Unable to send messages to service bus topic

[karlokr-p]

Is your question related to a specific version? If so, please specify:

azure-functions 1.7.2

What binding does your question apply to, if any? (e.g. Blob Trigger, Event Hub Binding, etc)

Service bus

Question

I am unable to successfully send a message to Azure Service Bus Topic. I've configured the serverless function with the following function.json file:

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "name": "inputmsg",
      "type": "serviceBusTrigger",
      "direction": "in",
      "queueName": "queuename",
      "connection": "AzureServiceBusConnectionString"
    },
    {
      "name": "msg",
      "type": "serviceBus",
      "direction": "out",
      "topicName": "outputtopicname",
      "connection": "AzureServiceBusConnectionString"
    }
  ],
  "retry": {
    "strategy": "exponentialBackoff",
    "maxRetryCount": 5,
    "minimumInterval": "00:00:01",
    "maximumInterval": "00:00:30"
  }
}

and the following function:

import json
import azure.functions as func

def main(inputmsg: func.ServiceBusMessage, msg: func.Out[str]):  
    data = json.loads(inputmsg.get_body().decode("utf-8"))
    result = process_data(data)
    msg.set(json.dumps(result))

I am unsure why the messages are not being sent to the service bus topic. With this code and configuration, I am able to read the message from the service bus queue, but sending them out to the topic does not work.

This is a similar configuration and code to another serverless function I've wrote which sends messages to a service bus queue, but that function works correctly.

I am also wondering how I could set custom properties on the message which is sent to the topic, so that I can make use of the correlation filters for topic subscriptions.

Thanks

[shreyabatra4]

@stefanushinardi