feat(tpl): unify validations / errors var representations

apps/emqx_auth/src/emqx_authz/emqx_authz_rule.erl

@@ -184,7 +184,7 @@ compile_topic({eq, Topic}) ->
     {eq, emqx_topic:words(bin(Topic))};
 compile_topic(Topic) ->
     Template = emqx_connector_template:parse(Topic),
-    ok = emqx_connector_template:validate([<<?VAR_USERNAME>>, <<?VAR_CLIENTID>>], Template),
+    ok = emqx_connector_template:validate([?VAR_USERNAME, ?VAR_CLIENTID], Template),
     case emqx_connector_template:trivial(Template) of
         true -> emqx_topic:words(bin(Topic));
         false -> {pattern, Template}

apps/emqx_auth/test/emqx_authz/emqx_authz_rule_SUITE.erl

@@ -78,13 +78,13 @@ t_compile(_) ->
         emqx_authz_rule:compile({allow, {ipaddr, "127.0.0.1"}, all, [{eq, "#"}, {eq, "+"}]})
     ),
 
-    ?assertEqual(
+    ?assertMatch(
         {allow,
             {ipaddrs, [
                 {{127, 0, 0, 1}, {127, 0, 0, 1}, 32},
                 {{192, 168, 1, 0}, {192, 168, 1, 255}, 24}
             ]},
-            subscribe, [{pattern, [{var, [<<"clientid">>]}]}]},
+            subscribe, [{pattern, [{var, "clientid", [_]}]}]},
         emqx_authz_rule:compile(
             {allow, {ipaddrs, ["127.0.0.1", "192.168.1.0/24"]}, subscribe, [?PH_S_CLIENTID]}
         )
@@ -106,7 +106,7 @@ t_compile(_) ->
                 {clientid, {re_pattern, _, _, _, _}}
             ]},
             publish, [
-                {pattern, [{var, [<<"username">>]}]}, {pattern, [{var, [<<"clientid">>]}]}
+                {pattern, [{var, "username", [_]}]}, {pattern, [{var, "clientid", [_]}]}
             ]},
         emqx_authz_rule:compile(
             {allow,
@@ -118,9 +118,9 @@ t_compile(_) ->
         )
     ),
 
-    ?assertEqual(
+    ?assertMatch(
         {allow, {username, {eq, <<"test">>}}, publish, [
-            {pattern, [<<"t/foo">>, {var, [<<"username">>]}, <<"boo">>]}
+            {pattern, [<<"t/foo">>, {var, "username", [_]}, <<"boo">>]}
         ]},
         emqx_authz_rule:compile({allow, {username, "test"}, publish, ["t/foo${username}boo"]})
     ),

apps/emqx_auth_http/src/emqx_authz_http.erl

@@ -39,15 +39,15 @@
 -endif.
 
 -define(PLACEHOLDERS, [
-    <<?VAR_USERNAME>>,
+    ?VAR_USERNAME,
-    <<?VAR_CLIENTID>>,
+    ?VAR_CLIENTID,
-    <<?VAR_PEERHOST>>,
+    ?VAR_PEERHOST,
-    <<?VAR_PROTONAME>>,
+    ?VAR_PROTONAME,
-    <<?VAR_MOUNTPOINT>>,
+    ?VAR_MOUNTPOINT,
-    <<?VAR_TOPIC>>,
+    ?VAR_TOPIC,
-    <<?VAR_ACTION>>,
+    ?VAR_ACTION,
-    <<?VAR_CERT_SUBJECT>>,
+    ?VAR_CERT_SUBJECT,
-    <<?VAR_CERT_CN_NAME>>
+    ?VAR_CERT_CN_NAME
 ]).
 
 -define(PLACEHOLDERS_FOR_RICH_ACTIONS, [

apps/emqx_auth_mongodb/src/emqx_authz_mongodb.erl

@@ -36,11 +36,11 @@
 -endif.
 
