Moves string slice sorting, copying and shuffling into pkg/util/slice

pkg/proxy/roundrobin.go

@@ -18,15 +18,14 @@ package proxy
 
 import (
 	"errors"
-	"math/rand"
 	"net"
 	"reflect"
-	"sort"
 	"strconv"
 	"sync"
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/slice"
 	"github.com/golang/glog"
 )
 
@@ -172,30 +171,6 @@ func filterValidEndpoints(endpoints []string) []string {
 	return result
 }
 
-func endpointsAreEqual(left, right []string) bool {
-	if len(left) != len(right) {
-		return false
-	}
-
-	leftSorted := make([]string, len(left))
-	copy(leftSorted, left)
-	sort.Strings(leftSorted)
-	rightSorted := make([]string, len(right))
-	copy(rightSorted, right)
-	sort.Strings(rightSorted)
-
-	return reflect.DeepEqual(leftSorted, rightSorted)
-}
-
-func shuffleEndpoints(endpoints []string) []string {
-	shuffled := make([]string, len(endpoints))
-	perm := rand.Perm(len(endpoints))
-	for i, v := range perm {
-		shuffled[v] = endpoints[i]
-	}
-	return shuffled
-}
-
 //remove any session affinity records associated to a particular endpoint (for example when a pod goes down).
 func removeSessionAffinityByEndpoint(lb *LoadBalancerRR, service string, endpoint string) {
 	for _, affinityDetail := range lb.serviceDtlMap[service].sessionAffinityMap {
@@ -236,14 +211,14 @@ func (lb *LoadBalancerRR) OnUpdate(endpoints []api.Endpoints) {
 	for _, endpoint := range endpoints {
 		existingEndpoints, exists := lb.endpointsMap[endpoint.Name]
 		validEndpoints := filterValidEndpoints(endpoint.Endpoints)
-		if !exists || !endpointsAreEqual(existingEndpoints, validEndpoints) {
+		if !exists || !reflect.DeepEqual(slice.SortStrings(slice.CopyStrings(existingEndpoints)), slice.SortStrings(validEndpoints)) {
 			glog.V(3).Infof("LoadBalancerRR: Setting endpoints for %s to %+v", endpoint.Name, endpoint.Endpoints)
 			updateServiceDetailMap(lb, endpoint.Name, validEndpoints)
 			// On update can be called without NewService being called externally.
 			// to be safe we will call it here.  A new service will only be created
 			// if one does not already exist.
 			lb.NewService(endpoint.Name, api.AffinityTypeNone, 0)
-			lb.endpointsMap[endpoint.Name] = shuffleEndpoints(validEndpoints)
+			lb.endpointsMap[endpoint.Name] = slice.ShuffleStrings(validEndpoints)
 
 			// Reset the round-robin index.
 			lb.rrIndex[endpoint.Name] = 0

pkg/proxy/roundrobin_test.go

@@ -18,7 +18,6 @@ package proxy
 
 import (
 	"net"
-	"sort"
 	"testing"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
@@ -57,26 +56,6 @@ func TestFilterWorks(t *testing.T) {
 	}
 }
 
-func TestShuffleWorks(t *testing.T) {
-	endpoints := []string{"foobar:1", "foobar:2", "foobar:3"}
-	shuffled := shuffleEndpoints(endpoints)
-
-	if len(shuffled) != 3 {
-		t.Errorf("Failed to shuffle to the correct size")
-	}
-
-	sort.Strings(shuffled)
-	if shuffled[0] != "foobar:1" {
-		t.Errorf("Index zero is not foobar:1")
-	}
-	if shuffled[1] != "foobar:2" {
-		t.Errorf("Index one is not foobar:2")
-	}
-	if shuffled[2] != "foobar:3" {
-		t.Errorf("Index two is not foobar:3")
-	}
-}
-
 func TestLoadBalanceFailsWithNoEndpoints(t *testing.T) {
 	loadBalancer := NewLoadBalancerRR()
 	var endpoints []api.Endpoints

pkg/util/slice/slice.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package slice provides utility methods for common operations on slices.
+package slice
+
+import (
+	"math/rand"
+	"sort"
+)
+
+// CopyStrings copies the contents of the specified string slice
+// into a new slice.
+func CopyStrings(s []string) []string {
+	c := make([]string, len(s))
+	copy(c, s)
+	return c
+}
+
+// SortStrings sorts the specified string slice in place. It returns the same
+// slice that was provided in order to facilitate method chaining.
+func SortStrings(s []string) []string {
+	sort.Strings(s)
+	return s
+}
+
+// ShuffleStrings copies strings from the specified slice into a copy in random
+// order. It returns a new slice.
+func ShuffleStrings(s []string) []string {
+	shuffled := make([]string, len(s))
+	perm := rand.Perm(len(s))
+	for i, j := range perm {
+		shuffled[j] = s[i]
+	}
+	return shuffled
+}

pkg/util/slice/slice_test.go

@@ -0,0 +1,56 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package slice
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestCopyStrings(t *testing.T) {
+	src := []string{"a", "c", "b"}
+	dest := CopyStrings(src)
+
+	if !reflect.DeepEqual(src, dest) {
+		t.Errorf("%v and %v are not equal", src, dest)
+	}
+
+	src[0] = "A"
+	if reflect.DeepEqual(src, dest) {
+		t.Errorf("CopyStrings didn't make a copy")
+	}
+}
+
+func TestSortStrings(t *testing.T) {
+	src := []string{"a", "c", "b"}
+	dest := SortStrings(src)
+	expected := []string{"a", "b", "c"}
+
+	if !reflect.DeepEqual(dest, expected) {
+		t.Errorf("SortString didn't sort the strings")
+	}
+}
+
+func TestSortStringsSortsInPlace(t *testing.T) {
+	src := []string{"a", "c", "b"}
+	_ = SortStrings(src)
+	expected := []string{"a", "b", "c"}
+
+	if !reflect.DeepEqual(src, expected) {
+		t.Errorf("SortString didn't sort in place")
+	}
+}