Generic delegate mechanism, similar to what the router did before.

4 files changed, 283 insertions, 0 deletions

diff --git a/src/delegate.erl b/src/delegate.erl
new file mode 100644
index 00000000..3a26c410
--- /dev/null
+++ b/src/delegate.erl
@@ -0,0 +1,129 @@
+%%   The contents of this file are subject to the Mozilla Public License
+%%   Version 1.1 (the "License"); you may not use this file except in
+%%   compliance with the License. You may obtain a copy of the License at
+%%   http://www.mozilla.org/MPL/
+%%
+%%   Software distributed under the License is distributed on an "AS IS"
+%%   basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
+%%   License for the specific language governing rights and limitations
+%%   under the License.
+%%
+%%   The Original Code is RabbitMQ.
+%%
+%%   The Initial Developers of the Original Code are LShift Ltd,
+%%   Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
+%%   Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
+%%   are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
+%%   Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
+%%   Ltd. Portions created by Cohesive Financial Technologies LLC are
+%%   Copyright (C) 2007-2010 Cohesive Financial Technologies
+%%   LLC. Portions created by Rabbit Technologies Ltd are Copyright
+%%   (C) 2007-2010 Rabbit Technologies Ltd.
+%%
+%%   All Rights Reserved.
+%%
+%%   Contributor(s): ______________________________________.
+%%
+
+-module(delegate).
+-include("delegate.hrl").
+
+-behaviour(gen_server2).
+
+-export([start_link/1, delegate_async/2, delegate_sync/2, server/1]).
+
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
+         terminate/2, code_change/3]).
+
+
+%%----------------------------------------------------------------------------
+
+start_link(Hash) ->
+    gen_server2:start_link({local, server(Hash)},
+                           ?MODULE, [], []).
+delegate_sync(Node, Thunk) when is_atom(Node) ->
+    gen_server2:call({server(), Node}, {thunk, Thunk}, infinity);
+
+delegate_sync(Pid, FPid) when is_pid(Pid) ->
+    [[Res]] = delegate_per_node([{node(Pid), [Pid]}],
+                                f_pid_node(fun delegate_sync/2, FPid)),
+    Res;
+
+delegate_sync(Pids, FPid) when is_list(Pids) ->
+    lists:flatten(
+        delegate_per_node(split_per_node(Pids),
+                          f_pid_node(fun delegate_sync/2, FPid))).
+
+delegate_async(Node, Thunk) when is_atom(Node) ->
+    gen_server2:cast({server(), Node}, {thunk, Thunk});
+
+delegate_async(Pid, FPid) when is_pid(Pid) ->
+    delegate_per_node([{node(Pid), [Pid]}],
+                      f_pid_node(fun delegate_async/2, FPid));
+
+delegate_async(Pids, FPid) when is_list(Pids) ->
+    delegate_per_node(split_per_node(Pids),
+                      f_pid_node(fun delegate_async/2, FPid)).
+
+%%----------------------------------------------------------------------------
+
+split_per_node(Pids) ->
+    dict:to_list(
+        lists:foldl(
+          fun (Pid, D) ->
+                  dict:update(node(Pid),
+                              fun (Pids1) -> [Pid | Pids1] end,
+                              [Pid], D)
+          end,
+          dict:new(), Pids)).
+
+f_pid_node(DelegateFun, FPid) ->
+    fun(Pid, Node) ->
+        DelegateFun(Node, fun() -> FPid(Pid) end)
+    end.
+
+% TODO this only gets called when we are ONLY talking to the local node - can
+% we improve this?
+delegate_per_node([{Node, Pids}], FPidNode) when Node == node() ->
+    % optimisation
+    [[FPidNode(Pid, node()) || Pid <- Pids]];
+
+delegate_per_node(NodePids, FPidNode) ->
+    rabbit_misc:upmap(
+          fun ({Node, Pids}) ->
+              [FPidNode(Pid, Node) || Pid <- Pids]
+          end,
+          NodePids).
+
+server() ->
+    server(erlang:phash(self(), ?DELEGATE_PROCESSES)).
+
+server(Hash) ->
+    list_to_atom(string:concat("delegate_process_", integer_to_list(Hash))).
+
+%%--------------------------------------------------------------------
+
+init([]) ->
+    {ok, no_state}.
+
+handle_call({thunk, Thunk}, _From, State) ->
+    {reply, catch Thunk(), State}.
+
+handle_cast({thunk, Thunk}, State) ->
+    catch Thunk(),
+    {noreply, State}.
+
+handle_info(_Info, State) ->
+    {noreply, State}.
+
+terminate(_Reason, _State) ->
+    ok.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+%%--------------------------------------------------------------------
diff --git a/src/delegate_sup.erl b/src/delegate_sup.erl
new file mode 100644
index 00000000..f7a1c586
--- /dev/null
+++ b/src/delegate_sup.erl
@@ -0,0 +1,56 @@
+%%   The contents of this file are subject to the Mozilla Public License
+%%   Version 1.1 (the "License"); you may not use this file except in
+%%   compliance with the License. You may obtain a copy of the License at
+%%   http://www.mozilla.org/MPL/
+%%
+%%   Software distributed under the License is distributed on an "AS IS"
+%%   basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
+%%   License for the specific language governing rights and limitations
+%%   under the License.
+%%
+%%   The Original Code is RabbitMQ.
+%%
+%%   The Initial Developers of the Original Code are LShift Ltd,
+%%   Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
+%%   Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
+%%   are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
+%%   Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
+%%   Ltd. Portions created by Cohesive Financial Technologies LLC are
+%%   Copyright (C) 2007-2010 Cohesive Financial Technologies
+%%   LLC. Portions created by Rabbit Technologies Ltd are Copyright
+%%   (C) 2007-2010 Rabbit Technologies Ltd.
+%%
+%%   All Rights Reserved.
+%%
+%%   Contributor(s): ______________________________________.
+%%
+
+-module(delegate_sup).
+-include("delegate.hrl").
+
+-behaviour(supervisor).
+
+-export([start_link/0]).
+
+-export([init/1]).
+
+-define(SERVER, ?MODULE).
+
+%%----------------------------------------------------------------------------
+
+start_link() ->
+    supervisor:start_link({local, ?SERVER}, ?MODULE, []).
+
+%%--------------------------------------------------------------------
+
+init(_Args) ->
+    {ok, {{one_for_one, 10, 10},
+        [{delegate:server(Hash), {delegate, start_link, [Hash]},
+          temporary, 16#ffffffff, worker, [delegate]} ||
+                Hash <- lists:seq(1, ?DELEGATE_PROCESSES)]}}.
+
+%%--------------------------------------------------------------------
diff --git a/src/rabbit.erl b/src/rabbit.erl
index 700acede..693731f9 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -85,6 +85,14 @@
                     {requires,    kernel_ready},
                     {enables,     core_initialized}]}).
 
