Added metrics for prometheus alerting capability

Signed-off-by: nicklesimba <[email protected]>

cmd/controlloop/controlloop.go

@@ -3,6 +3,8 @@ package main
 import (
 	"flag"
 	"fmt"
+	"log"
+	"net/http"
 	"os"
 	"os/signal"
 	"time"
@@ -26,6 +28,8 @@ import (
 	"github.com/k8snetworkplumbingwg/whereabouts/pkg/controlloop"
 	"github.com/k8snetworkplumbingwg/whereabouts/pkg/logging"
 	"github.com/k8snetworkplumbingwg/whereabouts/pkg/reconciler"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 const (
@@ -62,6 +66,24 @@ func main() {
 
 	networkController.Start(stopChan)
 
+	reconcilerSuccessTotal := prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "reconciler_success_total",
+		Help: "Increments upon successful run of IP reconciler",
+	})
+
+	reconcilerAttempted := prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "reconciler_attempted",
+		Help: "Increments after each attempt of an IP reconciler run",
+	})
+
+	prometheus.MustRegister(reconcilerSuccessTotal, reconcilerAttempted)
+
+	http.Handle("/metrics", promhttp.Handler())
+
+	go func() {
+		log.Fatal(http.ListenAndServe(":1984", nil))
+	}()
+
 	s := gocron.NewScheduler(time.UTC)
 	s.Cron("0 30 4 1/1 * ? *").Do(func() { // every day at 4:30 UTC (user configurable cron expression)
 		reconciler.InvokeIPReconciler(returnErr)
@@ -74,7 +96,9 @@ func main() {
 			s.Stop()
 			return
 		case err := <-returnErr:
+			reconcilerAttempted.Inc()
 			if err == nil {
+				reconcilerSuccessTotal.Inc()
 				logging.Verbosef("reconciler success")
 			} else {
 				logging.Verbosef("reconciler failure")