273 lines
9.1 KiB
Go
273 lines
9.1 KiB
Go
/*
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Copyright 2014 Google Inc. All rights reserved.
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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 etcd
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import (
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"fmt"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
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etcderr "github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors/etcd"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/api/rest"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/constraint"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/generic"
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etcdgeneric "github.com/GoogleCloudPlatform/kubernetes/pkg/registry/generic/etcd"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/pod"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
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"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
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"github.com/golang/glog"
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)
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// rest implements a RESTStorage for pods against etcd
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type REST struct {
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store *etcdgeneric.Etcd
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}
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// NewREST returns a RESTStorage object that will work against pods.
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func NewREST(h tools.EtcdHelper, factory pod.BoundPodFactory) (*REST, *BindingREST, *StatusREST) {
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prefix := "/registry/pods"
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store := &etcdgeneric.Etcd{
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NewFunc: func() runtime.Object { return &api.Pod{} },
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NewListFunc: func() runtime.Object { return &api.PodList{} },
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KeyRootFunc: func(ctx api.Context) string {
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return etcdgeneric.NamespaceKeyRootFunc(ctx, prefix)
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},
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KeyFunc: func(ctx api.Context, name string) (string, error) {
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return etcdgeneric.NamespaceKeyFunc(ctx, prefix, name)
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},
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ObjectNameFunc: func(obj runtime.Object) (string, error) {
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return obj.(*api.Pod).Name, nil
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},
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PredicateFunc: func(label, field labels.Selector) generic.Matcher {
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return pod.MatchPod(label, field)
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},
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EndpointName: "pods",
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Helper: h,
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}
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statusStore := *store
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bindings := &podLifecycle{h}
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store.CreateStrategy = pod.Strategy
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store.UpdateStrategy = pod.Strategy
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store.AfterUpdate = bindings.AfterUpdate
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store.ReturnDeletedObject = true
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store.AfterDelete = bindings.AfterDelete
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statusStore.UpdateStrategy = pod.StatusStrategy
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return &REST{store: store}, &BindingREST{store: store, factory: factory}, &StatusREST{store: &statusStore}
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}
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// WithPodStatus returns a rest object that decorates returned responses with extra
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// status information.
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func (r *REST) WithPodStatus(cache pod.PodStatusGetter) *REST {
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store := *r.store
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store.Decorator = pod.PodStatusDecorator(cache)
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store.AfterDelete = rest.AllFuncs(store.AfterDelete, pod.PodStatusReset(cache))
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return &REST{store: &store}
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}
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// New returns a new object
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func (r *REST) New() runtime.Object {
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return r.store.NewFunc()
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}
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// NewList returns a new list object
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func (r *REST) NewList() runtime.Object {
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return r.store.NewListFunc()
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}
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// List obtains a list of pods with labels that match selector.
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func (r *REST) List(ctx api.Context, label, field labels.Selector) (runtime.Object, error) {
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return r.store.List(ctx, label, field)
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}
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// Watch begins watching for new, changed, or deleted pods.
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func (r *REST) Watch(ctx api.Context, label, field labels.Selector, resourceVersion string) (watch.Interface, error) {
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return r.store.Watch(ctx, label, field, resourceVersion)
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}
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// Get gets a specific pod specified by its ID.
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func (r *REST) Get(ctx api.Context, name string) (runtime.Object, error) {
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return r.store.Get(ctx, name)
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}
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// Create creates a pod based on a specification.
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func (r *REST) Create(ctx api.Context, obj runtime.Object) (runtime.Object, error) {
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return r.store.Create(ctx, obj)
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}
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// Update changes a pod specification.
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func (r *REST) Update(ctx api.Context, obj runtime.Object) (runtime.Object, bool, error) {
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return r.store.Update(ctx, obj)
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}
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// Delete deletes an existing pod specified by its ID.
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func (r *REST) Delete(ctx api.Context, name string) (runtime.Object, error) {
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return r.store.Delete(ctx, name)
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}
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// ResourceLocation returns a pods location from its HostIP
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func (r *REST) ResourceLocation(ctx api.Context, name string) (string, error) {
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return pod.ResourceLocation(r, ctx, name)
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}
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func makeBoundPodsKey(machine string) string {
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return "/registry/nodes/" + machine + "/boundpods"
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}
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// BindingREST implements the REST endpoint for binding pods to nodes when etcd is in use.
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type BindingREST struct {
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store *etcdgeneric.Etcd
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factory pod.BoundPodFactory
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}
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func (r *BindingREST) New() runtime.Object {
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return &api.Binding{}
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}
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// Create ensures a pod is bound to a specific host.
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func (r *BindingREST) Create(ctx api.Context, obj runtime.Object) (out runtime.Object, err error) {
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binding := obj.(*api.Binding)
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err = r.assignPod(ctx, binding.PodID, binding.Host)
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err = etcderr.InterpretCreateError(err, "binding", "")
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out = &api.Status{Status: api.StatusSuccess}
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return
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}
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// setPodHostTo sets the given pod's host to 'machine' iff it was previously 'oldMachine'.
