// updateRcWithRetries retries updating the given rc on conflict with the following steps:
// 1. Get latest resource
// 2. applyUpdate
// 3. Update the resource
func updateRcWithRetries(c client.Interface, namespace string, rc *api.ReplicationController, applyUpdate updateRcFunc) (*api.ReplicationController, error) {
	// Deep copy the rc in case we failed on Get during retry loop
	obj, err := api.Scheme.Copy(rc)
	if err != nil {
		return nil, fmt.Errorf("failed to deep copy rc before updating it: %v", err)
	}
	oldRc := obj.(*api.ReplicationController)
	err = client.RetryOnConflict(client.DefaultBackoff, func() (e error) {
		// Apply the update, then attempt to push it to the apiserver.
		applyUpdate(rc)
		if rc, e = c.ReplicationControllers(namespace).Update(rc); e == nil {
			// rc contains the latest controller post update
			return
		}
		updateErr := e
		// Update the controller with the latest resource version, if the update failed we
		// can't trust rc so use oldRc.Name.
		if rc, e = c.ReplicationControllers(namespace).Get(oldRc.Name); e != nil {
			// The Get failed: Value in rc cannot be trusted.
			rc = oldRc
		}
		// Only return the error from update
		return updateErr
	})
	// If the error is non-nil the returned controller cannot be trusted, if it is nil, the returned
	// controller contains the applied update.
	return rc, err
}
func CreateNewControllerFromCurrentController(c client.Interface, codec runtime.Codec, cfg *NewControllerConfig) (*api.ReplicationController, error) {
	containerIndex := 0
	// load the old RC into the "new" RC
	newRc, err := c.ReplicationControllers(cfg.Namespace).Get(cfg.OldName)
	if err != nil {
		return nil, err
	}

	if len(cfg.Container) != 0 {
		containerFound := false

		for i, c := range newRc.Spec.Template.Spec.Containers {
			if c.Name == cfg.Container {
				containerIndex = i
				containerFound = true
				break
			}
		}

		if !containerFound {
			return nil, fmt.Errorf("container %s not found in pod", cfg.Container)
		}
	}

	if len(newRc.Spec.Template.Spec.Containers) > 1 && len(cfg.Container) == 0 {
		return nil, goerrors.New("Must specify container to update when updating a multi-container pod")
	}

	if len(newRc.Spec.Template.Spec.Containers) == 0 {
		return nil, goerrors.New(fmt.Sprintf("Pod has no containers! (%v)", newRc))
	}
	newRc.Spec.Template.Spec.Containers[containerIndex].Image = cfg.Image
	if len(cfg.PullPolicy) != 0 {
		newRc.Spec.Template.Spec.Containers[containerIndex].ImagePullPolicy = cfg.PullPolicy
	}

	newHash, err := api.HashObject(newRc, codec)
	if err != nil {
		return nil, err
	}

	if len(cfg.NewName) == 0 {
		cfg.NewName = fmt.Sprintf("%s-%s", newRc.Name, newHash)
	}
	newRc.Name = cfg.NewName

	newRc.Spec.Selector[cfg.DeploymentKey] = newHash
	newRc.Spec.Template.Labels[cfg.DeploymentKey] = newHash
	// Clear resource version after hashing so that identical updates get different hashes.
	newRc.ResourceVersion = ""
	return newRc, nil
}