title: Proto3 representing nested JSON structure
body: <p>I'm wondering how I can represent a variable size JSON structure in my gRPC implementation with Node.js. I have a grpc service and a message that I want to receive the following structure:</p>
  
  <pre><code>{
    "Key": "Value",
    "Nested": { ... }
  }
  </code></pre>
  
  <p>Here's my definition:</p>
  
  <pre><code>syntax = "proto3";
  
  service Users {
    rpc RetrieveMeta (RetrieveMetaRequest) returns (RetrieveMetaResponse) {}
    rpc UpdateMeta   (UpdateMetaRequest)   returns (UpdateMetaResponse)   {}
  }
  message RetrieveMetaRequest {
  
  }
  message RetrieveMetaResponse {
  
  }
  </code></pre>
  
  <p>I've read you can do so by importing a struct definition, however when I do that I get a file not found error as it performs a lookup within the current directory:</p>
  
  <pre><code>import "google/protobuf/struct.proto";
  </code></pre>
  
  <p>Throws:</p>
  
  <pre><code>Users/ddibiase-macbook/Projects/dfx-api/node_modules/protobufjs/dist/protobuf.js:4720
                              throw Error("failed to import '"+importFilename+"' in '"+filename+"': file not found");
                              ^
  
  Error: failed to import '/Users/ddibiase-macbook/Projects/dfx-api/protos/struct.proto'
  </code></pre>