Service reflection is failing if proto file imports another proto from different project.

What version of gRPC and what language are you using?

Here are the dependencies I use:

<PackageReference Include="Google.Protobuf" Version="3.21.3" />
<PackageReference Include="Grpc.Core.Api" Version="2.*" />
<PackageReference Include="Grpc.Tools" Version="2.*">

What runtime / compiler are you using (e.g. .NET Core SDK version dotnet --info)

.NET SDK:
 Version:   7.0.100
 Commit:    e12b7af219

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22000
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\7.0.100\

Host:
  Version:      7.0.0
  Architecture: x64
  Commit:       d099f075e4

.NET SDKs installed:
  5.0.414 [C:\Program Files\dotnet\sdk]
  7.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.31 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.31 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.31 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

What did you do?

I use GRPCurl service discovery, and I get the following error:

Failed to resolve symbol "radio_data.RadioDataService": Symbol not found: radio_data.RadioDataService
caused by: File not found: CalculationEngine.Shared.Grpc/Protos/data.proto

The reason is that my radio_data file imports another proto:

import "CalculationEngine.Shared.Grpc/Protos/data.proto";

And csproj file entry is the following:

<ItemGroup>
  <Protobuf Include="..\$(MSBuildProjectName)\Protos\radio_data.proto" ProtoRoot=".." GrpcServices="Server,Client" />
</ItemGroup>

Here’s generated DataReflection class for data.proto:

public static partial class DataReflection {

  #region Descriptor
  /// <summary>File descriptor for Protos/data.proto</summary>
  public static pbr::FileDescriptor Descriptor {
    get { return descriptor; }
  }
  private static pbr::FileDescriptor descriptor;

  static DataReflection() {
    byte[] descriptorData = global::System.Convert.FromBase64String(
        string.Concat(
          "ChFQcm90b3MvZGF0YS5wcm90bxIEZGF0YSIcCglCeXRlQ2h1bmsSDwoHQ29u",
          "dGVudBgBIAEoDCIwCgREYXRlEgwKBFllYXIYASABKAUSDQoFTW9udGgYAiAB",
          "KAUSCwoDRGF5GAMgASgFQiCqAh1DYWxjdWxhdGlvbkVuZ2luZS5TaGFyZWQu",
          "R3JwY2IGcHJvdG8z"));
    descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
        new pbr::FileDescriptor[] { },
        new pbr::GeneratedClrTypeInfo(null, null, new pbr::GeneratedClrTypeInfo[] {
          new pbr::GeneratedClrTypeInfo(typeof(global::CalculationEngine.Shared.Grpc.ByteChunk), global::CalculationEngine.Shared.Grpc.ByteChunk.Parser, new[]{ "Content" }, null, null, null, null),
          new pbr::GeneratedClrTypeInfo(typeof(global::CalculationEngine.Shared.Grpc.Date), global::CalculationEngine.Shared.Grpc.Date.Parser, new[]{ "Year", "Month", "Day" }, null, null, null, null)
        }));
  }
  #endregion
}

[JamesNK]

The problem is your proto files have different root paths.

models.proto has a compiled path of Protos/models.proto, but greet.proto is referencing it as GrpcModels/Protos/models.proto. These don’t line up, so reflection breaks.

It works if the Protobuf line is changed in the model project to this:

<Protobuf Include="..\$(MSBuildProjectName)\Protos\models.proto" GrpcServices="None" ProtoRoot=".." />

[vadimkhm]

@JamesNK the solution you provided is a good one, but I have one case where the GrpcModels project is in a different folder, and reflection does not work in this case, can you suggest any solution for the case when projects are in other folders:

/Models/GrpcModels.csproj FailingGRPCurl.csproj

In this case, I should do an import like this: import “Models/GrpcModels/Protos/model.proto”;

Of course, it would be easy to move projects to the same folder 😃, but logically I need some separation. And if possible, how to adapt to support different folders, that would be very helpful!

Thank you 😃