Add is elected leader check for readiness (#54)

* Add is elected leader check for readiness

* leader election release oncancel set to true

* fix lint

operator/cmd/main.go

@@ -20,6 +20,7 @@ import (
 	"crypto/tls"
 	"flag"
 	"fmt"
+	"net/http"
 	"os"
 	"time"
 
@@ -159,7 +160,7 @@ func mainWithError() error {
 		// the manager stops, so would be fine to enable this option. However,
 		// if you are doing or is intended to do any operation such as perform cleanups
 		// after the manager stops then its usage might be unsafe.
-		// LeaderElectionReleaseOnCancel: true,
+		LeaderElectionReleaseOnCancel: true,
 	})
 	if err != nil {
 		setupLog.Error(err, "unable to start manager")
@@ -209,7 +210,7 @@ func mainWithError() error {
 		sentry.CaptureException(err)
 		return fmt.Errorf("main: %w", err)
 	}
-	if err := mgr.AddReadyzCheck("readyz", healthz.Ping); err != nil {
+	if err := mgr.AddReadyzCheck("readyz", leaderReadinessCheck(mgr)); err != nil {
 		setupLog.Error(err, "unable to set up ready check")
 		sentry.CaptureException(err)
 		return fmt.Errorf("main: %w", err)
@@ -224,3 +225,14 @@ func mainWithError() error {
 
 	return nil
 }
+
+func leaderReadinessCheck(mgr ctrl.Manager) healthz.Checker {
+	return func(req *http.Request) error {
+		select {
+		case <-mgr.Elected():
+			return nil
+		default:
+			return fmt.Errorf("controller is not the leader yet")
+		}
+	}
+}