Promote volume plugins, prep for persistent vols

Move pkg/kubelet/volume/... to pkg/volume/...
Some renames to make the soon-to-come persistent volumes work clearer.

pkg/volume/host_path/host_path.go

@@ -0,0 +1,93 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 host_path
+
+import (
+	"fmt"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/types"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/volume"
+)
+
+// This is the primary entrypoint for volume plugins.
+func ProbeVolumePlugins() []volume.VolumePlugin {
+	return []volume.VolumePlugin{&hostPathPlugin{nil}}
+}
+
+type hostPathPlugin struct {
+	host volume.VolumeHost
+}
+
+var _ volume.VolumePlugin = &hostPathPlugin{}
+
+const (
+	hostPathPluginName = "kubernetes.io/host-path"
+)
+
+func (plugin *hostPathPlugin) Init(host volume.VolumeHost) {
+	plugin.host = host
+}
+
+func (plugin *hostPathPlugin) Name() string {
+	return hostPathPluginName
+}
+
+func (plugin *hostPathPlugin) CanSupport(spec *api.Volume) bool {
+	if spec.HostPath != nil {
+		return true
+	}
+	return false
+}
+
+func (plugin *hostPathPlugin) NewBuilder(spec *api.Volume, podRef *api.ObjectReference) (volume.Builder, error) {
+	return &hostPath{spec.HostPath.Path}, nil
+}
+
+func (plugin *hostPathPlugin) NewCleaner(volName string, podUID types.UID) (volume.Cleaner, error) {
+	return &hostPath{""}, nil
+}
+
+// HostPath volumes represent a bare host file or directory mount.
+// The direct at the specified path will be directly exposed to the container.
+type hostPath struct {
+	path string
+}
+
+// SetUp does nothing.
+func (hp *hostPath) SetUp() error {
+	return nil
+}
+
+// SetUpAt does not make sense for host paths - probably programmer error.
+func (hp *hostPath) SetUpAt(dir string) error {
+	return fmt.Errorf("SetUpAt() does not make sense for host paths")
+}
+
+func (hp *hostPath) GetPath() string {
+	return hp.path
+}
+
+// TearDown does nothing.
+func (hp *hostPath) TearDown() error {
+	return nil
+}
+
+// TearDownAt does not make sense for host paths - probably programmer error.
+func (hp *hostPath) TearDownAt(dir string) error {
+	return fmt.Errorf("TearDownAt() does not make sense for host paths")
+}