 -define(PLACEHOLDERS, [
-    <<?VAR_USERNAME>>,
+    ?VAR_USERNAME,
-    <<?VAR_CLIENTID>>,
+    ?VAR_CLIENTID,
-    <<?VAR_PEERHOST>>,
+    ?VAR_PEERHOST,
-    <<?VAR_CERT_CN_NAME>>,
+    ?VAR_CERT_CN_NAME,
-    <<?VAR_CERT_SUBJECT>>
+    ?VAR_CERT_SUBJECT
 ]).
 
 description() ->

apps/emqx_auth_mysql/src/emqx_authz_mysql.erl

@@ -38,11 +38,11 @@
 -endif.
 
 -define(PLACEHOLDERS, [
-    <<?VAR_USERNAME>>,
+    ?VAR_USERNAME,
-    <<?VAR_CLIENTID>>,
+    ?VAR_CLIENTID,
-    <<?VAR_PEERHOST>>,
+    ?VAR_PEERHOST,
-    <<?VAR_CERT_CN_NAME>>,
+    ?VAR_CERT_CN_NAME,
-    <<?VAR_CERT_SUBJECT>>
+    ?VAR_CERT_SUBJECT
 ]).
 
 description() ->

apps/emqx_auth_postgresql/src/emqx_authz_postgresql.erl

@@ -38,11 +38,11 @@
 -endif.
 
 -define(PLACEHOLDERS, [
-    <<?VAR_USERNAME>>,
+    ?VAR_USERNAME,
-    <<?VAR_CLIENTID>>,
+    ?VAR_CLIENTID,
-    <<?VAR_PEERHOST>>,
+    ?VAR_PEERHOST,
-    <<?VAR_CERT_CN_NAME>>,
+    ?VAR_CERT_CN_NAME,
-    <<?VAR_CERT_SUBJECT>>
+    ?VAR_CERT_SUBJECT
 ]).
 
 description() ->

apps/emqx_auth_redis/src/emqx_authz_redis.erl

@@ -36,11 +36,11 @@
 -endif.
 
 -define(PLACEHOLDERS, [
-    <<?VAR_CERT_CN_NAME>>,
+    ?VAR_CERT_CN_NAME,
-    <<?VAR_CERT_SUBJECT>>,
+    ?VAR_CERT_SUBJECT,
-    <<?VAR_PEERHOST>>,
+    ?VAR_PEERHOST,
-    <<?VAR_CLIENTID>>,
+    ?VAR_CLIENTID,
-    <<?VAR_USERNAME>>
+    ?VAR_USERNAME
 ]).
 
 description() ->

apps/emqx_connector/src/emqx_connector_template.erl

@@ -37,6 +37,7 @@
 -export_type([str/0]).
 -export_type([deep/0]).
 -export_type([placeholder/0]).
+-export_type([varname/0]).
 -export_type([bindings/0]).
 
 -type t() :: str() | {'$tpl', deeptpl()}.
@@ -55,8 +56,9 @@
     | port()
     | reference().
 
--type placeholder() :: {var, var()}.
+-type placeholder() :: {var, varname(), accessor()}.
--type var() :: _Name :: [binary()].
+-type accessor() :: [binary()].
+-type varname() :: string().
 
 -type scalar() :: atom() | unicode:chardata() | number().
 -type binding() :: scalar() | list(scalar()) | bindings().
@@ -64,7 +66,7 @@
 
 -type var_trans() ::
     fun((Value :: term()) -> unicode:chardata())
-    | fun((var(), Value :: term()) -> unicode:chardata()).
+    | fun((varname(), Value :: term()) -> unicode:chardata()).
 
 -type parse_opts() :: #{
     strip_double_quote => boolean()
@@ -103,7 +105,7 @@ parse(String, Opts) ->
 
 parse_split([Part, _PH, <<>>, Var]) ->
     % Regular placeholder
-    prepend(Part, [{var, parse_var(Var)}]);
+    prepend(Part, [{var, unicode:characters_to_list(Var), parse_accessor(Var)}]);
 parse_split([Part, _PH = <<B1, $$, Rest/binary>>, <<"$">>, _]) ->
     % Escaped literal, take all but the second byte, which is always `$`.
     % Important to make a whole token starting with `$` so the `unparse/11`
@@ -117,7 +119,7 @@ prepend(<<>>, To) ->
 prepend(Head, To) ->
     [Head | To].
 
