gRPC keeps returning error code 12 from server

Question

I need to implement a distributed database and I implemented based on gRPC example. The following is my code snippet. sundial_sync_server.h

#ifndef SUNDIAL_GRPC_SYNC_SERVER_H
#define SUNDIAL_GRPC_SYNC_SERVER_H

#endif //SUNDIAL_GRPC_SYNC_SERVER_H

#include "sundial_grpc.grpc.pb.h"
#include "sundial_grpc.pb.h"
#include <iostream>
#include <memory>
#include <string>
#include <grpcpp/grpcpp.h>
using grpc::Channel;
using grpc::ServerContext;
using grpc::Status;
using sundial_rpc::SundialRequest;
using sundial_rpc::SundialResponse;
using sundial_rpc::Sundial_GRPC_SYNC;
#ifndef ABC
#define ABC
class SundialServiceImp final : public Sundial_GRPC_SYNC::Service
{
    public:
    Status contactRemote(::grpc::ServerContext* context, const ::sundial_rpc::SundialRequest* request, ::sundial_rpc::SundialResponse* response) override;
    void run();

};
#endif

sundial_sync_server.cpp

#include "sundial_grpc.grpc.pb.h"
#include "sundial_grpc.pb.h"
#include <iostream>
#include <memory>
#include <string>
#include <grpcpp/grpcpp.h>
#include "txn.h"
#include "global.h"
#include "manager.h"
#include "stats.h"
#include "helper.h"
#include "grpc_sync_server.h"
#include "txn_table.h"
#include <grpcpp/grpcpp.h>
#include <grpcpp/health_check_service_interface.h>
#include <grpcpp/ext/proto_server_reflection_plugin.h>
using grpc::ServerContext;
using grpc::Status;
using sundial_rpc::SundialRequest;
using sundial_rpc::SundialResponse;
using sundial_rpc::Sundial_GRPC_SYNC;
using grpc::Server;
using grpc::ServerBuilder;
Status SundialServiceImp::contactRemote(::grpc::ServerContext* context, const ::sundial_rpc::SundialRequest* request, ::sundial_rpc::SundialResponse* response){
     if (request->request_type() == SundialRequest::SYS_REQ) {
        glob_manager->receive_sync_request(); 
        response->set_response_type( SundialResponse::SYS_RESP );
        return Status::OK;
    }
    uint64_t txn_id = request->txn_id();
    TxnManager * txn_man = txn_table->get_txn(txn_id);
    // If no TxnManager exists for the requesting transaction, create one.
    if (txn_man == NULL) {
        //printf("adding txnID=%ld into txn_table\n", txn_id);
        assert( request->request_type() == SundialRequest::READ_REQ );
        txn_man = new TxnManager();
        txn_man->set_txn_id( txn_id );
        txn_table->add_txn( txn_man );
    }
    // the transaction handles the RPC call
    txn_man->process_remote_request(request, response);
    // if the sub-transaction is no longer required, remove from txn_table
    if (response->response_type() == SundialResponse::RESP_ABORT
        || response->response_type() == SundialResponse::PREPARED_OK_RO
        || response->response_type() == SundialResponse::PREPARED_ABORT
        || response->response_type() == SundialResponse::ACK) {
        txn_table->remove_txn( txn_man );
        delete txn_man;
    }
    return Status::OK;
}

void SundialServiceImp::run(){
    std::istringstream in(ifconfig_string);
    string line;
    uint32_t num_nodes = 0;    
    string port;
    while (getline (in, line)) {
        if (line[0] == '#')
            continue;
        else {
            if (num_nodes == g_node_id) {
                port = line.substr(0, line.length());
                break;
            }
            num_nodes ++;
        }
    }
    port.append(sync_port);
    grpc::EnableDefaultHealthCheckService(true);
    grpc::reflection::InitProtoReflectionServerBuilderPlugin();
    ServerBuilder builder;
    builder.AddListeningPort(port, grpc::InsecureServerCredentials());   
    builder.RegisterService(this);   
    std::unique_ptr<Server> server(builder.BuildAndStart());
    std::cout << "Server listening on " << port << std::endl;
    server->Wait();
}

`sundial_sync_client.h'

#endif //SUNDIAL_GRPC_CLIENT_H
#include "sundial_grpc.grpc.pb.h"
#include "sundial_grpc.pb.h"
#include <iostream>
#include <memory>
#include <string>
#include <grpcpp/grpcpp.h>
using grpc::Channel;
using grpc::ClientContext;
using grpc::Status;
using sundial_rpc::SundialRequest;
using sundial_rpc::SundialResponse;
using sundial_rpc::Sundial_GRPC_SYNC;
//toDo: now assume we only have 2 nodes
#ifndef SSC
#define SSC
class Sundial_Sync_Client{
public:
    Sundial_Sync_Client(std::shared_ptr<Channel>* channel);
    Status contactRemote(uint64_t node_id,SundialRequest& request, SundialResponse* response);
private:
    std::unique_ptr<Sundial_GRPC_SYNC::Stub> stub_;
};
#endif

sundial_sync_client.cpp

#include "sundial_grpc.grpc.pb.h"
#include "sundial_grpc.pb.h"
#include "grpc_sync_client.h"
#include <iostream>
#include <memory>
#include <string>
#include <grpcpp/grpcpp.h>
#include "txn.h"
#include "global.h"
#include "helper.h"
#include "manager.h"
#include "stats.h"
using grpc::Channel;
using grpc::ClientContext;
using grpc::Status;
using sundial_rpc::SundialRequest;
using sundial_rpc::SundialResponse;
using sundial_rpc::Sundial_GRPC_SYNC;
//toDo: add more nodes to it
Sundial_Sync_Client::Sundial_Sync_Client(std::shared_ptr<Channel>* channel){
    for(int i=0; i<g_num_nodes;i++){
        if(i==g_node_id)
            continue;
    //stub_[i]=Sundial_GRPC_SYNC::NewStub(channel[i]);
    stub_=Sundial_GRPC_SYNC::NewStub(channel[i]);
    }
    
}

Status
Sundial_Sync_Client::contactRemote(uint64_t node_id, SundialRequest& request, SundialResponse* response){
    //toDo: choose the right stub with node id
    ClientContext context;
    printf("Client sends request\n");
    //Status status = stub_[node_id]->contactRemote(&context, request, &response);
    Status status = stub_->contactRemote(&context, request, response);
    if (status.ok()) {
        //printf("status ok\n");
        glob_stats->_stats[GET_THD_ID]->_resp_msg_count[ response->response_type() ] ++;
        glob_stats->_stats[GET_THD_ID]->_resp_msg_size[ response->response_type() ] += response->SpaceUsedLong();
        return status;
    } else {
        std::cout << status.error_code() << ": " << status.error_message()
                  << std::endl;
        return status;
    }

}

It runs pretty smoothly at the setup. I did get the ip address and let servers run at the right address. However, when I make the client send request, the status it returns always has error code 12 without error message.

Answer 1

Error code 12 is "UNIMPLEMENTED". Check your proto and make sure your server is implementing the correct RPC method (correct upper/lower case for method name and things like that)