		MetricsStartDuration: 10 * time.Minute,
 	}
 	cmd.Name = "prometheus-metrics-adapter"
 	cmd.addFlags()

pkg/custom-provider/provider.go

@@ -55,9 +55,10 @@ type prometheusProvider struct {
 	SeriesRegistry
 }
 
-func NewPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []MetricNamer, updateInterval time.Duration) (provider.CustomMetricsProvider, Runnable) {
+func NewPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []MetricNamer, updateInterval time.Duration, startDuration time.Duration) (provider.CustomMetricsProvider, Runnable) {
 	lister := &cachingMetricsLister{
 		updateInterval: updateInterval,
+		startDuration:  startDuration,
 		promClient:     promClient,
 		namers:         namers,
 
@@ -191,6 +192,7 @@ type cachingMetricsLister struct {
 
 	promClient     prom.Client
 	updateInterval time.Duration
+	startDuration  time.Duration
 	namers         []MetricNamer
 }
 
@@ -212,7 +214,7 @@ type selectorSeries struct {
 }
 
 func (l *cachingMetricsLister) updateMetrics() error {
-	startTime := pmodel.Now().Add(-1 * l.updateInterval)
+	startTime := pmodel.Now().Add(-1 * l.startDuration)
 
 	// don't do duplicate queries when it's just the matchers that change
 	seriesCacheByQuery := make(map[prom.Selector][]prom.Series)