How can I debug and Azure Functions that is receiving the same message again and again?

I have an Azure Functions in C#. The trigger is a message from a ServiceBus.

When it receives the message, it starts a process to convert same data. The process could be quite long, around 50/60 seconds and the process calls few APIs.

I get this error:

> [2023-02-14T00:42:01.683Z] Executed 'getDataSB' (Failed,
> Id=ec780726-d740-4445-b964-d8493233874a, Duration=22985ms)
>
> [2023-02-14T00:42:01.685Z] System.Private.CoreLib: Exception while
> executing function: getDataSB. System.Net.Http: Response
> status code does not indicate success: 302 (Found).
>
> [2023-02-14T00:42:01.747Z] Message processing error
> (Action=ProcessMessageCallback, EntityPath=vs,
> Endpoint=wb.servicebus.windows.net)
>
> [2023-02-14T00:42:01.748Z]
> System.Private.CoreLib: Exception while executing function:
> getDataSB. System.Net.Http: Response status code does
> not indicate success: 302 (Found).

I don't understand if the error is coming from the APIs or from the Azure Functions. I continue to receive the message again and again. I added a lot of logs but they are not displayed in the local console.

public class GetDataSB
{
    private readonly ILogger<GetDataSB> _logger;

    public GetReversoVerbSynonymSB(ILogger<GetDataSB> log)
    {
        _logger = log;
    }

    [FunctionName("getDataSB")]
    public async Task Run(
        [ServiceBusTrigger("vs", Connection = "SBConnectionString")]
        string myQueueItem)
    {
        ServiceBusRequest request = 
            JsonSerializer.Deserialize<ServiceBusRequest>(myQueueItem);

        string processName = Environment.GetEnvironmentVariable("ProcessName");

        await ProcessService.ProcessData(request, processName, _logger);
    }
}

ProcessService is a static class.

public static class ProcessService {
    public static async Task<IActionResult> ProcessData(
        ServiceBusRequest request, string SystemUser, ILogger log) {
        log.LogInformation("Reading data...");
    }
}

Is there a way to change the time out of the execution?

I thought to limit the number of concurrency adding in the host.json this setting:

{
    "version": "2.0",
    "logging": {
        "applicationInsights": {
            "samplingSettings": {
                "isEnabled": true,
                "excludedTypes": "Request"
            }
        }
    },
    "extensions": {
        "serviceBus": {
            "prefetchCount": 100,
            "messageHandlerOptions": {
                "autoComplete": true,
                "maxConcurrentCalls": 1,
                "maxAutoRenewDuration": "00:05:00"
            },
            "sessionHandlerOptions": {
                "autoComplete": true,
                "messageWaitTimeout": "00:00:30",
                "maxAutoRenewDuration": "00:55:00",
                "maxConcurrentSessions": 1
            }
        }
    }
}

It seems like your Azure Function is failing to process the message received from the ServiceBus and as a result, the same message is being delivered to the function again and again. There could be several reasons for this, such as issues with the APIs that you are calling or issues with the configuration of your Azure Function.

Steps to debug this issue:

1. Verify the response of the APIs that you are calling from your function.

2. The 302 response that you are seeing indicates a redirection response. This could be because the API endpoint that you are calling has been moved or is temporarily unavailable. Make sure that you are using the correct API endpoint and that it is available.

3. Check the logs of your Azure Function. You mentioned that you added a lot of logs, but they are not displayed in the local console. Make sure that you are using the correct logging configuration and that you are looking at the correct log stream. You can also try to use other logging frameworks like Serilog to log the details of the process.
   Check the configuration of your Azure Function. It is possible that the function is timing out before it can complete the process.

You can try to increase the timeout value of the Azure Function by modifying the functionTimeout property in the host.json file.

Check the ServiceBus configuration. It is possible that the message is not being properly acknowledged or processed by the Azure Function, causing it to be redelivered.

Use Azure Application Insights to monitor your Azure Function.

This helps you in identifying any performance issues, exceptions, or other problems that may be occurring in your function.

Thanks @Skin for the comments.

Attach the processes with Visual Studio debugger.

Selecting the process to debug.

For more information, refer the below MSDocs.
Attach processes with the debugger

Remote debugging