Python操作rabbitMQ的示例代碼

更新時(shí)間：2019年03月19日 10:18:26 作者：Warm and new

這篇文章主要介紹了Python操作rabbitMQ的示例代碼，文中通過示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

引入

RabbitMQ 是一個(gè)由 Erlang 語(yǔ)言開發(fā)的 AMQP 的開源實(shí)現(xiàn)。

rabbitMQ是一款基于AMQP協(xié)議的消息中間件，它能夠在應(yīng)用之間提供可靠的消息傳輸。在易用性，擴(kuò)展性，高可用性上表現(xiàn)優(yōu)秀。使用消息中間件利于應(yīng)用之間的解耦，生產(chǎn)者（客戶端）無需知道消費(fèi)者（服務(wù)端）的存在。而且兩端可以使用不同的語(yǔ)言編寫，大大提供了靈活性。

中文文檔

安裝

# 安裝配置epel源
  rpm -ivh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
 
# 安裝erlang
  yum -y install erlang
 
# 安裝RabbitMQ
  yum -y install rabbitmq-server

# 啟動(dòng)/停止
  service rabbitmq-server start/stop

rabbitMQ工作模型

簡(jiǎn)單模式

生產(chǎn)者

import pika
connection = pika.BlockingConnection(pika.ConnectionParameters( host='localhost'))

channel = connection.channel()

channel.queue_declare(queue='hello')

channel.basic_publish(exchange='',
           routing_key='hello',
           body='Hello World!')

print(" [x] Sent 'Hello World!'")
connection.close()

消費(fèi)者

connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()
 
channel.queue_declare(queue='hello')
 
def callback(ch, method, properties, body):
  print(" [x] Received %r" % body)
 
channel.basic_consume( callback,
            queue='hello',
            no_ack=True)
 
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

相關(guān)參數(shù)

1，no-ack ＝ False

如果消費(fèi)者遇到情況(its channel is closed, connection is closed, or TCP connection is lost)掛掉了，那么，RabbitMQ會(huì)重新將該任務(wù)添加到隊(duì)列中。

回調(diào)函數(shù)中的 ch.basic_ack(delivery_tag=method.delivery_tag)
basic_comsume中的no_ack=False

接收消息端應(yīng)該這么寫：


import pika

connection = pika.BlockingConnection(pika.ConnectionParameters(
    host='10.211.55.4'))
channel = connection.channel()

channel.queue_declare(queue='hello')

def callback(ch, method, properties, body):
  print(" [x] Received %r" % body)
  import time
  time.sleep(10)
  print 'ok'
  ch.basic_ack(delivery_tag = method.delivery_tag)

channel.basic_consume(callback,
           queue='hello',
           no_ack=False)

print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

2，durable ：消息不丟失

生產(chǎn)者

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters(host='10.211.55.4'))
channel = connection.channel()

# make message persistent
channel.queue_declare(queue='hello', durable=True)

channel.basic_publish(exchange='',
           routing_key='hello',
           body='Hello World!',
           properties=pika.BasicProperties(
             delivery_mode=2, # make message persistent
           ))
print(" [x] Sent 'Hello World!'")
connection.close()

3，消息獲取順序

默認(rèn)消息隊(duì)列里的數(shù)據(jù)是按照順序被消費(fèi)者拿走，例如：消費(fèi)者1 去隊(duì)列中獲取奇數(shù) 序列的任務(wù)，消費(fèi)者1去隊(duì)列中獲取偶數(shù) 序列的任務(wù)。

channel.basic_qos(prefetch_count=1) 表示誰(shuí)來誰(shuí)取，不再按照奇偶數(shù)排列

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters(host='10.211.55.4'))
channel = connection.channel()

# make message persistent
channel.queue_declare(queue='hello')


def callback(ch, method, properties, body):
  print(" [x] Received %r" % body)
  import time
  time.sleep(10)
  print 'ok'
  ch.basic_ack(delivery_tag = method.delivery_tag)

channel.basic_qos(prefetch_count=1)

channel.basic_consume(callback,
           queue='hello',
           no_ack=False)

print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

exchange模型

1，發(fā)布訂閱

發(fā)布訂閱和簡(jiǎn)單的消息隊(duì)列區(qū)別在于，發(fā)布訂閱會(huì)將消息發(fā)送給所有的訂閱者，而消息隊(duì)列中的數(shù)據(jù)被消費(fèi)一次便消失。所以，RabbitMQ實(shí)現(xiàn)發(fā)布和訂閱時(shí)，會(huì)為每一個(gè)訂閱者創(chuàng)建一個(gè)隊(duì)列，而發(fā)布者發(fā)布消息時(shí)，會(huì)將消息放置在所有相關(guān)隊(duì)列中。

exchange type = fanout

生產(chǎn)者

import pika
import sys

connection = pika.BlockingConnection(pika.ConnectionParameters(
    host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='logs',
             type='fanout')

message = ' '.join(sys.argv[1:]) or "info: Hello World!"
channel.basic_publish(exchange='logs',
           routing_key='',
           body=message)
print(" [x] Sent %r" % message)
connection.close()

