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=1, **kwargs)

Bases: zmq.sugar.context.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: zmq.sugar.socket.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.

flags : int
0 or NOBLOCK.
copy : bool
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.
track : bool
Should the message be tracked for notification that ZMQ has finished with it? (ignored if copy=True)
msg : bytes or Frame
The received message frame. If copy is False, then it will be a Frame, otherwise it will be bytes.
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.

data : bytes, 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).
flags : int
0, NOBLOCK, SNDMORE, or NOBLOCK|SNDMORE.
copy : bool
Should the message be sent in a copying or non-copying manner.
track : bool
Should the message be tracked for notification that ZMQ has finished with it? (ignored if copy=True)
routing_id : int
For use with SERVER sockets
group : str
For use with RADIO sockets
None : if copy or not track
None if message was sent, raises an exception otherwise.
MessageTracker : if track and not copy
a MessageTracker object, whose pending property will be True until the send is completed.
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.

bind(addr)

Bind the socket to an address.

This causes the socket to listen on a network port. Sockets on the other side of this connection will use Socket.connect(addr) to connect to this socket.

addr : str
The address string. This has the form ‘protocol://interface:port’, for example ‘tcp://127.0.0.1:5555’. Protocols supported include tcp, udp, pgm, epgm, inproc and ipc. If the address is unicode, it is encoded to utf-8 first.
bind_to_random_port(addr, min_port=49152, max_port=65536, max_tries=100)

Bind this socket to a random port in a range.

If the port range is unspecified, the system will choose the port.

addr : str
The address string without the port to pass to Socket.bind().
min_port : int, optional
The minimum port in the range of ports to try (inclusive).
max_port : int, optional
The maximum port in the range of ports to try (exclusive).
max_tries : int, optional
The maximum number of bind attempts to make.
port : int
The port the socket was bound to.
ZMQBindError
if max_tries reached before successful bind
close(linger=None)

Close the socket.

If linger is specified, LINGER sockopt will be set prior to closing.

This can be called to close the socket by hand. If this is not called, the socket will automatically be closed when it is garbage collected.

connect(addr)

Connect to a remote 0MQ socket.

addr : str
The address string. This has the form ‘protocol://interface:port’, for example ‘tcp://127.0.0.1:5555’. Protocols supported are tcp, upd, pgm, inproc and ipc. If the address is unicode, it is encoded to utf-8 first.
disable_monitor()

Shutdown the PAIR socket (created using get_monitor_socket) that is serving socket events.

New in version 14.4.

disconnect(addr)

Disconnect from a remote 0MQ socket (undoes a call to connect).

New in version libzmq-3.2.

New in version 13.0.

addr : str
The address string. This has the form ‘protocol://interface:port’, for example ‘tcp://127.0.0.1:5555’. Protocols supported are tcp, upd, pgm, inproc and ipc. If the address is unicode, it is encoded to utf-8 first.
fileno()

Return edge-triggered file descriptor for this socket.

This is a read-only edge-triggered file descriptor for both read and write events on this socket. It is important that all available events be consumed when an event is detected, otherwise the read event will not trigger again.

New in version 17.0.

get(option)

Get the value of a socket option.

See the 0MQ API documentation for details on specific options.

option : int

The option to get. Available values will depend on your version of libzmq. Examples include:

zmq.IDENTITY, HWM, LINGER, FD, EVENTS
optval : int or bytes
The value of the option as a bytestring or int.
get_hwm()

Get the High Water Mark.

On libzmq ≥ 3, this gets SNDHWM if available, otherwise RCVHWM

get_monitor_socket(events=None, addr=None)

Return a connected PAIR socket ready to receive the event notifications.

New in version libzmq-4.0.

New in version 14.0.

events : int [default: ZMQ_EVENTS_ALL]
The bitmask defining which events are wanted.
addr : string [default: None]
The optional endpoint for the monitoring sockets.
socket : (PAIR)
The socket is already connected and ready to receive messages.
get_string(option, encoding='utf-8')

Get the value of a socket option.

