// Watch starts a NotifyWatcher for the entity with the specified tag.
func Watch(facade base.FacadeCaller, tag names.Tag) (watcher.NotifyWatcher, error) {
var results params.NotifyWatchResults
args := params.Entities{
Entities: []params.Entity{{Tag: tag.String()}},
}
err := facade.FacadeCall("Watch", args, &results)
if err != nil {
return nil, err
}
if len(results.Results) != 1 {
return nil, fmt.Errorf("expected 1 result, got %d", len(results.Results))
}
result := results.Results[0]
if result.Error != nil {
return nil, result.Error
}
return watcher.NewNotifyWatcher(facade.RawAPICaller(), result), nil
}
