一. RabbitMQ队列
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#消息中间件 -消息队列 - 异步 提交的任务不需要实时得到结果或回应python线程Q 实现了在同一个进程间不同线程间的交互python线程Q 也可以实现进程间Q的通信 |
a. 安装
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#Centos7 安装#注意/etc/hosts文件 ip和主机名对应wget https://github.com/rabbitmq/rabbitmq-server/releases/download/rabbitmq_v3_6_10/rabbitmq-server-3.6.10-1.el7.noarch.rpmyum install epel-release -yyum install rabbitmq-server-3.6.10-1.el7.noarch.rpmrabbitmq-plugins enable rabbitmq_managementcp /usr/share/doc/rabbitmq-server-3.6.10/rabbitmq.config.example /etc/rabbitmq/rabbitmq.configsystemctl restart rabbitmq-serversystemctl status rabbitmq-server#创建用户 授权rabbitmqctl add_user alex alex3714rabbitmqctl set_permissions -p / alex ".*" ".*" ".*" |
启动失败：
[root@openstack ~]# systemctl start rabbitmq-server.service Job for rabbitmq-server.service failed. See ‘systemctl status rabbitmq-server.service’ and ‘journalctl -xn’ for details. [root@openstack ~]# systemctl status rabbitmq-server.service rabbitmq-server.service – RabbitMQ broker Loaded: loaded (/usr/lib/systemd/system/rabbitmq-server.service; enabled) Active: failed (Result: exit-code) since 六 2016-04-30 23:19:21 CST; 8s ago Process: 3593 ExecStop=/usr/lib/rabbitmq/bin/rabbitmqctl stop (code=exited, status=2) Process: 3563 ExecStart=/usr/lib/rabbitmq/bin/rabbitmq-server (code=exited, status=1/FAILURE) Main PID: 3563 (code=exited, status=1/FAILURE) 4月 30 23:19:21 openstack rabbitmqctl[3593]: * epmd reports: node ‘rabbit’ not running at all 4月 30 23:19:21 openstack rabbitmqctl[3593]: no other nodes on openstack 4月 30 23:19:21 openstack rabbitmqctl[3593]: * suggestion: start the node 4月 30 23:19:21 openstack rabbitmqctl[3593]: current node details: 4月 30 23:19:21 openstack rabbitmqctl[3593]: – node name: rabbitmqctl3593@openstack 4月 30 23:19:21 openstack rabbitmqctl[3593]: – home dir: /var/lib/rabbitmq 4月 30 23:19:21 openstack rabbitmqctl[3593]: – cookie hash: DuHinHyRsf96Yx7NcAaAuQ== 4月 30 23:19:21 openstack systemd[1]: rabbitmq-server.service: control process exited, code=exited status=2 4月 30 23:19:21 openstack systemd[1]: Failed to start RabbitMQ broker. 4月 30 23:19:21 openstack systemd[1]: Unit rabbitmq-server.service entered failed state.
解决办法：
firewall-cmd --permanent --add-port=5672/tcp firewall-cmd --reload setsebool -P nis_enabled 1
systemctl start rabbitmq-server再次启动:
[root@oldboy_zny rabbitmq]# systemctl start rabbitmq-server
[root@oldboy_zny rabbitmq]# systemctl status rabbitmq-server
rabbitmq-server.service - RabbitMQ broker
Loaded: loaded (/usr/lib/systemd/system/rabbitmq-server.service; enabled)
Active: active (running) since 一 2018-03-05 10:33:48 CST; 8s ago
Process: 22014 ExecStop=/usr/sbin/rabbitmqctl stop (code=exited, status=0/SUCCESS)
Main PID: 22152 (beam)
Status: "Initialized"
CGroup: /system.slice/rabbitmq-server.service
├─22152 /usr/lib64/erlang/erts-5.10.4/bin/beam -W w -A 64 -P 1048576 -t 5000000 -stbt db -zdbbl 32000 -K true -- -root /usr/lib64/erlang...
