From 190a72392ae712fbbee979e95a6017ccb578877d Mon Sep 17 00:00:00 2001
From: Joe Betz <jpbetz@google.com>
Date: Thu, 20 Feb 2020 13:40:23 -0800
Subject: [PATCH] Refresh discovery server resources for memCacheClient in
 parallel

---
 .../discovery/cached/memory/memcache.go       | 23 ++++++--
 .../discovery/cached/memory/memcache_test.go  | 52 ++++++++++++-------
 2 files changed, 50 insertions(+), 25 deletions(-)

diff --git a/staging/src/k8s.io/client-go/discovery/cached/memory/memcache.go b/staging/src/k8s.io/client-go/discovery/cached/memory/memcache.go
index 31e42156610..82a7cc470f3 100644
--- a/staging/src/k8s.io/client-go/discovery/cached/memory/memcache.go
+++ b/staging/src/k8s.io/client-go/discovery/cached/memory/memcache.go
@@ -190,16 +190,29 @@ func (d *memCacheClient) refreshLocked() error {
 		return err
 	}
 
+	wg := &sync.WaitGroup{}
+	resultLock := &sync.Mutex{}
 	rl := map[string]*cacheEntry{}
 	for _, g := range gl.Groups {
 		for _, v := range g.Versions {
-			r, err := d.serverResourcesForGroupVersion(v.GroupVersion)
-			rl[v.GroupVersion] = &cacheEntry{r, err}
-			if err != nil {
-				utilruntime.HandleError(fmt.Errorf("couldn't get resource list for %v: %v", v.GroupVersion, err))
-			}
+			gv := v.GroupVersion
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				defer utilruntime.HandleCrash()
+
+				r, err := d.serverResourcesForGroupVersion(gv)
+				if err != nil {
+					utilruntime.HandleError(fmt.Errorf("couldn't get resource list for %v: %v", gv, err))
+				}
+
+				resultLock.Lock()
+				defer resultLock.Unlock()
+				rl[gv] = &cacheEntry{r, err}
+			}()
 		}
 	}
+	wg.Wait()
 
 	d.groupToServerResources, d.groupList = rl, gl
 	d.cacheValid = true
diff --git a/staging/src/k8s.io/client-go/discovery/cached/memory/memcache_test.go b/staging/src/k8s.io/client-go/discovery/cached/memory/memcache_test.go
index 3a9d60da9bc..f8c2900cbb0 100644
--- a/staging/src/k8s.io/client-go/discovery/cached/memory/memcache_test.go
+++ b/staging/src/k8s.io/client-go/discovery/cached/memory/memcache_test.go
@@ -205,16 +205,22 @@ func TestServerGroupsFails(t *testing.T) {
 func TestPartialPermanentFailure(t *testing.T) {
 	fake := &fakeDiscovery{
 		groupList: &metav1.APIGroupList{
-			Groups: []metav1.APIGroup{{
-				Name: "astronomy",
-				Versions: []metav1.GroupVersionForDiscovery{{
-					GroupVersion: "astronomy/v8beta1",
-					Version:      "v8beta1",
-				}, {
-					GroupVersion: "astronomy2/v8beta1",
-					Version:      "v8beta1",
-				}},
-			}},
+			Groups: []metav1.APIGroup{
+				{
+					Name: "astronomy",
+					Versions: []metav1.GroupVersionForDiscovery{{
+						GroupVersion: "astronomy/v8beta1",
+						Version:      "v8beta1",
+					}},
+				},
+				{
+					Name: "astronomy2",
+					Versions: []metav1.GroupVersionForDiscovery{{
+						GroupVersion: "astronomy2/v8beta1",
+						Version:      "v8beta1",
+					}},
+				},
+			},
 		},
 		resourceMap: map[string]*resourceMapEntry{
 			"astronomy/v8beta1": {
@@ -286,16 +292,22 @@ func TestPartialPermanentFailure(t *testing.T) {
 func TestPartialRetryableFailure(t *testing.T) {
 	fake := &fakeDiscovery{
 		groupList: &metav1.APIGroupList{
-			Groups: []metav1.APIGroup{{
-				Name: "astronomy",
-				Versions: []metav1.GroupVersionForDiscovery{{
-					GroupVersion: "astronomy/v8beta1",
-					Version:      "v8beta1",
-				}, {
-					GroupVersion: "astronomy2/v8beta1",
-					Version:      "v8beta1",
-				}},
-			}},
+			Groups: []metav1.APIGroup{
+				{
+					Name: "astronomy",
+					Versions: []metav1.GroupVersionForDiscovery{{
+						GroupVersion: "astronomy/v8beta1",
+						Version:      "v8beta1",
+					}},
+				},
+				{
+					Name: "astronomy2",
+					Versions: []metav1.GroupVersionForDiscovery{{
+						GroupVersion: "astronomy2/v8beta1",
+						Version:      "v8beta1",
+					}},
+				},
+			},
 		},
 		resourceMap: map[string]*resourceMapEntry{
 			"astronomy/v8beta1": {