GraphClient.Connect() deadlock

[drgraduss]

Hi,

I'm using GraphClient as part of topshelf win service. During deployment I'm experiencing deadlock when GraphClient.Connect() method called. Below is stack trace from dump.

mscorlib.dll!System.Threading.Monitor.Wait(object obj, int millisecondsTimeout, bool exitContext)    Unknown
mscorlib.dll!System.Threading.Monitor.Wait(object obj, int millisecondsTimeout)    Unknown
mscorlib.dll!System.Threading.ManualResetEventSlim.Wait(int millisecondsTimeout, System.Threading.CancellationToken cancellationToken)    Unknown
mscorlib.dll!System.Threading.Tasks.Task.WaitAllBlockingCore(System.Collections.Generic.List<System.Threading.Tasks.Task> tasks, int millisecondsTimeout, System.Threading.CancellationToken cancellationToken)    Unknown
mscorlib.dll!System.Threading.Tasks.Task.WaitAll(System.Threading.Tasks.Task[] tasks, int millisecondsTimeout, System.Threading.CancellationToken cancellationToken)    Unknown
Neo4jClient.dll!Neo4jClient.Execution.ResponseBuilder.Execute(string commandDescription, System.Threading.Tasks.TaskFactory taskFactory)    Unknown
Neo4jClient.dll!Neo4jClient.Execution.ResponseBuilder<System.__Canon>.Execute()    Unknown
Neo4jClient.dll!Neo4jClient.GraphClient.Connect()    Unknown

After looking library code it looks there should be ConfigureAwait(false) setup on task returned in case taskFactory is null.

private Task<HttpResponseMessage> PrepareAsync(TaskFactory taskFactory)
{
    if (_executionConfiguration.UseJsonStreaming)
    {
        _request.Headers.Accept.Clear();
        _request.Headers.Remove("Accept");
        _request.Headers.Add("Accept", "application/json;stream=true");
        _request.Headers.Remove("X-Stream");
        _request.Headers.Add("X-Stream", "true");
    }

    _request.Headers.Add("User-Agent", _executionConfiguration.UserAgent);

    var userInfo = _request.RequestUri.UserInfo;
    if (!string.IsNullOrEmpty(userInfo))
    {
        var credentials = Convert.ToBase64String(Encoding.ASCII.GetBytes(userInfo));
        _request.Headers.Authorization = new AuthenticationHeaderValue("Basic", credentials);
    }

    if (taskFactory == null)
    {
        // use the standard factory
        return _executionConfiguration.HttpClient.SendAsync(_request);
    }

    // use a custom task factory
    return taskFactory.StartNew(() => _executionConfiguration.HttpClient.SendAsync(_request).Result);
}

[cskardon]

Hallo,

Do you feel up to doing a pull request? It'd be awesome to get that in place

[drgraduss]

Hi @cskardon

Here's pull request https://github.com/Readify/Neo4jClient/pull/158. Have a look as ExecuteAsync used across whole library.

[cskardon]

Awesome!! thank you, I'll get looking into it asap!