title: How can I make Azure functions work with an existing Service Bus Topic trigger?
body: <p>Been through the documentation and still not clear how this works. I have the following function.json:</p>
  
  <pre><code>{
    "bindings": [
      {
        "type": "serviceBusTrigger",
        "name": "message",
        "direction": "in",
        "subscriptionName": "notifications",
        "topicName": "order-placed",
        "connection": "orders",
        "accessRights": "Manage"
      }
    ],
    "disabled": false
  }
  </code></pre>
  
  <p>The connection string above is correct as per the doc. The subscription "notifications" does not exist - is this created by Azure functions or do I have to create a subscription for the topic using another mechanism? My function does not get called when I send a message to the bus targetting that topic. No subscription, no errors and no logs. I tried creating the subscription manually and that did not work. What am I missing?</p>