我第一次在python中使用asyncio玩，并尝试将其与ZMQ结合使用。
基本上，我的问题是我有一个REP / REQ系统，它在async def中具有我需要等待的功能。值如何不更新。
这是一段代码来说明这一点：
#Declaring the zmq context
context = zmq_asyncio.Context()
REP_server_django = context.socket(zmq.REP)
REP_server_django.bind("tcp://*:5558")
我将此对象发送到一个类，并在此函数中将其取回
async def readsonar(self, trigger_pin, REP_server_django):
i= 0
while True:
ping_from_view = await REP_server_django.recv() # line.1
value = await self.board.sonar_read(trigger_pin) # line.2
print(value) # line.3
json_data = json.dumps(value) # line.4
#json_data = json.dumps(i) # line.4bis
REP_server_django.send(json_data.encode()) # line.5
i+=1 # line.6
await asyncio.sleep(1/1000) # line.7
sonar_read正在使用pymata_express读取超声波传感器。如果我评论line.2和line.4，我将得到正确的i值。如果我注释line.1和line.5，则print(value)从sonar_read打印正确的值。但是，当我按如下所示运行它时，value不会更新。我想念什么吗？
编辑：编辑有关行注释的类型。我的意思是，如果我只读声纳并打印该值。它工作正常。如果我只有
.recv()和.send(json.dumps(i).encode())，它可以工作。但是，如果我尝试从声纳发送值。它锁定到未更新的给定valueEDIT2 ：（对Alan Yorinks的回答）：这是MWE，它考虑您发送的有关类中
zmq声明的内容。它来自pymata_express示例concurrent_tasks.py要重现该错误，请在两个不同的终端中运行这两个脚本。您将需要安装Frimata_express的arduino板。如果一切顺利
PART A.仅应在mve_req.py端吐出相同的值。您可以编辑不同的块（PARTS A，B或C）以查看行为。mve_rep.py
#ADAPTED FROM PYMATA EXPRESS EXAMPLE CONCURRENTTAKS
#https://github.com/MrYsLab/pymata-express/blob/master/examples/concurrent_tasks.py
import asyncio
import zmq
import json
import zmq.asyncio as zmq_asyncio
from pymata_express.pymata_express import PymataExpress
class ConcurrentTasks:
def __init__(self, board):
self.loop = board.get_event_loop()
self.board = board
self.ctxsync = zmq.Context()
self.context = zmq.asyncio.Context()
self.rep = self.context.socket(zmq.REP)
self.rep.bind("tcp://*:5558")
self.trigger_pin = 53
self.echo_pin = 51
loop.run_until_complete(self.async_init_and_run())
async def readsonar(self):
i = 0
while True:
#PART. A. WHAT I HOPE COULD WORK
rep_recv = await self.rep.recv() # line.1
value = await self.board.sonar_read(self.trigger_pin) # line.2
print(value) # line.3
json_data = json.dumps(value) # line.4
# json_data = json.dumps(i) # line.4bis
await self.rep.send(json_data.encode()) # line.5
i += 1 # line.6
await asyncio.sleep(1 / 1000) # line.7
'''
#PART. B. WORKS FINE IN UPDATING THE SONAR_RAED VALUE AND PRINTING IT
value = await self.board.sonar_read(self.trigger_pin) # line.2
print(value) # line.3
json_data = json.dumps(value) # line.4
i += 1 # line.6
await asyncio.sleep(1 / 1000) # line.7
'''
'''
#PART. C. WORKS FINE IN SENDING THE i VALUE OVER ZMQ
rep_recv = await self.rep.recv() # line.1
json_data = json.dumps(i) # line.4bis
await self.rep.send(json_data.encode()) # line.5
i += 1 # line.6
await asyncio.sleep(1 / 1000) # line.7
'''
async def async_init_and_run(self):
await self.board.set_pin_mode_sonar(self.trigger_pin, self.echo_pin)
readsonar = asyncio.create_task(self.readsonar())
await readsonar
# OTHER CREATED_TASK GO HERE, (removed them in the MVE, but they work fine)
if __name__ == "__main__":
loop = asyncio.get_event_loop()
my_board = PymataExpress()
try:
ConcurrentTasks(my_board)
except (KeyboardInterrupt, RuntimeError):
loop.run_until_complete(my_board.shutdown())
print('goodbye')
finally:
loop.close()
mve_req.py
import zmq
import time
import json
def start_zmq():
context = zmq.Context()
REQ_django = context.socket(zmq.REQ)
REQ_django.connect("tcp://localhost:5558")
return REQ_django, context
def get_sonar(REQ_django):
REQ_django.send(b"server_django")
ping_from_server_django = REQ_django.recv()
return ping_from_server_django.decode()
if __name__ == '__main__':
data = {"sensors":{}}
REQ_django, context = start_zmq()
while REQ_django:
data['sensors']['sonar'] = get_sonar(REQ_django)
json_data = json.dumps(data)
print(data)
#DO OTHER WORK
time.sleep(1)
REQ_django.close()
context.term()
最佳答案
完全公开的是，我是pymata-express和python-banyan.的作者。OP要求我发布此解决方案，因此，这并不意味着要无耻。
自从在Python 3中首次引入asyncio以来，我就一直在进行开发。当asyncio代码工作时，asyncio（IMHO）可以简化并发性和代码。但是，当出现问题时，调试和了解问题的原因可能会令人沮丧。
我提前表示歉意，因为这可能会有点冗长，但是我需要提供一些背景信息，以使该示例看起来不会像是一些随机的代码。
开发python-banyan框架是为了提供线程，多处理和异步的替代方法。简而言之，Banyan应用程序由针对性小的可执行文件组成，这些可执行文件使用通过LAN共享的协议消息相互通信。它的核心使用Zeromq。它的设计目的不是让流量通过WAN传输，而是将LAN用作“软件底板”。在某些方面，Banyan与MQTT相似，但是在LAN中使用时，速度要快得多。如果需要，它确实具有连接到MQTT网络的能力。
