From b2659e4a6fa5ca231681fcafcb5b714f7efedd4f Mon Sep 17 00:00:00 2001
From: Badlop <badlop@process-one.net>
Date: Tue, 28 Apr 2009 14:57:16 +0000
Subject: [PATCH] * src/ejabberd_hooks.erl: Support distributed hooks
 (EJAB-829)

SVN Revision: 2047
---
 ChangeLog              |  4 ++
 src/ejabberd_hooks.erl | 87 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index bd175f4ad..7b0ba705d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2009-04-28  Badlop  <badlop@process-one.net>
+
+	* src/ejabberd_hooks.erl: Support distributed hooks (EJAB-829)
+
 2009-04-27  Badlop  <badlop@process-one.net>
 
 	* src/xml.erl: More verbose error reporting for
diff --git a/src/ejabberd_hooks.erl b/src/ejabberd_hooks.erl
index 9851a241c..bb71f14e1 100644
--- a/src/ejabberd_hooks.erl
+++ b/src/ejabberd_hooks.erl
@@ -33,12 +33,16 @@
 -export([start_link/0,
 	 add/3,
 	 add/4,
+	 add_dist/5,
 	 delete/3,
 	 delete/4,
+	 delete_dist/5,
 	 run/2,
 	 run_fold/3,
 	 add/5,
+	 add_dist/6,
 	 delete/5,
+	 delete_dist/6,
 	 run/3,
 	 run_fold/4]).
 
@@ -52,6 +56,9 @@
 
 -include("ejabberd.hrl").
 
+%% Timeout of 5 seconds in calls to distributed hooks
+-define(TIMEOUT_DISTRIBUTED_HOOK, 5000).
+
 -record(state, {}).
 
 %%%----------------------------------------------------------------------
@@ -77,6 +84,12 @@ add(Hook, Module, Function, Seq) ->
 add(Hook, Host, Module, Function, Seq) ->
     gen_server:call(ejabberd_hooks, {add, Hook, Host, Module, Function, Seq}).
 
+add_dist(Hook, Node, Module, Function, Seq) ->
+    gen_server:call(ejabberd_hooks, {add, Hook, global, Node, Module, Function, Seq}).
+
+add_dist(Hook, Host, Node, Module, Function, Seq) ->
+    gen_server:call(ejabberd_hooks, {add, Hook, Host, Node, Module, Function, Seq}).
+
 %% @spec (Hook::atom(), Function::function(), Seq::integer()) -> ok
 %% @doc See del/4.
 delete(Hook, Function, Seq) when is_function(Function) ->
@@ -94,6 +107,12 @@ delete(Hook, Module, Function, Seq) ->
 delete(Hook, Host, Module, Function, Seq) ->
     gen_server:call(ejabberd_hooks, {delete, Hook, Host, Module, Function, Seq}).
 
+delete_dist(Hook, Node, Module, Function, Seq) ->
+    delete_dist(Hook, global, Node, Module, Function, Seq).
+
+delete_dist(Hook, Host, Node, Module, Function, Seq) ->
+    gen_server:call(ejabberd_hooks, {delete, Hook, Host, Node, Module, Function, Seq}).
+
 %% @spec (Hook::atom(), Args) -> ok
 %% @doc Run the calls of this hook in order, don't care about function results.
 %% If a call returns stop, no more calls are performed.
@@ -167,6 +186,24 @@ handle_call({add, Hook, Host, Module, Function, Seq}, _From, State) ->
 		    ok
 	    end,
     {reply, Reply, State};
+handle_call({add, Hook, Host, Node, Module, Function, Seq}, _From, State) ->
+    Reply = case ets:lookup(hooks, {Hook, Host}) of
+		[{_, Ls}] ->
+		    El = {Seq, Node, Module, Function},
+		    case lists:member(El, Ls) of
+			true ->
+			    ok;
+			false ->
+			    NewLs = lists:merge(Ls, [El]),
+			    ets:insert(hooks, {{Hook, Host}, NewLs}),
+			    ok
+		    end;
+		[] ->
+		    NewLs = [{Seq, Node, Module, Function}],
+		    ets:insert(hooks, {{Hook, Host}, NewLs}),
+		    ok
+	    end,
+    {reply, Reply, State};
 handle_call({delete, Hook, Host, Module, Function, Seq}, _From, State) ->
     Reply = case ets:lookup(hooks, {Hook, Host}) of
 		[{_, Ls}] ->
@@ -177,6 +214,16 @@ handle_call({delete, Hook, Host, Module, Function, Seq}, _From, State) ->
 		    ok
 	    end,
     {reply, Reply, State};
+handle_call({delete, Hook, Host, Node, Module, Function, Seq}, _From, State) ->
+    Reply = case ets:lookup(hooks, {Hook, Host}) of
+		[{_, Ls}] ->
+		    NewLs = lists:delete({Seq, Node, Module, Function}, Ls),
+		    ets:insert(hooks, {{Hook, Host}, NewLs}),
+		    ok;
+		[] ->
+		    ok
+	    end,
+    {reply, Reply, State};
 handle_call(_Request, _From, State) ->
     Reply = ok,
     {reply, Reply, State}.
@@ -217,6 +264,25 @@ code_change(_OldVsn, State, _Extra) ->
 
