如何轮询 azure 服务总线队列的消息？

Question

How do I poll the azure service bus to continuously check for the messages? Here is how I receive the message from the queue.

   from azure.servicebus import QueueClient

   client = QueueClient.from_connection_string(
       q_string,
       q_name)

   msg = None

   with client.get_receiver() as queue_receiver:
     messages = queue_receiver.fetch_next(max_batch_size=1, timeout=3)
     if len(messages) > 0:
        msg = messages[0]
        print(f"Received {msg.message}")

  return msg

I want to continuously look for the message and then process it.

Answer 1

As George chen says, I think service bus queue trigger meets your requirement.

_init_.py:

import logging

import azure.functions as func


def main(msg: func.ServiceBusMessage):
    logging.info('Python ServiceBus queue trigger processed message: %s',
                 msg.get_body().decode('utf-8'))

---

function.json:

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "name": "msg",
      "type": "serviceBusTrigger",
      "direction": "in",
      "queueName": "test",
      "connection": "str"
    }
  ]
}

---

env var:

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "DefaultEndpointsProtocol=https;AccountName=0730bowmanwindow;AccountKey=lti/ThmF+mw9BebOacp9gVazIh76Q39ecikHSCkaTcGK5hmInspX+EkjzpNmvCPWsnvapWziHQHL+kKt2V+lZw==;EndpointSuffix=core.windows.net",
    "FUNCTIONS_WORKER_RUNTIME": "python",
    "str": "Endpoint=sb://bowmantest.servicebus.xxxxxxx"
  }
}

If on azure, the env var is on configuration settings instead of local.settings.json.

When you do this, the trigger will help you to capture the information in the service bus queue.(instant)

Answer 2

You can use the ServiceBusReceiver to receive messages persistently in v7.0.0

from azure.servicebus import ServiceBusClient

import os
connstr = os.environ['SERVICE_BUS_CONNECTION_STR']
queue_name = os.environ['SERVICE_BUS_QUEUE_NAME']

with ServiceBusClient.from_connection_string(connstr) as client:
    # max_wait_time specifies how long the receiver should wait with no incoming 
    # messages before stopping receipt.  
    # Default is None; to receive forever.
    with client.get_queue_receiver(queue_name, max_wait_time=30) as receiver:
        msg = receiver.next() # it's a generator
            # If it is desired to halt receiving early, one can break out of the loop here safely.