ApsaraMQ for RocketMQ:Enviar e receber mensagens ordenadas

Informações de contexto

Para mais detalhes, consulte Ordered messages.

Pré-requisitos

Antes de começar, conclua as seguintes etapas:

• Instale o sdk para Python. Para mais informações, consulte Prepare the Python SDK environment.

• Primeiro, crie os recursos no console do ApsaraMQ for RocketMQ e os especifique no código. Esses recursos incluem instâncias, tópicos e grupos de consumidores. Para obter mais informações, consulte Create resources.

• Obtenha o par de AccessKey da sua conta Alibaba Cloud e defina as credenciais. Para saber mais, consulte Create an AccessKey.

Enviar mensagens ordenadas

O código de exemplo a seguir demonstra o envio de mensagens ordenadas com o sdk de cliente http para Python:

import sys

from mq_http_sdk.mq_exception import MQExceptionBase
from mq_http_sdk.mq_producer import *
from mq_http_sdk.mq_client import *

# Initialize the producer client. 
mq_client = MQClient(
    # The HTTP endpoint. You can obtain the endpoint in the HTTP Endpoint section of the Instance Details page in the ApsaraMQ for RocketMQ console. 
     "${HTTP_ENDPOINT}",
    # Make sure that the environment variables ALIBABA_CLOUD_ACCESS_KEY_ID and ALIBABA_CLOUD_ACCESS_KEY_SECRET are configured. 
    # The AccessKey ID that is used for authentication. 
    os.environ['ALIBABA_CLOUD_ACCESS_KEY_ID'],
    # The AccessKey secret that is used for authentication. 
    os.environ['ALIBABA_CLOUD_ACCESS_KEY_SECRET']
    )
# The topic in which the message is produced. You must create the topic in the ApsaraMQ for RocketMQ console. 
topic_name = "${TOPIC}"
# The ID of the instance to which the topic belongs. You must create the instance in the ApsaraMQ for RocketMQ console. 
# If the instance has a namespace, the instance ID must be specified. If the instance does not have a namespace, set the instanceID parameter to an empty string. You can obtain the namespace of the instance on the Instance Details page in the ApsaraMQ for RocketMQ console. 
instance_id = "${INSTANCE_ID}"

producer = mq_client.get_producer(instance_id, topic_name)

# Cyclically send eight messages. 
msg_count = 8
print("%sPublish Message To %s\nTopicName:%s\nMessageCount:%s\n" % (10 * "=", 10 * "=", topic_name, msg_count))

try:
    for i in range(msg_count):
        msg = TopicMessage(
            # The message content. 
            "I am test message %s.hello" % i, 
            # The message tag. 
            "tag %s" % i
        )
        # The custom attributes of the message. 
        msg.put_property("a", str(i))
        # The sharding key that is used to distribute ordered messages to a specific partition. Sharding keys can be used to identify different partitions. A sharding key is different from a message key. 
        msg.set_sharding_key(str(i % 3))
        re_msg = producer.publish_message(msg)
        print("Publish Message Succeed. MessageID:%s, BodyMD5:%s" % (re_msg.message_id, re_msg.message_body_md5))
except MQExceptionBase as e:
    if e.type == "TopicNotExist":
        print("Topic not exist, please create it.")
        sys.exit(1)
    print("Publish Message Fail. Exception:%s" % e)
            

Assinar mensagens ordenadas

O código de exemplo a seguir demonstra como assinar mensagens ordenadas com o sdk de cliente http para Python:

from mq_http_sdk.mq_exception import MQExceptionBase
from mq_http_sdk.mq_consumer import *
from mq_http_sdk.mq_client import *