├─22441 inet_gethost 4
└─22442 inet_gethost 4
3月 05 10:33:47 oldboy_zny rabbitmq-server[22152]: ## ##
3月 05 10:33:47 oldboy_zny rabbitmq-server[22152]: ########## Logs: /var/log/rabbitmq/rabbit@oldboy_zny.log
3月 05 10:33:47 oldboy_zny rabbitmq-server[22152]: ###### ## /var/log/rabbitmq/rabbit@oldboy_zny-sasl.log
3月 05 10:33:47 oldboy_zny rabbitmq-server[22152]: ##########
3月 05 10:33:47 oldboy_zny rabbitmq-server[22152]: Starting broker...
3月 05 10:33:48 oldboy_zny rabbitmq-server[22152]: systemd unit for activation check: "bin"
3月 05 10:33:48 oldboy_zny rabbitmq-server[22152]: 'systemctl' unavailable, falling back to sleep
3月 05 10:33:48 oldboy_zny systemd[1]: Started RabbitMQ broker.
3月 05 10:33:49 oldboy_zny python[22447]: SELinux is preventing /usr/bin/bash from getattr access on the file .
***** Plugin catchall (100. confidence) suggests **************************...
3月 05 10:33:53 oldboy_zny rabbitmq-server[22152]: completed with 6 plugins.
Hint: Some lines were ellipsized, use -l to show in full.
b. 创建用户 授权
#远程连接rabbitmq server的话,需要配置权限 #创建用户 rabbitmqctl add_user alex alex3714 #同时还要配置权限，允许从外面访问 rabbitmqctl set_permissions -p / alex ".*" ".*" ".*" set_permissions [-p vhost] {user} {conf} {write} {read} vhost The name of the virtual host to which to grant the user access, defaulting to /. user The name of the user to grant access to the specified virtual host. conf A regular expression matching resource names for which the user is granted configure permissions. write A regular expression matching resource names for which the user is granted write permissions. read A regular expression matching resource names for which the user is granted read permissions.
c. python rabbitMQ module 安装
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pip install pikaoreasy_install pikaor源码 https://pypi.python.org/pypi/pika |
二. 事例
参考博客：http://www.cnblogs.com/yuanchenqi/articles/8507109.html
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注意: 一般申明队列(如下代码)只需要在服务端申明,但客户端也可以申明,是防止如果服务端没有启动,客户端先启动后没有队列会报错 此时服务端如果有相同代码,会检查,如果有相同队列就不创建channel.queue_declare(queue='hello') |
a. 服务端和客户端一对一
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#查看队列 # rabbitmqctl list_queues#客户端再次申明队列是因为客户端要清楚去哪里取数据 channel.queue_declare(queue='hello') |
import pika credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('192.168.11.106',credentials=credentials)) #建立socket channel = connection.channel() #创建rabbitmq协议通道 channel.queue_declare(queue='hello') #通过通道生成一个队列 channel.basic_publish(exchange='', routing_key='hello', #队列 body='Hello World!') #内容 print(" [x] Sent 'Hello World!'") connection.close()
import pika credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('192.168.11.106',credentials=credentials)) #建立socket channel = connection.channel() channel.queue_declare(queue='hello') def callback(ch, method, properties, body): print(ch) #上面channel = connection.channel()对象 print(method) #除了服务端本身的数据，还带一些参数 print(properties) #属性 print(body) #byte数据 channel.basic_consume(callback, queue='hello', no_ack=True) print(' Waiting for messages. To exit press CTRL+C') channel.start_consuming()
b. 消息持久化
1. 模拟客户端中断 观察服务端队列的数据会不会返回(不会)
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#- 开启一个服务端,两个客户端#- 服务端向队列中存放一个值,一客户端从队列中取到数据,在睡20秒期间中断,表示出错,它不会报告给服务端#- 这时队列中为零,另一客户端也不会取到值# no_ack=True 表示客户端处理完了不需要向服务端确认消息 |
import pika credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('192.168.11.106',credentials=credentials)) #建立socket channel = connection.channel() #创建rabbitmq协议通道 channel.queue_declare(queue='hello') #通过通道生成一个队列 channel.basic_publish(exchange='', routing_key='hello', #队列 body='Hello World!') #内容 print(" [x] Sent 'Hello World!'") connection.close()
