Add support for traffic weight specification

Signed-off-by: Lucas Thiesen <lucas.thiesen@zalando.de>

pkg/collector/hostname_collector.go

@@ -3,6 +3,7 @@ package collector
 import (
 	"fmt"
 	"regexp"
+	"strconv"
 	"strings"
 	"time"
 
@@ -11,7 +12,7 @@ import (
 
 const (
 	HostnameMetricType = "hostname-rps"
-	HostnameRPSQuery   = `scalar(sum(rate(%s{host=~"%s"}[1m])))`
+	HostnameRPSQuery   = `scalar(sum(rate(%s{host=~"%s"}[1m])) * %.4f)`
 )
 
 type HostnameCollectorPlugin struct {
@@ -51,19 +52,37 @@ func (p *HostnameCollectorPlugin) NewCollector(
 	// RPS data from a specific hostname from prometheus. The idea
 	// of the copy is to not modify the original config struct.
 	confCopy := *config
-	hostnames := config.Config["hostname"]
+	//hostnames := config.Config["hostnames"]
+	//weights := config.Config["weights"]
 
-	if ok, err := regexp.MatchString("^[a-zA-Z0-9.,-]+$", hostnames); !ok || err != nil {
+	if _, ok := config.Config["hostnames"]; !ok {
-		return nil, fmt.Errorf(
+		return nil, fmt.Errorf("hostname is not specified, unable to create collector")
-			"hostname is not specified or invalid format, unable to create collector",
+	}
-		)
+	hostnames := strings.Split(config.Config["hostnames"], ",")
+	for _, h := range hostnames {
+		if ok, err := regexp.MatchString("^[a-zA-Z0-9.-]+$", h); !ok || err != nil {
+			return nil, fmt.Errorf(
+				"Invalid hostname format, unable to create collector: %s",
+				h,
+			)
+		}
+	}
+
+	weight := 1.0
+	if w, ok := config.Config["weight"]; ok {
+		num, err := strconv.ParseFloat(w, 64)
+		if err != nil {
+			return nil, fmt.Errorf("Could not parse weight annotation, unable to create collector: %s", w)
+		}
+		weight = num / 100.0
 	}
 
 	confCopy.Config = map[string]string{
 		"query": fmt.Sprintf(
 			HostnameRPSQuery,
 			p.metricName,
-			strings.Replace(strings.Replace(hostnames, ",", "|", -1), ".", "_", -1),
+			strings.Replace(strings.Join(hostnames, "|"), ".", "_", -1),
+			weight,
 		),
 	}
 

pkg/collector/hostname_collector_test.go

@@ -68,22 +68,28 @@ func TestHostnamePluginNewCollector(tt *testing.T) {
 		},
 		{
 			"Valid hostname no prom query config",
-			&MetricConfig{Config: map[string]string{"hostname": "foo.bar.baz"}},
+			&MetricConfig{Config: map[string]string{"hostnames": "foo.bar.baz"}},
-			`scalar(sum(rate(a_valid_one{host=~"foo_bar_baz"}[1m])))`,
+			`scalar(sum(rate(a_valid_one{host=~"foo_bar_baz"}[1m])) * 1.0000)`,
+			true,
+		},
+		{
+			"Valid hostname no prom query config",
+			&MetricConfig{Config: map[string]string{"hostnames": "foo.bar.baz", "weight": "42"}},
+			`scalar(sum(rate(a_valid_one{host=~"foo_bar_baz"}[1m])) * 0.4200)`,
 			true,
 		},
 		{
 			"Multiple valid hostnames no prom query config",
-			&MetricConfig{Config: map[string]string{"hostname": "foo.bar.baz,foz.bax.bas"}},
+			&MetricConfig{Config: map[string]string{"hostnames": "foo.bar.baz,foz.bax.bas"}},
-			`scalar(sum(rate(a_valid_one{host=~"foo_bar_baz|foz_bax_bas"}[1m])))`,
+			`scalar(sum(rate(a_valid_one{host=~"foo_bar_baz|foz_bax_bas"}[1m])) * 1.0000)`,
 			true,
 		},
 		{
 			"Valid hostname with prom query config",
 			&MetricConfig{
-				Config: map[string]string{"hostname": "foo.bar.baz", "query": "some_other_query"},
+				Config: map[string]string{"hostnames": "foo.bar.baz", "query": "some_other_query"},
 			},
-			`scalar(sum(rate(a_valid_one{host=~"foo_bar_baz"}[1m])))`,
+			`scalar(sum(rate(a_valid_one{host=~"foo_bar_baz"}[1m])) * 1.0000)`,
 			true,
 		},
 	} {
@@ -169,7 +175,7 @@ func TestHostnameCollectorInterval(t *testing.T) {
 	}
 	c, err := plugin.NewCollector(
 		&autoscalingv2.HorizontalPodAutoscaler{},
-		&MetricConfig{Config: map[string]string{"hostname": "foo.bar.baz"}},
+		&MetricConfig{Config: map[string]string{"hostnames": "foo.bar.baz"}},
 		interval,
 	)
 
@@ -179,11 +185,12 @@ func TestHostnameCollectorInterval(t *testing.T) {
 }
 
 func TestHostnameCollectorAndCollectorFabricInteraction(t *testing.T) {
-	expectedQuery := `scalar(sum(rate(a_metric{host=~"just_testing_com"}[1m])))`
+	expectedQuery := `scalar(sum(rate(a_metric{host=~"just_testing_com"}[1m])) * 0.4200)`
 	hpa := &autoscalingv2.HorizontalPodAutoscaler{
 		ObjectMeta: metav1.ObjectMeta{
 			Annotations: map[string]string{
-				"metric-config.external.foo.hostname-rps/hostname": "just.testing.com",
+				"metric-config.external.foo.hostname-rps/hostnames": "just.testing.com",
+				"metric-config.external.foo.hostname-rps/weight":    "42",
 			},
 		},
 		Spec: autoscalingv2.HorizontalPodAutoscalerSpec{
@@ -222,13 +229,14 @@ func TestHostnameCollectorAndCollectorFabricInteraction(t *testing.T) {
 }
 
 func TestHostnamePrometheusCollectorInteraction(t *testing.T) {
-	hostnameQuery := `scalar(sum(rate(a_metric{host=~"just_testing_com"}[1m])))`
+	hostnameQuery := `scalar(sum(rate(a_metric{host=~"just_testing_com"}[1m])) * 0.4200)`
 	promQuery := "sum(rate(rps[1m]))"
 	hpa := &autoscalingv2.HorizontalPodAutoscaler{
 		ObjectMeta: metav1.ObjectMeta{
 			Annotations: map[string]string{
-				"metric-config.external.foo.hostname-rps/hostname": "just.testing.com",
+				"metric-config.external.foo.hostname-rps/hostnames": "just.testing.com",
-				"metric-config.external.bar.prometheus/query":      promQuery,
+				"metric-config.external.foo.hostname-rps/weight":    "42",
+				"metric-config.external.bar.prometheus/query":       promQuery,
 			},
 		},
 		Spec: autoscalingv2.HorizontalPodAutoscalerSpec{