def connect(seeds, keyspace, datacenter=None, port=9042):
    class CustomRetryPolicy(RetryPolicy):
        def on_write_timeout(self, query, consistency, write_type,
                             required_responses, received_responses, retry_num):
            # retry at most 5 times regardless of query type
            if retry_num >= 5:
                return (self.RETHROW, None)

            return (self.RETRY, consistency)

    load_balancing_policy = None
    if datacenter:
        # If you are using multiple datacenters it's important to use
        # the DCAwareRoundRobinPolicy. If not then the client will
        # make cross DC connections. This defaults to round robin
        # which means round robin across all nodes irrespective of
        # data center.
        load_balancing_policy = DCAwareRoundRobinPolicy(local_dc=DATACENTER)

    cluster = Cluster(contact_points=seeds,
                      port=port,
                      default_retry_policy=CustomRetryPolicy(),
                      reconnection_policy=ExponentialReconnectionPolicy(1, 60),
                      load_balancing_policy=load_balancing_policy,
                      protocol_version=3)

    cluster.control_connection_timeout = 10.0
    cluster.compression = False
    session = cluster.connect(keyspace)
    print 'Connection established with %s at port %s' % (seeds, port)
    return session
示例#2
0
def connect(seeds, keyspace, datacenter=None, port=9042):
    from cassandra.io.libevreactor import LibevConnection
    from cassandra.cluster import Cluster
    from cassandra.policies import DCAwareRoundRobinPolicy, RetryPolicy, ExponentialReconnectionPolicy

    class CustomRetryPolicy(RetryPolicy):

        def on_write_timeout(self, query, consistency, write_type,
                             required_responses, received_responses, retry_num):

            # retry at most 5 times regardless of query type
            if retry_num >= 5:
                return (self.RETHROW, None)

            return (self.RETRY, consistency)


    load_balancing_policy = None
    if datacenter:
        # If you are using multiple datacenters it's important to use
        # the DCAwareRoundRobinPolicy. If not then the client will
        # make cross DC connections. This defaults to round robin
        # which means round robin across all nodes irrespective of
        # data center.
        load_balancing_policy = DCAwareRoundRobinPolicy(local_dc=datacenter)

    cluster = Cluster(contact_points=seeds,
                      port=port,
                      auth_provider=auth_provider,
                      default_retry_policy=CustomRetryPolicy(),
                      reconnection_policy=ExponentialReconnectionPolicy(1, 60),
                      load_balancing_policy=load_balancing_policy)

    cluster.connection_class = LibevConnection
    cluster.set_core_connections_per_host(0, 3) # local connections
    cluster.set_core_connections_per_host(1, 0) # remote connections
    cluster.control_connection_timeout = 10.0
    cluster.compression = False
    session = cluster.connect(keyspace)
    return session