// updatePodWithRetries retries updating the given pod on conflict with the following steps:
// 1. Get latest resource
// 2. applyUpdate
// 3. Update the resource
func updatePodWithRetries(c client.Interface, namespace string, pod *api.Pod, applyUpdate updatePodFunc) (*api.Pod, error) {
// Deep copy the pod in case we failed on Get during retry loop
obj, err := api.Scheme.Copy(pod)
if err != nil {
return nil, fmt.Errorf("failed to deep copy pod before updating it: %v", err)
}
oldPod := obj.(*api.Pod)
err = client.RetryOnConflict(client.DefaultBackoff, func() (e error) {
// Apply the update, then attempt to push it to the apiserver.
applyUpdate(pod)
if pod, e = c.Pods(namespace).Update(pod); e == nil {
return
}
updateErr := e
if pod, e = c.Pods(namespace).Get(oldPod.Name); e != nil {
pod = oldPod
}
// Only return the error from update
return updateErr
})
// If the error is non-nil the returned pod cannot be trusted, if it is nil, the returned
// controller contains the applied update.
return pod, err
}
func AddDeploymentKeyToReplicationController(oldRc *api.ReplicationController, client client.Interface, deploymentKey, deploymentValue, namespace string, out io.Writer) (*api.ReplicationController, error) {
var err error
// First, update the template label. This ensures that any newly created pods will have the new label
applyUpdate := func(rc *api.ReplicationController) {
if rc.Spec.Template.Labels == nil {
rc.Spec.Template.Labels = map[string]string{}
}
rc.Spec.Template.Labels[deploymentKey] = deploymentValue
}
if oldRc, err = updateRcWithRetries(client, namespace, oldRc, applyUpdate); err != nil {
return nil, err
}
// Update all pods managed by the rc to have the new hash label, so they are correctly adopted
// TODO: extract the code from the label command and re-use it here.
selector := labels.SelectorFromSet(oldRc.Spec.Selector)
options := api.ListOptions{LabelSelector: selector}
podList, err := client.Pods(namespace).List(options)
if err != nil {
return nil, err
}
for ix := range podList.Items {
pod := &podList.Items[ix]
applyUpdate := func(p *api.Pod) {
if p.Labels == nil {
p.Labels = map[string]string{
deploymentKey: deploymentValue,
}
} else {
p.Labels[deploymentKey] = deploymentValue
}
}
if pod, err = updatePodWithRetries(client, namespace, pod, applyUpdate); err != nil {
return nil, err
}
}
if oldRc.Spec.Selector == nil {
oldRc.Spec.Selector = map[string]string{}
}
// Copy the old selector, so that we can scrub out any orphaned pods
selectorCopy := map[string]string{}
for k, v := range oldRc.Spec.Selector {
selectorCopy[k] = v
}
applyUpdate = func(rc *api.ReplicationController) {
rc.Spec.Selector[deploymentKey] = deploymentValue
}
// Update the selector of the rc so it manages all the pods we updated above
if oldRc, err = updateRcWithRetries(client, namespace, oldRc, applyUpdate); err != nil {
return nil, err
}
// Clean up any orphaned pods that don't have the new label, this can happen if the rc manager
// doesn't see the update to its pod template and creates a new pod with the old labels after
// we've finished re-adopting existing pods to the rc.
selector = labels.SelectorFromSet(selectorCopy)
options = api.ListOptions{LabelSelector: selector}
podList, err = client.Pods(namespace).List(options)
for ix := range podList.Items {
pod := &podList.Items[ix]
if value, found := pod.Labels[deploymentKey]; !found || value != deploymentValue {
if err := client.Pods(namespace).Delete(pod.Name, nil); err != nil {
return nil, err
}
}
}
return oldRc, nil
}