Huge spike in FunctionInputConverterExceptions

Question

Huge spike in FunctionInputConverterExceptions

johnkors 25

I'm using an Azure Service Bus binding with Azure Functions. I suddenly started getting these errors in huge numbers without having done any changes.

Any ideas or updates?

Exception: Microsoft.Azure.Functions.Worker.Diagnostics.Exceptions.FunctionInputConverterException: Error converting 1 input parameters for Function 'MyFunction': Cannot convert input parameter 'userProperties' to type 'System.Collections.Generic.IDictionary`2[[System.String, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.String, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]]' from type 'System.String'.
   at Microsoft.Azure.Functions.Worker.Context.Features.DefaultModelBindingFeature.BindFunctionInput(FunctionContext context) in D:\a\1\s\src\DotNetWorker.Core\Context\Features\DefaultModelBindingFeature.cs:line 70
   at Microsoft.Azure.Functions.Worker.Invocation.DefaultFunctionExecutor.ExecuteAsync(FunctionContext context) in D:\a\1\s\src\DotNetWorker.Core\Invocation\DefaultFunctionExecutor.cs:line 45
   at Microsoft.Azure.Functions.Worker.OutputBindings.OutputBindingsMiddleware.Invoke(FunctionContext context, FunctionExecutionDelegate next) in D:\a\1\s\src\DotNetWorker.Core\OutputBindings\OutputBindingsMiddleware.cs:line 16
   at Microsoft.Azure.Functions.Worker.GrpcWorker.InvocationRequestHandlerAsync(InvocationRequest request, IFunctionsApplication application, IInvocationFeaturesFactory invocationFeaturesFactory, ObjectSerializer serializer, IOutputBindingsInfoProvider outputBindingsInfoProvider) in D:\a\1\s\src\DotNetWorker.Grpc\GrpcWorker.cs:line 167
Stack:    at Microsoft.Azure.Functions.Worker.Context.Features.DefaultModelBindingFeature.BindFunctionInput(FunctionContext context) in D:\a\1\s\src\DotNetWorker.Core\Context\Features\DefaultModelBindingFeature.cs:line 70
   at Microsoft.Azure.Functions.Worker.Invocation.DefaultFunctionExecutor.ExecuteAsync(FunctionContext context) in D:\a\1\s\src\DotNetWorker.Core\Invocation\DefaultFunctionExecutor.cs:line 45
   at Microsoft.Azure.Functions.Worker.OutputBindings.OutputBindingsMiddleware.Invoke(FunctionContext context, FunctionExecutionDelegate next) in D:\a\1\s\src\DotNetWorker.Core\OutputBindings\OutputBindingsMiddleware.cs:line 16
   at Microsoft.Azure.Functions.Worker.GrpcWorker.InvocationRequestHandlerAsync(InvocationRequest request, IFunctionsApplication application, IInvocationFeaturesFactory invocationFeaturesFactory, ObjectSerializer serializer, IOutputBindingsInfoProvider outputBindingsInfoProvider) in D:\a\1\s\src\DotNetWorker.Grpc\GrpcWorker.cs:line 167

Using "Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.0.13" "Microsoft.Azure.Functions.Worker.Sdk" Version="1.3.0" "Microsoft.Azure.Functions.Worker" Version="1.6.0"

navba-MSFT 27,625 Reputation points Microsoft Employee Moderator

2023-10-23T08:20:54.6833333+00:00
@johnkors Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

I understand that you are experiencing a sudden increase in FunctionInputConverterExceptions while using an Azure Service Bus binding with Azure Functions. The error message indicates that there is an issue converting the input parameter userProperties to type System.Collections.Generic.IDictionary. You have not made any changes to the codebase, and the error is occurring in large numbers.

I see that you have already raised a GitHub thread for the same issue: https://github.com/Azure/azure-functions-dotnet-worker/issues/1977

This error indicates that there is an issue with the data binding for the userProperties parameter in your Azure Function. The function is expecting a parameter of type System.Collections.Generic.IDictionary<string, string>, but it's receiving a System.String instead.

I am sharing a few suggestions here, if that helps:

Firstly check if the same code works fine in your local Dev environment ? or is it failing only in Azure ? If the issue persists, try to reproduce the issue in a local development environment. This can help identify if the issue is specific to the Azure environment or if it is a code-related issue.

If you can see the same error in your local dev environment, then you need to debug this and check the type of userProperties.

Check if the userProperties input parameter is being passed correctly to the Azure Function. Ensure that the input parameter is of the correct type and format as expected by the function. Ensure that the userProperties parameter is being correctly serialized as a dictionary of strings.

If none of these steps resolve the issue, you may need to provide more information about your Azure Function app and the Azure Service Bus binding configuration to help diagnose the problem. You may also try sharing a sample code snippet here which I can try reproducing the same issue at my end.

Sharing some of the useful articles here if that helps:
Azure Service Bus bindings for Azure Functions
Azure Service Bus trigger for Azure Functions

Azure Service Bus output binding for Azure Functions

Hope this helps.

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@johnkors I hope you had a chance to look at the comment by the Functions Product Owners here: https://github.com/Azure/azure-functions-dotnet-worker/issues/1977#issuecomment-1778169228

Also note the similar issue with NServiceBus has been discussed here:

https://discuss.particular.net/t/azure-function-isolated-worker-fails-when-binding-converting-userproperties/2840

You can try raising an issue here too. Sharing it here if that helps.

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Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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Huge spike in FunctionInputConverterExceptions

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