Async methods fail

[Raphael-Saldanha]

After upgrading to the latest version, the EncryptAsync thread remais locked

using (var client = new AmazonKeyManagementServiceClient())
using (var plainText = new MemoryStream(Encoding.UTF8.GetBytes("Amazon Web Services")))
{
    var request = new EncryptRequest
    {
        KeyId = "Aws-Kms-Login-Key",
        Plaintext = plainText
    };
                
    var result = client.EncryptAsync(request).Result.CiphertextBlob.ToArray();
}

To overcome the issue, it is required to run the code within a different task

var result = Task.Run(() => _ = client.EncryptAsync(request).Result).Result.CiphertextBlob.ToArray();

[Raphael-Saldanha]

The same problem can be found on AmazonS3Client's PutBucketAsync method.

[Raphael-Saldanha]

On a Asp.NET MVC Application, everything works as expected having the following package versions

• AWSSDK.Core: 3.3.107.5
• AWSSDK.KeyManagementService: 3.3.106.1

if the AWSSDK.Core updated from version 3.3.107.5 to 3.3.107.6 the AmazonKeyManagementServiceClient's EncryptAsync method thread will be blocked, I mean, it will never return any result.

The issue is also present by updating the AWSSDK.KeyManagementService to the 3.3.106.2, that as a requirement will also update the AWSSDK.Core to 3.3.107.6.

The issue is only present in Asp.NET MVC application. It is not possible to reproduce the issue on a Console Application running on both .NET Framework and .NET Core, using the packages on the versions mentioned above or even on their latest versions.

public class HomeController : Controller
{
    public ActionResult Index()
    {
        using (var client = new AmazonKeyManagementServiceClient("AKIA...", "KEY...", RegionEndpoint.USEast1))
        using (var plainText = new MemoryStream(Encoding.UTF8.GetBytes("Amazon Web Services")))
        {
            var request = new EncryptRequest
            {
                KeyId = "arn:aws:kms:us-east-1:XXXXXX:key/6756AB19-XXXX-XXXX-XXXX-4D00324E28BF",
                Plaintext = plainText
    ``        };

            var result = client.EncryptAsync(request).Result.CiphertextBlob.ToArray();
        }

        return View();
    }
}

[ukmoredec]

I'm experiencing the same thing in a Lambda function project w/ .net core 3.1, with a call to AmazonElastiCacheClient.DescribeReplicationGroupsAsync. Wrapping the call in a new Task like in the OP "fixes" the problem.

This is with Core 3.3.107.10 and ElastiCache 3.3.111.5--and a lot of other packages and mess working with older versions, I also can't reproduce it in a fresh Lambda function with the same two package versions above. This doesn't include a bunch of other services/configuration that the main project has, though. I'll try harder to come up with the smallest project that reproduces the problem, just wanted to +1 this for now.

[rajeshsv]

We have the same issue after upgrading to the latest version of nuget.

After spending quite a lot of time investigating we found the issue in AWSSDK.Core latest nuget where the async call does not return to the calling thread.

I have done a very basic sample application where using the AWSSDK.Core v 3.3.107.3 returns the call back but when we use the latest version the call does not come back

    protected void Page_Load(object sender, EventArgs e)
    {
        GetValueFromSSM();
    }

    private void GetValueFromSSM()
    {
        try
        {
            var accessKey = "";
            var secretKey = "";
            var parameterStoreKey = "";
            var objSsm = new AmazonSimpleSystemsManagementClient(accessKey, secretKey, Amazon.RegionEndpoint.EUWest1);
            var ssmRequest = new GetParameterRequest() { Name = parameterStoreKey, WithDecryption = false };
            // The below code works when  AWSSDK.Core is 3.3.107.3 
            var ssmValue = objSsm.GetParameterAsync(ssmRequest).GetAwaiter().GetResult();
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

The very simple example as above can be used to reproduce the error.

UPDATE 24 June 2020:
Just had a update from the AWS Support team that they have release a new version of AWSDK.Core that has the issue fixed.

[ukmoredec]

I cobbled together a ~minimal reproduction from our use case
AWSLambda2.zip

ConfigureAwait(false) on the await ...Async call gets around the problem as well.

Interestingly, running this with the Mock Lambda Test Tool with --no-ui also gets around the problem!

[boblodgett]

This sounds like another issue that was happening in ASP.NET web applications where the async calls were hanging. I released a fix for this today as of versions:
AWSSDK.Core 3.3.107.16
AWSSDK.KeyManagementService 3.3.106.12

Can you give these versions a try and let us know if it corrected this issue? This should fix the async calls from hanging.

[boblodgett]

Closing this issue as the fix released should correct the problem and I have not heard back. Please reopen if the issue persists after upgrading to the latest versions.

[ukmoredec]

Hi Bo, afraid I need to reopen. I've updated my minimal repro to use the latest versions, unless there are some hidden dependencies I'm missing, and the deadlock remains unless I ConfigureAwait(false) on every sdk call (which I guess I should do, but didn't need to before), or run with --no-ui. Do you mind taking a look at
AWSLambda2.zip and let me know if I'm doing something wrong? Thanks!

[danielmarbach]

Maybe this helps #1651