use plugin registry and prepare for conversion (#1003)

* use plugin registry and prepare for conersion

* Register plugins explicitly to a registry

* check interface impl instead of struc var

* setup plugins at top level

* treat plugin type combinations

* pass registry as arg of V1alpha1ToInternal

* move registry yet another level up

* check interface type separately

pkg/framework/plugins/defaultevictor/defaultevictor.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 
 	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/errors"
@@ -129,9 +130,13 @@ func New(args runtime.Object, handle framework.Handle) (framework.Plugin, error)
 			return nil
 		})
 	}
-	if defaultEvictorArgs.LabelSelector != nil && !defaultEvictorArgs.LabelSelector.Empty() {
+	selector, err := metav1.LabelSelectorAsSelector(defaultEvictorArgs.LabelSelector)
+	if err != nil {
+		return nil, fmt.Errorf("could not get selector from label selector")
+	}
+	if defaultEvictorArgs.LabelSelector != nil && !selector.Empty() {
 		ev.constraints = append(ev.constraints, func(pod *v1.Pod) error {
-			if !defaultEvictorArgs.LabelSelector.Matches(labels.Set(pod.Labels)) {
+			if !selector.Matches(labels.Set(pod.Labels)) {
 				return fmt.Errorf("pod labels do not match the labelSelector filter in the policy parameter")
 			}
 			return nil

pkg/framework/plugins/defaultevictor/types.go

@@ -15,7 +15,6 @@ package defaultevictor
 
 import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/labels"
 	"sigs.k8s.io/descheduler/pkg/api"
 )
 
@@ -24,14 +23,14 @@ import (
 
 // DefaultEvictorArgs holds arguments used to configure DefaultEvictor plugin.
 type DefaultEvictorArgs struct {
-	metav1.TypeMeta
+	metav1.TypeMeta `json:",inline"`
 
-	NodeSelector            string
-	EvictLocalStoragePods   bool
-	EvictSystemCriticalPods bool
-	IgnorePvcPods           bool
-	EvictFailedBarePods     bool
-	LabelSelector           labels.Selector
-	PriorityThreshold       *api.PriorityThreshold
-	NodeFit                 bool
+	NodeSelector            string                 `json:"nodeSelector"`
+	EvictLocalStoragePods   bool                   `json:"evictLocalStoragePods"`
+	EvictSystemCriticalPods bool                   `json:"evictSystemCriticalPods"`
+	IgnorePvcPods           bool                   `json:"ignorePvcPods"`
+	EvictFailedBarePods     bool                   `json:"evictFailedBarePods"`
+	LabelSelector           *metav1.LabelSelector  `json:"labelSelector"`
+	PriorityThreshold       *api.PriorityThreshold `json:"priorityThreshold"`
+	NodeFit                 bool                   `json:"nodeFit"`
 }

pkg/framework/plugins/defaultevictor/zz_generated.deepcopy.go

@@ -22,6 +22,7 @@ limitations under the License.
 package defaultevictor
 
 import (
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	runtime "k8s.io/apimachinery/pkg/runtime"
 	api "sigs.k8s.io/descheduler/pkg/api"
 )
@@ -31,7 +32,9 @@ func (in *DefaultEvictorArgs) DeepCopyInto(out *DefaultEvictorArgs) {
 	*out = *in
 	out.TypeMeta = in.TypeMeta
 	if in.LabelSelector != nil {
-		out.LabelSelector = in.LabelSelector.DeepCopySelector()
+		in, out := &in.LabelSelector, &out.LabelSelector
+		*out = new(v1.LabelSelector)
+		(*in).DeepCopyInto(*out)
 	}
 	if in.PriorityThreshold != nil {
 		in, out := &in.PriorityThreshold, &out.PriorityThreshold