add helper process for lifecycle hooks

1 files changed, 68 insertions, 0 deletions

diff --git a/src/supervised_lifecycle.erl b/src/supervised_lifecycle.erl
new file mode 100644
index 00000000..8b306f6f
--- /dev/null
+++ b/src/supervised_lifecycle.erl
@@ -0,0 +1,68 @@
+%% 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 Developer of the Original Code is GoPivotal, Inc.
+%% Copyright (c) 2007-2013 GoPivotal, Inc.  All rights reserved.
+%%
+
+%% Invoke callbacks on startup and termination.
+%%
+%% Simply hook this process into a supervision hierarchy, to have the
+%% callbacks invoked at a precise point during the establishment and
+%% teardown of that hierarchy, respectively.
+%%
+%% Or launch the process independently, and link to it, to have the
+%% callbacks invoked on startup and when the linked process
+%% terminates, respectively.
+
+-module(supervised_lifecycle).
+
+-behavior(gen_server).
+
+-export([start_link/3]).
+
+%% gen_server callbacks
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
+         code_change/3]).
+
+%%----------------------------------------------------------------------------
+
+-ifdef(use_specs).
+
+-spec(start_link/3 :: (atom(), rabbit_types:mfargs(), rabbit_types:mfargs()) ->
+                           rabbit_types:ok_pid_or_error()).
+
+-endif.
+
+%%----------------------------------------------------------------------------
+
+start_link(Name, StartMFA, StopMFA) ->
+    gen_server:start_link({local, Name}, ?MODULE, [StartMFA, StopMFA], []).
+
+%%----------------------------------------------------------------------------
+
+init([{M, F, A}, StopMFA]) ->
+    process_flag(trap_exit, true),
+    apply(M, F, A),
+    {ok, StopMFA}.
+
+handle_call(_Request, _From, State) -> {noreply, State}.
+
+handle_cast(_Msg, State) -> {noreply, State}.
+
+handle_info(_Info, State) -> {noreply, State}.
+
+terminate(_Reason, {M, F, A}) ->
+    apply(M, F, A),
+    ok.
+
+code_change(_OldVsn, State, _Extra) -> {ok, State}.