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// Returns the current state of the pod, or an error.
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func (r *BindingREST) setPodHostTo(ctx api.Context, podID, oldMachine, machine string) (finalPod *api.Pod, err error) {
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podKey, err := r.store.KeyFunc(ctx, podID)
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if err != nil {
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return nil, err
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}
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err = r.store.Helper.AtomicUpdate(podKey, &api.Pod{}, false, func(obj runtime.Object) (runtime.Object, error) {
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pod, ok := obj.(*api.Pod)
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if !ok {
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return nil, fmt.Errorf("unexpected object: %#v", obj)
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}
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if pod.Status.Host != oldMachine {
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return nil, fmt.Errorf("pod %v is already assigned to host %v", pod.Name, pod.Status.Host)
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}
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pod.Status.Host = machine
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finalPod = pod
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return pod, nil
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})
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return finalPod, err
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}
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// assignPod assigns the given pod to the given machine.
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func (r *BindingREST) assignPod(ctx api.Context, podID string, machine string) error {
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finalPod, err := r.setPodHostTo(ctx, podID, "", machine)
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if err != nil {
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return err
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}
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boundPod, err := r.factory.MakeBoundPod(machine, finalPod)
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if err != nil {
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return err
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}
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// Doing the constraint check this way provides atomicity guarantees.
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contKey := makeBoundPodsKey(machine)
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err = r.store.Helper.AtomicUpdate(contKey, &api.BoundPods{}, true, func(in runtime.Object) (runtime.Object, error) {
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boundPodList := in.(*api.BoundPods)
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boundPodList.Items = append(boundPodList.Items, *boundPod)
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if errors := constraint.Allowed(boundPodList.Items); len(errors) > 0 {
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return nil, fmt.Errorf("the assignment would cause the following constraints violation: %v", errors)
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}
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return boundPodList, nil
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})
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if err != nil {
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// Put the pod's host back the way it was. This is a terrible hack, but
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// can't really be helped, since there's not really a way to do atomic
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// multi-object changes in etcd.
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if _, err2 := r.setPodHostTo(ctx, podID, machine, ""); err2 != nil {
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glog.Errorf("Stranding pod %v; couldn't clear host after previous error: %v", podID, err2)
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}
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}
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return err
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}
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type podLifecycle struct {
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tools.EtcdHelper
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}
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func (h *podLifecycle) AfterUpdate(obj runtime.Object) error {
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pod := obj.(*api.Pod)
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if len(pod.Status.Host) == 0 {
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return nil
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}
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containerKey := makeBoundPodsKey(pod.Status.Host)
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return h.AtomicUpdate(containerKey, &api.BoundPods{}, true, func(in runtime.Object) (runtime.Object, error) {
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boundPods := in.(*api.BoundPods)
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for ix := range boundPods.Items {
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if boundPods.Items[ix].Name == pod.Name && boundPods.Items[ix].Namespace == pod.Namespace {
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boundPods.Items[ix].Spec = pod.Spec
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return boundPods, nil
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}
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}
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// This really shouldn't happen
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glog.Warningf("Couldn't find: %s in %#v", pod.Name, boundPods)
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return boundPods, fmt.Errorf("failed to update pod, couldn't find %s in %#v", pod.Name, boundPods)
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})
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}
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func (h *podLifecycle) AfterDelete(obj runtime.Object) error {
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pod := obj.(*api.Pod)
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if len(pod.Status.Host) == 0 {
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return nil
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}
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containerKey := makeBoundPodsKey(pod.Status.Host)
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return h.AtomicUpdate(containerKey, &api.BoundPods{}, true, func(in runtime.Object) (runtime.Object, error) {
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pods := in.(*api.BoundPods)
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newPods := make([]api.BoundPod, 0, len(pods.Items))
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found := false
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for _, boundPod := range pods.Items {
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if boundPod.Name != pod.Name || boundPod.Namespace != pod.Namespace {
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newPods = append(newPods, boundPod)
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} else {
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found = true
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}
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}
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if !found {
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// This really shouldn't happen, it indicates something is broken, and likely
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// there is a lost pod somewhere.
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// However it is "deleted" so log it and move on
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glog.Warningf("Couldn't find: %s in %#v", pod.Name, pods)
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}
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pods.Items = newPods
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return pods, nil
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})
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}
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// StatusREST implements the REST endpoint for changing the status of a pod.
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type StatusREST struct {
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store *etcdgeneric.Etcd
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}
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func (r *StatusREST) New() runtime.Object {
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return &api.Pod{}
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}
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// Update alters the status subset of an object.
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func (r *StatusREST) Update(ctx api.Context, obj runtime.Object) (runtime.Object, bool, error) {
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return r.store.Update(ctx, obj)
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}
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