消費(fèi)者

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters(
    host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='logs',
             type='fanout')

result = channel.queue_declare(exclusive=True)
queue_name = result.method.queue

channel.queue_bind(exchange='logs',
          queue=queue_name)

print(' [*] Waiting for logs. To exit press CTRL+C')

def callback(ch, method, properties, body):
  print(" [x] %r" % body)

channel.basic_consume(callback,
           queue=queue_name,
           no_ack=True)

channel.start_consuming()

2，關(guān)鍵字發(fā)送

之前事例，發(fā)送消息時(shí)明確指定某個(gè)隊(duì)列并向其中發(fā)送消息，RabbitMQ還支持根據(jù)關(guān)鍵字發(fā)送，即：隊(duì)列綁定關(guān)鍵字，發(fā)送者將數(shù)據(jù)根據(jù)關(guān)鍵字發(fā)送到消息exchange，exchange根據(jù) 關(guān)鍵字判定應(yīng)該將數(shù)據(jù)發(fā)送至指定隊(duì)列。

exchange type = direct

import pika
import sys

connection = pika.BlockingConnection(pika.ConnectionParameters(
    host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='direct_logs',
             type='direct')

result = channel.queue_declare(exclusive=True)
queue_name = result.method.queue

severities = sys.argv[1:]
if not severities:
  sys.stderr.write("Usage: %s [info] [warning] [error]\n" % sys.argv[0])
  sys.exit(1)

for severity in severities:
  channel.queue_bind(exchange='direct_logs',
            queue=queue_name,
            routing_key=severity)

print(' [*] Waiting for logs. To exit press CTRL+C')

def callback(ch, method, properties, body):
  print(" [x] %r:%r" % (method.routing_key, body))

channel.basic_consume(callback,
           queue=queue_name,
           no_ack=True)

channel.start_consuming()

3，模糊匹配

exchange type = topic

發(fā)送者路由值隊(duì)列中
old.boy.python old.* -- 不匹配
old.boy.python old.# -- 匹配

在topic類型下，可以讓隊(duì)列綁定幾個(gè)模糊的關(guān)鍵字，之后發(fā)送者將數(shù)據(jù)發(fā)送到exchange，exchange將傳入”路由值“和 ”關(guān)鍵字“進(jìn)行匹配，匹配成功，則將數(shù)據(jù)發(fā)送到指定隊(duì)列。

# 表示可以匹配 0 個(gè) 或多個(gè) 單詞
* 表示只能匹配一個(gè) 單詞

import pika
import sys

connection = pika.BlockingConnection(pika.ConnectionParameters(
    host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='topic_logs',
             type='topic')

result = channel.queue_declare(exclusive=True)
queue_name = result.method.queue

binding_keys = sys.argv[1:]
if not binding_keys:
  sys.stderr.write("Usage: %s [binding_key]...\n" % sys.argv[0])
  sys.exit(1)

for binding_key in binding_keys:
  channel.queue_bind(exchange='topic_logs',
            queue=queue_name,
            routing_key=binding_key)

print(' [*] Waiting for logs. To exit press CTRL+C')

def callback(ch, method, properties, body):
  print(" [x] %r:%r" % (method.routing_key, body))

channel.basic_consume(callback,
           queue=queue_name,
           no_ack=True)

channel.start_consuming()

基于rabbitMQ的RPC

Callback queue 回調(diào)隊(duì)列

一個(gè)客戶端向服務(wù)器發(fā)送請(qǐng)求，服務(wù)器端處理請(qǐng)求后，將其處理結(jié)果保存在一個(gè)存儲(chǔ)體中。而客戶端為了獲得處理結(jié)果，那么客戶在向服務(wù)器發(fā)送請(qǐng)求時(shí)，同時(shí)發(fā)送一個(gè)回調(diào)隊(duì)列地址 reply_to 。

Correlation id 關(guān)聯(lián)標(biāo)識(shí)

一個(gè)客戶端可能會(huì)發(fā)送多個(gè)請(qǐng)求給服務(wù)器，當(dāng)服務(wù)器處理完后，客戶端無法辨別在回調(diào)隊(duì)列中的響應(yīng)具體和那個(gè)請(qǐng)求時(shí)對(duì)應(yīng)的。為了處理這種情況，客戶端在發(fā)送每個(gè)請(qǐng)求時(shí)，同時(shí)會(huì)附帶一個(gè)獨(dú)有 correlation_id 屬性，這樣客戶端在回調(diào)隊(duì)列中根據(jù) correlation_id 字段的值就可以分辨此響應(yīng)屬于哪個(gè)請(qǐng)求。

客戶端發(fā)送請(qǐng)求：

某個(gè)應(yīng)用將請(qǐng)求信息交給客戶端，然后客戶端發(fā)送RPC請(qǐng)求，在發(fā)送RPC請(qǐng)求到RPC請(qǐng)求隊(duì)列時(shí)，客戶端至少發(fā)送帶有reply_to以及correlation_id兩個(gè)屬性的信息