See the 0MQ documentation for details on specific options.

option : int
The option to retrieve.
optval : unicode string (unicode on py2, str on py3)
The value of the option as a unicode string.
getsockopt(option)

s.get(option)

Get the value of a socket option.

See the 0MQ API documentation for details on specific options.

option : int

The option to get. Available values will depend on your version of libzmq. Examples include:

zmq.IDENTITY, HWM, LINGER, FD, EVENTS
optval : int or bytes
The value of the option as a bytestring or int.
getsockopt_string(option, encoding='utf-8')

Get the value of a socket option.

See the 0MQ documentation for details on specific options.

option : int
The option to retrieve.
optval : unicode string (unicode on py2, str on py3)
The value of the option as a unicode string.
getsockopt_unicode(option, encoding='utf-8')

Get the value of a socket option.

See the 0MQ documentation for details on specific options.

option : int
The option to retrieve.
optval : unicode string (unicode on py2, str on py3)
The value of the option as a unicode string.
hwm

Get the High Water Mark.

On libzmq ≥ 3, this gets SNDHWM if available, otherwise RCVHWM

join(group)

Join a RADIO-DISH group

Only for DISH sockets.

libzmq and pyzmq must have been built with ZMQ_BUILD_DRAFT_API

New in version 17.

leave(group)

Leave a RADIO-DISH group

Only for DISH sockets.

libzmq and pyzmq must have been built with ZMQ_BUILD_DRAFT_API

New in version 17.

monitor(addr, flags)

Start publishing socket events on inproc. See libzmq docs for zmq_monitor for details.

While this function is available from libzmq 3.2, pyzmq cannot parse monitor messages from libzmq prior to 4.0.

addr : str
The inproc url used for monitoring. Passing None as the addr will cause an existing socket monitor to be deregistered.
events : int [default: zmq.EVENT_ALL]
The zmq event bitmask for which events will be sent to the monitor.
poll(timeout=None, flags=1)

Poll the socket for events. See Poller to wait for multiple sockets at once.

timeout : int [default: None]
The timeout (in milliseconds) to wait for an event. If unspecified (or specified None), will wait forever for an event.
flags : int [default: POLLIN]
POLLIN, POLLOUT, or POLLIN|POLLOUT. The event flags to poll for.
events : int
The events that are ready and waiting, 0 if the timeout was reached with no events.
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.

flags : int
0 or NOBLOCK.
copy : bool
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.
track : bool
Should the message be tracked for notification that ZMQ has finished with it? (ignored if copy=True)
msg : bytes or Frame
The received message frame. If copy is False, then it will be a Frame, otherwise it will be bytes.
ZMQError
for any of the reasons zmq_msg_recv might fail (including if NOBLOCK is set and no new messages have arrived).
recv_json(flags=0, **kwargs)

Receive a Python object as a message using json to serialize.

Keyword arguments are passed on to json.loads

flags : int
Any valid flags for Socket.recv().
obj : Python object
The Python object that arrives as a message.
ZMQError
for any of the reasons recv() might fail
recv_multipart(flags=0, copy=True, track=False)

Receive a multipart message as a list of bytes or Frame objects

flags : int, optional
Any valid flags for Socket.recv().
copy : bool, optional
Should the message frame(s) be received in a copying or non-copying manner? If False a Frame object is returned for each part, if True a copy of the bytes is made for each frame.
track : bool, optional
Should the message frame(s) be tracked for notification that ZMQ has finished with it? (ignored if copy=True)
msg_parts : list
A list of frames in the multipart message; either Frames or bytes, depending on copy.
ZMQError
for any of the reasons recv() might fail
recv_pyobj(flags=0)

Receive a Python object as a message using pickle to serialize.

flags : int
Any valid flags for Socket.recv().
obj : Python object
The Python object that arrives as a message.
ZMQError
for any of the reasons recv() might fail
recv_serialized(deserialize, flags=0, copy=True)

Receive a message with a custom deserialization function.

