Asp.net 5 - Cannot find an implementation class for grain interface

[elmortega]

I´m getting this exception:

An unhandled exception occurred while processing the request.

ArgumentException: Cannot find an implementation class for grain interface: OrleansWebAppTest.Models.IHello. Make sure the grain assembly was correctly deployed and loaded in the silo. Loaded grain assemblies: file:///C:/Users/byrmanager/Documents/Visual Studio 2015/Projects/TemporalProjects/orleans/src/OrleansConsoleHost/bin/Debug/OrleansRuntime.DLL en Orleans.Runtime.TypeCodeMapper.GetImplementation(Type interfaceType, String grainClassNamePrefix) en C:\Users\byrmanager\Documents\Visual Studio 2015\Projects\TemporalProjects\orleans\src\Orleans\IDs\TypeCodeMapper.cs:línea 17

The public bool TryGetGrainClassData method in the GrainInterfaceMap.cs returns false as it doesn´t seem to be able to get an implementation for the provided interface as the this.typeToInterfaceData.TryGetValue(GetTypeKey(interfaceType, false), out interfaceData) method returns false

In my project.json:

"frameworks": { "dnx451": { "dependencies": { "Orleans": "1.0.0-", "OrleansProviders": "1.0.0-" } } },

[richorama]

Does the silo successfully load your assembly? You should it scan for assemblies at startup, it tells you if it found anything in each of the DLLs it looked in...

[elmortega]

How can I make sure the grain assembly was correctly deployed and loaded in the silo?

[richorama]

Orleans searches the directory where the host application is located, as well as the Applications sub-directory, and all directories under it.

[elmortega]

I thought I could just put my grain interfaces and implementation code in the webapp's model folder. but I guess that way the silo host wouldn't be able to load my grain classes, right?

[elmortega]

loadedAssemblies contains only one, the OrleansRuntime.DLL

[richorama]

How are you hosting the Orleans silos?

[elmortega]

Console Application http://dotnet.github.io/orleans/Step-by-step-Tutorials/Minimal-Orleans-Application

[richorama]

Are your grain assemblies in the bin\debug directory of the console application?

A convenient way of doing that is to add them as references and set them to copy locally.

[richorama]

did that fix the problem?

[elmortega]

It was solved when using the v1.1.0-VSIX project templates

[asifshiraz]

I'm facing the same problem. In my case, I'm initializing the TestCluster from inside a unit test's constructor. The Grain and GrainInterface projects are referenced by the Unit Tests and are available in the bin/x64/Debug folder of the Unit Tests project. Still, the Silo complains of not having the assembly loaded.

[sergeybykov]

@asifshiraz Can you open a separate issue with information about which version you are running. Are you grain classes public, BTW?

[jamescarter-le]

Be aware that if you have your grains in an .exe file and include this as a reference in your UnitTest project Orleans will not scan this assembly for Grains, they must be in a .dll file instead.

[philrowan-mtb]

I just came across this and found out my grain class was not inheriting Orleans.Grain and was only implementing my grain interface. Adding Orleans.Grain fixed it for me.

[sergeybykov]

A code analyzer could potentially help find such issues and produce warnings.

[sq735]

I just came across this and found out my grain class was not inheriting Orleans.Grain and was only implementing my grain interface. Adding Orleans.Grain fixed it for me.

@philrowan-mtb thanks a lot

[allenbrubaker]

I was getting the same issue. I was properly using the grain interface type when attempting to obtain the grain implementation via the GrainFactory; however, I finally solved it by adding a reference to the nuget package: Microsoft.Orleans.OrleansCodeGenerator.Build in the silo, grains, and grain interfaces projects.

I think perhaps the error message should be a little more accurate or at least contain verbiage pertaining to the above nuget dependency requirement. Or better yet the silo should fail to startup and throw an exception.

[sergeybykov]

I finally solved it by adding a reference to the nuget package: Microsoft.Orleans.OrleansCodeGenerator.Build in the silo, grains, and grain interfaces projects.

There's no need to add it to the silo project.

[fadingdust]

Note: Microsoft.Orleans.CodeGenerator.MSBuild is a viable alternative to Microsoft.Orleans.OrleansCodeGenerator.Build