服務(wù)端工作流：

等待接受客戶端發(fā)來RPC請(qǐng)求，當(dāng)請(qǐng)求出現(xiàn)的時(shí)候，服務(wù)器從RPC請(qǐng)求隊(duì)列中取出請(qǐng)求，然后處理后，將響應(yīng)發(fā)送到reply_to指定的回調(diào)隊(duì)列中

客戶端接受處理結(jié)果：

客戶端等待回調(diào)隊(duì)列中出現(xiàn)響應(yīng)，當(dāng)響應(yīng)出現(xiàn)時(shí)，它會(huì)根據(jù)響應(yīng)中correlation_id字段的值，將其返回給對(duì)應(yīng)的應(yīng)用

服務(wù)者

import pika

# 建立連接，服務(wù)器地址為localhost，可指定ip地址
connection = pika.BlockingConnection(pika.ConnectionParameters(
    host='localhost'))

# 建立會(huì)話
channel = connection.channel()

# 聲明RPC請(qǐng)求隊(duì)列
channel.queue_declare(queue='rpc_queue')

# 數(shù)據(jù)處理方法
def fib(n):
  if n == 0:
    return 0
  elif n == 1:
    return 1
  else:
    return fib(n-1) + fib(n-2)

# 對(duì)RPC請(qǐng)求隊(duì)列中的請(qǐng)求進(jìn)行處理
def on_request(ch, method, props, body):
  n = int(body)

  print(" [.] fib(%s)" % n)

  # 調(diào)用數(shù)據(jù)處理方法
  response = fib(n)

  # 將處理結(jié)果(響應(yīng))發(fā)送到回調(diào)隊(duì)列
  ch.basic_publish(exchange='',
           routing_key=props.reply_to,
           properties=pika.BasicProperties(correlation_id = \
                             props.correlation_id),
           body=str(response))
  ch.basic_ack(delivery_tag = method.delivery_tag)

# 負(fù)載均衡，同一時(shí)刻發(fā)送給該服務(wù)器的請(qǐng)求不超過一個(gè)
channel.basic_qos(prefetch_count=1)

channel.basic_consume(on_request, queue='rpc_queue')

print(" [x] Awaiting RPC requests")
channel.start_consuming()

客戶端

import pika
import uuid

class FibonacciRpcClient(object):
  def __init__(self):
    """
    客戶端啟動(dòng)時(shí)，創(chuàng)建回調(diào)隊(duì)列，會(huì)開啟會(huì)話用于發(fā)送RPC請(qǐng)求以及接受響應(yīng)
    """
    # 建立連接，指定服務(wù)器的ip地址
    self.connection = pika.BlockingConnection(pika.ConnectionParameters(
        host='localhost'))
        
    # 建立一個(gè)會(huì)話，每個(gè)channel代表一個(gè)會(huì)話任務(wù)
    self.channel = self.connection.channel()
    
    # 聲明回調(diào)隊(duì)列，再次聲明的原因是，服務(wù)器和客戶端可能先后開啟，該聲明是冪等的，多次聲明，但只生效一次
    result = self.channel.queue_declare(exclusive=True)
    # 將次隊(duì)列指定為當(dāng)前客戶端的回調(diào)隊(duì)列
    self.callback_queue = result.method.queue
    
    # 客戶端訂閱回調(diào)隊(duì)列，當(dāng)回調(diào)隊(duì)列中有響應(yīng)時(shí)，調(diào)用`on_response`方法對(duì)響應(yīng)進(jìn)行處理; 
    self.channel.basic_consume(self.on_response, no_ack=True,
                  queue=self.callback_queue)


  # 對(duì)回調(diào)隊(duì)列中的響應(yīng)進(jìn)行處理的函數(shù)
  def on_response(self, ch, method, props, body):
    if self.corr_id == props.correlation_id:
      self.response = body


  # 發(fā)出RPC請(qǐng)求
  def call(self, n):
  
    # 初始化 response
    self.response = None
    
    #生成correlation_id 
    self.corr_id = str(uuid.uuid4())
    
    # 發(fā)送RPC請(qǐng)求內(nèi)容到RPC請(qǐng)求隊(duì)列`rpc_queue`，同時(shí)發(fā)送的還有`reply_to`和`correlation_id`
    self.channel.basic_publish(exchange='',
                  routing_key='rpc_queue',
                  properties=pika.BasicProperties(
                     reply_to = self.callback_queue,
                     correlation_id = self.corr_id,
                     ),
                  body=str(n))
                  
    
    while self.response is None:
      self.connection.process_data_events()
    return int(self.response)

# 建立客戶端
fibonacci_rpc = FibonacciRpcClient()

# 發(fā)送RPC請(qǐng)求
print(" [x] Requesting fib(30)")
response = fibonacci_rpc.call(30)
print(" [.] Got %r" % response)

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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