Create and use LatencyTracker interface for better testability

Author: ttetyanka

cluster-autoscaler/core/scaledown/actuation/actuator.go

@@ -59,7 +59,7 @@ const (
 type Actuator struct {
 	ctx                   *context.AutoscalingContext
 	nodeDeletionTracker   *deletiontracker.NodeDeletionTracker
-	nodeLatencyTracker    *latencytracker.NodeLatencyTracker
+	nodeLatencyTracker    latencytracker.LatencyTracker
 	nodeDeletionScheduler *GroupDeletionScheduler
 	deleteOptions         options.NodeDeleteOptions
 	drainabilityRules     rules.Rules
@@ -80,7 +80,7 @@ type actuatorNodeGroupConfigGetter interface {
 }
 
 // NewActuator returns a new instance of Actuator.
-func NewActuator(ctx *context.AutoscalingContext, scaleStateNotifier nodegroupchange.NodeGroupChangeObserver, ndt *deletiontracker.NodeDeletionTracker, nlt *latencytracker.NodeLatencyTracker, deleteOptions options.NodeDeleteOptions, drainabilityRules rules.Rules, configGetter actuatorNodeGroupConfigGetter) *Actuator {
+func NewActuator(ctx *context.AutoscalingContext, scaleStateNotifier nodegroupchange.NodeGroupChangeObserver, ndt *deletiontracker.NodeDeletionTracker, nlt latencytracker.LatencyTracker, deleteOptions options.NodeDeleteOptions, drainabilityRules rules.Rules, configGetter actuatorNodeGroupConfigGetter) *Actuator {
 	ndb := NewNodeDeletionBatcher(ctx, scaleStateNotifier, ndt, ctx.NodeDeletionBatcherInterval)
 	legacyFlagDrainConfig := SingleRuleDrainConfig(ctx.MaxGracefulTerminationSec)
 	var evictor Evictor

cluster-autoscaler/core/scaledown/latencytracker/node_latency_tracker.go

@@ -4,10 +4,13 @@ import (
 	"time"
 
 	"k8s.io/autoscaler/cluster-autoscaler/metrics"
-
 	"k8s.io/klog/v2"
 )
 
+type LatencyTracker interface {
+	ObserveDeletion(nodeName string, timestamp time.Time)
+	UpdateStateWithUnneededList(list []NodeInfo, timestamp time.Time)
+}
 type NodeInfo struct {
 	Name          string
 	UnneededSince time.Time

cluster-autoscaler/core/scaledown/planner/planner.go

@@ -77,11 +77,11 @@ type Planner struct {
 	cc                    controllerReplicasCalculator
 	scaleDownSetProcessor nodes.ScaleDownSetProcessor
 	scaleDownContext      *nodes.ScaleDownContext
-	nodeLatencyTracker    *latencytracker.NodeLatencyTracker
+	nodeLatencyTracker    latencytracker.LatencyTracker
 }
 
 // New creates a new Planner object.
-func New(context *context.AutoscalingContext, processors *processors.AutoscalingProcessors, deleteOptions options.NodeDeleteOptions, drainabilityRules rules.Rules, nlt *latencytracker.NodeLatencyTracker) *Planner {
+func New(context *context.AutoscalingContext, processors *processors.AutoscalingProcessors, deleteOptions options.NodeDeleteOptions, drainabilityRules rules.Rules, nlt latencytracker.LatencyTracker) *Planner {
 	resourceLimitsFinder := resource.NewLimitsFinder(processors.CustomResourcesProcessor)
 	minUpdateInterval := context.AutoscalingOptions.NodeGroupDefaults.ScaleDownUnneededTime
 	if minUpdateInterval == 0*time.Nanosecond {