Extract Backoff interface

cluster-autoscaler/clusterstate/clusterstate.go

@@ -125,7 +125,7 @@ type ClusterStateRegistry struct {
 	incorrectNodeGroupSizes map[string]IncorrectNodeGroupSize
 	unregisteredNodes       map[string]UnregisteredNode
 	candidatesForScaleDown  map[string][]string
-	nodeGroupBackoffInfo    *backoff.Backoff
+	nodeGroupBackoffInfo    backoff.Backoff
 	lastStatus              *api.ClusterAutoscalerStatus
 	lastScaleDownUpdateTime time.Time
 	logRecorder             *utils.LogEventRecorder
@@ -148,7 +148,7 @@ func NewClusterStateRegistry(cloudProvider cloudprovider.CloudProvider, config C
 		incorrectNodeGroupSizes: make(map[string]IncorrectNodeGroupSize),
 		unregisteredNodes:       make(map[string]UnregisteredNode),
 		candidatesForScaleDown:  make(map[string][]string),
-		nodeGroupBackoffInfo:    backoff.NewBackoff(InitialNodeGroupBackoffDuration, MaxNodeGroupBackoffDuration, NodeGroupBackoffResetTimeout),
+		nodeGroupBackoffInfo:    backoff.NewExponentialBackoff(InitialNodeGroupBackoffDuration, MaxNodeGroupBackoffDuration, NodeGroupBackoffResetTimeout),
 		lastStatus:              emptyStatus,
 		logRecorder:             logRecorder,
 	}

cluster-autoscaler/utils/backoff/backoff.go

@@ -20,64 +20,14 @@ import (
 	"time"
 )
 
-type backoffInfo struct {
-	duration            time.Duration
-	backoffUntil        time.Time
-	lastFailedExecution time.Time
-}
-
-// Backoff handles backing off executions.
-type Backoff struct {
-	maxBackoffDuration     time.Duration
-	initialBackoffDuration time.Duration
-	backoffResetTimeout    time.Duration
-	backoffInfo            map[string]backoffInfo
-}
-
-// NewBackoff creates an instance of  Backoff.
-func NewBackoff(initialBackoffDuration time.Duration, maxBackoffDuration time.Duration, backoffResetTimeout time.Duration) *Backoff {
-	return &Backoff{maxBackoffDuration, initialBackoffDuration, backoffResetTimeout, make(map[string]backoffInfo)}
-}
-
-// RemoveStaleBackoffData removes stale backoff data.
-func (b *Backoff) RemoveStaleBackoffData(currentTime time.Time) {
-	for key, backoffInfo := range b.backoffInfo {
-		if backoffInfo.lastFailedExecution.Add(b.backoffResetTimeout).Before(currentTime) {
-			delete(b.backoffInfo, key)
-		}
-	}
-}
-
-// Backoff execution for the given key. Returns time till execution is backed off.
-func (b *Backoff) Backoff(key string, currentTime time.Time) time.Time {
-	duration := b.initialBackoffDuration
-	if backoffInfo, found := b.backoffInfo[key]; found {
-		// Multiple concurrent scale-ups failing shouldn't cause backoff
-		// duration to increase, so we only increase it if we're not in
-		// backoff right now.
-		if backoffInfo.backoffUntil.Before(currentTime) {
-			duration = 2 * backoffInfo.duration
-			if duration > b.maxBackoffDuration {
-				duration = b.maxBackoffDuration
-			}
-		}
-	}
-	backoffUntil := currentTime.Add(duration)
-	b.backoffInfo[key] = backoffInfo{
-		duration:            duration,
-		backoffUntil:        backoffUntil,
-		lastFailedExecution: currentTime,
-	}
-	return backoffUntil
-}
-
-// RemoveBackoff removes backoff data for the given key.
-func (b *Backoff) RemoveBackoff(key string) {
-	delete(b.backoffInfo, key)
-}
-
-// IsBackedOff returns true if execution is backed off for the given key.
-func (b *Backoff) IsBackedOff(key string, currentTime time.Time) bool {
-	backoffInfo, found := b.backoffInfo[key]
-	return found && backoffInfo.backoffUntil.After(currentTime)
+// Backoff allows time-based backing off of node groups considered in scale up algorithm
+type Backoff interface {
+	// Backoff execution for the given key. Returns time till execution is backed off.
+	Backoff(key string, currentTime time.Time) time.Time
+	// IsBackedOff returns true if execution is backed off for the given key.
+	IsBackedOff(key string, currentTime time.Time) bool
+	// RemoveBackoff removes backoff data for the given key.
+	RemoveBackoff(key string)
+	// RemoveStaleBackoffData removes stale backoff data.
+	RemoveStaleBackoffData(currentTime time.Time)
 }

