InfluxDB configuration string template builder helper

Signed-off-by: Lorenzo Fontana <lo@linux.com>

internal/ingress/controller/template/template.go

@@ -38,6 +38,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/ingress-nginx/internal/file"
 	"k8s.io/ingress-nginx/internal/ingress"
+	"k8s.io/ingress-nginx/internal/ingress/annotations/influxdb"
 	"k8s.io/ingress-nginx/internal/ingress/annotations/ratelimit"
 	"k8s.io/ingress-nginx/internal/ingress/controller/config"
 	ing_net "k8s.io/ingress-nginx/internal/net"
@@ -153,6 +154,7 @@ var (
 		"buildOpentracingLoad":        buildOpentracingLoad,
 		"buildOpentracing":            buildOpentracing,
 		"proxySetHeader":              proxySetHeader,
+		"buildInfluxDB":               buildInfluxDB,
 	}
 )
 
@@ -897,6 +899,29 @@ func buildOpentracing(input interface{}) string {
 	return buf.String()
 }
 
+// buildInfluxDB produces the single line configuration
+// needed by the InfluxDB module to send request's metrics
+// for the current resource
+func buildInfluxDB(input interface{}) string {
+	cfg, ok := input.(influxdb.Config)
+	if !ok {
+		glog.Errorf("expected an 'influxdb.Config' type but %T was returned", input)
+		return ""
+	}
+
+	if !cfg.InfluxDBEnabled {
+		return ""
+	}
+
+	return fmt.Sprintf(
+		"influxdb server_name=%s host=%s port=%s measurement=%s enabled=true;",
+		cfg.InfluxDBServerName,
+		cfg.InfluxDBHost,
+		cfg.InfluxDBPort,
+		cfg.InfluxDBMeasurement,
+	)
+}
+
 func proxySetHeader(loc interface{}) string {
 	location, ok := loc.(*ingress.Location)
 	if !ok {

rootfs/etc/nginx/template/nginx.tmpl

@@ -980,9 +980,7 @@ stream {
             {{ template "CORS" $location }}
             {{ end }}
 
-            {{ if $location.InfluxDB.InfluxDBEnabled }}
-            influxdb server_name=$location.InfluxDB.InfluxDBServerName host=$location.InfluxDB.InfluxDBHost port=$location.InfluxDB.InfluxDBPort measurement=$location.InfluxDB.InfluxDBMeasurement enabled=true;
-            {{ end }}
+            {{ buildInfluxDB $location.InfluxDB }}
 
             {{ if not (empty $location.Redirect.URL) }}
             if ($uri ~* {{ $path }}) {