Fix resync of the clusters

pkg/controller/postgresql.go

@@ -3,6 +3,8 @@ package controller
 import (
 	"fmt"
 	"reflect"
+	"sync/atomic"
+	"time"
 
 	"k8s.io/client-go/pkg/api"
 	"k8s.io/client-go/pkg/api/meta"
@@ -18,6 +20,19 @@ import (
 	"github.com/zalando-incubator/postgres-operator/pkg/util/constants"
 )
 
+func (c *Controller) clusterResync(stopCh <-chan struct{}) {
+	ticker := time.NewTicker(c.opConfig.ResyncPeriod)
+
+	for {
+		select {
+		case <-ticker.C:
+			c.clusterListFunc(api.ListOptions{ResourceVersion: "0"})
+		case <-stopCh:
+			return
+		}
+	}
+}
+
 func (c *Controller) clusterListFunc(options api.ListOptions) (runtime.Object, error) {
 	c.logger.Info("Getting list of currently running clusters")
 
@@ -37,6 +52,11 @@ func (c *Controller) clusterListFunc(options api.ListOptions) (runtime.Object, e
 		return nil, fmt.Errorf("could not extract list of postgresql objects: %v", err)
 	}
 
+	if time.Now().Unix()-atomic.LoadInt64(&c.lastClusterSyncTime) <= int64(c.opConfig.ResyncPeriod.Seconds()) {
+		c.logger.Debugln("skipping resync of clusters")
+		return object, err
+	}
+
 	var activeClustersCnt, failedClustersCnt int
 	for _, obj := range objList {
 		pg, ok := obj.(*spec.Postgresql)
@@ -63,6 +83,8 @@ func (c *Controller) clusterListFunc(options api.ListOptions) (runtime.Object, e
 		c.logger.Infof("No clusters running")
 	}
 
+	atomic.StoreInt64(&c.lastClusterSyncTime, time.Now().Unix())
+
 	return object, err
 }