From c0ba41ce331de250a0d3b16b48d604d39e8e05ba Mon Sep 17 00:00:00 2001
From: Vivek Singh <vivekkmr45@yahoo.in>
Date: Sun, 22 Mar 2020 23:23:50 +0530
Subject: [PATCH] Use default namespace in metrics exporter

Signed-off-by: Vivek Singh <vivekkmr45@yahoo.in>
---
 gateway/handlers/notifiers.go    |  2 +-
 gateway/main.go                  |  2 +-
 gateway/metrics/exporter.go      | 22 ++++++++++++----------
 gateway/metrics/exporter_test.go |  4 ++--
 4 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/gateway/handlers/notifiers.go b/gateway/handlers/notifiers.go
index f7a2c956..10fa2349 100644
--- a/gateway/handlers/notifiers.go
+++ b/gateway/handlers/notifiers.go
@@ -51,7 +51,7 @@ type PrometheusFunctionNotifier struct {
 func (p PrometheusFunctionNotifier) Notify(method string, URL string, originalURL string, statusCode int, event string, duration time.Duration) {
 	serviceName := getServiceName(originalURL)
 	if len(p.FunctionNamespace) > 0 {
-		if index := strings.Index(serviceName, "."); index == -1 {
+		if !strings.Contains(serviceName, ".") {
 			serviceName = fmt.Sprintf("%s.%s", serviceName, p.FunctionNamespace)
 		}
 	}
diff --git a/gateway/main.go b/gateway/main.go
index 5f971684..19477285 100644
--- a/gateway/main.go
+++ b/gateway/main.go
@@ -65,7 +65,7 @@ func main() {
 	fmt.Println(metadataQuery)
 
 	metricsOptions := metrics.BuildMetricsOptions()
-	exporter := metrics.NewExporter(metricsOptions, credentials)
+	exporter := metrics.NewExporter(metricsOptions, credentials, config.Namespace)
 	exporter.StartServiceWatcher(*config.FunctionsProviderURL, metricsOptions, "func", servicePollInterval)
 	metrics.RegisterExporter(exporter)
 
diff --git a/gateway/metrics/exporter.go b/gateway/metrics/exporter.go
index e16c4392..c3e5c0a3 100644
--- a/gateway/metrics/exporter.go
+++ b/gateway/metrics/exporter.go
@@ -23,17 +23,19 @@ import (
 
 // Exporter is a prometheus exporter
 type Exporter struct {
-	metricOptions MetricOptions
-	services      []types.FunctionStatus
-	credentials   *auth.BasicAuthCredentials
+	metricOptions     MetricOptions
+	services          []types.FunctionStatus
+	credentials       *auth.BasicAuthCredentials
+	FunctionNamespace string
 }
 
 // NewExporter creates a new exporter for the OpenFaaS gateway metrics
-func NewExporter(options MetricOptions, credentials *auth.BasicAuthCredentials) *Exporter {
+func NewExporter(options MetricOptions, credentials *auth.BasicAuthCredentials, namespace string) *Exporter {
 	return &Exporter{
-		metricOptions: options,
-		services:      []types.FunctionStatus{},
-		credentials:   credentials,
+		metricOptions:     options,
+		services:          []types.FunctionStatus{},
+		credentials:       credentials,
+		FunctionNamespace: namespace,
 	}
 }
 
@@ -91,8 +93,7 @@ func (e *Exporter) StartServiceWatcher(endpointURL url.URL, metricsOptions Metri
 				}
 
 				if len(namespaces) == 0 {
-					emptyNamespace := ""
-					services, err := e.getFunctions(endpointURL, emptyNamespace)
+					services, err := e.getFunctions(endpointURL, e.FunctionNamespace)
 					if err != nil {
 						log.Println(err)
 						continue
@@ -170,8 +171,9 @@ func (e *Exporter) getFunctions(endpointURL url.URL, namespace string) ([]types.
 
 func (e *Exporter) getNamespaces(endpointURL url.URL) ([]string, error) {
 	namespaces := []string{}
+	endpointURL.Path = path.Join(endpointURL.Path, "system/namespaces")
 
-	get, _ := http.NewRequest(http.MethodGet, endpointURL.String()+"system/namespaces", nil)
+	get, _ := http.NewRequest(http.MethodGet, endpointURL.String(), nil)
 	if e.credentials != nil {
 		get.SetBasicAuth(e.credentials.User, e.credentials.Password)
 	}
diff --git a/gateway/metrics/exporter_test.go b/gateway/metrics/exporter_test.go
index 93cd0390..069b5b8a 100644
--- a/gateway/metrics/exporter_test.go
+++ b/gateway/metrics/exporter_test.go
@@ -33,7 +33,7 @@ func readGauge(g prometheus.Metric) metricResult {
 
 func Test_Describe_DescribesThePrometheusMetrics(t *testing.T) {
 	metricsOptions := BuildMetricsOptions()
-	exporter := NewExporter(metricsOptions, nil)
+	exporter := NewExporter(metricsOptions, nil, "openfaas-fn")
 
 	ch := make(chan *prometheus.Desc)
 	// defer close(ch)
@@ -65,7 +65,7 @@ func Test_Describe_DescribesThePrometheusMetrics(t *testing.T) {
 
 func Test_Collect_CollectsTheNumberOfReplicasOfAService(t *testing.T) {
 	metricsOptions := BuildMetricsOptions()
-	exporter := NewExporter(metricsOptions, nil)
+	exporter := NewExporter(metricsOptions, nil, "openfaas-fn")
 
 	expectedService := types.FunctionStatus{
 		Name:     "function_with_two_replica",