cluster-autoscaler/utils/backoff/exponential_backoff.go

@@ -0,0 +1,83 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+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 backoff
+
+import (
+	"time"
+)
+
+// Backoff handles backing off executions.
+type exponentialBackoff struct {
+	maxBackoffDuration     time.Duration
+	initialBackoffDuration time.Duration
+	backoffResetTimeout    time.Duration
+	backoffInfo            map[string]exponentialBackoffInfo
+}
+
+type exponentialBackoffInfo struct {
+	duration            time.Duration
+	backoffUntil        time.Time
+	lastFailedExecution time.Time
+}
+
+// NewExponentialBackoff creates an instance of exponential backoff.
+func NewExponentialBackoff(initialBackoffDuration time.Duration, maxBackoffDuration time.Duration, backoffResetTimeout time.Duration) Backoff {
+	return &exponentialBackoff{maxBackoffDuration, initialBackoffDuration, backoffResetTimeout, make(map[string]exponentialBackoffInfo)}
+}
+
+// Backoff execution for the given key. Returns time till execution is backed off.
+func (b *exponentialBackoff) Backoff(key string, currentTime time.Time) time.Time {
+	duration := b.initialBackoffDuration
+	if backoffInfo, found := b.backoffInfo[key]; found {
+		// Multiple concurrent scale-ups failing shouldn't cause backoff
+		// duration to increase, so we only increase it if we're not in
+		// backoff right now.
+		if backoffInfo.backoffUntil.Before(currentTime) {
+			duration = 2 * backoffInfo.duration
+			if duration > b.maxBackoffDuration {
+				duration = b.maxBackoffDuration
+			}
+		}
+	}
+	backoffUntil := currentTime.Add(duration)
+	b.backoffInfo[key] = exponentialBackoffInfo{
+		duration:            duration,
+		backoffUntil:        backoffUntil,
+		lastFailedExecution: currentTime,
+	}
+	return backoffUntil
+}
+
+// IsBackedOff returns true if execution is backed off for the given key.
+func (b *exponentialBackoff) IsBackedOff(key string, currentTime time.Time) bool {
+	backoffInfo, found := b.backoffInfo[key]
+	return found && backoffInfo.backoffUntil.After(currentTime)
+}
+
+// RemoveBackoff removes backoff data for the given key.
+func (b *exponentialBackoff) RemoveBackoff(key string) {
+	delete(b.backoffInfo, key)
+}
+
+// RemoveStaleBackoffData removes stale backoff data.
+func (b *exponentialBackoff) RemoveStaleBackoffData(currentTime time.Time) {
+	for key, backoffInfo := range b.backoffInfo {
+		if backoffInfo.lastFailedExecution.Add(b.backoffResetTimeout).Before(currentTime) {
+			delete(b.backoffInfo, key)
+		}
+	}
+}

cluster-autoscaler/utils/backoff/exponential_backoff_test.go

@@ -24,7 +24,7 @@ import (
 )
 
 func TestBackoffTwoKeys(t *testing.T) {
-	backoff := NewBackoff(10*time.Minute, time.Hour, 3*time.Hour)
+	backoff := NewExponentialBackoff(10*time.Minute, time.Hour, 3*time.Hour)
 	startTime := time.Now()
 	assert.False(t, backoff.IsBackedOff("key1", startTime))
 	assert.False(t, backoff.IsBackedOff("key2", startTime))
@@ -35,7 +35,7 @@ func TestBackoffTwoKeys(t *testing.T) {
 }
 
 func TestMaxBackoff(t *testing.T) {
-	backoff := NewBackoff(1*time.Minute, 3*time.Minute, 3*time.Hour)
+	backoff := NewExponentialBackoff(1*time.Minute, 3*time.Minute, 3*time.Hour)
 	startTime := time.Now()
 	backoff.Backoff("key1", startTime)
 	assert.True(t, backoff.IsBackedOff("key1", startTime))
@@ -49,7 +49,7 @@ func TestMaxBackoff(t *testing.T) {
 }
 
 func TestRemoveBackoff(t *testing.T) {
-	backoff := NewBackoff(1*time.Minute, 3*time.Minute, 3*time.Hour)
+	backoff := NewExponentialBackoff(1*time.Minute, 3*time.Minute, 3*time.Hour)
 	startTime := time.Now()
 	backoff.Backoff("key1", startTime)
 	assert.True(t, backoff.IsBackedOff("key1", startTime))
@@ -58,14 +58,14 @@ func TestRemoveBackoff(t *testing.T) {
 }
 
 func TestResetStaleBackoffData(t *testing.T) {
-	backoff := NewBackoff(1*time.Minute, 3*time.Minute, 3*time.Hour)
+	backoff := NewExponentialBackoff(1*time.Minute, 3*time.Minute, 3*time.Hour)
 	startTime := time.Now()
 	backoff.Backoff("key1", startTime)
 	backoff.Backoff("key2", startTime.Add(time.Hour))
 	backoff.RemoveStaleBackoffData(startTime.Add(time.Hour))
-	assert.Equal(t, 2, len(backoff.backoffInfo))
+	assert.Equal(t, 2, len(backoff.(*exponentialBackoff).backoffInfo))
 	backoff.RemoveStaleBackoffData(startTime.Add(4 * time.Hour))
-	assert.Equal(t, 1, len(backoff.backoffInfo))
+	assert.Equal(t, 1, len(backoff.(*exponentialBackoff).backoffInfo))
 	backoff.RemoveStaleBackoffData(startTime.Add(5 * time.Hour))
-	assert.Equal(t, 0, len(backoff.backoffInfo))
+	assert.Equal(t, 0, len(backoff.(*exponentialBackoff).backoffInfo))
 }