ZMQ Support

LabGraph has two types of nodes which allow us to use the ZeroMQ (ZMQ) library: ZMQPollerNode and ZMQSenderNode. They work with ZMQ sockets that use the PUB and SUB modes; other modes like REQ/REP and PAIR are currently unsupported.

ZMQMessage

The basic message type that is used by both the ZMQPollerNode and ZMQSenderNode to communicate ZMQ data to the graph. It has just one field, data, which contains the raw bytes sent over the ZMQ socket.

ZMQPollerNode

This node polls ZMQ data of a particular ZMQ topic at a particular read address (both configurable). Any data polled by the node is published as a ZMQMessage back to the rest of the graph. This node has the following configuration parameters via ZMQPollerConfig:

• read_addr: The address through which ZMQ data should be polled.

• zmq_topic: The ZMQ topic being polled.

• poll_time: How long each iteration of the polling loop should take (in seconds)

ZMQSenderNode

This node subscribes to a stream of ZMQMessages, and publishes its contents over ZMQ at a configured address/topic. This node has the following configuration parameters via ZMQSenderConfig:

• write_addr: The address to which ZMQ data should be written.

• zmq_topic: The ZMQ topic being written to.