190707Python-RabbitMQ

一、简单的RabbitMQ示例

• 生产者

# Author:Li Dongfei
import pika
connection = pika.BlockingConnection(
    pika.ConnectionParameters('localhost')
    )  #建立一个连接
channel = connection.channel()  #声明一个管道
channel.queue_declare(queue='hello')  #生成一个queue
channel.basic_publish(exchange='',
                     routing_key='hello',  #queue名字
                     body='Hello World!')
print(" [x] Sent 'Hello World!'")
connection.close()

• 消费者

# Author:Li Dongfei
import pika
connection = pika.BlockingConnection(
    pika.ConnectionParameters('localhost')
    )
channel = connection.channel()
channel.queue_declare(queue='hello')
def callback(ch, method, properties, body):
    print("-->", ch, method, properties)
    print(" [x] Received %r" %body)
channel.basic_consume(callback,  #开始消费消息，如果收到消息就调用callback函数来处理消息
                      queue='hello',
                      no_ack=True
                      )
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()  #开始收消息

二、RabbitMQ命令行工具

C:\>cd C:\Program Files\RabbitMQ Server\rabbitmq_server-3.7.12\sbin
C:\Program Files\RabbitMQ Server\rabbitmq_server-3.7.12\sbin>rabbitmqctl.bat list_queues  #列出当前的queue

三、rabbitmq持久化

• 队列持久化

channel.queue_declare(queue='hello', durable=True)  #durable=True声明队列持久化

• 消息持久化

channel.basic_publish(exchange='',
                     routing_key='hello',  #queue名字
                     body='Hello World!',
                      properties=pika.BasicProperties(
                          delivery_mode=2 #消息持久化
                      ))

四、消息调度

• 在消费者中定义

channel.basic_qos(prefetch_count=1)  #只要当前有一条消息在处理则不要给我发消息

五、广播模式

• fanout：所有bind到此exchange的queue都可以接受消息
• 订阅/发布
  
  生成者

# Author:Li Dongfei
import pika
connection = pika.BlockingConnection(
    pika.ConnectionParameters('localhost')
    )
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()

消费者

# Author:Li Dongfei
import pika

connection = pika.BlockingConnection(
    pika.ConnectionParameters('localhost')
    )
channel = connection.channel()
channel.exchange_declare(exchange='logs',
                         exchange_type='fanout')

result = channel.queue_declare(exclusive=True)  #exclusive 唯一的
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()

• direct：通过routingKey和exchange决定的哪个唯一的queue可以接受消息
  
  生产者

# Author:Li Dongfei

import pika, sys

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

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

serverity = 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=serverity,
                      body=message)
print(" [x] Sent %r:%r" %(serverity, message))
connection.close()

消费者

# Author:Li Dongfei

import pika, sys

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

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

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

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

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

print(' [*] Wating 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()

• topic：所有符合routingKey的routingKey所bind的queue可以接受消息

六、rabbitMQ rpc

• client

# Author:Li Dongfei

import pika, uuid

class FibonacciTpcClient(object):
    def __init__(self):
        self.connection = pika.BlockingConnection(pika.ConnectionParameters(
            host='localhost'
        ))

        self.channel = self.connection.channel()

        result = self.channel.queue_declare(exclusive=True)
        self.callback_queue = result.method.queue

        self.channel.basic_consume(self.on_response, no_ack=True,
                                   queue=self.callback_queue)

    def on_response(self, ch, method, props, body):
        if self.corr_id == props.correlation_id:
            self.response = body

    def call(self, n):
        self.response = None
        self.corr_id = str(uuid.uuid4())
        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)

fibonacci_rpc = FibonacciTpcClient()

print(" [x] Requesting fib(30)")
response = fibonacci_rpc.call(30)
print(" [.] Got %r" %response)

• server

# Author:Li Dongfei

import pika, time

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

channel = connection.channel()
channel.queue_declare(queue='rpc_queue')

def fib(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fib(n-1) + fib(n-2)

def on_request(ch, method, props, body):
    n = int(body)
    print(" [.] fib(%s)" %n)
    response = fib(n)

    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)

channel.basic_qos(prefetch_count=1)
channel.basic_consume(on_request, queue='rpc_queue')

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