Hello, I have been working in a extension to riak_pb, but every time that I try to use my new message in my extension of riak_erlang_client I obtain this message "Socket error while sending riakc request: einval. Bad value on output port 'tcp_inet'". These files represent a dummy example that replicate my error. Any suggestion?

(riak_api) demo_api_pb_service.erl

-module(demo_api_pb_service).

-behaviour(riak_api_pb_service).

-export([init/0,
         decode/2,
         encode/1,
         process/2,
         process_stream/3]).

-include_lib("riak_pb/include/demo_pb.hrl").

init() ->
    undefined.

%% @doc decode/2 callback. Decodes an incoming message.
decode(Code, Bin) when Code == 605 ->
    Msg =  riak_pb_codec:decode(Code, Bin),
    case Msg of
        #greeting{msg=M, from=F} ->
            Hook = {M,F},
            {ok, Msg, {"demo.greet", Hook}}
    end.

%% @doc encode/1 callback. Encodes an outgoing response message.
encode(Message) ->
    {ok, riak_pb_codec:encode(Message)}.

%% Get bucket properties
process(#greeting{msg = M}, State) ->
  {error, {format, "Message: ~p", [M]}, State}.

process_stream(_, _, State) ->
    {ignore, State}.

(riak_api) riak_api_app.erl

-module(riak_api_app).

-behaviour(application).
-export([start/2,
         stop/1]).

-define(SERVICES, [{riak_api_basic_pb_service, 1, 2},
                   {riak_api_basic_pb_service, 7, 8},
                   %% Note: Riak core cannot register this itself,
                   %% because it is started before riak_api.
                   {riak_core_pb_bucket, 19, 22},
                   {riak_core_pb_bucket, 29, 30},
                   {riak_core_pb_bucket_type, 31, 32},
                   {demo_api_pb_service, 600, 610}
                  ]).

%% @doc The application:start callback.
-spec start(Type, StartArgs)
           -> {ok, Pid} | {ok, Pid, State} | {error, Reason} when
      Type :: normal
             | {takeover, Node :: node()}
             | {failover, Node :: node()},
      Pid :: pid(),
      State :: term(),
      StartArgs :: term(),
      Reason :: term().
start(_Type, _StartArgs) ->
    riak_core_util:start_app_deps(riak_api),

    case riak_api_sup:start_link() of
        {ok, Pid} ->
            riak_core:register(riak_api, [{stat_mod, riak_api_stat}]),
            ok = riak_api_pb_service:register(?SERVICES),
            {ok, Pid};
        {error, Reason} ->
            {error, Reason}
    end.

%% @doc The application:stop callback.
-spec stop(State::term()) -> ok.
stop(_State) ->
    ok = riak_api_pb_service:deregister(?SERVICES),
    ok.

(riak_erlang_client) riakc_pb_socket.erl

-module(riakc_pb_socket).
-include_lib("kernel/include/inet.hrl").
-include_lib("riak_pb/include/riak_pb.hrl").
-include_lib("riak_pb/include/riak_kv_pb.hrl").
-include_lib("riak_pb/include/riak_pb_kv_codec.hrl").
-include_lib("riak_pb/include/riak_search_pb.hrl").
-include_lib("riak_pb/include/riak_yokozuna_pb.hrl").
-include_lib("riak_pb/include/riak_dt_pb.hrl").
-include_lib("riak_pb/include/demo_pb.hrl").
-include("riakc.hrl").
-behaviour(gen_server).

...
%% Reactive extension
-export([greeting/3]).

...

greeting(Pid, Msg, From)->
  Req = #greeting{msg= Msg, from=From},
  call_infinity(Pid, {req, Req, infinity}).
  
...

(riak_pb) riak_pb_messages.csv

...
80,DtFetchReq,riak_dt
81,DtFetchResp,riak_dt
82,DtUpdateReq,riak_dt
83,DtUpdateResp,riak_dt
253,RpbAuthReq,riak
254,RpbAuthResp,riak
...
605,Greeting,demo
...

1 (riak_pb) demo.proto

// java package specifiers
option java_package = "com.basho.riak.protobuf";
option java_outer_classname = "DemotPB";

message Greeting {
    required bytes msg  = 1;
    required bytes from = 2;
}

Output console

1> {ok, Pid} = riakc_pb_socket:start("127.0.0.1", 8087).
{ok,<0.34.0>}
2> riakc_pb_socket:ping(Pid).
pong
3> riakc_pb_socket:greeting(Pid, <<"Hello world!">>, <<"humbert">>).
{error,disconnected}
=ERROR REPORT==== 4-Aug-2015::18:00:54 ===
Socket error while sending riakc request: einval.
=ERROR REPORT==== 4-Aug-2015::18:00:54 ===
Bad value on output port 'tcp_inet'

Hello, I solved the problem with the help of @sargun in the channel of riak at webchat.freenode.net.

The error was in the code of my message (625). This number (605 >= 255) breaks the format of 8-bit message code to identify the Protocol Buffers message.

I changed the code of my message and it works!

Thanks