feat: Parse metrics port from env (#171)

* feat: Parse metrics port from env

* gofmt

runtime-watcher/internal/serverconfig/config.go

@@ -10,18 +10,21 @@ import (
 )
 
 const (
-	minPort, maxPort = 1, 65535
-	defaultPort      = 8443
-	envWebhookPort   = "WEBHOOK_PORT"
-	envCACert        = "CA_CERT"
-	envTLSCert       = "TLS_CERT"
-	envTLSKey        = "TLS_KEY"
-	envKCPAddress    = "KCP_ADDR"
-	envKCPContract   = "KCP_CONTRACT"
+	minPort, maxPort   = 1, 65535
+	defaultWebhookPort = 8443
+	defaultMetricsPort = 2112
+	envWebhookPort     = "WEBHOOK_PORT"
+	envMetricsPort     = "METRICS_PORT"
+	envCACert          = "CA_CERT"
+	envTLSCert         = "TLS_CERT"
+	envTLSKey          = "TLS_KEY"
+	envKCPAddress      = "KCP_ADDR"
+	envKCPContract     = "KCP_CONTRACT"
 )
 
 type ServerConfig struct {
 	Port        int
+	MetricsPort int
 	CACertPath  string
 	TLSCertPath string
 	TLSKeyPath  string
@@ -34,7 +37,7 @@ func ParseFromEnv(logger logr.Logger) (ServerConfig, error) {
 
 	config := ServerConfig{}
 
-	config.Port = defaultPort
+	config.Port = defaultWebhookPort
 	webhookPort, found := os.LookupEnv(envWebhookPort)
 	if found {
 		port, err := strconv.Atoi(webhookPort)
@@ -48,6 +51,20 @@ func ParseFromEnv(logger logr.Logger) (ServerConfig, error) {
 		}
 	}
 
+	config.MetricsPort = defaultMetricsPort
+	metricsPort, found := os.LookupEnv(envMetricsPort)
+	if found {
+		port, err := strconv.Atoi(metricsPort)
+		if err != nil {
+			logger.Error(err, flagError(envMetricsPort).Error())
+		}
+		if err = validatePortRange(port); err != nil {
+			logger.Error(err, flagError(envMetricsPort).Error())
+		} else {
+			config.MetricsPort = port
+		}
+	}
+
 	config.CACertPath = os.Getenv(envCACert)
 	if config.CACertPath == "" {
 		return config, flagError(envCACert)

runtime-watcher/main.go

@@ -23,6 +23,7 @@ import (
 	"os"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
 
@@ -59,16 +60,6 @@ func main() {
 
 	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))
 
-	http.Handle("/metrics", promhttp.Handler())
-	metricsServer := &http.Server{
-		Addr:              ":2112",
-		ReadHeaderTimeout: internal.HTTPTimeout,
-	}
-	err := metricsServer.ListenAndServe()
-	if err != nil {
-		logger.Error(err, "failed to wire up metrics endpoint")
-	}
-
 	logger.Info("starting the Runtime Watcher", "Version:", buildVersion)
 
 	config, err := serverconfig.ParseFromEnv(logger)
@@ -77,6 +68,16 @@ func main() {
 		return
 	}
 
+	http.Handle("/metrics", promhttp.Handler())
+	metricsServer := &http.Server{
+		Addr:              fmt.Sprintf(":%d", config.MetricsPort),
+		ReadHeaderTimeout: internal.HTTPTimeout,
+	}
+	err = metricsServer.ListenAndServe()
+	if err != nil {
+		logger.Error(err, "failed to wire up metrics endpoint")
+	}
+
 	restConfig := ctrl.GetConfigOrDie()
 	restClient, err := client.New(restConfig, client.Options{})
 	if err != nil {