eventlet.green.zmq – ØMQ support

pyzmq [1] is a python binding to the C++ ØMQ [2] library written in Cython [3]. eventlet.green.zmq is greenthread aware version of pyzmq.

The zmq module wraps the Socket and Context found in pyzmq to be non blocking.

class eventlet.green.zmq.Context(io_threads: int = 1, **kwargs: Any)

Bases: Context

Subclass of zmq.Context

socket(socket_type)

Overridden method to ensure that the green version of socket is used

Behaves the same as zmq.Context.socket(), but ensures that a Socket with all of its send and recv methods set to be non-blocking is returned

class eventlet.green.zmq.Socket(context, socket_type)

Bases: Socket

Green version of :class:`zmq.core.socket.Socket

The following three methods are always overridden:

  • send

  • recv

  • getsockopt

To ensure that the zmq.NOBLOCK flag is set and that sending or receiving is deferred to the hub (using eventlet.hubs.trampoline()) if a zmq.EAGAIN (retry) error is raised

For some socket types, the following methods are also overridden:

  • send_multipart

  • recv_multipart

recv(flags=0, copy=True, track=False)

Receive a message.

With flags=NOBLOCK, this raises ZMQError if no messages have arrived; otherwise, this waits until a message arrives. See Poller for more general non-blocking I/O.

Parameters

flagsint

0 or NOBLOCK.

copybool

Should the message be received in a copying or non-copying manner? If False a Frame object is returned, if True a string copy of message is returned.

trackbool

Should the message be tracked for notification that ZMQ has finished with it? (ignored if copy=True)

Returns

msgbytes or Frame

The received message frame. If copy is False, then it will be a Frame, otherwise it will be bytes.

Raises

ZMQError

for any of the reasons zmq_msg_recv might fail (including if NOBLOCK is set and no new messages have arrived).

send(msg, flags=0, copy=True, track=False)

Send a single zmq message frame on this socket.

This queues the message to be sent by the IO thread at a later time.

With flags=NOBLOCK, this raises ZMQError if the queue is full; otherwise, this waits until space is available. See Poller for more general non-blocking I/O.

Parameters

databytes, Frame, memoryview

The content of the message. This can be any object that provides the Python buffer API (i.e. memoryview(data) can be called).

flagsint

0, NOBLOCK, SNDMORE, or NOBLOCK|SNDMORE.

copybool

Should the message be sent in a copying or non-copying manner.

trackbool

Should the message be tracked for notification that ZMQ has finished with it? (ignored if copy=True)

routing_idint

For use with SERVER sockets

groupstr

For use with RADIO sockets

Returns

Noneif copy or not track

None if message was sent, raises an exception otherwise.

MessageTrackerif track and not copy

a MessageTracker object, whose pending property will be True until the send is completed.

Raises

TypeError

If a unicode object is passed

ValueError

If track=True, but an untracked Frame is passed.

ZMQError

If the send does not succeed for any reason (including if NOBLOCK is set and the outgoing queue is full).

Changed in version 17.0: DRAFT support for routing_id and group arguments.