+
+-rabbit_boot_step({delegate_sup,
+                   [{description, "cluster delegate"},
+                    {mfa,         {rabbit_sup, start_restartable_child,
+                                   [delegate_sup]}},
+                    {requires,    kernel_ready},
+                    {enables,     core_initialized}]}).
+
 -rabbit_boot_step({rabbit_router,
                    [{description, "cluster router"},
                     {mfa,         {rabbit_sup, start_restartable_child,
diff --git a/src/rabbit_tests.erl b/src/rabbit_tests.erl
index 82f2d199..29ec7999 100644
--- a/src/rabbit_tests.erl
+++ b/src/rabbit_tests.erl
@@ -62,6 +62,8 @@ all_tests() ->
     passed = test_user_management(),
     passed = test_server_status(),
     passed = test_hooks(),
+    passed = test_delegates_async(),
+    passed = test_delegates_sync(),
     passed.
 
 test_priority_queue() ->
@@ -811,6 +813,94 @@ test_hooks() ->
     end,
     passed.
 
+test_delegates_async() ->
+    SecondaryNode = rabbit_misc:makenode("hare"),
+
+    Self = self(),
+    Sender = fun(Pid) -> Pid ! {invoked, Self} end,
+
+    Receiver = fun() ->
+        receive
+            {invoked, Pid} ->
+                Pid ! response,
+                ok
+        after 100 ->
+            io:format("Async message not sent~n"),
+            throw(timeout)
+        end
+    end,
+
+    delegate:delegate_async(spawn(Receiver), Sender),
+    delegate:delegate_async(spawn(SecondaryNode, Receiver), Sender),
+    await_response(2),
+
+    LocalPids = [spawn(Receiver) || _ <- lists:seq(1,10)],
+    RemotePids = [spawn(SecondaryNode, Receiver) || _ <- lists:seq(1,10)],
+    delegate:delegate_async(LocalPids ++ RemotePids, Sender),
+    await_response(20),
+
+    passed.
+
+await_response(0) ->
+    ok;
+
+await_response(Count) ->
+    receive
+        response -> ok,
+        await_response(Count - 1)
+    after 100 ->
+        io:format("Async reply not received~n"),
+        throw(timeout)
+    end.
+
+test_delegates_sync() ->
+    SecondaryNode = rabbit_misc:makenode("hare"),
+    "foo" = delegate:delegate_sync(node(), fun() -> "foo" end),
+    "bar" = delegate:delegate_sync(SecondaryNode, fun() -> "bar" end),
+
+    Sender = fun(Pid) ->
+        gen_server2:call(Pid, invoked)
+    end,
+
+    Responder = fun() ->
+        receive
+            {'$gen_call', From, invoked} ->
+                gen_server2:reply(From, response)
+        after 100 ->
+            io:format("Sync hook not invoked~n"),
+            throw(timeout)
+        end
+    end,
+
+    BadResponder = fun() ->
+        receive
+            {'$gen_call', _From, invoked} ->
+                throw(exception)
+        after 100 ->
+            io:format("Crashing sync hook not invoked~n"),
+            throw(timeout)
+        end
+    end,
+
+    response = delegate:delegate_sync(spawn(Responder), Sender),
+    response = delegate:delegate_sync(spawn(SecondaryNode, Responder), Sender),
+
+    {'EXIT', _} = delegate:delegate_sync(spawn(BadResponder), Sender),
+    {'EXIT', _} = delegate:delegate_sync(spawn(SecondaryNode, BadResponder), Sender),
+
+    LocalGoodPids = [spawn(Responder) || _ <- lists:seq(1,2)],
+    RemoteGoodPids = [spawn(Responder) || _ <- lists:seq(1,2)],
+    LocalBadPids = [spawn(SecondaryNode, BadResponder) || _ <- lists:seq(1,2)],
+    RemoteBadPids = [spawn(SecondaryNode, BadResponder) || _ <- lists:seq(1,2)],
+
+    [response, response, response, response] =
+        delegate:delegate_sync(LocalGoodPids ++ RemoteGoodPids, Sender),
+    [{'EXIT', _}, {'EXIT', _}, {'EXIT', _}, {'EXIT', _}] =
+        delegate:delegate_sync(LocalBadPids ++ RemoteBadPids, Sender),
+
+    passed.
+
+
 %---------------------------------------------------------------------
 
 control_action(Command, Args) -> control_action(Command, node(), Args).