refactor(persistent_sessions): don't start session sup when disabled

apps/emqx/src/emqx_persistent_session_sup.erl

@@ -26,10 +26,6 @@ start_link() ->
     supervisor:start_link({local, ?MODULE}, ?MODULE, []).
 
 init([]) ->
-    case emqx_persistent_session:is_store_enabled() of
-        false ->
-            {ok, {{one_for_all, 0, 1}, []}};
-        true ->
     %% We want this supervisor to own the table for restarts
     SessionTab = emqx_session_router:create_init_tab(),
 
@@ -47,8 +43,12 @@ init([]) ->
 
     GCWorker = child_spec(emqx_persistent_session_gc, worker),
 
-            {ok, {{one_for_all, 0, 1}, [ResumeSup, SessionRouterPool, GCWorker]}}
-    end.
+    Spec = #{ strategy  => one_for_all
+            , intensity => 0
+            , period    => 1
+            },
+
+    {ok, {Spec, [ResumeSup, SessionRouterPool, GCWorker]}}.
 
 child_spec(Mod, worker) ->
     #{id => Mod,

apps/emqx/src/emqx_sup.erl

@@ -68,7 +68,8 @@ init([]) ->
     SessionSup = child_spec(emqx_persistent_session_sup, supervisor),
     CMSup = child_spec(emqx_cm_sup, supervisor),
     SysSup = child_spec(emqx_sys_sup, supervisor),
-    Children = [KernelSup, SessionSup] ++
+    Children = [KernelSup] ++
+               [SessionSup || emqx_persistent_session:is_store_enabled()] ++
                [RouterSup || emqx_boot:is_enabled(router)] ++
                [BrokerSup || emqx_boot:is_enabled(broker)] ++
                [CMSup || emqx_boot:is_enabled(broker)] ++