Troubleshoot a Power Fx function

  • 5 minutes

Building Power Fx functions in Dataverse is a great way to streamline your apps. Sometimes, situations don't work as expected. Whether your function isn't returning the correct result, is showing errors, or isn't running at all, know that these situations happen and that troubleshooting is a normal part of the process. With a few key strategies, you can quickly track down and fix issues.

This guide can help you:

  • Identify common issues.
  • Debug formulas and test different inputs.
  • Avoid common pitfalls, such as delegation issues and permission-related blockers.
  • Optimize your functions for better performance.

The next sections outline how you can get your Power Fx functions working smoothly.

Test unexpected output results

You tested functions in earlier exercises because it's a smart way to make sure that your logic works smoothly and to catch issues early. Testing with known parameters also helps you figure out why a function might be returning unexpected results.

If your function doesn't have an output parameter, try adding a temporary one for testing only. That way, you get more than only a success/failure result, you can view actual data that you can learn from.

For more complex logic, break it down into smaller, simpler functions and then test each part on its own. After determining that everything works, you can piece it back together with confidence.

Debug a function with Trace()

The Trace() function is a powerful tool for debugging. It records diagnostic details about how your function runs in the background.

Before using Trace(), you need to turn on logging for your environment:

  1. In make.powerapps.com, select the Tables gear icon and then select Organization.
  2. Show the Plug-in Trace Log Setting and then make sure that it's set to All.

    Screenshot of the Plug-in Trace Log Setting.

After you turn on logging, you can start using Trace() to debug Power Fx functions. The following steps outline how to use it in a canvas app:

  1. Wrap your function call in a Trace() function, as follows:

    Trace(Environment.<FunctionSchemaName>({InputParameter:" test"}));

  2. In the left navigation pane of your canvas app, select Advanced Tools > Open live monitor.

  3. Run your function in the canvas app. Results and details appear in the Live Monitor window, which can help you understand what's happening in the background.

    Screenshot of Live Monitor.

For more information about using Trace(), see documentation on the Trace function.

Extra troubleshooting tips

If your function isn't behaving as expected, a few common elements to check include:

  • Delegation issues - If your function isn't returning the correct data, check for delegation warnings in your formula. Some Power Fx functions might not be fully delegable, which could limit the amount of data being processed.
  • Platform limitations - Certain functions might have restrictions in Power Fx functions. Be sure to review any known limitations and determine if a suggested workaround is available.
  • Security and Permissions - If users don't see the expected results, verify that they have the necessary permissions for any data sources that your function relies on.

Testing and troubleshooting Power Fx functions might seem tricky at first, but with the correct approach, you can quickly figure out how to troubleshoot with ease. Whether you're running test cases, using Trace(), or checking for delegation and security issues, each step helps ensure that your function runs smoothly. Keep experimenting, refining, and building. Before you know it, you could be a Power Fx pro.