import pika import time credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('192.168.11.106',credentials=credentials)) #建立socket channel = connection.channel() channel.queue_declare(queue='hello') def callback(ch, method, properties, body): print("received msg...start process",body) time.sleep(10) print("end process...") channel.basic_consume(callback, queue='hello', no_ack=True) print(' Waiting for messages. To exit press CTRL+C') channel.start_consuming()
2. 模拟客户端中断 观察服务端队列的数据会不会返回(会)
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#1. 生产者端发消息时，加参数 消息持久化 properties=pika.BasicProperties( delivery_mode=2, # make message persistent ),#2. 消费者端，消息处理完毕时，发送确认包 ch.basic_ack(delivery_tag=method.delivery_tag) channel.basic_consume(callback, #取到消息后，调用callback 函数 queue='task1',) #no_ack=True) #消息处理后，不向rabbit-server确认消息已消费完毕#- 开启一个服务端,两个客户端#- 服务端向队列中存放一个值,一客户端从队列中取到数据,在睡20秒期间中断,表示出错,它会报给服务端,服务端队列还有值#- 这时启动另一客户端还可以取到值 |
import pika credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('192.168.11.106',credentials=credentials)) #建立socket channel = connection.channel() #创建rabbitmq协议通道 channel.queue_declare(queue='hello') #通过通道生成一个队列 channel.basic_publish(exchange='', routing_key='hello', #队列 properties=pika.BasicProperties( delivery_mode=2, # make message persistent ), body='Hello World!') #内容 print(" [x] Sent 'Hello World!'") connection.close()
import pika import time credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('192.168.11.106',credentials=credentials)) #建立socket channel = connection.channel() channel.queue_declare(queue='hello') def callback(ch, method, properties, body): print("received msg...start process",body) time.sleep(10) print("end process...") ch.basic_ack(delivery_tag=method.delivery_tag) channel.basic_consume(callback, queue='hello', ) print(' Waiting for messages. To exit press CTRL+C') channel.start_consuming()
c. 队列持久化
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#队列持久化channel.queue_declare(queue='hello',durable=True)systemctl restart rabbitmq-server #重启服务发现hello队列还在,但是消息不在rabbitmqctl list_queues #hello #队列和消息持久化channel.queue_declare(queue='hello',durable=True)properties=pika.BasicProperties( delivery_mode=2, # make message persistent),systemctl restart rabbitmq-server #重启服务发现队列和消息都还在rabbitmqctl list_queues #hello 6 |
import pika credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('192.168.11.106',credentials=credentials)) #建立socket channel = connection.channel() #创建rabbitmq协议通道 channel.queue_declare(queue='hello',durable=True) #通过通道生成一个队列 channel.basic_publish(exchange='', routing_key='hello', #队列 properties=pika.BasicProperties( delivery_mode=2, # make message persistent ), body='Hello World!') #内容 print(" [x] Sent 'Hello World!'") connection.close()
d. fanout 广播
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#服务端： - 不需要申明队列#客户端： - 每个客户端都需要申明一个队列,自动设置队列名称,收听广播,当收听完后queue删除 - 把队列绑定到exchange上#注意：客户端先打开,服务端再打开,客户端会收到消息 #应用： - 微博粉丝在线,博主发消息,粉丝可以收到#如果服务端先启动向exchange发消息,这时客户端没有启动,没有队列保存数据(exchange不负责保存数据)#这时数据会丢,队列中没有数据#exchange只负责转发 |
import pika import sys import time credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('172.16.42.128',credentials=credentials)) #建立socket channel = connection.channel() #创建rabbitmq协议通道 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(" Send %r" % message) connection.close()
import pika import time credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('172.16.42.128',credentials=credentials)) #建立socket channel = connection.channel() channel.exchange_declare(exchange='logs', type='fanout') queue_obj = channel.queue_declare(exclusive=True) #随机创建一个队列对象 exclusive=True会在使用此queue的消费者断开后,自动将queue删除 queue_name = queue_obj.method.queue #不指定queue名字,rabbit会随机分配一个名字, channel.queue_bind(exchange='logs',queue=queue_name) #把queue绑定到exchange 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()
