rebar3 proto plugin

The purpose of this plugin is to provide an auto-incrementing id for each protocol name, for using the protocol definition that uses protocol numbers instead of protocol names.

This plugin would generate a module proto_info.erl, which provides frequently-used functions defined by users.

Cooperates with rebar3_gpb_plugin, so configure it first.

rebar.config's options specification

• o_meta_file: The output file records the protocol name, auto-incrementing id, and pb module generated by gpb.
• o_proto_info: The output file generated functions defined by custom_info.
• custom_info: The file defines functions for o_proto_info's file.

Use

Add the plugin to your rebar config:

    {project_plugins, [
        {rebar3_gpb_plugin, "2.22.1"},
        {rebar3_proto_plugin, "0.1.18"}
    ]}.

Config the proto_opts and provider_hooks:

    {proto_opts, [
                  {o_meta_file, "proto_info.meta"},
                  {o_proto_info, "src/proto_info.erl"},
                  {custom_info, ["src/proto_info_custom.erl"]},


                  {proto_hrl, true},
                  {proto_hrl_uppercase, true},
                  {o_proto_hrl, "include/pt_define.hrl"}
                 ]}.


    {provider_hooks, [
        {pre, [
               {compile, {protobuf, compile}},
               {compile, {proto, generate}},

               {clean, {protobuf, clean}}
              ]},
        {post, [
               ]
        }
    ]}.

Define custom functions in the file custom_info above, each function in fun_list would be applied with the argument MetaList, and expected to return a map like: #{fun_name => ?, clauses => [ #{args => ?, return => ?} ]}).

MetaList is a list, each element is a map that contains keys msg_code, msg_name and pb_module.

-module(proto_info_custom).

-export([
          fun_list/0
        ]).

fun_list() ->
    [fun get_msg_handle/1].

get_msg_handle(MetaList) ->
    Fun = fun(PbModule) ->
                  case atom_to_list(PbModule) of
                      "pb_" ++ Proto ->
                          list_to_atom("handle_"++Proto);
                      _ ->
                          undefined
                  end
          end,
    ClausesMapsList = [ #{args => [MsgCode], return => Fun(PbModule)}
                        || #{msg_code := MsgCode, pb_module := PbModule} <- MetaList],
    #{fun_name => ?FUNCTION_NAME,
      clauses => ClausesMapsList}.

Example

A simple example locate in doc/example_app.

proto_info.meta and src/pb/proto_info.erl are generated by current plugin.