From daec2bd7455ddd427616e4d7e4a2459a67f0f3a3 Mon Sep 17 00:00:00 2001
From: Pengfei Ni <peni@microsoft.com>
Date: Wed, 7 Feb 2018 22:26:03 +0800
Subject: [PATCH] Add cache for route tables

---
 pkg/cloudprovider/providers/azure/azure.go    |  7 ++++
 .../providers/azure/azure_routes.go           |  7 ++--
 .../providers/azure/azure_routes_test.go      |  1 +
 .../providers/azure/azure_test.go             |  1 +
 .../providers/azure/azure_wrap.go             | 32 ++++++++++++++-----
 5 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/pkg/cloudprovider/providers/azure/azure.go b/pkg/cloudprovider/providers/azure/azure.go
index 1fd3eed2fc0..d26ea04080b 100644
--- a/pkg/cloudprovider/providers/azure/azure.go
+++ b/pkg/cloudprovider/providers/azure/azure.go
@@ -138,6 +138,7 @@ type Cloud struct {
 	vmCache  *timedCache
 	lbCache  *timedCache
 	nsgCache *timedCache
+	rtCache  *timedCache
 
 	*BlobDiskController
 	*ManagedDiskController
@@ -266,6 +267,12 @@ func NewCloud(configReader io.Reader) (cloudprovider.Interface, error) {
 	}
 	az.nsgCache = nsgCache
 
+	rtCache, err := az.newRouteTableCache()
+	if err != nil {
+		return nil, err
+	}
+	az.rtCache = rtCache
+
 	if err := initDiskControllers(&az); err != nil {
 		return nil, err
 	}
diff --git a/pkg/cloudprovider/providers/azure/azure_routes.go b/pkg/cloudprovider/providers/azure/azure_routes.go
index e08ca912581..c78de23d730 100644
--- a/pkg/cloudprovider/providers/azure/azure_routes.go
+++ b/pkg/cloudprovider/providers/azure/azure_routes.go
@@ -98,10 +98,9 @@ func (az *Cloud) createRouteTable() error {
 		return err
 	}
 
-	glog.V(10).Infof("RouteTablesClient.Get(%q): start", az.RouteTableName)
-	_, err = az.RouteTablesClient.Get(az.ResourceGroup, az.RouteTableName, "")
-	glog.V(10).Infof("RouteTablesClient.Get(%q): end", az.RouteTableName)
-	return err
+	// Invalidate the cache right after updating
+	az.rtCache.Delete(az.RouteTableName)
+	return nil
 }
 
 // CreateRoute creates the described managed route
diff --git a/pkg/cloudprovider/providers/azure/azure_routes_test.go b/pkg/cloudprovider/providers/azure/azure_routes_test.go
index 02041f0fa22..31f31ee4eb4 100644
--- a/pkg/cloudprovider/providers/azure/azure_routes_test.go
+++ b/pkg/cloudprovider/providers/azure/azure_routes_test.go
@@ -37,6 +37,7 @@ func TestCreateRoute(t *testing.T) {
 			Location:       "location",
 		},
 	}
+	cloud.rtCache, _ = cloud.newRouteTableCache()
 	expectedTable := network.RouteTable{
 		Name:     &cloud.RouteTableName,
 		Location: &cloud.Location,
diff --git a/pkg/cloudprovider/providers/azure/azure_test.go b/pkg/cloudprovider/providers/azure/azure_test.go
index 8226815efa2..e638e4522d4 100644
--- a/pkg/cloudprovider/providers/azure/azure_test.go
+++ b/pkg/cloudprovider/providers/azure/azure_test.go
@@ -881,6 +881,7 @@ func getTestCloud() (az *Cloud) {
 	az.vmCache, _ = az.newVMCache()
 	az.lbCache, _ = az.newLBCache()
 	az.nsgCache, _ = az.newNSGCache()
+	az.rtCache, _ = az.newRouteTableCache()
 
 	return az
 }
diff --git a/pkg/cloudprovider/providers/azure/azure_wrap.go b/pkg/cloudprovider/providers/azure/azure_wrap.go
index 792946cc907..d2bb36fe81a 100644
--- a/pkg/cloudprovider/providers/azure/azure_wrap.go
+++ b/pkg/cloudprovider/providers/azure/azure_wrap.go
@@ -33,6 +33,7 @@ var (
 	vmCacheTTL  = time.Minute
 	lbCacheTTL  = 2 * time.Minute
 	nsgCacheTTL = 2 * time.Minute
+	rtCacheTTL  = 2 * time.Minute
 )
 
 // checkExistsFromError inspects an error and returns a true if err is nil,
@@ -83,19 +84,16 @@ func (az *Cloud) getVirtualMachine(nodeName types.NodeName) (vm compute.VirtualM
 }
 
 func (az *Cloud) getRouteTable() (routeTable network.RouteTable, exists bool, err error) {
-	var realErr error
-
-	routeTable, err = az.RouteTablesClient.Get(az.ResourceGroup, az.RouteTableName, "")
-	exists, realErr = checkResourceExistsFromError(err)
-	if realErr != nil {
-		return routeTable, false, realErr
+	cachedRt, err := az.rtCache.Get(az.RouteTableName)
+	if err != nil {
+		return routeTable, false, err
 	}
 
-	if !exists {
+	if cachedRt == nil {
 		return routeTable, false, nil
 	}
 
-	return routeTable, exists, err
+	return *(cachedRt.(*network.RouteTable)), true, nil
 }
 
 func (az *Cloud) getPublicIPAddress(pipResourceGroup string, pipName string) (pip network.PublicIPAddress, exists bool, err error) {
@@ -220,3 +218,21 @@ func (az *Cloud) newNSGCache() (*timedCache, error) {
 
 	return newTimedcache(nsgCacheTTL, getter)
 }
+
+func (az *Cloud) newRouteTableCache() (*timedCache, error) {
+	getter := func(key string) (interface{}, error) {
+		rt, err := az.RouteTablesClient.Get(az.ResourceGroup, key, "")
+		exists, realErr := checkResourceExistsFromError(err)
+		if realErr != nil {
+			return nil, realErr
+		}
+
+		if !exists {
+			return nil, nil
+		}
+
+		return &rt, nil
+	}
+
+	return newTimedcache(rtCacheTTL, getter)
+}