e. direct 组播
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#客户端一： - python3 receive1.py info #客户端二： - python3 receive1.py error#客户端三： - python3 receive1.py warning#客户端四： - python3 receive1.py warning error info#服务端： - python3 receive1.py warning |
import pika import sys import time credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('172.16.42.128',credentials=credentials)) #建立socket channel = connection.channel() #创建rabbitmq协议通道 channel.exchange_declare(exchange='direct_logs',type='direct') severity = sys.argv[1] if len(sys.argv) > 1 else 'info' message = ' '.join(sys.argv[2:]) or 'Hello World!' channel.basic_publish(exchange='direct_logs', routing_key=severity, body=message) print(" Send %r:%r" % (severity, message)) connection.close()
import pika import time import sys credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('172.16.42.128',credentials=credentials)) #建立socket 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] " % 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()
f. topic 规则传播
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#客户端一： - python3 receive1.py *.django #客户端二： - python3 receive1.py mysql.error#客户端三： - python3 receive1.py mysql.*#服务端： - python3 receive1.py #匹配相应的客户端 |
import pika import time import sys credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('172.16.42.128',credentials=credentials)) #建立socket 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: print(sys.argv[1:]) sys.stderr.write("Usage: %s [binding_key]... " % 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()
import pika import sys import time credentials = pika.PlainCredentials("egon","egon123") #授权的账号 密码 connection = pika.BlockingConnection( pika.ConnectionParameters('172.16.42.128',credentials=credentials)) #建立socket channel = connection.channel() #创建rabbitmq协议通道 channel.exchange_declare(exchange='topic_logs',type='topic') routing_key = sys.argv[1] if len(sys.argv) > 1 else 'anonymous.info' message = ' '.join(sys.argv[2:]) or 'Hello World!' channel.basic_publish(exchange='topic_logs', routing_key=routing_key, body=message) print(" [x] Sent %r:%r" % (routing_key, message))
以生产者消费者举例四种模式：
生产者：
# ! /usr/bin/env python
# -*- coding: utf-8 -*-
# Author : 张宁阳
# date： 2018/3/6
# ######################### 简答模式生产者 #########################
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters( host='192.168.20.56',port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
channel.queue_declare(queue='hello')
channel.basic_publish(exchange='',
routing_key='hello',
body='ssssssssssssss')
print(" 已经 发送 'ssssssssssssssssss'")
connection.close()
######################基于exchang分发模式的生产者###########################
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters( host='192.168.20.56',port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
channel.exchange_declare(exchange='logs',
exchange_type='fanout')
message = "info: Hello World!"
channel.basic_publish(exchange='logs',
routing_key='',
body=message)
print(" [x] Sent %r" % message)
connection.close()
##########基于exchange关键字模式的生产者##############
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters( host='192.168.20.56',port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
channel.exchange_declare(exchange='direct_logs',
exchange_type='direct')
message = "info: Hello World!"
channel.basic_publish(exchange='direct_logs',
routing_key='info',#关键字：info、error、warning
body=message)
print(" [x] Sent %r" % message)
connection.close()
##########基于exchange模糊匹配模式的生产者##############
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters( host='192.168.20.56',port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
channel.exchange_declare(exchange='topic_logs',
exchange_type='topic')
message = "info: Hello World!"
