GraphQL.ExecutionError

[RaySheikh]

Hi, I recently started getting the error below after publishing my project specially when more users started using the app. I am using asp.net core 2.1 with EF core repository pattern. This completely locks up the server. Any help would be greatly appreciated. This will randomly happen with different queries..

GraphQL.Controllers.GraphQLController:Error: GraphQL errors: GraphQL.ExecutionError: Error trying to resolve currentUser. ---> System.InvalidOperationException: A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread safe.
   at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection()
   at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSectionAsync(CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.MoveNext(CancellationToken cancellationToken)
   at System.Linq.AsyncEnumerable.Aggregate_[TSource,TAccumulate,TResult](IAsyncEnumerable`1 source, TAccumulate seed, Func`3 accumulator, Func`2 resultSelector, CancellationToken cancellationToken)

Startup.cs

services.AddDbContext<AppContext>(options => options.UseSqlServer(appconn, opt => opt.EnableRetryOnFailure()));

            //DI
            services.AddScoped<IAppRepository, AppRepository>();
            services.AddScoped<AppSchema>();
            services.AddScoped<AppQuery>();
            services.AddScoped<AppMutation>();
            services.AddScoped<UserType>();
            services.AddScoped<IDocumentExecuter, DocumentExecuter>();
            var sp = services.BuildServiceProvider();
            services.AddSingleton<ISchema>(new AppSchema(new FuncDependencyResolver(type => sp.GetService(type))));

            services.AddGraphQL(options =>
            {
                options.EnableMetrics = true;
                options.ExposeExceptions = this.Environment.IsDevelopment();
            });

controller.cs

[Route("[controller]")]
    public class GraphQLController : Controller
    {
        private IDocumentExecuter _documentExecuter { get; set; }
        private ISchema _schema { get; set; }
        private readonly ILogger _logger;

        public GraphQLController(ISchema schema, IDocumentExecuter documentExecuter, ILogger<GraphQLController> logger)
        {
            _schema = schema;
            _documentExecuter = documentExecuter;
            _logger = logger;
        }

        [HttpGet]
        public IActionResult Index()
        {
            _logger.LogInformation("Got request for GraphiQL. Sending GUI back");
            return View();
        }

        [HttpPost]
        public async Task<IActionResult> Post([FromBody] GraphQLQuery query)
        {
            if (query == null) { throw new ArgumentNullException(nameof(query)); }

            var inputs = query.Variables.ToInputs();
            var executionOptions = new ExecutionOptions()
            {
                Schema = _schema,
                Query = query.Query,
                Inputs = inputs
            };
            var result = await _documentExecuter.ExecuteAsync(executionOptions).ConfigureAwait(false);

            if (result.Errors?.Count > 0)
            {
                _logger.LogError("GraphQL errors: {0}", result.Errors);
                return BadRequest(result);
            }
            _logger.LogDebug("GraphQL execution result: {result}", JsonConvert.SerializeObject(result.Data));
            return Ok(result);
        }
    }

Query.cs

Field<UserType>(
                "currentUser",
                description: "Get current user",
                arguments: new QueryArguments(new QueryArgument<IntGraphType> { Name = "id" }),
                resolve: context => repo.GetUserByIdAsync(context.GetArgument<int>("id"))
                );

[joemcbride]

This is related to #648 . Please read through that thread.

Question
#648 (comment)

Answer
#648 (comment)

A fix:
#648 (comment)