fix(sso): Improved SSO user deletion command

apps/emqx_dashboard/include/emqx_dashboard.hrl

@@ -24,6 +24,7 @@
 -define(ROLE_SUPERUSER, <<"administrator">>).
 -define(ROLE_DEFAULT, ?ROLE_SUPERUSER).
 
+-define(BACKEND_LOCAL, local).
 -define(SSO_USERNAME(Backend, Name), {Backend, Name}).
 
 -type dashboard_sso_backend() :: atom().

apps/emqx_dashboard/src/emqx_dashboard_admin.erl

@@ -427,7 +427,7 @@ flatten_username(#{username := ?SSO_USERNAME(Backend, Name)} = Data) ->
         backend => Backend
     };
 flatten_username(#{username := Username} = Data) when is_binary(Username) ->
-    Data#{backend => local}.
+    Data#{backend => ?BACKEND_LOCAL}.
 
 -spec add_sso_user(dashboard_sso_backend(), binary(), dashboard_user_role(), binary()) ->
     {ok, map()} | {error, any()}.

apps/emqx_dashboard/src/emqx_dashboard_api.erl

@@ -379,7 +379,7 @@ sso_parameters() ->
 sso_parameters(Params) ->
     emqx_dashboard_sso_api:sso_parameters(Params).
 
-username(#{query_string := #{<<"backend">> := local}}, Username) ->
+username(#{query_string := #{<<"backend">> := ?BACKEND_LOCAL}}, Username) ->
     Username;
 username(#{query_string := #{<<"backend">> := Backend}}, Username) ->
     ?SSO_USERNAME(Backend, Username);

apps/emqx_dashboard/src/emqx_dashboard_token.erl

@@ -191,7 +191,7 @@ token_ttl() ->
 format(Token, ?SSO_USERNAME(Backend, Name), Role, ExpTime) ->
     format(Token, Backend, Name, Role, ExpTime);
 format(Token, Username, Role, ExpTime) ->
-    format(Token, local, Username, Role, ExpTime).
+    format(Token, ?BACKEND_LOCAL, Username, Role, ExpTime).
 
 format(Token, Backend, Username, Role, ExpTime) ->
     #?ADMIN_JWT{

apps/emqx_dashboard_sso/src/emqx_dashboard_sso_cli.erl

@@ -34,16 +34,13 @@ admins(["passwd", Username, Password]) ->
             print_error(Reason)
     end;
 admins(["del", Username]) ->
-    case emqx_dashboard_admin:remove_user(bin(Username)) of
+    delete_user(bin(Username));
-        {ok, _} ->
+admins(["del", Username, BackendName]) ->
-            emqx_ctl:print("ok~n");
+    case atom(BackendName) of
-        {error, Reason} ->
+        {ok, ?BACKEND_LOCAL} ->
-            print_error(Reason)
+            delete_user(bin(Username));
-    end;
+        {ok, Backend} ->
-admins(["del", Username, Backend]) ->
+            delete_user(?SSO_USERNAME(Backend, bin(Username)));
-    case emqx_dashboard_admin:remove_user(?SSO_USERNAME(atom(Backend), bin(Username))) of
-        {ok, _} ->
-            emqx_ctl:print("ok~n");
         {error, Reason} ->
             print_error(Reason)
     end;
@@ -52,9 +49,18 @@ admins(_) ->
         [
             {"admins add <Username> <Password> <Description> <Role>", "Add dashboard user"},
             {"admins passwd <Username> <Password>", "Reset dashboard user password"},
-            {"admins del <Username> <Backend>", "Delete dashboard user"}
+            {"admins del <Username> <Backend>",
+                "Delete dashboard user, <Backend> can be omitted, the default value is 'local'"}
         ]
     ).
 
 atom(S) ->
-    erlang:list_to_atom(S).
+    emqx_utils:safe_to_existing_atom(S).
+
+delete_user(Username) ->
+    case emqx_dashboard_admin:remove_user(Username) of
+        {ok, _} ->
+            emqx_ctl:print("ok~n");
+        {error, Reason} ->
+            print_error(Reason)
+    end.