#routing_key="模糊匹配字符"
routing_keys=["old.boy.python ","old.boy"]
for key in routing_keys:
channel.basic_publish(exchange='topic_logs',
routing_key=key,
body=message)
print(" [x] Sent %r" % message)
connection.close()
消费者
# ! /usr/bin/env python
# -*- coding: utf-8 -*-
# Author : 张宁阳
# date： 2018/3/6
##########################基于简单模式的 消费者 ##########################
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.20.56',port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
channel.queue_declare(queue='hello')
def callback(ch, method, properties, body):
print(" 已经 接受 %r" % body)
channel.basic_consume(callback,
queue='hello',
no_ack=True)
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()
##############基于exchange分发模式消费者#####################
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters( host='192.168.20.56',port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
channel.exchange_declare(exchange='logs',
exchange_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()
##########################基于exchange的关键字模式的 消费者 ##########################
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.20.56', port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
# 生成交换机
channel.exchange_declare(exchange='direct_logs',
exchange_type='direct')
# 创建的队列
result = channel.queue_declare(exclusive=True)
# 创建的队列的随机名称
queue_name = result.method.queue
# 给队列与direct_logs这个交换机绑定三个关键字
severities = ["info", "warning", "error"]
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()
##########################基于exchange的模糊匹配模式的 消费者 ##########################
import pika
import sys
connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.20.56', port=5672,
credentials=pika.credentials.PlainCredentials(
username='alex',
password='alex3714'
)))
channel = connection.channel()
channel.exchange_declare(exchange='topic_logs',
exchange_type='topic')
result = channel.queue_declare(exclusive=True)
queue_name = result.method.queue
bind_keys=["old.*","old.#"]
for bind_key in bind_keys:
channel.queue_bind(exchange='topic_logs',
queue=queue_name,
routing_key=bind_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 回调队列
一个客户端向服务器发送请求，服务器端处理请求后，将其处理结果保存在一个存储体中。而客户端为了获得处理结果，那么客户在向服务器发送请求时，同时发送一个回调队列地址reply_to。
Correlation id 关联标识
一个客户端可能会发送多个请求给服务器，当服务器处理完后，客户端无法辨别在回调队列中的响应具体和那个请求时对应的。为了处理这种情况，客户端在发送每个请求时，同时会附带一个独有correlation_id属性，这样客户端在回调队列中根据correlation_id字段的值就可以分辨此响应属于哪个请求。
客户端发送请求：某个应用将请求信息交给客户端，然后客户端发送RPC请求，在发送RPC请求到RPC请求队列时，客户端至少发送带有reply_to以及correlation_id两个属性的信息 服务器端工作流： 等待接受客户端发来RPC请求，当请求出现的时候，服务器从RPC请求队列中取出请求，然后处理后，将响应发送到reply_to指定的回调队列中 客户端接受处理结果： 客户端等待回调队列中出现响应，当响应出现时，它会根据响应中correlation_id字段的值，将其返回给对应的应用
服务器端
#!/usr/bin/env python
import pika
# 建立连接，服务器地址为localhost，可指定ip地址
connection = pika.BlockingConnection(pika.ConnectionParameters(
host='localhost'))
# 建立会话
channel = connection.channel()
# 声明RPC请求队列
channel.queue_declare(queue='rpc_queue')
# 数据处理方法
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return fib(n-1) + fib(n-2)
# 对RPC请求队列中的请求进行处理
def on_request(ch, method, props, body):
n = int(body)
print(" [.] fib(%s)" % n)
# 调用数据处理方法
response = fib(n)
# 将处理结果(响应)发送到回调队列
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)
# 负载均衡，同一时刻发送给该服务器的请求不超过一个
channel.basic_qos(prefetch_count=1)
channel.basic_consume(on_request, queue='rpc_queue')
print(" [x] Awaiting RPC requests")
channel.start_consuming()
客户端
#!/usr/bin/env python
import pika
import uuid
class FibonacciRpcClient(object):
def __init__(self):
”“”
客户端启动时，创建回调队列，会开启会话用于发送RPC请求以及接受响应
“”“
# 建立连接，指定服务器的ip地址
self.connection = pika.BlockingConnection(pika.ConnectionParameters(
host='localhost'))
# 建立一个会话，每个channel代表一个会话任务
self.channel = self.connection.channel()
# 声明回调队列，再次声明的原因是，服务器和客户端可能先后开启，该声明是幂等的，多次声明，但只生效一次
result = self.channel.queue_declare(exclusive=True)
# 将次队列指定为当前客户端的回调队列
self.callback_queue = result.method.queue
# 客户端订阅回调队列，当回调队列中有响应时，调用`on_response`方法对响应进行处理;
self.channel.basic_consume(self.on_response, no_ack=True,
queue=self.callback_queue)
# 对回调队列中的响应进行处理的函数
def on_response(self, ch, method, props, body):
if self.corr_id == props.correlation_id:
self.response = body
# 发出RPC请求
def call(self, n):
# 初始化 response
self.response = None
#生成correlation_id
self.corr_id = str(uuid.uuid4())
# 发送RPC请求内容到RPC请求队列`rpc_queue`，同时发送的还有`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)
# 建立客户端
fibonacci_rpc = FibonacciRpcClient()
# 发送RPC请求
print(" [x] Requesting fib(30)")
response = fibonacci_rpc.call(30)
print(" [.] Got %r" % response)