From a2465519148f165b12b35e0bdc03ac1236da5fdc Mon Sep 17 00:00:00 2001
From: JimMoen <LnJimMoen@outlook.com>
Date: Wed, 31 Jul 2024 16:15:51 +0800
Subject: [PATCH 1/2] fix: add a startup timeout limit for the plugin
 application

---
 apps/emqx_plugins/src/emqx_plugins.erl | 34 ++++++++++++++++++++------
 changes/ce/fix-13552.en.md             |  8 ++++++
 2 files changed, 35 insertions(+), 7 deletions(-)
 create mode 100644 changes/ce/fix-13552.en.md

diff --git a/apps/emqx_plugins/src/emqx_plugins.erl b/apps/emqx_plugins/src/emqx_plugins.erl
index 253d1b4ef..b13a28e2d 100644
--- a/apps/emqx_plugins/src/emqx_plugins.erl
+++ b/apps/emqx_plugins/src/emqx_plugins.erl
@@ -992,19 +992,22 @@ do_load_plugin_app(AppName, Ebin) ->
     end.
 
 start_app(App) ->
-    case application:ensure_all_started(App) of
-        {ok, Started} ->
+    case run_with_timeout(application, ensure_all_started, [App], 10_000) of
+        {ok, {ok, Started}} ->
             case Started =/= [] of
                 true -> ?SLOG(debug, #{msg => "started_plugin_apps", apps => Started});
                 false -> ok
-            end,
-            ?SLOG(debug, #{msg => "started_plugin_app", app => App}),
-            ok;
-        {error, {ErrApp, Reason}} ->
+            end;
+        {ok, {error, Reason}} ->
+            throw(#{
+                msg => "failed_to_start_app",
+                app => App,
+                reason => Reason
+            });
+        {error, Reason} ->
             throw(#{
                 msg => "failed_to_start_plugin_app",
                 app => App,
-                err_app => ErrApp,
                 reason => Reason
             })
     end.
@@ -1525,3 +1528,20 @@ bin(B) when is_binary(B) -> B.
 
 wrap_to_list(Path) ->
     binary_to_list(iolist_to_binary(Path)).
+
+run_with_timeout(Module, Function, Args, Timeout) ->
+    Self = self(),
+    Fun = fun() ->
+        Result = apply(Module, Function, Args),
+        Self ! {self(), Result}
+    end,
+    Pid = spawn(Fun),
+    TimerRef = erlang:send_after(Timeout, self(), {timeout, Pid}),
+    receive
+        {Pid, Result} ->
+            erlang:cancel_timer(TimerRef),
+            {ok, Result};
+        {timeout, Pid} ->
+            exit(Pid, kill),
+            {error, timeout}
+    end.
diff --git a/changes/ce/fix-13552.en.md b/changes/ce/fix-13552.en.md
new file mode 100644
index 000000000..5af1b4140
--- /dev/null
+++ b/changes/ce/fix-13552.en.md
@@ -0,0 +1,8 @@
+Add a startup timeout limit for the plug-in application. Currently the timeout is 10 seconds.
+
+Starting a bad plugin while EMQX is running will result in a thrown runtime error.
+When EMQX is closed and restarted, the main starting process may hang due to the the plugin application to start failures.
+
+Maybe restarting with modified:
+- Modifed config file: make the bad plugin enabled.
+- Add a plugin with bad plugin config.

From c658cfe26997a8026606b2ef85221f9255d2dd6d Mon Sep 17 00:00:00 2001
From: JimMoen <LnJimMoen@outlook.com>
Date: Wed, 31 Jul 2024 17:17:13 +0800
Subject: [PATCH 2/2] fix: make static_check happy

---
 apps/emqx_plugins/src/emqx_plugins.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/apps/emqx_plugins/src/emqx_plugins.erl b/apps/emqx_plugins/src/emqx_plugins.erl
index b13a28e2d..005df026b 100644
--- a/apps/emqx_plugins/src/emqx_plugins.erl
+++ b/apps/emqx_plugins/src/emqx_plugins.erl
@@ -1539,7 +1539,7 @@ run_with_timeout(Module, Function, Args, Timeout) ->
     TimerRef = erlang:send_after(Timeout, self(), {timeout, Pid}),
     receive
         {Pid, Result} ->
-            erlang:cancel_timer(TimerRef),
+            _ = erlang:cancel_timer(TimerRef),
             {ok, Result};
         {timeout, Pid} ->
             exit(Pid, kill),