# Initialize the consumer client. 
mq_client = MQClient(
    # The HTTP endpoint. You can obtain the endpoint in the HTTP Endpoint section of the Instance Details page in the ApsaraMQ for RocketMQ console. 
     "${HTTP_ENDPOINT}",
    # Make sure that the environment variables ALIBABA_CLOUD_ACCESS_KEY_ID and ALIBABA_CLOUD_ACCESS_KEY_SECRET are configured. 
    # The AccessKey ID that is used for authentication. 
    os.environ['ALIBABA_CLOUD_ACCESS_KEY_ID'],
    # The AccessKey secret that is used for authentication. 
    os.environ['ALIBABA_CLOUD_ACCESS_KEY_SECRET']
    )
# The topic in which the message is produced. You must create the topic in the ApsaraMQ for RocketMQ console. 
topic_name = "${TOPIC}"
# The ID of the consumer group that you created in the ApsaraMQ for RocketMQ console. 
group_id = "${GROUP_ID}"
# The ID of the instance to which the topic belongs. You must create the instance in the ApsaraMQ for RocketMQ console. 
# If the instance has a namespace, the instance ID must be specified. If the instance does not have a namespace, set the instanceID parameter to an empty string. You can obtain the namespace of the instance on the Instance Details page in the ApsaraMQ for RocketMQ console. 
instance_id = "${INSTANCE_ID}"

consumer = mq_client.get_consumer(instance_id, topic_name, group_id)
# Consume messages in long polling mode. The consumer may pull partitionally ordered messages from multiple partitions. The consumer consumes the messages in the same partition in the order in which the messages are sent. 
# If the broker fails to receive an acknowledgement (ACK) for a message in a partition from the consumer, the broker delivers the same message in the partition to the consumer again. 
# The consumer can consume the next batch of messages from a partition only after all the messages that are pulled from the partition in the previous batch are acknowledged as consumed. 
# In long polling mode, if no message in the topic is available for consumption, the request is suspended on the broker for the specified time period. If a message becomes available for consumption within the specified period of time, a response is immediately sent to the consumer. In this example, the is specified as 3 seconds. 
wait_seconds = 3
# The maximum number of messages that can be consumed at a time. In this example, the value is specified as 3. The largest value you can specify is 16. 
batch = 3
print(("%sConsume And Ak Message From Topic%s\nTopicName:%s\nMQConsumer:%s\nWaitSeconds:%s\n" \
        % (10 * "=", 10 * "=", topic_name, group_id, wait_seconds)))
while True:
    try:
        recv_msgs = consumer.consume_message_orderly(batch, wait_seconds)
        print("=======>Receive %d messages:" % len(recv_msgs))
        for msg in recv_msgs:
            print("\tMessageId: %s, MessageBodyMD5: %s,NextConsumeTime: %s,ConsumedTimes: %s,PublishTime: %s\n\tBody: %s \
                    \n\tReceiptHandle: %s \
                    \n\tProperties: %s,ShardingKey: %s\n" % \
                  (msg.message_id, msg.message_body_md5,
                   msg.next_consume_time, msg.consumed_times,
                   msg.publish_time, msg.message_body,
                   msg.receipt_handle, msg.properties, msg.get_sharding_key()))
    except MQExceptionBase as e:
        if e.type == "MessageNotExist":
            print(("No new message! RequestId: %s" % e.req_id))
            continue

        print(("Consume Message Fail! Exception:%s\n" % e))
        time.sleep(2)
        continue

    # If the broker does not receive an ACK from the consumer before the period of time specified by the msg.next_consume_time parameter elapses, the broker delivers the message to the consumer again. 
    # A unique timestamp is specified for the handle of a message each time the message is consumed. 
    try:
        receipt_handle_list = [msg.receipt_handle for msg in recv_msgs]
        consumer.ack_message(receipt_handle_list)
        print(("========>Ak %s Message Succeed.\n\n" % len(receipt_handle_list)))
    except MQExceptionBase as e:
        print(("\nAk Message Fail! Exception:%s" % e))
        # If the handle of a message times out, the broker cannot receive an ACK for the message from the consumer. 
        if e.sub_errors:
            for sub_error in e.sub_errors:
                print(("\tErrorHandle:%s,ErrorCode:%s,ErrorMsg:%s" % \
                      (sub_error["ReceiptHandle"], sub_error["ErrorCode"], sub_error["ErrorMessage"])))