%%%----------------------------------------------------------------------
%%% File : ejabberd_node_groups.erl
%%% Author : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : Distributed named node groups based on pg2 module
%%% Created : 1 Nov 2006 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2015 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License along
%%% with this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------
-module(ejabberd_node_groups).
-behaviour(ejabberd_config).
-author('alexey@process-one.net').
-behaviour(gen_server).
%% API
-export([start_link/0,
join/1,
leave/1,
get_members/1,
get_closest_node/1]).
-export([init/1, handle_call/3, handle_cast/2,
handle_info/2, terminate/2, code_change/3, opt_type/1]).
-define(PG2, pg2).
-record(state, {}).
%%====================================================================
%% API
%%====================================================================
%%--------------------------------------------------------------------
%% Function: start_link() -> {ok,Pid} | ignore | {error,Error}
%% Description: Starts the server
%%--------------------------------------------------------------------
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
join(Name) ->
PG = {?MODULE, Name},
pg2:create(PG),
pg2:join(PG, whereis(?MODULE)).
leave(Name) ->
PG = {?MODULE, Name},
pg2:leave(PG, whereis(?MODULE)).
get_members(Name) ->
PG = {?MODULE, Name},
[node(P) || P <- pg2:get_members(PG)].
get_closest_node(Name) ->
PG = {?MODULE, Name},
node(pg2:get_closest_pid(PG)).
%%====================================================================
%% gen_server callbacks
%%====================================================================
%%--------------------------------------------------------------------
%% Function: init(Args) -> {ok, State} |
%% {ok, State, Timeout} |
%% ignore |
%% {stop, Reason}
%% Description: Initiates the server
%%--------------------------------------------------------------------
init([]) ->
{FE, BE} =
case ejabberd_config:get_option(
node_type,
fun(frontend) -> frontend;
(backend) -> backend;
(generic) -> generic
end, generic) of
frontend ->
{true, false};
backend ->
{false, true};
generic ->
{true, true};
undefined ->
{true, true}
end,
if
FE ->
join(frontend);
true ->
ok
end,
if
BE ->
join(backend);
true ->
ok
end,
{ok, #state{}}.
%%--------------------------------------------------------------------
%% Function: %% handle_call(Request, From, State) -> {reply, Reply, State} |
%% {reply, Reply, State, Timeout} |
%% {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, Reply, State} |
%% {stop, Reason, State}
%% Description: Handling call messages
%%--------------------------------------------------------------------
handle_call(_Request, _From, State) ->
Reply = ok,
{reply, Reply, State}.
%%--------------------------------------------------------------------
%% Function: handle_cast(Msg, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% Description: Handling cast messages
%%--------------------------------------------------------------------
handle_cast(_Msg, State) ->
{noreply, State}.
%%--------------------------------------------------------------------
%% Function: handle_info(Info, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% Description: Handling all non call/cast messages
%%--------------------------------------------------------------------
handle_info(_Info, State) ->
{noreply, State}.
%%--------------------------------------------------------------------
%% Function: terminate(Reason, State) -> void()
%% Description: This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any necessary
%% cleaning up. When it returns, the gen_server terminates with Reason.
%% The return value is ignored.
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
ok.
%%--------------------------------------------------------------------
%% Func: code_change(OldVsn, State, Extra) -> {ok, NewState}
%% Description: Convert process state when code is changed
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
opt_type(node_type) ->
fun (frontend) -> frontend;
(backend) -> backend;
(generic) -> generic
end;
opt_type(_) -> [node_type].
