从不同目录导入 proto 文件

Question

I'm struggling writing the right configuration for grpc imports.

So the .net solution structure is like:
\Protos\Common\common.proto
\Protos\Vehicle\car.proto
\CarMicroservice

Inside car.proto I have: import "common.proto"

What I want is the generated grpc code to be inside the project CarMicroservice.
Inside CarMicroservice.csproj I have written the path to the protos:

<Protobuf Include="common.proto" ProtoRoot="..\Protos\Common\" />
<Protobuf Include="car.proto" ProtoRoot="..\Protos\Vehicle\" />

But getting error: 'common.proto' no such file or directory

The question is: How do I correctly import common.proto inside the car.proto?

Note: I already looked at the similar issue, but couldn't make it work for my case
Importing.proto files from another project

Answer 1

Ok, I finally solved the issue. Also @DazWilkin pointed it out.

1. You can't use relative paths in the import , so you should use absolute path of the project. In my case it was: import "Common/common.proto"
2. Use the project root for the location of proto files. So instead of ProtoRoot="..\Protos\Common\" use ProtoRoot="../Protos/"
   Now comes the interesting part.
   For some reason when I used backslashes for the ProtoRoot path as "..\Protos\
   I was getting errors as 'file not found'. So don't use the backslashes for paths. The final code in CarMicroservice.csproj is like the following:

<Protobuf Include="Common/common.proto" ProtoRoot="../Protos/" />
<Protobuf Include="Vehicle/car.proto" ProtoRoot="../Protos/" />

Answer 2

Alternatively, there are two other ways to specify include directories for protoc .

First, there is a global property named Protobuf_AdditionalImportsPath . If you specify this property in your .csproj / .fsproj , it will be passed on to protoc for every .proto in that project. You can use it like this:

<PropertyGroup>
    <Protobuf_AdditionalImportsPath>../../my/other/directory</Protobuf_AdditionalImportsPath>
</PropertyGroup>

There is also a AdditionalImportDirs property you can specify directly on <Protobuf> elements. This will likely only be valid for the .proto s you specify it on:

<Protobuf Include="MyProto.proto" Link="MyProto.proto" AdditionalImportDirs="../../my/other/directory" />

Keep in mind that in both cases, you can specify any directory you want, regardless of whether it is a parent of the .proto you're compiling.

Also keep in mind that the import path you specify in your .proto needs be relative to one of the import directories you specify.