[migration phase 1] MatchInterPodAffinity as filter plugin

pkg/scheduler/framework/plugins/interpodaffinity/interpod_affinity.go

@@ -0,0 +1,61 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package interpodaffinity
+
+import (
+	"context"
+	"fmt"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/kubernetes/pkg/scheduler/algorithm"
+	"k8s.io/kubernetes/pkg/scheduler/algorithm/predicates"
+	"k8s.io/kubernetes/pkg/scheduler/framework/plugins/migration"
+	framework "k8s.io/kubernetes/pkg/scheduler/framework/v1alpha1"
+	"k8s.io/kubernetes/pkg/scheduler/nodeinfo"
+)
+
+// InterPodAffinity is a plugin that checks inter pod affinity
+type InterPodAffinity struct {
+	predicate predicates.FitPredicate
+}
+
+var _ framework.FilterPlugin = &InterPodAffinity{}
+
+// Name is the name of the plugin used in the plugin registry and configurations.
+const Name = "InterPodAffinity"
+
+// Name returns name of the plugin. It is used in logs, etc.
+func (pl *InterPodAffinity) Name() string {
+	return Name
+}
+
+// Filter invoked at the filter extension point.
+func (pl *InterPodAffinity) Filter(ctx context.Context, cycleState *framework.CycleState, pod *v1.Pod, nodeInfo *nodeinfo.NodeInfo) *framework.Status {
+	meta, ok := migration.PredicateMetadata(cycleState).(predicates.PredicateMetadata)
+	if !ok {
+		return migration.ErrorToFrameworkStatus(fmt.Errorf("%+v convert to predicates.PredicateMetadata error", cycleState))
+	}
+	_, reasons, err := pl.predicate(pod, meta, nodeInfo)
+	return migration.PredicateResultToFrameworkStatus(reasons, err)
+}
+
+// New initializes a new plugin and returns it.
+func New(nodeInfo predicates.NodeInfo, podLister algorithm.PodLister) framework.Plugin {
+	return &InterPodAffinity{
+		predicate: predicates.NewPodAffinityPredicate(nodeInfo, podLister),
+	}
+}