fix(connector_psql): Wrap password in a fun

apps/emqx/src/emqx_secret.erl

@@ -0,0 +1,37 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2022 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+%% Note: this module CAN'T be hot-patched to avoid invalidating the
+%% closures, so it must not be changed.
+-module(emqx_secret).
+
+%% API:
+-export([wrap/1, unwrap/1]).
+
+%%================================================================================
+%% API funcions
+%%================================================================================
+
+wrap(Term) ->
+    fun() ->
+        Term
+    end.
+
+unwrap(Term) when is_function(Term, 0) ->
+    %% Handle potentially nested funs
+    unwrap(Term());
+unwrap(Term) ->
+    Term.

apps/emqx_connector/src/emqx_connector_pgsql.erl

@@ -97,7 +97,7 @@ on_start(
         {host, Host},
         {port, Port},
         {username, User},
-        {password, Password},
+        {password, emqx_secret:wrap(Password)},
         {database, DB},
         {auto_reconnect, reconn_interval(AutoReconn)},
         {pool_size, PoolSize},
@@ -158,7 +158,7 @@ reconn_interval(false) -> false.
 connect(Opts) ->
     Host = proplists:get_value(host, Opts),
     Username = proplists:get_value(username, Opts),
-    Password = proplists:get_value(password, Opts),
+    Password = emqx_secret:unwrap(proplists:get_value(password, Opts)),
     PrepareStatement = proplists:get_value(prepare_statement, Opts),
     case epgsql:connect(Host, Username, Password, conn_opts(Opts)) of
         {ok, Conn} ->