Add cache for load balancer

pkg/cloudprovider/providers/azure/azure.go

@@ -136,6 +136,7 @@ type Cloud struct {
 	VirtualMachineScaleSetVMsClient VirtualMachineScaleSetVMsClient
 
 	vmCache *timedCache
+	lbCache *timedCache
 
 	*BlobDiskController
 	*ManagedDiskController
@@ -252,6 +253,12 @@ func NewCloud(configReader io.Reader) (cloudprovider.Interface, error) {
 	}
 	az.vmCache = vmCache
 
+	lbCache, err := az.newLBCache()
+	if err != nil {
+		return nil, err
+	}
+	az.lbCache = lbCache
+
 	if err := initDiskControllers(&az); err != nil {
 		return nil, err
 	}

pkg/cloudprovider/providers/azure/azure_backoff.go

@@ -142,7 +142,12 @@ func (az *Cloud) CreateOrUpdateLBWithRetry(lb network.LoadBalancer) error {
 		resp := <-respChan
 		err := <-errChan
 		glog.V(10).Infof("LoadBalancerClient.CreateOrUpdate(%s): end", *lb.Name)
-		return processRetryResponse(resp.Response, err)
+		done, err := processRetryResponse(resp.Response, err)
+		if done && err == nil {
+			// Invalidate the cache right after updating
+			az.lbCache.Delete(*lb.Name)
+		}
+		return done, err
 	})
 }
 
@@ -283,7 +288,12 @@ func (az *Cloud) DeleteLBWithRetry(lbName string) error {
 		respChan, errChan := az.LoadBalancerClient.Delete(az.ResourceGroup, lbName, nil)
 		resp := <-respChan
 		err := <-errChan
-		return processRetryResponse(resp, err)
+		done, err := processRetryResponse(resp, err)
+		if done && err == nil {
+			// Invalidate the cache right after deleting
+			az.lbCache.Delete(lbName)
+		}
+		return done, err
 	})
 }
 

pkg/cloudprovider/providers/azure/azure_test.go

@@ -879,6 +879,7 @@ func getTestCloud() (az *Cloud) {
 	az.VirtualMachinesClient = newFakeAzureVirtualMachinesClient()
 	az.vmSet = newAvailabilitySet(az)
 	az.vmCache, _ = az.newVMCache()
+	az.lbCache, _ = az.newLBCache()
 
 	return az
 }

pkg/cloudprovider/providers/azure/azure_wrap.go

@@ -30,6 +30,7 @@ import (
 
 var (
 	vmCacheTTL = time.Minute
+	lbCacheTTL = 2 * time.Minute
 )
 
 // checkExistsFromError inspects an error and returns a true if err is nil,
@@ -139,19 +140,16 @@ func (az *Cloud) getSubnet(virtualNetworkName string, subnetName string) (subnet
 }
 
 func (az *Cloud) getAzureLoadBalancer(name string) (lb network.LoadBalancer, exists bool, err error) {
-	var realErr error
-
-	lb, err = az.LoadBalancerClient.Get(az.ResourceGroup, name, "")
-	exists, realErr = checkResourceExistsFromError(err)
-	if realErr != nil {
-		return lb, false, realErr
+	cachedLB, err := az.lbCache.Get(name)
+	if err != nil {
+		return lb, false, err
 	}
 
-	if !exists {
+	if cachedLB == nil {
 		return lb, false, nil
 	}
 
-	return lb, exists, err
+	return *(cachedLB.(*network.LoadBalancer)), true, nil
 }
 
 func (az *Cloud) newVMCache() (*timedCache, error) {
@@ -171,3 +169,21 @@ func (az *Cloud) newVMCache() (*timedCache, error) {
 
 	return newTimedcache(vmCacheTTL, getter)
 }
+
+func (az *Cloud) newLBCache() (*timedCache, error) {
+	getter := func(key string) (interface{}, error) {
+		lb, err := az.LoadBalancerClient.Get(az.ResourceGroup, key, "")
+		exists, realErr := checkResourceExistsFromError(err)
+		if realErr != nil {
+			return nil, realErr
+		}
+
+		if !exists {
+			return nil, nil
+		}
+
+		return &lb, nil
+	}
+
+	return newTimedcache(lbCacheTTL, getter)
+}