Update scheduler framework plugins to align with the latest changes to the framework design

pkg/scheduler/framework/plugins/examples/BUILD

@@ -0,0 +1,31 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "multipoint.go",
+        "prebind.go",
+        "stateful.go",
+    ],
+    importpath = "k8s.io/kubernetes/pkg/scheduler/plugins/examples",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/scheduler/plugins/v1alpha1:go_default_library",
+        "//staging/src/k8s.io/api/core/v1:go_default_library",
+        "//vendor/k8s.io/klog:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

pkg/scheduler/framework/plugins/examples/multipoint/multipoint.go

@@ -0,0 +1,68 @@
+/*
+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 multipoint
+
+import (
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	framework "k8s.io/kubernetes/pkg/scheduler/framework/v1alpha1"
+)
+
+// CommunicatingPlugin is an example of a plugin that implements two
+// extension points. It communicates through pluginContext with another function.
+type CommunicatingPlugin struct{}
+
+var _ = framework.ReservePlugin(CommunicatingPlugin{})
+
+// Name is the name of the plug used in Registry and configurations.
+const Name = "multipoint-communicating-plugin"
+
+// Name returns name of the plugin. It is used in logs, etc.
+func (mc CommunicatingPlugin) Name() string {
+	return Name
+}
+
+// Reserve is the functions invoked by the framework at "reserve" extension point.
+func (mc CommunicatingPlugin) Reserve(pc *framework.PluginContext, pod *v1.Pod, nodeName string) *framework.Status {
+	if pod == nil {
+		return framework.NewStatus(framework.Error, "pod cannot be nil")
+	}
+	if pod.Name == "my-test-pod" {
+		pc.Lock()
+		pc.Write(framework.ContextKey(pod.Name), "never bind")
+		pc.Unlock()
+	}
+	return nil
+}
+
+// Prebind is the functions invoked by the framework at "prebind" extension point.
+func (mc CommunicatingPlugin) Prebind(pc *framework.PluginContext, pod *v1.Pod, nodeName string) *framework.Status {
+	if pod == nil {
+		return framework.NewStatus(framework.Error, "pod cannot be nil")
+	}
+	pc.RLock()
+	defer pc.RUnlock()
+	if v, e := pc.Read(framework.ContextKey(pod.Name)); e == nil && v == "never bind" {
+		return framework.NewStatus(framework.Unschedulable, "pod is not permitted")
+	}
+	return nil
+}
+
+// New initializes a new plugin and returns it.
+func New(_ *runtime.Unknown, _ framework.Framework) (framework.Plugin, error) {
+	return &CommunicatingPlugin{}, nil
+}

pkg/scheduler/framework/plugins/examples/prebind/prebind.go

@@ -0,0 +1,55 @@
+/*
+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 prebind
+
+import (
+	"fmt"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	framework "k8s.io/kubernetes/pkg/scheduler/framework/v1alpha1"
+)
+
+// StatelessPrebindExample is an example of a simple plugin that has no state
+// and implements only one hook for prebind.
+type StatelessPrebindExample struct{}
+
+var _ = framework.PrebindPlugin(StatelessPrebindExample{})
+
+// Name is the name of the plugin used in Registry and configurations.
+const Name = "stateless-prebind-plugin-example"
+
+// Name returns name of the plugin. It is used in logs, etc.
+func (sr StatelessPrebindExample) Name() string {
+	return Name
+}
+
+// Prebind is the functions invoked by the framework at "prebind" extension point.
+func (sr StatelessPrebindExample) Prebind(pc *framework.PluginContext, pod *v1.Pod, nodeName string) *framework.Status {
+	if pod == nil {
+		return framework.NewStatus(framework.Error, fmt.Sprintf("pod cannot be nil"))
+	}
+	if pod.Namespace != "foo" {
+		return framework.NewStatus(framework.Unschedulable, "only pods from 'foo' namespace are allowed")
+	}
+	return nil
+}
+
+// New initializes a new plugin and returns it.
+func New(_ *runtime.Unknown, _ framework.Framework) (framework.Plugin, error) {
+	return &StatelessPrebindExample{}, nil
+}

pkg/scheduler/framework/plugins/examples/stateful/stateful.go

@@ -0,0 +1,72 @@
+/*
+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 stateful
+
+import (
+	"fmt"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/klog"
+	framework "k8s.io/kubernetes/pkg/scheduler/framework/v1alpha1"
+)
+
+// MultipointExample is an example plugin that is executed at multiple extension points.
+// This plugin is stateful. It receives arguments at initialization (NewMultipointPlugin)
+// and changes its state when it is executed.
+type MultipointExample struct {
+	mpState map[int]string
+	numRuns int
+}
+
+var _ = framework.ReservePlugin(&MultipointExample{})
+var _ = framework.PrebindPlugin(&MultipointExample{})
+
+// Name is the name of the plug used in Registry and configurations.
+const Name = "multipoint-plugin-example"
+
+// Name returns name of the plugin. It is used in logs, etc.
+func (mp *MultipointExample) Name() string {
+	return Name
+}
+
+// Reserve is the functions invoked by the framework at "reserve" extension point.
+func (mp *MultipointExample) Reserve(pc *framework.PluginContext, pod *v1.Pod, nodeName string) *framework.Status {
+	mp.numRuns++
+	return nil
+}
+
+// Prebind is the functions invoked by the framework at "prebind" extension point.
+func (mp *MultipointExample) Prebind(pc *framework.PluginContext, pod *v1.Pod, nodeName string) *framework.Status {
+	mp.numRuns++
+	if pod == nil {
+		return framework.NewStatus(framework.Error, "pod must not be nil")
+	}
+	return nil
+}
+
+// New initializes a new plugin and returns it.
+func New(config *runtime.Unknown, _ framework.FrameworkHandle) (framework.Plugin, error) {
+	if config == nil {
+		klog.Error("MultipointExample configuration cannot be empty")
+		return nil, fmt.Errorf("MultipointExample configuration cannot be empty")
+	}
+	mp := MultipointExample{
+		mpState: make(map[int]string),
+	}
+	return &mp, nil
+}