Implement minTtl feature (#222)

api/v1alpha1/githubactionrunner_types.go

@@ -2,8 +2,6 @@ package v1alpha1
 
 import (
 	"errors"
-	"time"
-
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
@@ -33,6 +31,11 @@ type GithubActionRunnerSpec struct {
 	// +operator-sdk:csv:customresourcedefinitions:type=spec,displayName="Maximum Pool Size",xDescriptors={"urn:alm:descriptor:com.tectonic.ui:podCount"}
 	MaxRunners int `json:"maxRunners"`
 
+	// Minimum time to live for a runner. This can avoid trashing by keeping pods around longer than required by jobs, keeping caches hot.
+	// +kubebuilder:default="0m"
+	// +operator-sdk:csv:customresourcedefinitions:type=spec,displayName="Minimum time to live"
+	MinTTL metav1.Duration `json:"minTtl"`
+
 	// +kubebuilder:validation:Required
 	// +operator-sdk:csv:customresourcedefinitions:type=spec,displayName="Pod Template"
 	PodTemplateSpec v1.PodTemplateSpec `json:"podTemplateSpec"`
@@ -46,7 +49,7 @@ type GithubActionRunnerSpec struct {
 	// +kubebuilder:validation:Optional
 	// +kubebuilder:default="1m"
 	// +operator-sdk:csv:customresourcedefinitions:type=spec,displayName="Reconciliation Period"
-	ReconciliationPeriod string `json:"reconciliationPeriod"`
+	ReconciliationPeriod metav1.Duration `json:"reconciliationPeriod"`
 
 	// What order to delete idle pods in
 	// +kubebuilder:default="LeastRecent"
@@ -75,16 +78,6 @@ func (r GithubActionRunnerSpec) IsValid() (bool, error) {
 	return true, nil
 }
 
-// GetReconciliationPeriod returns period as a Duration
-func (r GithubActionRunnerSpec) GetReconciliationPeriod() time.Duration {
-	duration, err := time.ParseDuration(r.ReconciliationPeriod)
-	if err != nil {
-		return time.Minute
-	}
-
-	return duration
-}
-
 // GithubActionRunnerStatus defines the observed state of GithubActionRunner
 type GithubActionRunnerStatus struct {
 	// the current size of the build pool

config/crd/bases/garo.tietoevry.com_githubactionrunners.yaml

@@ -54,6 +54,10 @@ spec:
                 description: Minimum pool-size. Note that you need one runner in order for jobs to be schedulable, else they fail claiming no runners match the selector labels.
                 minimum: 1
                 type: integer
+              minTtl:
+                default: 0m
+                description: Minimum time to live for a runner. This can avoid trashing by keeping pods around longer than required by jobs, keeping caches hot.
+                type: string
               organization:
                 description: Your GitHub organization
                 type: string
@@ -3822,6 +3826,7 @@ spec:
             required:
             - maxRunners
             - minRunners
+            - minTtl
             - organization
             - podTemplateSpec
             type: object

controllers/githubactionrunner_controller.go

@@ -146,7 +146,7 @@ func (r *GithubActionRunnerReconciler) handleScaling(ctx context.Context, instan
 
 // scaleDown will scale down an idle runner based on policy in CR
 func (r *GithubActionRunnerReconciler) scaleDown(ctx context.Context, podRunnerPairs podRunnerPairList, instance *garov1alpha1.GithubActionRunner) error {
-	idles := podRunnerPairs.getIdles(instance.Spec.DeletionOrder)
+	idles := podRunnerPairs.getIdles(instance.Spec.DeletionOrder, instance.Spec.MinTTL.Duration)
 	for _, pair := range idles {
 		err := r.unregisterRunner(ctx, instance, pair)
 		if err != nil { // should be improved, here we just assume it's because it's running a job and cannot be removed, skip to next candidate
@@ -178,7 +178,7 @@ func shouldScaleDown(podRunnerPairs podRunnerPairList, instance *garov1alpha1.Gi
 }
 
 func (r *GithubActionRunnerReconciler) manageOutcome(ctx context.Context, instance *garov1alpha1.GithubActionRunner, issue error) (reconcile.Result, error) {
-	return r.ManageOutcomeWithRequeue(ctx, instance, issue, instance.Spec.GetReconciliationPeriod())
+	return r.ManageOutcomeWithRequeue(ctx, instance, issue, instance.Spec.ReconciliationPeriod.Duration)
 }
 
 // SetupWithManager configures the controller by using the passed mgr

controllers/podrunner_types.go

@@ -8,6 +8,7 @@ import (
 	"github.com/thoas/go-funk"
 	corev1 "k8s.io/api/core/v1"
 	"sort"
+	"time"
 )
 
 type podRunnerPair struct {
@@ -77,9 +78,9 @@ func (r podRunnerPairList) numIdle() int {
 	return r.numRunners() - r.numBusy()
 }
 
-func (r podRunnerPairList) getIdles(sortOrder v1alpha1.SortOrder) []podRunnerPair {
+func (r podRunnerPairList) getIdles(sortOrder v1alpha1.SortOrder, minTTL time.Duration) []podRunnerPair {
 	idles := funk.Filter(r.pairs, func(pair podRunnerPair) bool {
-		return !(pair.runner.GetBusy() || util.IsBeingDeleted(&pair.pod))
+		return !(pair.runner.GetBusy() || util.IsBeingDeleted(&pair.pod)) && time.Now().After(pair.pod.CreationTimestamp.Add(minTTL))
 	}).([]podRunnerPair)
 
 	sort.SliceStable(idles, func(i, j int) bool {

controllers/podrunner_types_test.go

@@ -19,7 +19,7 @@ var podList = v1.PodList{
 			TypeMeta: metav1.TypeMeta{},
 			ObjectMeta: metav1.ObjectMeta{
 				Name:              "name1",
-				CreationTimestamp: metav1.NewTime(time.Now()),
+				CreationTimestamp: metav1.NewTime(time.Now().Add(-time.Minute)),
 			},
 			Spec:   v1.PodSpec{},
 			Status: v1.PodStatus{},
@@ -28,7 +28,7 @@ var podList = v1.PodList{
 			TypeMeta: metav1.TypeMeta{},
 			ObjectMeta: metav1.ObjectMeta{
 				Name:              "name2",
-				CreationTimestamp: metav1.NewTime(time.Now().Add(time.Minute)),
+				CreationTimestamp: metav1.NewTime(time.Now()),
 			},
 			Spec:   v1.PodSpec{},
 			Status: v1.PodStatus{},
@@ -87,7 +87,7 @@ func TestSort(t *testing.T) {
 	}
 
 	for _, tc := range testCases {
-		podList := tc.podRunnerPairList.getIdles(tc.sortOrder)
-		assert.Equal(t, podList, tc.podRunnerPair)
+		podList := tc.podRunnerPairList.getIdles(tc.sortOrder, time.Duration(0))
+		assert.Equal(t, tc.podRunnerPair, podList)
 	}
 }