fix: avoid emqx starting crash if bootstrap_file is not existed

apps/emqx_management/src/emqx_mgmt_app.erl

@@ -28,13 +28,9 @@
 -include("emqx_mgmt.hrl").
 
 start(_Type, _Args) ->
-    case emqx_mgmt_auth:init_bootstrap_file() of
+    _ = emqx_mgmt_auth:init_bootstrap_file(),
-        ok ->
+    emqx_conf:add_handler([api_key], emqx_mgmt_auth),
-            emqx_conf:add_handler([api_key], emqx_mgmt_auth),
+    emqx_mgmt_sup:start_link().
-            emqx_mgmt_sup:start_link();
-        {error, Reason} ->
-            {error, Reason}
-    end.
 
 stop(_State) ->
     emqx_conf:remove_handler([api_key]),

apps/emqx_management/test/emqx_mgmt_api_api_keys_SUITE.erl

@@ -52,7 +52,12 @@ groups() ->
     [
         {parallel, [parallel], [t_create, t_update, t_delete, t_authorize, t_create_unexpired_app]},
         {parallel, [parallel], ?EE_CASES},
-        {sequence, [], [t_bootstrap_file, t_bootstrap_file_with_role, t_create_failed]}
+        {sequence, [], [
+            t_application_start_with_non_exist_file,
+            t_bootstrap_file,
+            t_bootstrap_file_with_role,
+            t_create_failed
+        ]}
     ].
 
 init_per_suite(Config) ->
@@ -62,6 +67,18 @@ init_per_suite(Config) ->
 end_per_suite(_) ->
     emqx_mgmt_api_test_util:end_suite([emqx_conf, emqx_management]).
 
+t_application_start_with_non_exist_file(_) ->
+    application:stop(emqx_management),
+
+    Original = emqx_config:get_raw([api_key, bootstrap_file]),
+    update_file(<<"non-exist-file">>),
+
+    %% assert: start the application succeed with a non-exist bootstrap_file
+    ok = application:start(emqx_management),
+
+    update_file(Original),
+    ok.
+
 t_bootstrap_file(_) ->
     TestPath = <<"/api/v5/status">>,
     Bin = <<"test-1:secret-1\ntest-2:secret-2">>,