New in version 17.

deserialize : callable
The deserialization function to use. deserialize will be called with one argument: the list of frames returned by recv_multipart() and can return any object.
flags : int, optional
Any valid flags for Socket.recv().
copy : bool, optional
Whether to recv bytes or Frame objects.
obj : object
The object returned by the deserialization function.
ZMQError
for any of the reasons recv() might fail
recv_string(flags=0, encoding='utf-8')

Receive a unicode string, as sent by send_string.

flags : int
Any valid flags for Socket.recv().
encoding : str [default: ‘utf-8’]
The encoding to be used
s : unicode string (unicode on py2, str on py3)
The Python unicode string that arrives as encoded bytes.
ZMQError
for any of the reasons recv() might fail
recv_unicode(flags=0, encoding='utf-8')

Receive a unicode string, as sent by send_string.

flags : int
Any valid flags for Socket.recv().
encoding : str [default: ‘utf-8’]
The encoding to be used
s : unicode string (unicode on py2, str on py3)
The Python unicode string that arrives as encoded bytes.
ZMQError
for any of the reasons recv() might fail
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.

data : bytes, 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).
flags : int
0, NOBLOCK, SNDMORE, or NOBLOCK|SNDMORE.
copy : bool
Should the message be sent in a copying or non-copying manner.
track : bool
Should the message be tracked for notification that ZMQ has finished with it? (ignored if copy=True)
routing_id : int
For use with SERVER sockets
group : str
For use with RADIO sockets
None : if copy or not track
None if message was sent, raises an exception otherwise.
MessageTracker : if track and not copy
a MessageTracker object, whose pending property will be True until the send is completed.
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.

send_json(obj, flags=0, **kwargs)

Send a Python object as a message using json to serialize.

Keyword arguments are passed on to json.dumps

obj : Python object
The Python object to send
flags : int
Any valid flags for Socket.send()
send_multipart(msg_parts, flags=0, copy=True, track=False)

Send a sequence of buffers as a multipart message.

The zmq.SNDMORE flag is added to all msg parts before the last.

msg_parts : iterable
A sequence of objects to send as a multipart message. Each element can be any sendable object (Frame, bytes, buffer-providers)
flags : int, optional
Any valid flags for Socket.send(). SNDMORE is added automatically for frames before the last.
copy : bool, optional
Should the frame(s) be sent in a copying or non-copying manner. If copy=False, frames smaller than self.copy_threshold bytes will be copied anyway.
track : bool, optional
Should the frame(s) be tracked for notification that ZMQ has finished with it (ignored if copy=True).

None : if copy or not track MessageTracker : if track and not copy

a MessageTracker object, whose pending property will be True until the last send is completed.
send_pyobj(obj, flags=0, protocol=2)

Send a Python object as a message using pickle to serialize.

obj : Python object
The Python object to send.
flags : int
Any valid flags for Socket.send().
protocol : int
The pickle protocol number to use. The default is pickle.DEFAULT_PROTOCOL where defined, and pickle.HIGHEST_PROTOCOL elsewhere.
send_serialized(msg, serialize, flags=0, copy=True, **kwargs)

Send a message with a custom serialization function.

New in version 17.

msg : The message to be sent. Can be any object serializable by serialize. serialize : callable

The serialization function to use. serialize(msg) should return an iterable of sendable message frames (e.g. bytes objects), which will be passed to send_multipart.
flags : int, optional
Any valid flags for Socket.send().
copy : bool, optional
Whether to copy the frames.
send_string(u, flags=0, copy=True, encoding='utf-8')

Send a Python unicode string as a message with an encoding.

0MQ communicates with raw bytes, so you must encode/decode text (unicode on py2, str on py3) around 0MQ.

u : Python unicode string (unicode on py2, str on py3)
The unicode string to send.
flags : int, optional
Any valid flags for Socket.send().
encoding : str [default: ‘utf-8’]
The encoding to be used
send_unicode(u, flags=0, copy=True, encoding='utf-8', **kwargs)

Send a Python unicode string as a message with an encoding.

