Visual Studio: New Durable Functions Project: System.InvalidOperationException: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.

[jaliyaudagedara]

Description

When creating a new Azure Function App Project and selecting Durable Functions Orchestration, the basic functionality is erroring out when the default Function1_HttpStart is triggered.

Error: System.InvalidOperationException: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.

Azure Functions Core Tools
Core Tools Version:       4.0.5611 Commit hash: N/A +591b8aec842e333a87ea9e23ba390bb5effe0655 (64-bit)
Function Runtime Version: 4.31.1.22191

[2024-04-22T09:04:53.962Z] Found C:\Users\Jaliya\Desktop\FunctionApp1\FunctionApp1\FunctionApp1.csproj. Using for user secrets file configuration.
[2024-04-22T09:04:58.877Z] Azure Functions .NET Worker (PID: 46364) initialized in debug mode. Waiting for debugger to attach...
[2024-04-22T09:04:58.941Z] Worker process started and initialized.

Functions:

        Function1_HttpStart: [GET,POST] http://localhost:7036/api/Function1_HttpStart

        Function1: orchestrationTrigger

        SayHello: activityTrigger

For detailed output, run func with --verbose flag.
[2024-04-22T09:05:03.912Z] Host lock lease acquired by instance ID '000000000000000000000000CF6A328F'.
[2024-04-22T09:05:15.399Z] Executing 'Functions.Function1_HttpStart' (Reason='This function was programmatically called via the host APIs.', Id=867fd6a5-d97b-430a-aef5-aa1c66621d8a)
[2024-04-22T09:05:15.661Z] Scheduling new Function1 orchestration with instance ID '41abf12af72249beab7a62f92bfbdc12' and 0 bytes of input data.
[2024-04-22T09:05:15.838Z] Started orchestration with ID = '41abf12af72249beab7a62f92bfbdc12'.
[2024-04-22T09:05:15.893Z] Executing 'Functions.Function1' (Reason='(null)', Id=a9158030-742b-4336-8488-0bddcfaddc25)
[2024-04-22T09:05:16.038Z] Function 'Function1_HttpStart', Invocation id '867fd6a5-d97b-430a-aef5-aa1c66621d8a': An exception was thrown by the invocation.
[2024-04-22T09:05:16.039Z] Result: Function 'Function1_HttpStart', Invocation id '867fd6a5-d97b-430a-aef5-aa1c66621d8a': An exception was thrown by the invocation.
Exception: System.InvalidOperationException: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.
[2024-04-22T09:05:16.040Z]    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpResponseStream.Write(Byte[] buffer, Int32 offset, Int32 count)

Visual Studio Version:

Microsoft Visual Studio Enterprise 2022 (64-bit) - Preview
Version 17.10.0 Preview 4.0

Steps to reproduce

1. Create a new Azure Function App Project and select Durable Functions Orchestration
2. Execute the Function1_HttpStart endpoint
   

[jaliyaudagedara]

This was a known issue for some time, and I saw the template was fixed on this PR (Azure/azure-functions-templates#1513).

Related issues:

• Update .NET isolated templates to make sure we're using async patterns when working with HttpRequestData azure-functions-templates#1509
• Isolated Process with DurableClient and ASP.NET Core integration will throw exception on CreateCheckStatusResponse azure-functions-durable-extension#2683

But somehow VS isn't using the updated templates.

The code generated by VS,

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
    <OutputType>Exe</OutputType>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
  <ItemGroup>
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="1.20.1" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.DurableTask" Version="1.0.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.1.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="1.2.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="1.16.4" />
    <PackageReference Include="Microsoft.ApplicationInsights.WorkerService" Version="2.21.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.ApplicationInsights" Version="1.1.0" />
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
  <ItemGroup>
    <Using Include="System.Threading.ExecutionContext" Alias="ExecutionContext" />
  </ItemGroup>
</Project>

using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.DurableTask;
using Microsoft.DurableTask.Client;
using Microsoft.Extensions.Logging;

namespace FunctionApp1
{
    public static class Function1
    {
        [Function(nameof(Function1))]
        public static async Task<List<string>> RunOrchestrator(
            [OrchestrationTrigger] TaskOrchestrationContext context)
        {
            ILogger logger = context.CreateReplaySafeLogger(nameof(Function1));
            logger.LogInformation("Saying hello.");
            var outputs = new List<string>();

            // Replace name and input with values relevant for your Durable Functions Activity
            outputs.Add(await context.CallActivityAsync<string>(nameof(SayHello), "Tokyo"));
            outputs.Add(await context.CallActivityAsync<string>(nameof(SayHello), "Seattle"));
            outputs.Add(await context.CallActivityAsync<string>(nameof(SayHello), "London"));

            // returns ["Hello Tokyo!", "Hello Seattle!", "Hello London!"]
            return outputs;
        }

        [Function(nameof(SayHello))]
        public static string SayHello([ActivityTrigger] string name, FunctionContext executionContext)
        {
            ILogger logger = executionContext.GetLogger("SayHello");
            logger.LogInformation("Saying hello to {name}.", name);
            return $"Hello {name}!";
        }

        [Function("Function1_HttpStart")]
        public static async Task<HttpResponseData> HttpStart(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post")] HttpRequestData req,
            [DurableClient] DurableTaskClient client,
            FunctionContext executionContext)
        {
            ILogger logger = executionContext.GetLogger("Function1_HttpStart");

            // Function input comes from the request content.
            string instanceId = await client.ScheduleNewOrchestrationInstanceAsync(
                nameof(Function1));

            logger.LogInformation("Started orchestration with ID = '{instanceId}'.", instanceId);

            // Returns an HTTP 202 response with an instance management payload.
            // See https://learn.microsoft.com/azure/azure-functions/durable/durable-functions-http-api#start-orchestration
            return client.CreateCheckStatusResponse(req, instanceId);
        }
    }
}

[jviau]

The templates have been updated: Azure/azure-functions-templates#1513