metadata.py 文件源码

def get_replicas(self, keyspace, token):
        """
        Get  a set of :class:`.Host` instances representing all of the
        replica nodes for a given :class:`.Token`.
        """
        tokens_to_hosts = self.tokens_to_hosts_by_ks.get(keyspace, None)
        if tokens_to_hosts is None:
            self.rebuild_keyspace(keyspace, build_if_absent=True)
            tokens_to_hosts = self.tokens_to_hosts_by_ks.get(keyspace, None)

        if tokens_to_hosts:
            # token range ownership is exclusive on the LHS (the start token), so
            # we use bisect_right, which, in the case of a tie/exact match,
            # picks an insertion point to the right of the existing match
            point = bisect_right(self.ring, token)
            if point == len(self.ring):
                return tokens_to_hosts[self.ring[0]]
            else:
                return tokens_to_hosts[self.ring[point]]
        return []