gRPC-java - Compilation of a .proto file

Question

I have compiled my .proto file using the protobuf compiler and received a selection of Java files. I received a proto.java file and a .java file for each item in the .proto file, including the message type and each RPC call e.g. publicKeyRequest.java and Quote.java as the RPC and request parameter type.

Is this all the files that are needed as I still cannot seem to to get any simple response back from the server?

I want to generate a request for the PublicKeyRequest RPC call. I generated the request object, but I do not know how to actually send it via the channel.

This is the full .proto file:

syntax = "proto3";

option java_multiple_files = true;
option java_package = "io.grpc.decryptiondevice";
option java_outer_classname = "DecryptionDeviceProto";

package decryptiondevice;

service DecryptionDevice {

    // Decryption Request RPC
    //
    // Request contains ciphertext and proof
    // Returns the plaintext record
    rpc DecryptRecord(DecryptionRequest) returns (Record) {}

    // Get Signed Root Tree Hash RPC
    //
    // Caller provides a nonce
    // Returns a signed RTH and nonce
    rpc GetRootTreeHash(RootTreeHashRequest) returns (RootTreeHash) {}


    // Get Public key RPC
    //
    // Returns a Remote attestation report containing the public key as user        data
       rpc GetPublicKey(PublicKeyRequest) returns (Quote) {}
}


// Decryption Request
// - Byte array containing ciphertext
// - Proofs represented as JSON trees
message DecryptionRequest {
    bytes ciphertext        = 1;
    string proofOfPresence  = 2;
    string proofOfExtension = 3;
}


// A plaintext record
message Record {
    bytes plaintext = 1;
}


// RTH request contains
// - A random nonce
message RootTreeHashRequest {
    bytes nonce = 1;
}


// Root Tree Hash
// Random nonce used as message ID
// Signature over rth and nonce
message RootTreeHash {
    bytes rth   = 1;
    bytes nonce = 2;
    bytes sig   = 3;
}


// Public key request message
message PublicKeyRequest {
    bytes nonce = 1;
}


// Attestation Quote, containing the public key
message Quote {
    string quote = 1; //some format.. to be defined later
    //PEM formatted key
    bytes RSA_EncryptionKey = 2;
    bytes RSA_VerificationKey = 3;
}

And this is the code I am attempting to run on the client side:

public static void main(String[] args) {

    DeviceClient client = new DeviceClient("localhost", 50051);
    MannagedChanel channel = ManagedChannelBuilder.forAddress("localhost", 50051).usePlaintext(true);

    ByteString nonce = ByteString.copyFromUtf8("someRandomString");
    PublicKeyRequest keyRequest = PublicKeyRequest.newBuilder().setNonce(nonce).build();

    // Here I want to send this to the server
    ByteString response = DecryptionDeviceProto.getKey(keyRequest, channel);//this line is not even close to being valid, but this is the sort thing I wish to achieve

    Sys.out.println(response);
}

Apologies if this is very wrong, I am new to gRPC. A few points about this system:

A client and server has already been written in Go which has been tested and works with this same .proto file.
I am attempting to rewrite the client in Java to communicate with the same server.

You should work through one or both of the Java grpc tutorials at grpc.io. In general you'd want to use the Stub classes generated from the .proto file to call the server. — Uli

Eric Anderson Eric Anderson · Accepted Answer · 2017-07-31T18:27:07

There are two sets of files that need to be generated: Java Protobuf and Java gRPC. To my knowledge, for all languages except Go, these are two separate generation steps (that can be combined into one protoc invocation, but they are conceptually separate).

It seems you are generating the Java Protobuf code, but not the Java gRPC code. You need to use the protoc-gen-grpc-java plugin to protoc. If you are using Maven or Gradle, read grpc-java's README. If you are running protoc manually, you can download a pre-built binary from Maven Central and see an answer to a similar question.

gRPC-java - Compilation of a .proto file

1 Answers