'Return the attributes of one watch/alarm.
:param cnxt: RPC context.
:param watch_name: Name of the watch you want to see, or None to see
all.'

@context.request_context
def show_watch(self, cnxt, watch_name):

    if watch_name:
        wrn = [watch_name]
    else:
        try:
            wrn = [w.name for w in watch_rule.WatchRule.get_all(cnxt)]
        except Exception as ex:
            LOG.warning('show_watch    (all)    db    error    %s', ex)
            return
    wrs = [watchrule.WatchRule.load(cnxt, w) for w in wrn]
    result = [api.format_watch(w) for w in wrs]
    return result