 run1([], _Hook, _Args) ->
     ok;
+run1([{_Seq, Node, Module, Function} | Ls], Hook, Args) ->
+    case rpc:call(Node, Module, Function, Args, ?TIMEOUT_DISTRIBUTED_HOOK) of
+	timeout ->
+	    ?ERROR_MSG("Timeout on RPC to ~p~nrunning hook: ~p",
+		       [Node, {Hook, Args}]),
+	    run1(Ls, Hook, Args);
+	{badrpc, Reason} ->
+	    ?ERROR_MSG("Bad RPC error to ~p: ~p~nrunning hook: ~p",
+		       [Node, Reason, {Hook, Args}]),
+	    run1(Ls, Hook, Args);
+	stop ->
+	    ?INFO_MSG("~nThe process ~p in node ~p ran a hook in node ~p.~n"
+		      "Stop.", [self(), node(), Node]), % debug code
+	    ok;
+	Res ->
+	    ?INFO_MSG("~nThe process ~p in node ~p ran a hook in node ~p.~n"
+		      "The response is:~n~s", [self(), node(), Node, Res]), % debug code
+	    run1(Ls, Hook, Args)
+    end;
 run1([{_Seq, Module, Function} | Ls], Hook, Args) ->
     Res = if is_function(Function) ->
 		  catch apply(Function, Args);
@@ -237,6 +303,27 @@ run1([{_Seq, Module, Function} | Ls], Hook, Args) ->
 
 run_fold1([], _Hook, Val, _Args) ->
     Val;
+run_fold1([{_Seq, Node, Module, Function} | Ls], Hook, Val, Args) ->
+    case rpc:call(Node, Module, Function, [Val | Args], ?TIMEOUT_DISTRIBUTED_HOOK) of
+	{badrpc, Reason} ->
+	    ?ERROR_MSG("Bad RPC error to ~p: ~p~nrunning hook: ~p",
+		       [Node, Reason, {Hook, Args}]),
+	    run_fold1(Ls, Hook, Val, Args);
+	timeout ->
+	    ?ERROR_MSG("Timeout on RPC to ~p~nrunning hook: ~p",
+		       [Node, {Hook, Args}]),
+	    run_fold1(Ls, Hook, Val, Args);
+	stop ->
+	    stopped;
+	{stop, NewVal} ->
+	    ?INFO_MSG("~nThe process ~p in node ~p ran a hook in node ~p.~n"
+		      "Stop, and the NewVal is:~n~p", [self(), node(), Node, NewVal]), % debug code
+	    NewVal;
+	NewVal ->
+	    ?INFO_MSG("~nThe process ~p in node ~p ran a hook in node ~p.~n"
+		      "The NewVal is:~n~p", [self(), node(), Node, NewVal]), % debug code
+	    run_fold1(Ls, Hook, NewVal, Args)
+    end;
 run_fold1([{_Seq, Module, Function} | Ls], Hook, Val, Args) ->
     Res = if is_function(Function) ->
 		  catch apply(Function, [Val | Args]);