0MQ communicates with raw bytes, so you must encode/decode text (unicode on py2, str on py3) around 0MQ.

u : Python unicode string (unicode on py2, str on py3)
The unicode string to send.
flags : int, optional
Any valid flags for Socket.send().
encoding : str [default: ‘utf-8’]
The encoding to be used
set(option, optval)

Set socket options.

See the 0MQ API documentation for details on specific options.

option : int

The option to set. Available values will depend on your version of libzmq. Examples include:

zmq.SUBSCRIBE, UNSUBSCRIBE, IDENTITY, HWM, LINGER, FD
optval : int or bytes
The value of the option to set.

Warning

All options other than zmq.SUBSCRIBE, zmq.UNSUBSCRIBE and zmq.LINGER only take effect for subsequent socket bind/connects.

set_hwm(value)

Set the High Water Mark.

On libzmq ≥ 3, this sets both SNDHWM and RCVHWM

Warning

New values only take effect for subsequent socket bind/connects.

set_string(option, optval, encoding='utf-8')

Set socket options with a unicode object.

This is simply a wrapper for setsockopt to protect from encoding ambiguity.

See the 0MQ documentation for details on specific options.

option : int
The name of the option to set. Can be any of: SUBSCRIBE, UNSUBSCRIBE, IDENTITY
optval : unicode string (unicode on py2, str on py3)
The value of the option to set.
encoding : str
The encoding to be used, default is utf8
setsockopt()

s.set(option, optval)

Set socket options.

See the 0MQ API documentation for details on specific options.

option : int

The option to set. Available values will depend on your version of libzmq. Examples include:

zmq.SUBSCRIBE, UNSUBSCRIBE, IDENTITY, HWM, LINGER, FD
optval : int or bytes
The value of the option to set.

Warning

All options other than zmq.SUBSCRIBE, zmq.UNSUBSCRIBE and zmq.LINGER only take effect for subsequent socket bind/connects.

setsockopt_string(option, optval, encoding='utf-8')

Set socket options with a unicode object.

This is simply a wrapper for setsockopt to protect from encoding ambiguity.

See the 0MQ documentation for details on specific options.

option : int
The name of the option to set. Can be any of: SUBSCRIBE, UNSUBSCRIBE, IDENTITY
optval : unicode string (unicode on py2, str on py3)
The value of the option to set.
encoding : str
The encoding to be used, default is utf8
setsockopt_unicode(option, optval, encoding='utf-8')

Set socket options with a unicode object.

This is simply a wrapper for setsockopt to protect from encoding ambiguity.

See the 0MQ documentation for details on specific options.

option : int
The name of the option to set. Can be any of: SUBSCRIBE, UNSUBSCRIBE, IDENTITY
optval : unicode string (unicode on py2, str on py3)
The value of the option to set.
encoding : str
The encoding to be used, default is utf8
classmethod shadow(address)

Shadow an existing libzmq socket

address is the integer address of the libzmq socket or an FFI pointer to it.

New in version 14.1.

subscribe(topic)

Subscribe to a topic

Only for SUB sockets.

New in version 15.3.

unbind(addr)

Unbind from an address (undoes a call to bind).

New in version libzmq-3.2.

New in version 13.0.

addr : str
The address string. This has the form ‘protocol://interface:port’, for example ‘tcp://127.0.0.1:5555’. Protocols supported are tcp, upd, pgm, inproc and ipc. If the address is unicode, it is encoded to utf-8 first.
underlying

The address of the underlying libzmq socket

unsubscribe(topic)

Unsubscribe from a topic

Only for SUB sockets.

New in version 15.3.

[1]http://github.com/zeromq/pyzmq
[2]http://www.zeromq.com
[3]http://www.cython.org