fix: delete home pod when the foreign one is deleted

Pod deletion initiated from the home pod was not completed correctly.
Indeed, the pod's container statuses in the home was never set to
terminated so the virtual kubelet was not able to delete pod.

This fix updates the container statuses in one go, when the foreign pod
is deleted, ie. we miss to update the home pod when the foreign
containers are terminated. Fixing this problem is out of scope and would
probably require modifying the pod black listing mechanism which seems
too risky at this time. Issue described here:
#721.

Resolves: #598

pkg/virtualKubelet/apiReflection/reflectors/incoming/apiTypes.go

@@ -13,7 +13,9 @@ var ReflectorBuilder = map[apimgmt.ApiType]func(reflector ri.APIReflector, opts
 
 func podsReflectorBuilder(reflector ri.APIReflector, opts map[options.OptionKey]options.Option) ri.IncomingAPIReflector {
 	return &PodsIncomingReflector{
-		APIReflector: reflector}
+		APIReflector:  reflector,
+		HomePodGetter: GetHomePodFunc,
+	}
 }
 
 func replicaSetsReflectorBuilder(reflector ri.APIReflector, _ map[options.OptionKey]options.Option) ri.IncomingAPIReflector {

pkg/virtualKubelet/apiReflection/reflectors/incoming/pods.go

@@ -12,7 +12,7 @@ import (
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/util/retry"
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 
 	"github.com/liqotech/liqo/pkg/virtualKubelet"
 	apimgmt "github.com/liqotech/liqo/pkg/virtualKubelet/apiReflection"
@@ -22,10 +22,14 @@ import (
 	"github.com/liqotech/liqo/pkg/virtualKubelet/forge"
 )
 
+// HomePodGetter function to retrieve the shadow home pod given the foreign pod.
+type HomePodGetter func(reflector ri.APIReflector, foreignPod *corev1.Pod) (*corev1.Pod, error)
+
 // PodsIncomingReflector is the incoming reflector in charge of detecting status change in foreign pods
 // and pushing the updated object to the vk internals.
 type PodsIncomingReflector struct {
 	ri.APIReflector
+	HomePodGetter HomePodGetter
 }
 
 // SetSpecializedPreProcessingHandlers allows to set the pre-routine handlers for the PodsIncomingReflector.
@@ -90,46 +94,41 @@ func (r *PodsIncomingReflector) PreUpdate(newObj, _ interface{}) (interface{}, w
 // sharedPreRoutine is a common function used by both PreAdd and PreUpdate. It is in charge of fetching the home pod from
 // the internal caches, updating its status and returning to the calling function.
 func (r *PodsIncomingReflector) sharedPreRoutine(foreignPod *corev1.Pod) *corev1.Pod {
-	if foreignPod.Labels == nil {
-		return nil
-	}
-
-	homePodName, ok := foreignPod.Labels[virtualKubelet.ReflectedpodKey]
-	if !ok {
-		return nil
-	}
-
-	homeNamespace, err := r.NattingTable().DeNatNamespace(foreignPod.Namespace)
+	homePod, err := r.GetHomePod(foreignPod)
 	if err != nil {
-		klog.Error(err)
-		return nil
-	}
-
-	homePod, err := r.GetCacheManager().GetHomeNamespacedObject(apimgmt.Pods, homeNamespace, homePodName)
-	if err != nil {
-		err = errors.Wrap(err, "local pod not found, incoming update blocked")
-		klog.V(4).Info(err)
+		klog.Error(errors.Wrap(err, "cannot get home pod"))
 		return nil
 	}
 
+	var homePodObj interface{} = homePod
 	// forge.ForeignToHomeStatus blacklists the received pod if the deletionTimestamp is set
-	homePod, err = forge.ForeignToHomeStatus(foreignPod, homePod.(runtime.Object).DeepCopyObject())
+	homePodObj, err = forge.ForeignToHomeStatus(foreignPod, homePodObj.(runtime.Object).DeepCopyObject())
 	if err != nil {
 		klog.Error(err)
 		return nil
 	}
 
-	return homePod.(*corev1.Pod)
+	return homePodObj.(*corev1.Pod)
 }
 
 // PreDelete removes the received object from the blacklist for freeing the occupied space.
 func (r *PodsIncomingReflector) PreDelete(obj interface{}) (interface{}, watch.EventType) {
 	foreignPod := obj.(*corev1.Pod)
-	foreignKey := fmt.Sprintf("%s/%s", foreignPod.Namespace, foreignPod.Name)
+	foreignKey := r.Keyer(foreignPod.Namespace, foreignPod.Name)
 	delete(reflectors.Blacklist[apimgmt.Pods], foreignKey)
 	klog.V(3).Infof("pod %s removed from blacklist because deleted", foreignKey)
 
-	return nil, watch.Deleted
+	homePod, err := r.GetHomePod(foreignPod)
+	if err != nil {
+		klog.Error(errors.Wrapf(err, "cannot get home pod for foreign pod: %s", foreignKey))
+		return nil, watch.Deleted
+	}
+
+	homePod = forge.ForeignReplicasetDeleted(homePod)
+
+	klog.V(3).Infof("%s, home pod for foreign pod: %s, set to be deleted", homePod.ObjectMeta.Name, foreignKey)
+
+	return homePod, watch.Deleted
 }
 
 // CleanupNamespace is in charge of cleaning a local namespace from all the reflected objects. All the home objects in
@@ -210,3 +209,37 @@ func (r *PodsIncomingReflector) isAllowed(ctx context.Context, obj interface{})
 	}
 	return !ok
 }
+
+// GetHomePod retrieves the shadow home pod given the foreign pod.
+func (r *PodsIncomingReflector) GetHomePod(foreignPod *corev1.Pod) (*corev1.Pod, error) {
+	return r.HomePodGetter(r, foreignPod)
+}
+
+// GetHomePodFunc retrieves the shadow home pod given the foreign pod.
+func GetHomePodFunc(reflector ri.APIReflector, foreignPod *corev1.Pod) (*corev1.Pod, error) {
+	if foreignPod.Labels == nil {
+		return nil, errors.New("foreign pod labels not found")
+	}
+
+	homePodName, ok := foreignPod.Labels[virtualKubelet.ReflectedpodKey]
+	if !ok {
+		return nil, fmt.Errorf("foreign pod label with key: %s, not found", virtualKubelet.ReflectedpodKey)
+	}
+
+	homeNamespace, err := reflector.NattingTable().DeNatNamespace(foreignPod.Namespace)
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot get home pod namespace")
+	}
+
+	homePodObj, err := reflector.GetCacheManager().GetHomeNamespacedObject(apimgmt.Pods, homeNamespace, homePodName)
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot get home pod from cache manager")
+	}
+
+	homePod, ok := homePodObj.(*corev1.Pod)
+	if !ok {
+		return nil, fmt.Errorf("could not execute type conversion: GetHomeNamespacedObject expected to return a Pod object")
+	}
+
+	return homePod, nil
+}