python3 访问 rabbitmq 示例

关于 rabbitmq

之前用过 kafka，要是拿这两者做对比的话，大概有以下异同：

1. 两者都是一个分布式架构
2. kafka 具有较高的吞吐量，rabbimq 吞吐量较小
3. rabbitmq 的可靠性更好，确认机制（生产者和 exchange，消费者和队列），支持事务，但会造成阻塞，委托（添加回调来处理发送失败的消息）和备份交换器（将发送失败的消息存下来后面再处理）机制
4. kafka 常用于日志收集业务，rabbitmq 常用于抢购，支付业务

rabbitmq demo

producer

# coding: utf-8
import json
import pika

credentials = pika.PlainCredentials('sm', 'sm')
connection = pika.BlockingConnection(pika.ConnectionParameters('32.86.5.93', 5672, '/', credentials))
channel = connection.channel()

# 声明queue，需要注意这里的配置，消费者声明 queue 时需要与生产者保持一致
channel.queue_declare(queue='viosm', arguments={"x-max-length": 10000})

body = json.dumps({"test": "test"})
# n RabbitMQ a message can never be sent directly to the queue, it always needs to go through an exchange.
# 推送到交换机，因为队列是一进一出的，如果推送到队列，只能有一个消费者来获取（来自毛绒绒胖虫子）
ret = channel.basic_publish(exchange="smai",
                            routing_key="",
                            body=body)
print(ret)  # 返回 None
connection.close()

consumer

# coding: utf-8
import json
import pika

credentials = pika.PlainCredentials('sm', 'sm')
connection = pika.BlockingConnection(pika.ConnectionParameters('32.86.5.93', 5672, '/', credentials))
channel = connection.channel()

# You may ask why we declare the queue again ‒ we have already declared it in our previous code.
# We could avoid that if we were sure that the queue already exists. For example if send.py program
# was run before. But we're not yet sure which program to run first. In such cases it's a good
# practice to repeat declaring the queue in both programs.
channel.queue_declare(queue='viosm', arguments={"x-max-length": 10000})  # 这里需要与生产者的声明保持一致

def msg_consumer(ch, method, properties, data_bytes):
    data_json = data_bytes.decode()
    data_dict = json.loads(data_json)
    print("{}".format(data_dict))
    ch.basic_ack(delivery_tag=method.delivery_tag)  # 手动提交偏移量

channel.basic_consume('viosm',       # 队列名
                      msg_consumer,  # 回调函数
                      consumer_tag="seemmo_consumer",
                      # auto_ack=True,  # 自动提交偏移量
                      )

channel.start_consuming()
# forever

ending ~