-parse_var(Var) ->
+parse_accessor(Var) ->
     case string:split(Var, <<".">>, all) of
         [<<>>] ->
             ?PH_VAR_THIS;
@@ -126,10 +128,9 @@ parse_var(Var) ->
             Name
     end.
 
--spec validate([var() | binary()], t()) ->
+-spec validate([varname()], t()) ->
-    ok | {error, [_Error :: {var(), disallowed}]}.
+    ok | {error, [_Error :: {varname(), disallowed}]}.
-validate(AllowedIn, Template) ->
+validate(Allowed, Template) ->
-    Allowed = [try_parse_var(V) || V <- AllowedIn],
     {_, Errors} = render(Template, #{}),
     {Used, _} = lists:unzip(Errors),
     case lists:usort(Used) -- Allowed of
@@ -139,11 +140,6 @@ validate(AllowedIn, Template) ->
             {error, [{Var, disallowed} || Var <- Disallowed]}
     end.
 
-try_parse_var(Var) when is_binary(Var) ->
-    parse_var(Var);
-try_parse_var(Name) when is_list(Name) ->
-    Name.
-
 -spec trivial(t()) ->
     boolean().
 trivial(Template) ->
@@ -156,7 +152,7 @@ unparse({'$tpl', Template}) ->
 unparse(Template) ->
     unicode:characters_to_list(lists:map(fun unparse_part/1, Template)).
 
-unparse_part({var, Name}) ->
+unparse_part({var, Name, _Accessor}) ->
     render_placeholder(Name);
 unparse_part(Part = <<"${", _/binary>>) ->
     <<"$", Part/binary>>;
@@ -164,7 +160,7 @@ unparse_part(Part) ->
     Part.
 
 render_placeholder(Name) ->
-    "${" ++ lists:join($., Name) ++ "}".
+    "${" ++ Name ++ "}".
 
 %% @doc Render a template with given bindings.
 %% Returns a term with all placeholders replaced with values from bindings.
@@ -172,17 +168,17 @@ render_placeholder(Name) ->
 %% By default, all binding values are converted to strings using `to_string/1`
 %% function. Option `var_trans` can be used to override this behaviour.
 -spec render(t(), bindings()) ->
-    {term(), [_Error :: {var(), undefined}]}.
+    {term(), [_Error :: {varname(), undefined}]}.
 render(Template, Bindings) ->
     render(Template, Bindings, #{}).
 
 -spec render(t(), bindings(), render_opts()) ->
-    {term(), [_Error :: {var(), undefined}]}.
+    {term(), [_Error :: {varname(), undefined}]}.
 render(Template, Bindings, Opts) when is_list(Template) ->
     lists:mapfoldl(
         fun
-            ({var, Name}, EAcc) ->
+            ({var, Name, Accessor}, EAcc) ->
-                {String, Errors} = render_binding(Name, Bindings, Opts),
+                {String, Errors} = render_binding(Name, Accessor, Bindings, Opts),
                 {String, Errors ++ EAcc};
             (String, EAcc) ->
                 {String, EAcc}
@@ -193,8 +189,8 @@ render(Template, Bindings, Opts) when is_list(Template) ->
 render({'$tpl', Template}, Bindings, Opts) ->
     render_deep(Template, Bindings, Opts).
 
-render_binding(Name, Bindings, Opts) ->
+render_binding(Name, Accessor, Bindings, Opts) ->
-    case lookup_var(Name, Bindings) of
+    case lookup_var(Accessor, Bindings) of
         {ok, Value} ->
             {render_value(Name, Value, Opts), []};
         {error, Reason} ->
@@ -231,12 +227,12 @@ render_strict(Template, Bindings, Opts) ->
 %% lists are not analyzed for "printability" and are treated as nested terms.
 %% The result is a usual template, and can be fed to other functions in this
 %% module.
--spec parse_deep(unicode:chardata()) ->
+-spec parse_deep(term()) ->
     t().
 parse_deep(Term) ->
     parse_deep(Term, #{}).
 
--spec parse_deep(unicode:chardata(), parse_opts()) ->
+-spec parse_deep(term(), parse_opts()) ->
     t().
 parse_deep(Term, Opts) ->
     {'$tpl', parse_deep_term(Term, