Support parallel extauth script (thanks to Jesse Thompson)(EJAB-1280)

doc/guide.html

@@ -1060,7 +1060,9 @@ There are also <A HREF="http://www.ejabberd.im/extauth">several example authenti
 </P><DL CLASS="description"><DT CLASS="dt-description">
 <B><TT>{extauth_program, PathToScript}</TT></B></DT><DD CLASS="dd-description"> 
 Indicate in this option the full path to the external authentication script.
-The script must be executable by ejabberd.</DD><DT CLASS="dt-description"><B><TT>{extauth_cache, false|CacheTimeInteger}</TT></B></DT><DD CLASS="dd-description"> 
+The script must be executable by ejabberd.</DD><DT CLASS="dt-description"><B><TT>{extauth_instances, Integer}</TT></B></DT><DD CLASS="dd-description"> 
+Indicate how many instances of the script to run simultaneously to serve authentication in the virtual host.
+The default value is the minimum number: 1.</DD><DT CLASS="dt-description"><B><TT>{extauth_cache, false|CacheTimeInteger}</TT></B></DT><DD CLASS="dd-description"> 
 The value <TT>false</TT> disables the caching feature, this is the default.
 The integer <TT>0</TT> (zero) enables caching for statistics, but doesn&#X2019;t use that cached information to authenticate users.
 If another integer value is set, caching is enabled both for statistics and for authentication:
@@ -1069,10 +1071,12 @@ the authentication information since the user last disconnected,
 to verify again the user authentication without querying again the extauth script.
 Note: caching should not be enabled in a host if internal auth is also enabled.
 If caching is enabled, <TT>mod_last</TT> or <TT>mod_last_odbc</TT> must be enabled also in that vhost.
-</DD></DL><P>This example sets external authentication, the extauth script, and enables caching for 10 minutes:
+</DD></DL><P>This example sets external authentication, the extauth script, enables caching for 10 minutes,
+and starts three instances of the script for each virtual host defined in ejabberd:
 </P><PRE CLASS="verbatim">{auth_method, [external]}.
 {extauth_program, "/etc/ejabberd/JabberAuth.class.php"}.
 {extauth_cache, 600}.
+{extauth_instances, 3}. 
 </PRE><P> <A NAME="saslanonymous"></A> </P><!--TOC subsubsection SASL Anonymous and Anonymous Login-->
 <H4 CLASS="subsubsection"><!--SEC ANCHOR --><A HREF="#saslanonymous">SASL Anonymous and Anonymous Login</A></H4><!--SEC END --><P> <A NAME="saslanonymous"></A> 
 </P><P>The value <TT>anonymous</TT> will enable the internal authentication method.</P><P>The anonymous authentication method can be configured with the following

doc/guide.tex

@@ -1239,6 +1239,10 @@ These are the specific options:
   Indicate in this option the full path to the external authentication script.
   The script must be executable by ejabberd.
 
+  \titem{\{extauth\_instances, Integer\}} 
+  Indicate how many instances of the script to run simultaneously to serve authentication in the virtual host.
+  The default value is the minimum number: 1.
+
   \titem{\{extauth\_cache, false|CacheTimeInteger\}} 
   The value \term{false} disables the caching feature, this is the default.
   The integer \term{0} (zero) enables caching for statistics, but doesn't use that cached information to authenticate users.
@@ -1250,11 +1254,13 @@ These are the specific options:
   If caching is enabled, \term{mod\_last} or \term{mod\_last\_odbc} must be enabled also in that vhost.
 \end{description}
 
-This example sets external authentication, the extauth script, and enables caching for 10 minutes:
+This example sets external authentication, the extauth script, enables caching for 10 minutes,
+and starts three instances of the script for each virtual host defined in ejabberd:
 \begin{verbatim}
 {auth_method, [external]}.
 {extauth_program, "/etc/ejabberd/JabberAuth.class.php"}.
 {extauth_cache, 600}.
+{extauth_instances, 3}. 
 \end{verbatim}
 
 \makesubsubsection{saslanonymous}{SASL Anonymous and Anonymous Login}

src/extauth.erl

@@ -43,16 +43,29 @@
 -define(CALL_TIMEOUT, 10000). % Timeout is in milliseconds: 10 seconds == 10000
 
 start(Host, ExtPrg) ->
-    spawn(?MODULE, init, [Host, ExtPrg]).
+    lists:foreach(
+	fun(This) ->
+	    spawn(?MODULE, init, [get_process_name(Host, This), ExtPrg])
+	end,
+	lists:seq(0, get_instances(Host)-1)
+    ).
 
-init(Host, ExtPrg) ->
-    register(gen_mod:get_module_proc(Host, eauth), self()),
+init(ProcessName, ExtPrg) ->
+    register(ProcessName, self()),
     process_flag(trap_exit,true),
     Port = open_port({spawn, ExtPrg}, [{packet,2}]),
     loop(Port, ?INIT_TIMEOUT).
 
 stop(Host) ->
-    gen_mod:get_module_proc(Host, eauth) ! stop.
+    lists:foreach(
+	fun(This) ->
+	    get_process_name(Host, This) ! stop
+	end,
+	lists:seq(0, get_instances(Host)-1)
+    ).
+
+get_process_name(Host, Integer) ->
+    gen_mod:get_module_proc(lists:append([Host, integer_to_list(Integer)]), eauth).
 
 check_password(User, Server, Password) ->
     call_port(Server, ["auth", User, Server, Password]).
@@ -77,12 +90,24 @@ remove_user(User, Server, Password) ->
 
 call_port(Server, Msg) ->
     LServer = jlib:nameprep(Server),
-    gen_mod:get_module_proc(LServer, eauth) ! {call, self(), Msg},
+    ProcessName = get_process_name(LServer, random_instance(get_instances(LServer))),
+    ProcessName ! {call, self(), Msg},
     receive
 	{eauth,Result} ->
 	    Result
     end.
 
+random_instance(MaxNum) ->
+    {A1,A2,A3} = now(),
+    random:seed(A1, A2, A3),
+    random:uniform(MaxNum) - 1.
+
+get_instances(Server) ->
+    case ejabberd_config:get_local_option({extauth_instances, Server}) of
+	Num when is_integer(Num) -> Num;
+	_ -> 1
+    end.
+
 loop(Port, Timeout) ->
     receive
 	{call, Caller, Msg} ->