Azure 持久函数 - CallActivityAsync 时出现 InvalidOperationException

Question

我正在玩 Azure Durable functions。目前我在调用 activity 后在 Orchestration 函数中得到 InvalidOperationException。它抱怨检测到 多线程执行。如果 orchestrator 函数先前从不受支持的异步回调 恢复，则可能会发生这种情况。

有人遇到过这样的问题吗？我做错了什么？完整的代码可以在 GitHub

上找到

这是编排函数的行：

var res = await ctx.CallActivityAsync<int>("LengthCheck", "inputData");

LengthCheck 活动函数是：

[FunctionName("LengthCheck")]
public static Task<int> Calc([ActivityTrigger] string input)
{
    var task = Task.Delay(TimeSpan.FromSeconds(5));
    task.Wait();
    return Task.FromResult(input.Length);
}

堆栈跟踪是：

ac6fd5cdd07a4dc9b2577657d65c4f27: Function 'InpaintOrchestration (Orchestrator)', version '' failed with an error. Reason: System.InvalidOperationException: Multithreaded execution was detected. This can happen if the orchestrator function previously resumed from an unsupported async callback.

at Microsoft.Azure.WebJobs.DurableOrchestrationContext.ThrowIfInvalidAccess()

at Microsoft.Azure.WebJobs.DurableOrchestrationContext.d__47`1.MoveNext()

End of stack trace from previous location where exception was thrown

at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)

at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()

Answer 1

只要协调器函数以不受支持的方式执行异步工作，就会发生此异常。在这种情况下，“不受支持”实际上意味着 await 被用于 non-durable 任务（而“non-durable”意味着它是来自其他 API 以外的任务IDurableOrchestrationContext).

您可以在此处找到有关协调程序函数的代码约束的更多信息：https://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-code-constraints。

以下是我快速扫描您的代码时违反的规则：

Orchestrator code should be non-blocking. For example, that means no I/O and no calls to Thread.Sleep or equivalent APIs. If an orchestrator needs to delay, it can use the CreateTimer API.

Orchestrator code must never initiate any async operation except by using the IDurableOrchestrationContext API. For example, no Task.Run, Task.Delay or HttpClient.SendAsync. The Durable Task Framework executes orchestrator code on a single thread and cannot interact with any other threads that could be scheduled by other async APIs.

当我们检测到进行了不支持的异步调用时，就会出现此异常。我注意到这段代码中发生了这种情况：

    private static async Task SaveImageLabToBlob(ZsImage imageLab, CloudBlobContainer container, string fileName)
    {
        var argbImage = imageLab
            .Clone()
            .FromLabToRgb()
            .FromRgbToArgb(Area2D.Create(0, 0, imageLab.Width, imageLab.Height));

        using (var bitmap = argbImage.FromArgbToBitmap())
        using (var outputStream = new MemoryStream())
        {
            // modify image
            bitmap.Save(outputStream, ImageFormat.Png);

            // save the result back
            outputStream.Position = 0;
            var resultImageBlob = container.GetBlockBlobReference(fileName);
            await resultImageBlob.UploadFromStreamAsync(outputStream);
        }
    }

进行异步或阻塞调用的正确方法是将它们包装在 activity 函数中，这些函数没有任何这些约束。

在此扩展的最新版本（v1.3.2 及更高版本）中，我们在异常消息中描述 code-constraints 的文档中包含了 link。

Answer 2

我的持久协调器功能也发生了这种情况。我必须摆脱 activity 函数调用的所有 .ConfigureAwait(false) 结尾。

 //invoking First activity function
        var id = await context.CallActivityAsync<Guid>(Function1, requestModel);
        

        //invoking second activity function that uses data from the first activity function without ConfigureAwait(false)
        var readModel = await context.CallActivityAsync<ReadModel>(Function2, id);
       

        //invoking third activity function that uses data from the second activity function without ConfigureAwait(false)
        await context.CallActivityAsync(Function3, cartReadModel);

Azure 持久函数 - CallActivityAsync 时出现 InvalidOperationException

Azure Durable function - InvalidOperationException when CallActivityAsync

c#

azure

azure-functions

azure-durable-functions