Using the Driver

Connecting to a Cluster

To take advantage of the higher level features of the driver, Goblin provides the Cluster object. Cluster is used to create multi-host clients that leverage connection pooling and sharing. Its interface is based on the TinkerPop Java driver:

>>> async def print_results(gremlin='1+1'):
...     # opens a cluster with default config
...     cluster = await driver.Cluster.open('')
...     client = await cluster.connect()
...     # round robin requests to available hosts
...     resp = await client.submit(gremlin=gremlin)
...     async for msg in resp:
...         print(msg)
...     await cluster.close()  # Close all connections to all hosts

And that is it. While Cluster is simple to learn and use, it provides a wide variety of configuration options.

Configuring Cluster

Configuration options can be set on Cluster in one of two ways, either passed as keyword arguments to open, or stored in a configuration file and passed to the open using the kwarg configfile. Configuration files can be either YAML or JSON format. Currently, Cluster uses the following configuration:

Key	Description	Default
scheme	URI scheme, typically ‘ws’ or ‘wss’ for secure websockets	‘ws’
hosts	A list of hosts the cluster will connect to	[‘localhost’]
port	The port of the Gremlin Server to connect to, same for all hosts	8182
ssl_certfile	File containing ssl certificate	‘’
ssl_keyfile	File containing ssl key	‘’
ssl_password	File containing password for ssl keyfile	‘’
username	Username for Gremlin Server authentication	‘’
password	Password for Gremlin Server authentication	‘’
response_timeout	Timeout for reading responses from the stream	None
max_conns	The maximum number of connections open at any time to this host	4
min_conns	The minimum number of connection open at any time to this host	1
max_times_acquired	The maximum number of times a single pool connection can be acquired and shared	16
max_inflight	The maximum number of unresolved messages that may be pending on any one connection	64
message_serializer	String denoting the class used for message serialization, currently only supports basic GraphSONMessageSerializer	‘classpath’

For information related to improving driver performance, please refer to the performance section.