System.Threading.SynchronizationLockException: Cannot wait on monitors on this runtime. #1598
Description
This is in a Blazor WebAssembly app. Trying to load DynamoDB items with the object persistence model, I receive a SynchronizationLockException on LoadAsync(). However, the same operation works fine with the low-level API.
Expected Behavior
I should receive a "Book" object.
Current Behavior
Doing:
Book book = await dynamoDBContext.LoadAsync<Book>(1);
Throws:
System.Threading.SynchronizationLockException: Cannot wait on monitors on this runtime.
See details below.
Steps to Reproduce (for bugs)
Create a test DynamoDB table called Book with an index called "Id" (number).
Create a new Blazor WebAssembly project in Visual Studio (client side template). This will create the default Blazor app for you. Then replace/create the following files. Don't forget to replace "XXX" by your own credentials to access the table of course.
Replace Program.cs with:
using Amazon;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.DataModel;
using Amazon.DynamoDBv2.Model;
using Amazon.Runtime;
using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Threading.Tasks;
namespace AWSTest1
{
class HttpInjectorFactory : HttpClientFactory
{
private readonly HttpClient _injectedClient;
public HttpInjectorFactory(HttpClient injectedClient)
{
_injectedClient = injectedClient;
}
public override HttpClient CreateHttpClient(IClientConfig clientConfig)
{
return _injectedClient;
}
public override bool DisposeHttpClientsAfterUse(IClientConfig clientConfig)
{
return false;
}
public override bool UseSDKHttpClientCaching(IClientConfig clientConfig)
{
return false;
}
}
public class Program
{
public static async Task Main(string[] args)
{
var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("app");
builder.Services.AddSingleton(new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });
var host = builder.Build();
AWSConfigs.RegionEndpoint = RegionEndpoint.USEast2;
AWSConfigs.HttpClientFactory = new HttpInjectorFactory(host.Services.GetRequiredService<HttpClient>());
AWSConfigs.UseAlternateUserAgentHeader = true;
// Request Book id 1 using low-level API, no error
var dynamoDBClient = new AmazonDynamoDBClient("XXX", "XXX");
Dictionary<string, AttributeValue> key = new Dictionary<string, AttributeValue>
{
{ "Id", new AttributeValue { N = "1" } }
};
GetItemRequest request = new GetItemRequest
{
TableName = "Book",
Key = key,
};
var result = await dynamoDBClient.GetItemAsync(request);
// Request Book id 1 using object persistence model, throws SynchronizationLockException
var dynamoDBContext = new DynamoDBContext(dynamoDBClient);
Book book = await dynamoDBContext.LoadAsync<Book>(1);
await host.RunAsync();
}
}
}
Create Book.cs:
using Amazon.DynamoDBv2.DataModel;
namespace AWSTest1
{
[DynamoDBTable("Book")]
public class Book
{
[DynamoDBHashKey]
public int Id { get; set; }
}
}
Your Environment
- AWSSDK.Core version used: 3.3.106.17
- Service assembly and version used: AWSSDK.DynamoDBv2 3.3.105.39
- Operating System and version: Windows 10.0.18363
- Visual Studio version: 16.6.0 Preview 5.0
- Targeted .NET platform: .NET Standard 2.1