Python RabbitMQ消息队列实现rpc

Python  /  管理员 发布于 7年前   217

上个项目中用到了ActiveMQ，只是简单应用，安装完成后直接是用就可以了。由于新项目中一些硬件的限制，需要把消息队列换成RabbitMQ。

RabbitMQ中的几种模式和机制比ActiveMQ多多了，根据业务需要，使用RPC实现功能，其中踩过的一些坑，有必要记录一下了。

上代码，目录结构分为 c_server、c_client、c_hanlder:

c_server:

#!/usr/bin/env python# -*- coding:utf-8 -*-import pikaimport timeimport jsonimport ioimport yamls_exchange = input("请输入交换机名称->>").decode('utf-8').strip()s_queue = input("输入消息队列名称->>").decode('utf-8').strip()credentials = pika.PlainCredentials('system', 'manager')connection = pika.BlockingConnection(pika.ConnectionParameters(host='XXX.XXX.XXX.XXX',credentials=credentials))# 定义channel = connection.channel()channel.exchange_declare(exchange=s_exchange, exchange_type='direct')channel.queue_declare(queue=s_queue, exclusive=True)channel.queue_bind(queue=s_queue, exchange=s_exchange)def s_manage(content): # 解决unicode转码问题 json.JSONDecoder().decode(content) str_content = yaml.safe_load(json.loads(content,encoding='utf-8')) str_res = {  "errorid": 0,  "resp": str_content['cmd'],  "errorcont": "成功" } return json.dumps(str_res)def on_request(ch, method, props, body): response = s_manage(body) ch.basic_publish(exchange='',      routing_key=props.reply_to,      properties=pika.BasicProperties(correlation_id = \   props.correlation_id),      body=response) ch.basic_ack(delivery_tag = method.delivery_tag)channel.basic_qos(prefetch_count=1)channel.basic_consume(on_request, queue=s_queue)print(" [x] Awaiting RPC requests")channel.start_consuming()

c_client:

#!/usr/bin/env python# -*- coding:utf-8 -*-import pikaimport uuidimport jsonimport ioclass RpcClient(object):  def __init__(self):    self.credentials = pika.PlainCredentials('guest', 'guest')    self.connection = pika.BlockingConnection(pika.ConnectionParameters(host='XXX.XXX.XXX.XXX',        credentials=self.credentials))    self.channel = self.connection.channel()  def on_response(self, ch, method, props, body):    if self.callback_id == props.correlation_id:      self.response = body    ch.basic_ack(delivery_tag=method.delivery_tag)  def get_response(self, callback_queue, callback_id):    '''取队列里的值，获取callback_queued的执行结果'''    self.callback_id = callback_id    self.response = None    self.channel.queue_declare('q_manager', durable=True)    self.channel.basic_consume(self.on_response, # 只要收到消息就执行on_response      queue=callback_queue)    while self.response is None:      self.connection.process_data_events() # 非阻塞版的start_consuming    return self.response  def call(self, queue_name, command, exchange,rout_key): # 命令下发    '''队列里发送数据'''    # result = self.channel.queue_declare(exclusive=False) #exclusive=False 必须这样写    self.callback_queue = 'q_manager' # result.method.queue    self.corr_id = str(uuid.uuid4())    self.channel.basic_publish(exchange=exchange,      routing_key=queue_name,      properties=pika.BasicProperties(        reply_to=self.callback_queue, # 发送返回信息的队列name        correlation_id=self.corr_id, # 发送uuid 相当于验证码      ),      body=command)    return self.callback_queue,self.corr_idclient

c_handler:

#!/usr/bin/env python# -*- coding:utf-8 -*-from c_client import *import random, timeimport threadingimport jsonimport sysclass Handler(object):  def __init__(self):    self.information = {}  # 后台进程信息  def check_all(self, *args):    '''查看所有信息'''    time.sleep(2)    print('获取消息')    for key in self.information:      print("cid【%s】\t 队列【%s】\t 命令【%s】"%(key, self.information[key][0],       self.information[key][1]))  def check_task(self, cmd):    '''查看task_id执行结果'''    time.sleep(2)    try:      task_id = int(cmd)      print(task_id)      callback_queue= self.information[task_id][2]      callback_id= self.information[task_id][3]      client = RpcClient()      response = client.get_response(callback_queue, callback_id)      print(response)      # print(response.decode())      del self.information[task_id]    except KeyError as e :      print("error: [%s]" % e)    except IndexError as e:      print("error: [%s]" % e)  def run(self, user_cmd, host, exchange='', rout_key='',que=''):    try:      time.sleep(2)      command = user_cmd      task_id = random.randint(10000, 99999)      client = RpcClient()      response = client.call(queue_name=host, command=command,exchange=exchange,rout_key=que)      self.information[task_id] = [host, command, response[0], response[1]]    except IndexError as e:      print("[error]：%s"%e)  def reflect(self, str,cmd,host,exchange,que):    '''反射'''    if hasattr(self, str):      getattr(self, str)(cmd,host,exchange,que)  def start(self, m,cmd, host, exchange,que):    while True:      user_resp = input("输入处理消息内容ID->>").decode('utf-8').strip()      self.check_task(user_resp)      str = m      print(self.information)      t1 = threading.Thread(target=self.reflect, args=(str,cmd,host,exchange,que)) #多线程      t1.start()s_exchange = input("请输入交换机名称->>").decode('utf-8').strip()s_queue = input("输入消息队列名称->>").decode('utf-8').strip()d_cmd_state =input("输入json命令->>").decode('utf-8').strip()s_cmd = json.dumps(d_cmd_state)handler = Handler()handler.start('run',s_cmd, s_queue, s_exchange, s_queue)handler

注意要点：1、c_client 发布消息到rabbitmq 需要携带 服务器返回的队列名称，及corr_id

2、c_handler 做了处理，每次发送的内容都会放到task列表中，直到显示ID号，就可以查询返回的内容，调用如下：

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