migrate application handling code to app_utils

4 files changed, 118 insertions, 95 deletions

diff --git a/src/app_utils.erl b/src/app_utils.erl
new file mode 100644
index 0000000000..dfbf710661
--- /dev/null
+++ b/src/app_utils.erl
@@ -0,0 +1,109 @@
+%% 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 VMware, Inc.
+%% Copyright (c) 2007-2012 VMware, Inc.  All rights reserved.
+%%
+-module(app_utils).
+
+-export([load_applications/1, start_applications/1,
+         stop_applications/1, app_dependency_order/2]).
+
+-ifdef(use_specs).
+
+-spec start_applications([atom()])              -> 'ok'.
+-spec load_applications([atom()])               -> 'ok'.
+-spec stop_applications([atom()])               -> 'ok'.
+-spec app_dependency_order([atom()], boolean()) -> [digraph:vertex()].
+
+-endif.
+
+%%---------------------------------------------------------------------------
+%% Public API
+
+load_applications(Apps) ->
+    load_applications(queue:from_list(Apps), sets:new()),
+    ok.
+
+start_applications(Apps) ->
+    manage_applications(fun lists:foldl/3,
+                        fun application:start/1,
+                        fun application:stop/1,
+                        already_started,
+                        cannot_start_application,
+                        Apps).
+
+stop_applications(Apps) ->
+    manage_applications(fun lists:foldr/3,
+                        fun application:stop/1,
+                        fun application:start/1,
+                        not_started,
+                        cannot_stop_application,
+                        Apps).
+
+app_dependency_order(RootApps, StripUnreachable) ->
+    {ok, G} = rabbit_misc:build_acyclic_graph(
+                fun (App, _Deps) -> [{App, App}] end,
+                fun (App,  Deps) -> [{Dep, App} || Dep <- Deps] end,
+                [{App, app_dependencies(App)} ||
+                    {App, _Desc, _Vsn} <- application:loaded_applications()]),
+    try
+        case StripUnreachable of
+            true -> digraph:del_vertices(G, digraph:vertices(G) --
+                     digraph_utils:reachable(RootApps, G));
+            false -> ok
+        end,
+        digraph_utils:topsort(G)
+    after
+        true = digraph:delete(G)
+    end.
+
+%%---------------------------------------------------------------------------
+%% Private API
+
+load_applications(Worklist, Loaded) ->
+    case queue:out(Worklist) of
+        {empty, _WorkList} ->
+            ok;
+        {{value, App}, Worklist1} ->
+            case sets:is_element(App, Loaded) of
+                true  -> load_applications(Worklist1, Loaded);
+                false -> case application:load(App) of
+                             ok                             -> ok;
+                             {error, {already_loaded, App}} -> ok;
+                             Error                          -> throw(Error)
+                         end,
+                         load_applications(
+                           queue:join(Worklist1,
+                                      queue:from_list(app_dependencies(App))),
+                           sets:add_element(App, Loaded))
+            end
+    end.
+
+app_dependencies(App) ->
+    case application:get_key(App, applications) of
+        undefined -> [];
+        {ok, Lst} -> Lst
+    end.
+
+manage_applications(Iterate, Do, Undo, SkipError, ErrorTag, Apps) ->
+    Iterate(fun (App, Acc) ->
+                    case Do(App) of
+                        ok -> [App | Acc];
+                        {error, {SkipError, _}} -> Acc;
+                        {error, Reason} ->
+                            lists:foreach(Undo, Acc),
+                            throw({error, {ErrorTag, App, Reason}})
+                    end
+            end, [], Apps),
+    ok.
+
diff --git a/src/rabbit.erl b/src/rabbit.erl
index b7e640ffb2..ee0f82a12e 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -298,7 +298,7 @@ prepare() ->
 start() ->
     start_it(fun() ->
                 ok = prepare(),
-                ok = rabbit_misc:start_applications(app_startup_order()),
+                ok = app_utils:start_applications(app_startup_order()),
                 ok = print_plugin_info(rabbit_plugins:active_plugins())
              end).
 
@@ -310,10 +310,10 @@ boot() ->
 
                 io:format("~nActivating RabbitMQ plugins ...~n"),
 
-                ok = rabbit_misc:load_applications(ToBeLoaded),
+                ok = app_utils:load_applications(ToBeLoaded),
                 StartupApps = 
-                    rabbit_misc:calculate_app_dependency_ordering(ToBeLoaded),
-                ok = rabbit_misc:start_applications(StartupApps),
+                    app_utils:app_dependency_order(ToBeLoaded, false),
+                ok = app_utils:start_applications(StartupApps),
                 
                 ok = print_plugin_info(Plugins)
              end).
@@ -328,7 +328,7 @@ start_it(StartFun) ->
 
 stop() ->
     rabbit_log:info("Stopping Rabbit~n"),
-    ok = rabbit_misc:stop_applications(app_shutdown_order()).
+    ok = app_utils:stop_applications(app_shutdown_order()).
 
 stop_and_halt() ->
     try
@@ -416,12 +416,12 @@ stop(_State) ->
 %% application life cycle
 
 app_startup_order() ->
-    ok = rabbit_misc:load_applications(?APPS),
-    rabbit_misc:calculate_app_dependency_ordering(?APPS).
+    ok = app_utils:load_applications(?APPS),
+    app_utils:app_dependency_order(?APPS, false).
 
 app_shutdown_order() ->
     Apps = ?APPS ++ rabbit_plugins:active_plugins(),
-    rabbit_misc:calculate_app_dependency_ordering(Apps, true).
+    app_utils:app_dependency_order(Apps, true).
 