Banyan的一部分是一个称为OneGPIO的概念。它是一个协议消息传递规范，抽象了GPIO功能以独立于任何硬件实现。为了实现硬件细节，开发了专用的Banyan组件，称为Banyan硬件网关。有适用于Raspberry Pi，Arduino，ESP-8266和Adafruit Crickit Hat的网关。 GPIO应用程序发布通用的OneGPIO消息，任何或所有网关都可以选择接收该消息。要从一个硬件平台转移到另一个硬件平台，将启动与硬件相关的网关，并且无需进行修改即可启动控制组件（如下所示的代码）。从一个硬件平台到另一个硬件平台，任何组件都不需要修改代码，控制组件和网关都无需修改。启动控制组件时，可通过命令行选项指定诸如引脚号之类的变量。对于Arduino网关，使用pymata-express来控制Arduino的GPIO。 Pymata-express是StandardFirmata客户端的异步实现。需要注意的是，下面的代码不是asyncio。 Banyan框架允许人们使用适合问题的工具进行开发，但允许解耦解决方案的各个部分，在这种情况下，该应用程序允许将asyncio与非asyncio混合使用，而不会在执行过程中通常遇到任何麻烦所以。
在提供的代码中，类定义下的所有代码均用于提供对命令行配置选项的支持。
import argparse
import signal
import sys
import threading
import time
from python_banyan.banyan_base import BanyanBase
class HCSR04(BanyanBase, threading.Thread):
def __init__(self, **kwargs):
"""
kwargs contains the following parameters
:param back_plane_ip_address: If none, the local IP address is used
:param process_name: HCSR04
:param publisher_port: publishing port
:param subscriber_port: subscriber port
:param loop_time: receive loop idle time
:param trigger_pin: GPIO trigger pin number
:param echo_pin: GPIO echo pin number
"""
self.back_plane_ip_address = kwargs['back_plane_ip_address'],
self.process_name = kwargs['process_name']
self.publisher_port = kwargs['publisher_port']
self.subscriber_port = kwargs['subscriber_port'],
self.loop_time = kwargs['loop_time']
self.trigger_pin = kwargs['trigger_pin']
self.echo_pin = kwargs['echo_pin']
self.poll_interval = kwargs['poll_interval']
self.last_distance_value = 0
# initialize the base class
super(HCSR04, self).__init__(back_plane_ip_address=kwargs['back_plane_ip_address'],
subscriber_port=kwargs['subscriber_port'],
publisher_port=kwargs['publisher_port'],
process_name=kwargs['process_name'],
loop_time=kwargs['loop_time'])
threading.Thread.__init__(self)
self.daemon = True
self.lock = threading.Lock()
# subscribe to receive messages from arduino gateway
self.set_subscriber_topic('from_arduino_gateway')
# enable hc-sr04 in arduino gateway
payload = {'command': 'set_mode_sonar', 'trigger_pin': self.trigger_pin,
'echo_pin': self.echo_pin}
self.publish_payload(payload, 'to_arduino_gateway')
# start the thread
self.start()
try:
self.receive_loop()
except KeyboardInterrupt:
self.clean_up()
sys.exit(0)
def incoming_message_processing(self, topic, payload):
print(topic, payload)
with self.lock:
self.last_distance_value = payload['value']
def run(self):
while True:
with self.lock:
distance = self.last_distance_value
payload = {'distance': distance}
topic = 'distance_poll'
self.publish_payload(payload, topic)
time.sleep(self.poll_interval)
def hcsr04():
parser = argparse.ArgumentParser()
# allow user to bypass the IP address auto-discovery.
# This is necessary if the component resides on a computer
# other than the computing running the backplane.
parser.add_argument("-b", dest="back_plane_ip_address", default="None",
help="None or IP address used by Back Plane")
parser.add_argument("-i", dest="poll_interval", default=1.0,
help="Distance polling interval")
parser.add_argument("-n", dest="process_name", default="HC-SRO4 Demo",
help="Set process name in banner")
parser.add_argument("-p", dest="publisher_port", default="43124",
help="Publisher IP port")
parser.add_argument("-s", dest="subscriber_port", default="43125",
help="Subscriber IP port")
parser.add_argument("-t", dest="loop_time", default=".1",
help="Event Loop Timer in seconds")
parser.add_argument("-x", dest="trigger_pin", default="12",
help="Trigger GPIO pin number")
parser.add_argument("-y", dest="echo_pin", default="13",
help="Echo GPIO pin number")
args = parser.parse_args()
if args.back_plane_ip_address == 'None':
args.back_plane_ip_address = None
kw_options = {'back_plane_ip_address': args.back_plane_ip_address,
'publisher_port': args.publisher_port,
'subscriber_port': args.subscriber_port,
'process_name': args.process_name,
'loop_time': float(args.loop_time),
'trigger_pin': int(args.trigger_pin),
'echo_pin': int(args.echo_pin),
'poll_interval': int(args.poll_interval)
}
# replace with the name of your class
HCSR04(**kw_options)
# signal handler function called when Control-C occurs
def signal_handler(sig, frame):
print('Exiting Through Signal Handler')
raise KeyboardInterrupt
# listen for SIGINT
signal.signal(signal.SIGINT, signal_handler)
signal.signal(signal.SIGTERM, signal_handler)
if __name__ == '__main__':
hcsr04()
关于python - 带有异步的pyzmq REQ/REP等待变量，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/57156822/