293 lines
9.3 KiB
Go
293 lines
9.3 KiB
Go
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/*
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Copyright 2015 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package downwardapi
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import (
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"fmt"
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"path"
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"sort"
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"strings"
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"k8s.io/apimachinery/pkg/types"
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utilerrors "k8s.io/apimachinery/pkg/util/errors"
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"k8s.io/kubernetes/pkg/api/v1"
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"k8s.io/kubernetes/pkg/fieldpath"
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utilstrings "k8s.io/kubernetes/pkg/util/strings"
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"k8s.io/kubernetes/pkg/volume"
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volumeutil "k8s.io/kubernetes/pkg/volume/util"
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"github.com/golang/glog"
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)
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// ProbeVolumePlugins is the entry point for plugin detection in a package.
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func ProbeVolumePlugins() []volume.VolumePlugin {
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return []volume.VolumePlugin{&downwardAPIPlugin{}}
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}
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const (
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downwardAPIPluginName = "kubernetes.io/downward-api"
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)
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// downwardAPIPlugin implements the VolumePlugin interface.
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type downwardAPIPlugin struct {
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host volume.VolumeHost
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}
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var _ volume.VolumePlugin = &downwardAPIPlugin{}
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func wrappedVolumeSpec() volume.Spec {
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return volume.Spec{
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Volume: &v1.Volume{VolumeSource: v1.VolumeSource{EmptyDir: &v1.EmptyDirVolumeSource{Medium: v1.StorageMediumMemory}}},
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}
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}
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func (plugin *downwardAPIPlugin) Init(host volume.VolumeHost) error {
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plugin.host = host
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return nil
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}
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func (plugin *downwardAPIPlugin) GetPluginName() string {
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return downwardAPIPluginName
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}
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func (plugin *downwardAPIPlugin) GetVolumeName(spec *volume.Spec) (string, error) {
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volumeSource, _ := getVolumeSource(spec)
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if volumeSource == nil {
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return "", fmt.Errorf("Spec does not reference a DownwardAPI volume type")
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}
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// Return user defined volume name, since this is an ephemeral volume type
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return spec.Name(), nil
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}
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func (plugin *downwardAPIPlugin) CanSupport(spec *volume.Spec) bool {
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return spec.Volume != nil && spec.Volume.DownwardAPI != nil
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}
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func (plugin *downwardAPIPlugin) RequiresRemount() bool {
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return true
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}
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func (plugin *downwardAPIPlugin) NewMounter(spec *volume.Spec, pod *v1.Pod, opts volume.VolumeOptions) (volume.Mounter, error) {
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v := &downwardAPIVolume{
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volName: spec.Name(),
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items: spec.Volume.DownwardAPI.Items,
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pod: pod,
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podUID: pod.UID,
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plugin: plugin,
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}
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return &downwardAPIVolumeMounter{
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downwardAPIVolume: v,
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source: *spec.Volume.DownwardAPI,
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opts: &opts,
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}, nil
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}
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func (plugin *downwardAPIPlugin) NewUnmounter(volName string, podUID types.UID) (volume.Unmounter, error) {
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return &downwardAPIVolumeUnmounter{
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&downwardAPIVolume{
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volName: volName,
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podUID: podUID,
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plugin: plugin,
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},
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}, nil
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}
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func (plugin *downwardAPIPlugin) ConstructVolumeSpec(volumeName, mountPath string) (*volume.Spec, error) {
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downwardAPIVolume := &v1.Volume{
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Name: volumeName,
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VolumeSource: v1.VolumeSource{
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DownwardAPI: &v1.DownwardAPIVolumeSource{},
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},
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}
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return volume.NewSpecFromVolume(downwardAPIVolume), nil
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}
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// downwardAPIVolume retrieves downward API data and placing them into the volume on the host.
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type downwardAPIVolume struct {
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volName string
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items []v1.DownwardAPIVolumeFile
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pod *v1.Pod
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podUID types.UID // TODO: remove this redundancy as soon NewUnmounter func will have *v1.POD and not only types.UID
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plugin *downwardAPIPlugin
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volume.MetricsNil
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}
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// downwardAPIVolumeMounter fetches info from downward API from the pod
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// and dumps it in files
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type downwardAPIVolumeMounter struct {
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*downwardAPIVolume
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source v1.DownwardAPIVolumeSource
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opts *volume.VolumeOptions
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}
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// downwardAPIVolumeMounter implements volume.Mounter interface
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var _ volume.Mounter = &downwardAPIVolumeMounter{}
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// downward API volumes are always ReadOnlyManaged
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func (d *downwardAPIVolume) GetAttributes() volume.Attributes {
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return volume.Attributes{
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ReadOnly: true,
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Managed: true,
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SupportsSELinux: true,
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}
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}
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// Checks prior to mount operations to verify that the required components (binaries, etc.)
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// to mount the volume are available on the underlying node.
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// If not, it returns an error
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func (b *downwardAPIVolumeMounter) CanMount() error {
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return nil
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}
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// SetUp puts in place the volume plugin.
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// This function is not idempotent by design. We want the data to be refreshed periodically.
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// The internal sync interval of kubelet will drive the refresh of data.
