Sending and Receiving Normal Messages

Notes and Constraints

The Python SDK of RocketMQ using TCP is compatible only with Linux, and does not support SSL.

Preparing the Environment

1. Run the python command to check whether Python has been installed. If the following information is displayed, Python has been installed:

   Python 3.7.1 (default, Jul  5 2020, 14:37:24) 
   [GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux
   Type "help", "copyright", "credits" or "license" for more information.
   >>>

   If Python is not installed, run the following command:

   yum install python

2. Install the librocketmq library and rocketmq-client-python. For details, see rocketmq-client-python.
   

   Download rocketmq-client-cpp-2.2.0 to obtain the librocketmq library.

3. Add librocketmq.so to the system's dynamic library search path.
   1. Find the path of librocketmq.so.

      find / -name librocketmq.so

   2. Add librocketmq.so to the system's dynamic library search path.

      ln -s /librocketmq.so_path/librocketmq.so /usr/lib
      sudo ldconfig

Sending Normal Messages

The following code is an example. Replace the information in bold with the actual values.

from rocketmq.client import Producer, Message

topic = 'TopicTest'
name_srv = '192.168.0.1:8100'


def create_message():
    msg = Message(topic)
    msg.set_keys('messageKey')
    msg.set_tags('messageTag')
    msg.set_property('property', 'test')
    msg.set_body('message body')
    return msg


def send_message_sync():
    producer = Producer('producerGroup')
    producer.set_name_server_address(name_srv)
    producer.start()
    msg = create_message()
    ret = producer.send_sync(msg)
    print('send message status: ' + str(ret.status) + ' msgId: ' + ret.msg_id)
    producer.shutdown()


if __name__ == '__main__':
    send_message_sync()

The parameters in the example code are described as follows. For details about how to obtain the parameter values, see Collecting Connection Information.

• topic: topic name.
• name_srv: instance address and port.
• set_keys: sets the message index key. A message can be exactly searched by keywords.
• set_tags: sets message tags. Consumers filter messages by tags.

Subscribing to Normal Messages

The following code is an example. Replace the information in bold with the actual values.

import time

from rocketmq.client import PushConsumer, ConsumeStatus


def callback(msg):
    print(msg.id, msg.body, msg.get_property('property'))
    return ConsumeStatus.CONSUME_SUCCESS


def start_consume_message():
    consumer = PushConsumer('consumer_group')
    consumer.set_name_server_address('192.168.0.1:8100')
    consumer.subscribe('TopicTest', callback)
    print('start consume message')
    consumer.start()

    while True:
        time.sleep(3600)


if __name__ == '__main__':
    start_consume_message()

The parameters in the example code are described as follows. For details about how to obtain the parameter values, see Collecting Connection Information.

• consumer_group: consumer group name.
• 192.168.0.1:8100: instance address and port.
• TopicTest: topic name.