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%% 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, start_applications/2,
stop_applications/1, stop_applications/2, app_dependency_order/2,
wait_for_applications/1]).
-ifdef(use_specs).
-type error_handler() :: fun((atom(), any()) -> 'ok').
-spec load_applications([atom()]) -> 'ok'.
-spec start_applications([atom()]) -> 'ok'.
-spec stop_applications([atom()]) -> 'ok'.
-spec start_applications([atom()], error_handler()) -> 'ok'.
-spec stop_applications([atom()], error_handler()) -> 'ok'.
-spec wait_for_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) ->
start_applications(
Apps, fun (App, Reason) ->
throw({error, {cannot_start_application, App, Reason}})
end).
stop_applications(Apps) ->
stop_applications(
Apps, fun (App, Reason) ->
throw({error, {cannot_stop_application, App, Reason}})
end).
start_applications(Apps, ErrorHandler) ->
manage_applications(fun lists:foldl/3,
fun application:start/1,
fun application:stop/1,
already_started,
ErrorHandler,
Apps).
stop_applications(Apps, ErrorHandler) ->
manage_applications(fun lists:foldr/3,
fun application:stop/1,
fun application:start/1,
not_started,
ErrorHandler,
Apps).
wait_for_applications(Apps) ->
[wait_for_application(App) || App <- Apps], ok.
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
wait_for_application(Application) ->
case lists:keymember(Application, 1, application:which_applications()) of
true -> ok;
false -> timer:sleep(1000),
wait_for_application(Application)
end.
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, ErrorHandler, Apps) ->
Iterate(fun (App, Acc) ->
case Do(App) of
ok -> [App | Acc];
{error, {SkipError, _}} -> Acc;
{error, Reason} ->
lists:foreach(Undo, Acc),
ErrorHandler(App, Reason)
end
end, [], Apps),
ok.
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