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xmpp.chapril.org-ejabberd/src/ejabberd_rdbms.erl
2011-02-14 13:47:22 +01:00

131 lines
3.9 KiB
Erlang

%%%----------------------------------------------------------------------
%%% File : ejabberd_rdbms.erl
%%% Author : Mickael Remond <mickael.remond@process-one.net>
%%% Purpose : Manage the start of the database modules when needed
%%% Created : 31 Jan 2003 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2011 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., 59 Temple Place, Suite 330, Boston, MA
%%% 02111-1307 USA
%%%
%%%----------------------------------------------------------------------
-module(ejabberd_rdbms).
-author('alexey@process-one.net').
-export([start/0
,start_odbc/1
,stop_odbc/1
,running/1
]).
-include("ejabberd.hrl").
-include("ejabberd_config.hrl").
-include_lib("stdlib/include/ms_transform.hrl").
-define(SUPERVISOR, ejabberd_sup).
start() ->
%% Check if ejabberd has been compiled with ODBC
case catch ejabberd_odbc_sup:module_info() of
{'EXIT',{undef,_}} ->
?INFO_MSG("ejabberd has not been compiled with relational database support. Skipping database startup.", []);
_ ->
%% If compiled with ODBC, start ODBC on the needed host
start_hosts()
end.
%% Start relationnal DB module on the nodes where it is needed
start_hosts() ->
lists:foreach(
fun(Host) ->
case needs_odbc(Host) of
true -> start_odbc(Host);
false -> ok
end
end, ?MYHOSTS).
%% Start the ODBC module on the given host
start_odbc(Host) ->
SupervisorName = sup_name(Host),
ChildSpec =
{SupervisorName,
{ejabberd_odbc_sup, start_link, [Host]},
transient,
infinity,
supervisor,
[ejabberd_odbc_sup]},
case supervisor:start_child(?SUPERVISOR, ChildSpec) of
{ok, _PID} ->
ok;
_Error ->
?ERROR_MSG("Start of supervisor ~p failed:~n~p~nRetrying...~n", [SupervisorName, _Error]),
start_odbc(Host)
end.
stop_odbc(Host) ->
SupervisorName = sup_name(Host),
case running(Host) of
false -> ok;
true ->
case [H || H <- dependent_hosts(Host), ejabberd_hosts:running(H)] of
[] ->
?INFO_MSG("About to terminate ~p", [SupervisorName]),
ok = supervisor:terminate_child(?SUPERVISOR, SupervisorName),
ok = supervisor:delete_child(?SUPERVISOR, SupervisorName);
RunningHosts ->
?WARNING_MSG("Not stopping ODBC for ~p because the virtual hosts ~p are still using it.",
[Host, RunningHosts]),
{error, still_in_use}
end
end.
%% Returns true if we have configured odbc_server for the given host
needs_odbc(Host) ->
try
LHost = exmpp_stringprep:nameprep(Host),
case ejabberd_config:get_local_option({odbc_server, LHost}) of
undefined ->
false;
{host, _} ->
false;
_ ->
true
end
catch
_ ->
false
end.
running(Host) ->
Supervisors = supervisor:which_children(?SUPERVISOR),
SupervisorName = gen_mod:get_module_proc(Host, ejabberd_odbc_sup),
case lists:keysearch(SupervisorName, 1, Supervisors) of
false -> false;
{value, Cspec} when is_tuple(Cspec) -> true
end.
dependent_hosts(Host) ->
MS = ets:fun2ms(fun (#local_config{key={odbc_server, DHost},
value={host, H}})
when H =:= Host ->
DHost
end),
ejabberd_config:search(MS).
sup_name(Host) ->
gen_mod:get_module_proc(Host, ejabberd_odbc_sup).