 %%---------------------------------------------------------------------------
 %% boot step logic
diff --git a/src/rabbit_misc.erl b/src/rabbit_misc.erl
index 6371c24c12..955d769cbb 100644
--- a/src/rabbit_misc.erl
+++ b/src/rabbit_misc.erl
@@ -42,9 +42,6 @@
 -export([dirty_read_all/1, dirty_foreach_key/2, dirty_dump_log/1]).
 -export([format/2, format_many/1, format_stderr/2]).
 -export([with_local_io/1, local_info_msg/2]).
--export([calculate_app_dependency_ordering/1,
-         calculate_app_dependency_ordering/2]).
--export([load_applications/1, start_applications/1, stop_applications/1]).
 -export([unfold/2, ceil/1, queue_fold/3]).
 -export([sort_field_table/1]).
 -export([pid_to_string/1, string_to_pid/1]).
@@ -170,12 +167,6 @@
 -spec(format_stderr/2 :: (string(), [any()]) -> 'ok').
 -spec(with_local_io/1 :: (fun (() -> A)) -> A).
 -spec(local_info_msg/2 :: (string(), [any()]) -> 'ok').
--spec(start_applications/1 :: ([atom()]) -> 'ok').
--spec(load_applications/1 :: ([atom()]) -> 'ok').
--spec(calculate_app_dependency_ordering/1 :: ([atom()]) -> [digraph:vertex()]).
--spec(calculate_app_dependency_ordering/2 :: ([atom()], 
-                                              boolean()) -> [digraph:vertex()]).
--spec(stop_applications/1 :: ([atom()]) -> 'ok').
 -spec(unfold/2  :: (fun ((A) -> ({'true', B, A} | 'false')), A) -> {[B], A}).
 -spec(ceil/1 :: (number()) -> integer()).
 -spec(queue_fold/3 :: (fun ((any(), B) -> B), B, queue()) -> B).
@@ -615,83 +606,6 @@ with_local_io(Fun) ->
 local_info_msg(Format, Args) ->
     with_local_io(fun () -> error_logger:info_msg(Format, Args) end).
 
-manage_applications(Iterate, Do, Undo, SkipError, ErrorTag, Apps) ->
-    Iterate(fun (App, Acc) ->
-                    case Do(App) of
-                        ok -> [App | Acc];
-                        {error, {SkipError, _}} -> Acc;
-                        {error, Reason} ->
-                            lists:foreach(Undo, Acc),
-                            throw({error, {ErrorTag, App, Reason}})
-                    end
-            end, [], Apps),
-    ok.
-
-load_applications(Apps) ->
-    load_applications(queue:from_list(Apps), sets:new()),
-    ok.
-
-load_applications(Worklist, Loaded) ->
-    case queue:out(Worklist) of
-        {empty, _WorkList} ->
-            ok;
-        {{value, App}, Worklist1} ->
-            case sets:is_element(App, Loaded) of
-                true  -> load_applications(Worklist1, Loaded);
-                false -> case application:load(App) of
-                             ok                             -> ok;
-                             {error, {already_loaded, App}} -> ok;
-                             Error                          -> throw(Error)
-                         end,
-                         load_applications(
-                           queue:join(Worklist1,
-                                      queue:from_list(app_dependencies(App))),
-                           sets:add_element(App, Loaded))
-            end
-    end.
-
-app_dependencies(App) ->
-    case application:get_key(App, applications) of
-        undefined -> [];
-        {ok, Lst} -> Lst
-    end.
-
-start_applications(Apps) ->
-    manage_applications(fun lists:foldl/3,
-                        fun application:start/1,
-                        fun application:stop/1,
-                        already_started,
-                        cannot_start_application,
-                        Apps).
-
-stop_applications(Apps) ->
-    manage_applications(fun lists:foldr/3,
-                        fun application:stop/1,
-                        fun application:start/1,
-                        not_started,
-                        cannot_stop_application,
-                        Apps).
-
-calculate_app_dependency_ordering(RootApps) ->
-    calculate_app_dependency_ordering(RootApps, false).
-
-calculate_app_dependency_ordering(RootApps, StripUnreachable) ->
-    {ok, G} = build_acyclic_graph(
-                fun (App, _Deps) -> [{App, App}] end,
-                fun (App,  Deps) -> [{Dep, App} || Dep <- Deps] end,
-                [{App, app_dependencies(App)} ||
-                    {App, _Desc, _Vsn} <- application:loaded_applications()]),
-    try
-        case StripUnreachable of
-            true -> digraph:del_vertices(G, digraph:vertices(G) -- 
-                     digraph_utils:reachable(RootApps, G));
-            false -> ok
-        end,
-        digraph_utils:topsort(G)
-    after
-        true = digraph:delete(G)
-    end.
-
 unfold(Fun, Init) ->
     unfold(Fun, [], Init).
 
diff --git a/src/rabbit_networking.erl b/src/rabbit_networking.erl
index f0c75d23f4..4562608a45 100644
--- a/src/rabbit_networking.erl
+++ b/src/rabbit_networking.erl
@@ -147,7 +147,7 @@ start() ->
     ok.
 
 ensure_ssl() ->
-    ok = rabbit_misc:start_applications([crypto, public_key, ssl]),
+    ok = app_utils:start_applications([crypto, public_key, ssl]),
     {ok, SslOptsConfig} = application:get_env(rabbit, ssl_options),
 
     % unknown_ca errors are silently ignored prior to R14B unless we