Source sequence doesn't contain any elements.

Describe the bug When I try to add vertices to Cosmos DB, I get the following message & stack trace.

Error Message: Source sequence doesn’t contain any elements. Stack Trace:

   at System.Linq.AsyncEnumerable.<<FirstAsync>g__Core|283_0>d`1.MoveNext() in /_/Ix.NET/Source/System.Linq.Async/System/Linq/Operators/First.cs:line 33
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Runtime.CompilerServices.ValueTaskAwaiter`1.GetResult()
   at RoadHuntin.Library.Core.Create.Handler`2.<Handle>d__3.MoveNext() in E:\Code\RoadHuntinClient\backend\src\RoadHuntin.Library\Core\Create.cs:line 37
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MediatR.Pipeline.RequestExceptionProcessorBehavior`2.<Handle>d__2.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at MediatR.Pipeline.RequestExceptionProcessorBehavior`2.<Handle>d__2.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MediatR.Pipeline.RequestExceptionActionProcessorBehavior`2.<Handle>d__2.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at MediatR.Pipeline.RequestExceptionActionProcessorBehavior`2.<Handle>d__2.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MediatR.Pipeline.RequestPostProcessorBehavior`2.<Handle>d__2.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MediatR.Pipeline.RequestPreProcessorBehavior`2.<Handle>d__2.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at RoadHuntin.WebAPI.Controllers.RoutesController.<Post>d__4.MoveNext() in E:\Code\RoadHuntinClient\backend\src\RoadHuntin.WebAPI\Controllers\RoutesController.cs:line 46
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfIActionResultExecutor.<Execute>d__0.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Runtime.CompilerServices.ValueTaskAwaiter`1.GetResult()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<<InvokeActionMethodAsync>g__Logged|12_1>d.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<<InvokeNextActionFilterAsync>g__Awaited|10_0>d.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<<InvokeInnerFilterAsync>g__Awaited|13_0>d.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<<InvokeNextExceptionFilterAsync>g__Awaited|25_0>d.MoveNext()

Expected behavior Vertex should be created and returned.

Version information

• ExRam.Gremlinq.Providers.CosmosDb 8.0.0-preview-0707
• ExRam.Gremlinq.Core 8.0.0-preview-0707

Minimal working example This is the code from where the error is being generated:

DI registration::

services.AddScoped<IGremlinQuerySource>(provider => {
                var logger = provider.GetService<ILogger<IGremlinQuerySource>>();
                var options = (provider.GetService<IOptions<GremlinOptions>>()).Value;

                return g
                    .ConfigureEnvironment(env => env
                        .UseLogger(logger)
                        .UseModel(GraphModel
                            .FromBaseTypes<Vertex, Edge>(lookup => lookup.IncludeAssembliesOfBaseTypes())
                            .ConfigureProperties(model => model
                                .ConfigureElement<Vertex>(conf => conf.IgnoreOnUpdate(x => x.PartitionKey))
                                )
                            )
                        .UseCosmosDb(builder => builder
                            .At(new Uri(options.EndpointUri), options.Database, options.Container)
                            .AuthenticateBy(options.PrimaryKey)
                            .ConfigureWebSocket(builder => builder
                                .ConfigureQueryLoggingOptions(o => o
                                    .SetQueryLoggingVerbosity(QueryLoggingVerbosity.QueryAndParameters))
                                )
                            )
                        );
            });

Code Usage:

var model = _mapper.Map<TEntity>(request);
model = await _g.V<TEntity>().AddV(model).FirstAsync();

Additional context

• This was working before and has suddenly stopped working and I can’t see any error or exceptions.
• I tried reverting my code to the old stage and still the same error.
• What I was doing was, I was storing non GraphSON documents on the CosmosDB alongside the usual GraphSON therefore I am using GremlinQ and ComsosDB SQL.NET API side-by-side. I was able to get it working last night but since today morning I’ve been seeing this error now with no idea how-to debug it. I thought I might’ve messed something in the CosmosDB so I’ve tried:
  • Different containers (this doesn’t work), I get the same error.
  • I tried creating a new vertices from gremlin via Web Portal, this works as expected.

I think my main issue is how-to debug this since I’m getting no error which I’d assume means that everything went alright so FirstAsync() should work.

[danielcweber]

Note that there’s Gremlinq.*.AspNet packages that handle DI just fine. Even less documentation there though, but it’s all in the code and in the tests.

If you want to contribute, the Samples-Project could very well benefit from a second project that does the same but by utilizing the *.AspNet packages if you manage to figure things out from the code.

[danielcweber]

On first sight, you definitely want to register everything Gremlin as Singleton to avoid recreation on every query.