start and start_cold both defer to rabbit_misc to calculate application load order

3 files changed, 43 insertions, 22 deletions

diff --git a/src/rabbit.erl b/src/rabbit.erl
index 7f2845b60f..13afdc682e 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -305,9 +305,21 @@ start_cold() ->
     start_it(fun() ->
                 ok = prepare(),
                 Plugins = determine_required_plugins(),
-                ToBeLoaded = ?APPS ++ Plugins,
-                StartupApps = application_load_order(ToBeLoaded, ToBeLoaded),
-                ok = rabbit_misc:start_applications(StartupApps)
+                ToBeLoaded = Plugins ++ ?APPS,
+
+                io:format("~n"
+                          "Activating RabbitMQ plugins ...~n"),
+
+                load_applications(queue:from_list(ToBeLoaded), sets:new()),
+                StartupApps = 
+                    rabbit_misc:calculate_app_dependency_ordering(ToBeLoaded),
+                ok = rabbit_misc:start_applications(StartupApps),
+
+                io:format("~w plugins activated:~n", [length(Plugins)]),
+                [io:format("* ~s-~s~n", [AppName, 
+                        element(2, application:get_key(AppName, vsn))])
+                    || AppName <- Plugins],
+                io:nl()
              end).
 
 start_it(StartFun) ->
@@ -408,20 +420,7 @@ stop(_State) ->
 
 application_load_order() ->
     ok = load_applications(),
-    LoadedApps = application:loaded_applications(),
-    application_load_order(LoadedApps, ?APPS).
-
-application_load_order(LoadedApps, RootApps) ->
-    {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 <- LoadedApps]),
-    true = digraph:del_vertices(
-             G, digraph:vertices(G) --
-                    digraph_utils:reachable(RootApps, G)),
-    Result = digraph_utils:topsort(G),
-    true = digraph:delete(G),
-    Result.
+    rabbit_misc:calculate_app_dependency_ordering(?APPS).
 
 load_applications() ->
     load_applications(queue:from_list(?APPS), sets:new()).
diff --git a/src/rabbit_misc.erl b/src/rabbit_misc.erl
index 28c61a2e50..2fffc2cdab 100644
--- a/src/rabbit_misc.erl
+++ b/src/rabbit_misc.erl
@@ -42,7 +42,8 @@
 -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([start_applications/1, stop_applications/1]).
+-export([calculate_app_dependency_ordering/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]).
@@ -169,6 +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(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}).
 -spec(ceil/1 :: (number()) -> integer()).
@@ -637,6 +639,26 @@ stop_applications(Apps) ->
                         cannot_stop_application,
                         Apps).
 
+calculate_app_dependency_ordering(RootApps) ->
+    {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
+        true = digraph:del_vertices(G, digraph:vertices(G) -- 
+                                        digraph_utils:reachable(RootApps, G)),
+        digraph_utils:topsort(G)
+    after
+        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).
 
diff --git a/src/rabbit_plugins.erl b/src/rabbit_plugins.erl
index 3ce0d3b173..0a5f8d5197 100644
--- a/src/rabbit_plugins.erl
+++ b/src/rabbit_plugins.erl
@@ -84,12 +84,12 @@ stop() ->
     ok.
 
 prepare_plugins(EnabledPluginsFile, PluginsDistDir, DestDir) ->
-    AllPlugins = rabbit_plugins:find_plugins(PluginsDistDir),
-    Enabled = rabbit_plugins:read_enabled_plugins(EnabledPluginsFile),
-    ToUnpack = rabbit_plugins:calculate_required_plugins(Enabled, AllPlugins),
+    AllPlugins = find_plugins(PluginsDistDir),
+    Enabled = read_enabled_plugins(EnabledPluginsFile),
+    ToUnpack = calculate_required_plugins(Enabled, AllPlugins),
     ToUnpackPlugins = lookup_plugins(ToUnpack, AllPlugins),
 
-    Missing = Enabled -- rabbit_plugins:plugin_names(ToUnpackPlugins),
+    Missing = Enabled -- plugin_names(ToUnpackPlugins),
     case Missing of
         [] -> ok;
         _  -> io:format("Warning: the following enabled plugins were "