Sharding.py 文件源码

def get_mongos(self, force=False):
        if not force and self.mongos_db:
            return self.mongos_db
        elif self.db.is_mongos():
            return self.db
        else:
            db = self.connection['config']
            for doc in db.mongos.find().sort('ping', DESCENDING):
                try:
                    mongos_uri = MongoUri(doc['_id'])
                    logging.debug("Found cluster mongos: %s" % mongos_uri)
                    self.mongos_db = DB(mongos_uri, self.config, False, 'nearest')
                    logging.info("Connected to cluster mongos: %s" % mongos_uri)
                    return self.mongos_db
                except DBConnectionError:
                    logging.debug("Failed to connect to mongos: %s, trying next available mongos" % mongos_uri)
            raise OperationError('Could not connect to any mongos!')