Add "PercentageRunnersBusy" horizontal runner autoscaler metric type (#223)

* hpa scheme based off busy runners

* running make manifests

Co-authored-by: Zachary Benamram <zacharybenamram@blend.com>

api/v1alpha1/horizontalrunnerautoscaler_types.go

@@ -56,6 +56,26 @@ type MetricSpec struct {
 	// For example, a repository name is the REPO part of `github.com/USER/REPO`.
 	// +optional
 	RepositoryNames []string `json:"repositoryNames,omitempty"`
+
+	// ScaleUpThreshold is the percentage of busy runners greater than which will
+	// trigger the hpa to scale runners up.
+	// +optional
+	ScaleUpThreshold string `json:"scaleUpThreshold,omitempty"`
+
+	// ScaleDownThreshold is the percentage of busy runners less than which will
+	// trigger the hpa to scale the runners down.
+	// +optional
+	ScaleDownThreshold string `json:"scaleDownThreshold,omitempty"`
+
+	// ScaleUpFactor is the multiplicative factor applied to the current number of runners used
+	// to determine how many pods should be added.
+	// +optional
+	ScaleUpFactor string `json:"scaleUpFactor,omitempty"`
+
+	// ScaleDownFactor is the multiplicative factor applied to the current number of runners used
+	// to determine how many pods should be removed.
+	// +optional
+	ScaleDownFactor string `json:"scaleDownFactor,omitempty"`
 }
 
 type HorizontalRunnerAutoscalerStatus struct {

api/v1alpha1/runnerdeployment_types.go

@@ -22,6 +22,7 @@ import (
 
 const (
 	AutoscalingMetricTypeTotalNumberOfQueuedAndInProgressWorkflowRuns = "TotalNumberOfQueuedAndInProgressWorkflowRuns"
+	AutoscalingMetricTypePercentageRunnersBusy                        = "PercentageRunnersBusy"
 )
 
 // RunnerReplicaSetSpec defines the desired state of RunnerDeployment