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// TODO: Add volume specific ticker and refresh loop
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func (b *downwardAPIVolumeMounter) SetUp(fsGroup *int64) error {
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return b.SetUpAt(b.GetPath(), fsGroup)
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}
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func (b *downwardAPIVolumeMounter) SetUpAt(dir string, fsGroup *int64) error {
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glog.V(3).Infof("Setting up a downwardAPI volume %v for pod %v/%v at %v", b.volName, b.pod.Namespace, b.pod.Name, dir)
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// Wrap EmptyDir. Here we rely on the idempotency of the wrapped plugin to avoid repeatedly mounting
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wrapped, err := b.plugin.host.NewWrapperMounter(b.volName, wrappedVolumeSpec(), b.pod, *b.opts)
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if err != nil {
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glog.Errorf("Couldn't setup downwardAPI volume %v for pod %v/%v: %s", b.volName, b.pod.Namespace, b.pod.Name, err.Error())
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return err
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}
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if err := wrapped.SetUpAt(dir, fsGroup); err != nil {
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glog.Errorf("Unable to setup downwardAPI volume %v for pod %v/%v: %s", b.volName, b.pod.Namespace, b.pod.Name, err.Error())
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return err
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}
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data, err := b.collectData(b.source.DefaultMode)
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if err != nil {
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glog.Errorf("Error preparing data for downwardAPI volume %v for pod %v/%v: %s", b.volName, b.pod.Namespace, b.pod.Name, err.Error())
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return err
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}
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writerContext := fmt.Sprintf("pod %v/%v volume %v", b.pod.Namespace, b.pod.Name, b.volName)
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writer, err := volumeutil.NewAtomicWriter(dir, writerContext)
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if err != nil {
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glog.Errorf("Error creating atomic writer: %v", err)
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return err
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}
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err = writer.Write(data)
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if err != nil {
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glog.Errorf("Error writing payload to dir: %v", err)
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return err
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}
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err = volume.SetVolumeOwnership(b, fsGroup)
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if err != nil {
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glog.Errorf("Error applying volume ownership settings for group: %v", fsGroup)
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return err
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}
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return nil
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}
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// collectData collects requested downwardAPI in data map.
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// Map's key is the requested name of file to dump
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// Map's value is the (sorted) content of the field to be dumped in the file.
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func (d *downwardAPIVolume) collectData(defaultMode *int32) (map[string]volumeutil.FileProjection, error) {
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if defaultMode == nil {
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return nil, fmt.Errorf("No defaultMode used, not even the default value for it")
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}
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errlist := []error{}
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data := make(map[string]volumeutil.FileProjection)
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for _, fileInfo := range d.items {
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var fileProjection volumeutil.FileProjection
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fPath := path.Clean(fileInfo.Path)
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if fileInfo.Mode != nil {
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fileProjection.Mode = *fileInfo.Mode
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} else {
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fileProjection.Mode = *defaultMode
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}
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if fileInfo.FieldRef != nil {
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// TODO: unify with Kubelet.podFieldSelectorRuntimeValue
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if values, err := fieldpath.ExtractFieldPathAsString(d.pod, fileInfo.FieldRef.FieldPath); err != nil {
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glog.Errorf("Unable to extract field %s: %s", fileInfo.FieldRef.FieldPath, err.Error())
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errlist = append(errlist, err)
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} else {
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fileProjection.Data = []byte(sortLines(values))
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}
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} else if fileInfo.ResourceFieldRef != nil {
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containerName := fileInfo.ResourceFieldRef.ContainerName
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nodeAllocatable, err := d.plugin.host.GetNodeAllocatable()
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if err != nil {
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errlist = append(errlist, err)
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} else if values, err := fieldpath.ExtractResourceValueByContainerNameAndNodeAllocatable(fileInfo.ResourceFieldRef, d.pod, containerName, nodeAllocatable); err != nil {
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glog.Errorf("Unable to extract field %s: %s", fileInfo.ResourceFieldRef.Resource, err.Error())
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errlist = append(errlist, err)
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} else {
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fileProjection.Data = []byte(sortLines(values))
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}
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}
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data[fPath] = fileProjection
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}
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return data, utilerrors.NewAggregate(errlist)
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}
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// sortLines sorts the strings generated from map based data
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// (annotations and labels)
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func sortLines(values string) string {
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splitted := strings.Split(values, "\n")
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sort.Strings(splitted)
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return strings.Join(splitted, "\n")
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}
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func (d *downwardAPIVolume) GetPath() string {
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return d.plugin.host.GetPodVolumeDir(d.podUID, utilstrings.EscapeQualifiedNameForDisk(downwardAPIPluginName), d.volName)
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}
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// downwardAPIVolumeCleaner handles cleaning up downwardAPI volumes
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type downwardAPIVolumeUnmounter struct {
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*downwardAPIVolume
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}
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// downwardAPIVolumeUnmounter implements volume.Unmounter interface
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var _ volume.Unmounter = &downwardAPIVolumeUnmounter{}
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func (c *downwardAPIVolumeUnmounter) TearDown() error {
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return c.TearDownAt(c.GetPath())
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}
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func (c *downwardAPIVolumeUnmounter) TearDownAt(dir string) error {
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return volume.UnmountViaEmptyDir(dir, c.plugin.host, c.volName, wrappedVolumeSpec(), c.podUID)
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}
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func (b *downwardAPIVolumeMounter) getMetaDir() string {
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return path.Join(b.plugin.host.GetPodPluginDir(b.podUID, utilstrings.EscapeQualifiedNameForDisk(downwardAPIPluginName)), b.volName)
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}
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func getVolumeSource(spec *volume.Spec) (*v1.DownwardAPIVolumeSource, bool) {
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var readOnly bool
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var volumeSource *v1.DownwardAPIVolumeSource
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if spec.Volume != nil && spec.Volume.DownwardAPI != nil {
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volumeSource = spec.Volume.DownwardAPI
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readOnly = spec.ReadOnly
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}
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return volumeSource, readOnly
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}
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