将 Python Pika 与 Amazon MQ for RabbitMQ 结合使用

打开新的终端窗口，为项目创建新目录，然后导航到该目录。

$ mkdir pika-tutorial
$ cd pika-tutorial

创建一个名为 basicClient.py 的文件，其中包含以下 Python 代码。

import ssl
import pika

class BasicPikaClient:

    def __init__(self, rabbitmq_broker_id, rabbitmq_user, rabbitmq_password, region):

        # SSL Context for TLS configuration of Amazon MQ for RabbitMQ
        ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)
        ssl_context.set_ciphers('ECDHE+AESGCM:!ECDSA')

        url = f"amqps://{rabbitmq_user}:{rabbitmq_password}@{rabbitmq_broker_id}.mq.{region}.amazonaws.com:5671"
        parameters = pika.URLParameters(url)
        parameters.ssl_options = pika.SSLOptions(context=ssl_context)

        self.connection = pika.BlockingConnection(parameters)
        self.channel = self.connection.channel()

复制以下代码示例的内容，并将其作为 publisher.py 保存在本地上一个步骤创建的相同目录中。

from basicClient import BasicPikaClient

class BasicMessageSender(BasicPikaClient):

    def declare_queue(self, queue_name):
        print(f"Trying to declare queue({queue_name})...")
        self.channel.queue_declare(queue=queue_name)

    def send_message(self, exchange, routing_key, body):
        channel = self.connection.channel()
        channel.basic_publish(exchange=exchange,
                              routing_key=routing_key,
                              body=body)
        print(f"Sent message. Exchange: {exchange}, Routing Key: {routing_key}, Body: {body}")

    def close(self):
        self.channel.close()
        self.connection.close()

if __name__ == "__main__":

    # Initialize Basic Message Sender which creates a connection
    # and channel for sending messages.
    basic_message_sender = BasicMessageSender(
        "<broker-id>",
        "<username>",
        "<password>",
        "<region>"
    )

    # Declare a queue
    basic_message_sender.declare_queue("hello world queue")

    # Send a message to the queue.
    basic_message_sender.send_message(exchange="", routing_key="hello world queue", body=b'Hello World!')

    # Close connections.
    basic_message_sender.close()

BasicMessageSender 类继承自 BasicPikaClient 并实施了用于声明队列、向队列发送消息和关闭连接的其他方法。代码示例使用等于队列名称的路由密钥，将消息路由到默认交换器。

在 if __name__ == "__main__": 下，将传递给 BasicMessageSender 构造函数语句的参数替换为以下信息。

在创建 publisher.py 的同一目录中运行以下命令。

$ python3 publisher.py

如果代码运行成功，您将在终端窗口中看到以下输出。

Trying to declare queue(hello world queue)...
Sent message. Exchange: , Routing Key: hello world queue, Body: b'Hello World!'

复制以下代码示例的内容，并将其作为 consumer.py 保存在本地同一目录中。

from basicClient import BasicPikaClient

class BasicMessageReceiver(BasicPikaClient):

    def get_message(self, queue):
        method_frame, header_frame, body = self.channel.basic_get(queue)
        if method_frame:
            print(method_frame, header_frame, body)
            self.channel.basic_ack(method_frame.delivery_tag)
            return method_frame, header_frame, body
        else:
            print('No message returned')

    def close(self):
        self.channel.close()
        self.connection.close()


if __name__ == "__main__":

    # Create Basic Message Receiver which creates a connection
    # and channel for consuming messages.
    basic_message_receiver = BasicMessageReceiver(
        "<broker-id>",
        "<username>",
        "<password>",
        "<region>"
    )

    # Consume the message that was sent.
    basic_message_receiver.get_message("hello world queue")

    # Close connections.
    basic_message_receiver.close()

与您在上一个步骤中创建的发布者类似，BasicMessageReciever 继承自 BasicPikaClient 并实施用于接收单条消息和关闭连接的其他方法。

在 if __name__ == "__main__": 语句下，将传递给 BasicMessageReciever 构造函数的参数替换为您的信息。

在您的项目目录中运行以下命令。

$ python3 consumer.py

如果代码运行成功，您将在终端窗口中看到消息正文以及包括路由密钥的标头。

<Basic.GetOk(['delivery_tag=1', 'exchange=', 'message_count=0', 'redelivered=False', 'routing_key=hello world queue'])> <BasicProperties> b'Hello World!'

在 consumer.py 中，将以下方法定义添加到 BasicMessageReceiver 类。

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

    self.channel.basic_consume(queue=queue, on_message_callback=callback, auto_ack=True)

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

在 consumer.py 中的 if __name__ == "__main__": 下，调用您在上一个步骤中定义的 consume_messages 方法。

if __name__ == "__main__":

    # Create Basic Message Receiver which creates a connection and channel for consuming messages.
    basic_message_receiver = BasicMessageReceiver(
        "<broker-id>",
        "<username>",
        "<password>",
        "<region>"
    )

    # Consume the message that was sent.
    # basic_message_receiver.get_message("hello world queue")

    # Consume multiple messages in an event loop.
    basic_message_receiver.consume_messages("hello world queue")

    # Close connections.
    basic_message_receiver.close()

再次运行 consumer.py，如果运行成功，队列消息将显示在终端窗口中。

[*] Waiting for messages. To exit press CTRL+C
[x] Received b'Hello World!'
[x] Received b'Hello World!'
...