Add simple metrics module for use with grapherl

diff --git a/src/mod_metrics.erl b/src/mod_metrics.erl
new file mode 100644 (file)
index 0000000..c3a57c9
--- /dev/null
+++ b/src/mod_metrics.erl
@@ -0,0 +1,125 @@
+%%%-------------------------------------------------------------------
+%%% File    : mod_metrics.erl
+%%% Author  : Christophe Romain <christophe.romain@process-one.net>
+%%% Purpose : Simple metrics handler for runtime statistics
+%%% Created : 22 Oct 2015 by Christophe Romain <christophe.romain@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(mod_metrics).
+
+-behaviour(ejabberd_config).
+-author('christophe.romain@process-one.net').
+-behaviour(gen_mod).
+
+-include("ejabberd.hrl").
+-include("logger.hrl").
+-include("jlib.hrl").
+
+-define(HOOKS, [offline_message_hook,
+                sm_register_connection_hook, sm_remove_connection_hook,
+                user_send_packet, user_receive_packet,
+                s2s_send_packet, s2s_receive_packet,
+                remove_user, register_user]).
+
+-export([start/2, stop/1, send_metrics/4]).
+
+-export([offline_message_hook/3,
+         sm_register_connection_hook/3, sm_remove_connection_hook/3,
+         user_send_packet/4, user_receive_packet/5,
+         s2s_send_packet/3, s2s_receive_packet/3,
+         remove_user/2, register_user/2]).
+
+%%====================================================================
+%% API
+%%====================================================================
+
+start(Host, _Opts) ->
+    [ejabberd_hooks:add(Hook, Host, ?MODULE, Hook, 20)
+     || Hook <- ?HOOKS].
+
+stop(Host) ->
+    [ejabberd_hooks:delete(Hook, Host, ?MODULE, Hook, 20)
+     || Hook <- ?HOOKS].
+
+%%====================================================================
+%% Hooks handlers
+%%====================================================================
+
+offline_message_hook(_From, #jid{lserver=LServer}, _Packet) ->
+    push(LServer, offline_message).
+
+sm_register_connection_hook(_SID, #jid{lserver=LServer}, _Info) ->
+    push(LServer, sm_register_connection).
+sm_remove_connection_hook(_SID, #jid{lserver=LServer}, _Info) ->
+    push(LServer, sm_remove_connection).
+
+user_send_packet(Packet, _C2SState, #jid{lserver=LServer}, _To) ->
+    push(LServer, user_send_packet),
+    Packet.
+user_receive_packet(Packet, _C2SState, _JID, _From, #jid{lserver=LServer}) ->
+    push(LServer, user_receive_packet),
+    Packet.
+
+s2s_send_packet(#jid{lserver=LServer}, _To, _Packet) ->
+    push(LServer, s2s_send_packet).
+s2s_receive_packet(_From, #jid{lserver=LServer}, _Packet) ->
+    push(LServer, s2s_receive_packet).
+
+remove_user(_User, Server) ->
+    push(jlib:nameprep(Server), remove_user).
+register_user(_User, Server) ->
+    push(jlib:nameprep(Server), register_user).
+
+%%====================================================================
+%% metrics push handler
+%%====================================================================
+
+push(Host, Probe) ->
+    spawn(?MODULE, send_metrics, [Host, Probe, {127,0,0,1}, 11111]).
+
+send_metrics(Host, Probe, Peer, Port) ->
+    % our default metrics handler is https://github.com/processone/grapherl
+    % grapherl metrics are named first with service domain, then nodename
+    % and name of the data itself, followed by type timestamp and value
+    % example => process-one.net/xmpp-1.user_receive_packet:c/1441784958:1
+    [_, NodeId] = str:tokens(jlib:atom_to_binary(node()), <<"@">>),
+    [Node | _] = str:tokens(NodeId, <<".">>),
+    BaseId = <<Host/binary, "/", Node/binary, ".">>,
+    DateTime = erlang:universaltime(),
+    UnixTime = calendar:datetime_to_gregorian_seconds(DateTime) - 62167219200,
+    TS = integer_to_binary(UnixTime),
+    case gen_udp:open(0) of
+       {ok, Socket} ->
+           case Probe of
+               {Key, Val} ->
+                   BVal = integer_to_binary(Val),
+                   Data = <<BaseId/binary, (jlib:atom_to_binary(Key))/binary,
+                           ":g/", TS/binary, ":", BVal/binary>>,
+                   gen_udp:send(Socket, Peer, Port, Data);
+               Key ->
+                   Data = <<BaseId/binary, (jlib:atom_to_binary(Key))/binary,
+                           ":c/", TS/binary, ":1">>,
+                   gen_udp:send(Socket, Peer, Port, Data)
+           end,
+           gen_udp:close(Socket);
+       Error ->
+           ?WARNING_MSG("can not open udp socket to grapherl: ~p", [Error])
+    end.