title: How to create a Logic App Custom Connector polling trigger?
body: <p>I've been able to create a Logic App Custom Connector with a webhook trigger by following <a href="https://docs.microsoft.com/en-us/connectors/custom-connectors/create-webhook-trigger" rel="nofollow noreferrer">the docs</a>, however I can't find any documentation on creating a polling trigger. I was only able to find <a href="https://github.com/jeffhollan/LogicAppTriggersExample" rel="nofollow noreferrer">Jeff Hollan's trigger examples</a>, but the polling trigger doesn't seem compatible with the custom connector.</p>
  
  <p>I tried setting up a polling trigger by performing the following steps:</p>
  
  <ul>
  <li>Create an Azure Function with a GET operation expecting a date time query parameter</li>
  <li>Have the function return a set of entities that have changed since the last poll</li>
  <li>Configure the custom connector to call the Azure Function with the date time query parameter</li>
  <li>Configure the response body of the custom connector</li>
  <li>Try different things in the 'Trigger configuration' section, but this is most confusing to me.</li>
  </ul>
  
  <p>Whatever I tried, the trigger always fails with a 404 in the trigger outputs, similar to what <a href="https://social.msdn.microsoft.com/Forums/en-US/93bb2b20-e56b-4e36-83d1-31845c88a3b1/azure-logic-apps-custom-connector-webhook-trigger?forum=azurelogicapps&amp;prof=required" rel="nofollow noreferrer">I initially had</a> with the webhook trigger type.</p>
  
  <p>There are a few things that confuse me:</p>
  
  <p><strong>1. Path of trigger query seems screwed up</strong></p>
  
  <p>It looks like the custom connector UI screws up the path to the trigger. I noticed this when I downloaded the OpenAPI file. The path to my trigger API should be <code>/api/trigger/tasks/completed</code>, but in the OpenAPI file it read <code>/trigger/api/trigger/tasks/completed</code>. It appears the custom connector adds <code>/trigger</code> in front of the path. I sometimes noticed it doing this multiple times, giving me something similar to <code>/trigger/trigger/trigger/api/trigger/tasks/completed</code>. I fixed this in the OpenAPI file and re-imported it into the custom connector.</p>
  
  <p><strong>2. Trigger Configuration section</strong></p>
  
  <p>I don't understand what to do in the Trigger Configuration section of a polling trigger.</p>
  
  <p><a href="https://i.stack.imgur.com/hFmkC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hFmkC.png" alt="enter image description here"></a></p>
  
  <ul>
  <li>I assume the query parameter to monitor state change is some parameter I define myself, e.g. a timestamp, to determine what entities to return.</li>
  <li>As the 'select value to pass to selected query param' I would expect I could pick a timestamp from the trigger response. It looks like I can only pick values from a collection, not scalar values from the response as I would expect. How does that work?</li>
  <li>Is 'trigger hint' just some information or does it actually control something?</li>
  </ul>