How do I combine proto buf definitions from separate name spaces in a single proto buf file?

[John Buczkowski]

I'm building out a series of ProtoBuf definitions for a .NetCore gRPC application.

I'm using the Orchestrator pattern as I will be creating a series of microservices.

I am running into issues with my proto definitions throwing compiler errors as being "undefined."

The definitions are in several different files (with different C# namespaces).

What follows is a simplified version of my definitions.

Consider the following protobuf files:

**service.proto**

    syntax = "proto3";

    option csharp_namespace = "RequestHandlerService";

    package test;

    

    service Handler

    {

      rpc AddItem1(G_RequestType1) returns (G_RequestResponse) { }

      rpc AddItem2(G_RequestType2) returns (G_RequestResponse) { }

    }

    

    message G_RequestType1{

      string originId = 1;

      string request = 2;

    }

    

    message G_RequestType2{

      string originId = 1;

      string request = 2;

    }

    

    message G_RequestResponse{

      string response = 1;

    }

**windowsservice.proto:**

    syntax = "proto3";

    import "google/protobuf/timestamp.proto";

    option csharp_namespace = "Windows.RequestHandler.Service";

    package windows.requesthandler.service;

    

    service WindowsHandler

    {

        rpc Action1(G_Action1Request) returns (G_Action1Response) { }

        rpc Action2(G_Action2Request) returns (G_Action2Reponse) { }

    }

    

    message G_Action1Request{

        string transactionId = 1;

        google.protobuf.Timestamp DateTimeStamp = 2;

        string filePath = 3;

    }

    

    message G_Action2Request{

        string transactionId = 1;

        google.protobuf.Timestamp DateTimeStamp = 2;

        string textToInsert = 3;

    }

    

    message G_Action1Response {

        google.protobuf.Timestamp DateTimeStamp = 1;

        string fileSecurityStatusMessage = 2;

        G_Action1Request action1Request = 3;

    }

    

    message G_Action2Response {

        google.protobuf.Timestamp DateTimeStamp = 1;

        string fileModifierStatusMessage = 2;

    G_Action2Request action2Request = 3;

    }

    

    

    message G_WindowsRequest {

        int32 requestId = 1;

        oneof RequestType{

            G_Action1Request action1Request = 2;

            G_Action2Request action2Requestion = 3;

        }

    }

    

    message G_WindowsRequestResponse {

        bool wasSuccessful = 1;

        string response = 2;

        oneof ResponseType{

            G_Action1Response action1Response = 3;

            G_Action2Response action2Respone = 4;

        }

    }

**orchestrator.proto**

    syntax = "proto3";

    option csharp_namespace = "OrchestratorService";

    package test;

    

    import "service.proto";

    import "windowsservice.proto";

    

    service Orchestrator

    {

      rpc RegisterClient(G_RegisterClientRequest) returns (stream G_Response) { }

      rpc EnqueueRequest(G_OrchestrationRequest) returns (G_Response) { }

    }

    

    message G_OrchestrationRequest{

      string originId = 1;

      oneof RequestType{

        G_RequestType1 requestType1 = 2;

        G_RequestType2 requestType2 = 3;

        G_Response response = 4;

        G_WindowsRequest windowsRequest = 5;

        G_WindowsRequestResponse windowsRequestResponse = 6;

      }

    }

    

    message G_RegisterClientRequest{

      string clientId = 1;

    }

    

    message G_Response{

      bool wasSuccessful = 1;

      string response = 2;

    }

Here is the <ItemGroup> definition from the csproj file for my Orchestrator project:

     <ItemGroup>

    <Protobuf Include="../Protos/orchestrator.proto" GrpcServices="Server" ProtoRoot="../Protos/">

    <Link>Protos/orchestrator.proto</Link>

    </Protobuf>

    <Protobuf Include="../Protos/service.proto" GrpcServices="Client" ProtoRoot="../Protos/">

    <Link>Protos/service.proto</Link>

    </Protobuf>

    <Protobuf Include="../Protos/windowsservice.proto" GrpcServices="Client" ProtoRoot="../Protos/">

      <Link>Protos/windowservice.proto</Link>

    </Protobuf>

    </ItemGroup>

Both **G_WindowsRequest** and **G_WindowsRequestResponse** are throwing a compiler error saying they are undefined. Is this an issue with **csharp_namespace** and/or **package** resolution?

Is there a way to enforce separate package/csharp_namespace definitions within the separate proto definitions, but reference those definitions within the rolled up "orchestrator" proto file definition?

**Here is a snippet of the compiler errors I am seeing:**

> 2>  orchestrator.proto(22,5): error : "G_WindowsRequest" is not

> defined. 2>  orchestrator.proto(23,5): error :

> "G_WindowsRequestResponse" is not defined. 2>Done building target

> "_Protobuf_CoreCompile" in project "Protos.csproj" -- FAILED. 2>

> 2>Done building project "Protos.csproj" -- FAILED. 2> 2>Build FAILED.

> 2> 2>orchestrator.proto(22,5): error : "G_WindowsRequest" is not

> defined. 2>orchestrator.proto(23,5): error :

> "G_WindowsRequestResponse" is not defined. 2>    0 Warning(s) 2>    2

> Error(s)

[Jan Tattermusch]

G_WindowsRequest is declared in package "windows.requesthandler.service", but in orchestrator.proto (which itself is under package "test"), you're only referring to it as "G_WindowsRequest", without specifying the package name. The protobuf compiler has no way of knowing which "G_WindowsRequest" you want (FWIW there could be 50 other definitions of that name under different packages).

I think you need to use the fully qualified name windows.requesthandler.service.G_WindowsRequest, since G_WindowsRequest is from a different namespace than you're currently in. That should fix the issue you're seeing.