2022-05-23 00:16:32 +04:00

82 lines
2.2 KiB
Python

"""Module holding utility and convenience functions for zmq event monitoring."""
# Copyright (C) PyZMQ Developers
# Distributed under the terms of the Modified BSD License.
import struct
from typing import List
import zmq
from zmq._typing import TypedDict
from zmq.error import _check_version
class _MonitorMessage(TypedDict):
event: int
value: int
endpoint: bytes
def parse_monitor_message(msg: List[bytes]) -> _MonitorMessage:
"""decode zmq_monitor event messages.
Parameters
----------
msg : list(bytes)
zmq multipart message that has arrived on a monitor PAIR socket.
First frame is::
16 bit event id
32 bit event value
no padding
Second frame is the endpoint as a bytestring
Returns
-------
event : dict
event description as dict with the keys `event`, `value`, and `endpoint`.
"""
if len(msg) != 2 or len(msg[0]) != 6:
raise RuntimeError("Invalid event message format: %s" % msg)
event_id, value = struct.unpack("=hi", msg[0])
event: _MonitorMessage = {
'event': event_id,
'value': value,
'endpoint': msg[1],
}
return event
def recv_monitor_message(socket: zmq.Socket, flags: int = 0) -> _MonitorMessage:
"""Receive and decode the given raw message from the monitoring socket and return a dict.
Requires libzmq ≥ 4.0
The returned dict will have the following entries:
event : int, the event id as described in libzmq.zmq_socket_monitor
value : int, the event value associated with the event, see libzmq.zmq_socket_monitor
endpoint : string, the affected endpoint
Parameters
----------
socket : zmq PAIR socket
The PAIR socket (created by other.get_monitor_socket()) on which to recv the message
flags : bitfield (int)
standard zmq recv flags
Returns
-------
event : dict
event description as dict with the keys `event`, `value`, and `endpoint`.
"""
_check_version((4, 0), 'libzmq event API')
# will always return a list
msg = socket.recv_multipart(flags)
# 4.0-style event API
return parse_monitor_message(msg)
__all__ = ['parse_monitor_message', 'recv_monitor_message']