move application lifecycle (loading) into one place - rabbit_misc

2 files changed, 34 insertions, 41 deletions

diff --git a/src/rabbit.erl b/src/rabbit.erl
index 87526aaede..588cc39013 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -308,11 +308,9 @@ start_cold() ->
                 Plugins = rabbit_plugins:bootstrap_envinronment(),
                 ToBeLoaded = Plugins ++ ?APPS,
 
-                io:format("~n"
-                          "Activating RabbitMQ plugins ...~n"),
-                io:format("Plugins: ~p~n", [Plugins]),
+                io:format("~nActivating RabbitMQ plugins ...~n"),
 
-                load_applications(queue:from_list(ToBeLoaded), sets:new()),
+                ok = rabbit_misc:load_applications(ToBeLoaded),
                 StartupApps = 
                     rabbit_misc:calculate_app_dependency_ordering(ToBeLoaded),
                 ok = rabbit_misc:start_applications(StartupApps),
@@ -417,38 +415,9 @@ stop(_State) ->
 %% application life cycle
 
 application_load_order() ->
-    ok = load_applications(),
+    ok = rabbit_misc:load_applications(?APPS),
     rabbit_misc:calculate_app_dependency_ordering(?APPS).
 
-load_applications() ->
-    load_applications(queue:from_list(?APPS), sets:new()).
-
-%% FIXME: should we move this into rabbit_misc?
-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.
-
 %%---------------------------------------------------------------------------
 %% boot step logic
 
diff --git a/src/rabbit_misc.erl b/src/rabbit_misc.erl
index 2fffc2cdab..87865ebc31 100644
--- a/src/rabbit_misc.erl
+++ b/src/rabbit_misc.erl
@@ -42,7 +42,7 @@
 -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, 
+-export([calculate_app_dependency_ordering/1, load_applications/1,
          start_applications/1, stop_applications/1]).
 -export([unfold/2, ceil/1, queue_fold/3]).
 -export([sort_field_table/1]).
@@ -170,6 +170,7 @@
 -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()]) -> 'ok').
 -spec(stop_applications/1 :: ([atom()]) -> 'ok').
 -spec(unfold/2  :: (fun ((A) -> ({'true', B, A} | 'false')), A) -> {[B], A}).
@@ -623,6 +624,35 @@ manage_applications(Iterate, Do, Undo, SkipError, ErrorTag, Apps) ->
             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,
@@ -653,12 +683,6 @@ calculate_app_dependency_ordering(RootApps) ->
         true = digraph:delete(G)
     end.
 
-app_dependencies(App) ->
-    case application:get_key(App, applications) of
-        undefined -> [];
-        {ok, Lst} -> Lst
-    end.
-
 unfold(Fun, Init) ->
     unfold(Fun, [], Init).