HTTP 500 error from HTTP Triggered Azure Function even though Log Stream indicates successful completion of the function

Question

I have a HTTP Triggered function that runs locally in Visual Studio fine. Monitoring in the Log Stream also show successful completion. However, the browser shows a 500 error even though there is nothing to return to the browser. How can I get rid of this error message?

    public static class ValidateFunction

    {

        [FunctionName("Validate")]

        public static async Task Run(

            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,

            ILogger log)

        {

            log.LogInformation("Validate HTTP trigger function processed a request.");

            var responsebody = await HttpService.LeanIXAPI.Validate();

            var writeResponse = FtpService.WriteFTP.WriteToArcherFTP(responsebody, "test", "./ValidationResults.txt");

            log.LogInformation($"Validate response was: {writeResponse}");

            return;

        }

    }

Answer 1

Hello @Matthew Castrigno

To resolve this issue, you can try adding a try-catch block around the code in the function and return an appropriate response to the browser in case of an exception.

For example:

public static class ValidateFunction {
[FunctionName("Validate")] 
public static async Task Run( [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req, ILogger log)
{ 
	try { 
		log.LogInformation("Validate HTTP trigger function processed a request."); 
		var responsebody = await HttpService.LeanIXAPI.Validate(); 
		var writeResponse = FtpService.WriteFTP.WriteToArcherFTP(responsebody, "test", "./ValidationResults.txt"); 
		log.LogInformation($"Validate response was: {writeResponse}"); 
		return new OkResult(); 
		}
	catch (Exception ex) 
	{ 
		log.LogError(ex, "An error occurred in the Validate function."); 
		return new StatusCodeResult(StatusCodes.Status500InternalServerError);
	} 
} 
}

In this example, the function returns an HTTP 200 OK response if the function completes successfully, and an HTTP 500 Internal Server Error response if an exception is thrown. You can modify the response as per your requirement.

---

I hope that this response has addressed your query and helped you overcome your challenges. If so, please mark this response as Answered. This will not only acknowledge our efforts, but also assist other community members who may be looking for similar solutions.