[BUG] Blob client freeze when downloading blob (full framework only)

Describe the bug The code hang on BlobClient.DownloadAsync()

Expected behavior It should not “freeze”

Actual behavior (include Exception or Stack Trace) It freeze and prevent code from executing what next 😦

To Reproduce

1. Create Azure blob storage premium

1. Create a container test

2. Uploads 2 files names test.txt and test2.txt with content abc

3. Run the following code (don’t forget to set the ConnectionString)

using System;
using System.Diagnostics;
using System.Net.Http;
using System.Threading.Tasks;
using Azure;
using Azure.Core.Pipeline;
using Azure.Storage.Blobs;

namespace ReproBugBlobHang
{
	internal static class Program
	{
		private const string ContainerName = "test";
		private const string ConnectionString = "";

		private static readonly string[] Urls =
		{
			"test.txt",
			"test2.txt",
		};

		private static void Main()
		{
			var blobClientOptions = new BlobClientOptions {Transport = new HttpClientTransport(new HttpClient() {Timeout = TimeSpan.FromSeconds(1)})};
			var t1 = RunAsync(blobClientOptions);
			var t2 = RunAsync(blobClientOptions);
			Task.WaitAll(t1, t2);
		}

		private static async Task RunAsync(BlobClientOptions blobClientOptions)
		{
			foreach (var url in Urls)
			{
				var stopwatch = Stopwatch.StartNew();
				try
				{
					var connection = new BlobClient(ConnectionString, ContainerName, url, blobClientOptions);
					Console.WriteLine("BEGIN");
					var response = await connection.DownloadAsync();
					Console.WriteLine("END");
					Console.WriteLine(response);
				}
				catch (RequestFailedException ex) when (ex.Status == 404)
				{
					Console.WriteLine("NOT FOUND");
				}

				Console.WriteLine(stopwatch.ElapsedMilliseconds);
			}
		}
	}
}

csproj

<Project Sdk="Microsoft.NET.Sdk">

	<PropertyGroup>
		<OutputType>Exe</OutputType>
		<TargetFramework>net472</TargetFramework>
	</PropertyGroup>

	<ItemGroup>
		<PackageReference Include="Azure.Storage.Blobs" Version="12.3.0" />
		<PackageReference Include="System.Net.Http" Version="4.3.4" />
	</ItemGroup>

</Project>

Output:

D:/dev/git/rider/repro-jetbrains/ConsoleApplication2/ReproBugBlobHang/bin/Debug/net472/ReproBugBlobHang.exe
BEGIN
BEGIN
END
Status: 206, Value: Azure.Storage.Blobs.Models.BlobDownloadInfo
372
BEGIN
END
Status: 206, Value: Azure.Storage.Blobs.Models.BlobDownloadInfo
229
BEGIN

Then it hang until timeouts and throw

Unhandled Exception: System.AggregateException: One or more errors occurred. ---> System.AggregateException: Retry failed after 6 tries. ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.HttpClientTransport.<ProcessAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.RequestActivityPolicy.<ProcessNextAsync>d__10.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.RequestActivityPolicy.<ProcessAsync>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.BufferResponsePolicy.<ProcessAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.LoggingPolicy.<ProcessAsync>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.LoggingPolicy.<ProcessAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.HttpPipelineSynchronousPolicy.<ProcessAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.HttpPipelineSynchronousPolicy.<ProcessAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at Azure.Core.Pipeline.RetryPolicy.<ProcessAsync>d__11.MoveNext()
   --- End of inner exception stack trace ---
   at Azure.Core.Pipeline.RetryPolicy.<ProcessAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.HttpPipelineSynchronousPolicy.<ProcessAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Core.Pipeline.HttpPipelineSynchronousPolicy.<ProcessAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Storage.Blobs.BlobRestClient.Blob.<DownloadAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Storage.Blobs.Specialized.BlobBaseClient.<StartDownloadAsync>d__45.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Storage.Blobs.Specialized.BlobBaseClient.<DownloadInternal>d__44.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Storage.Blobs.Specialized.BlobBaseClient.<DownloadAsync>d__43.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Storage.Blobs.Specialized.BlobBaseClient.<DownloadAsync>d__41.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Storage.Blobs.Specialized.BlobBaseClient.<DownloadAsync>d__39.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at ReproBugBlobHang.Program.<RunAsync>d__4.MoveNext() in Program.cs:line 39
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.WaitAll(Task[] tasks, Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.WaitAll(Task[] tasks, Int32 millisecondsTimeout)
   at System.Threading.Tasks.Task.WaitAll(Task[] tasks)
   at ReproBugBlobHang.Program.Main() in Program.cs:line 27

Environment:

• Azure.Storage.Blobs 12.3.0
• Windows 10 .Net Framework 4.7.2 / .Net Framework

Note It’s working fine with TargetFramework: netcoreapp3.1

[christianrondeau]

Thanks @tg-msft for responding so quickly! This issue looks indeed very similar. We can try our repro after #12103 has been released (due to timing we had to port some code to .NET Core, which resolved the issue) or earlier if we have the opportunity to build azure sdk from source. You can leave that issue closed in the meantime, I will report back if the issue still shows up.

[tg-msft]

Sorry for closing the issue - we’re trying to make our bot a little more helpful and it was overeager here.

Can you take a look at https://github.com/Azure/azure-sdk-for-net/issues/11503? I think it’s a duplicate of this issue and we’re trying out a fix for it. We can reopen this issue otherwise.