cluster.py 文件源码

def prepare_on_all_hosts(self, query, excluded_host):
        """
        Prepare the given query on all hosts, excluding ``excluded_host``.
        Intended for internal use only.
        """
        futures = []
        for host in tuple(self._pools.keys()):
            if host != excluded_host and host.is_up:
                future = ResponseFuture(self, PrepareMessage(query=query), None, self.default_timeout)

                # we don't care about errors preparing against specific hosts,
                # since we can always prepare them as needed when the prepared
                # statement is used.  Just log errors and continue on.
                try:
                    request_id = future._query(host)
                except Exception:
                    log.exception("Error preparing query for host %s:", host)
                    continue

                if request_id is None:
                    # the error has already been logged by ResponsFuture
                    log.debug("Failed to prepare query for host %s: %r",
                              host, future._errors.get(host))
                    continue

                futures.append((host, future))

        for host, future in futures:
            try:
                future.result()
            except Exception:
                log.exception("Error preparing query for host %s:", host)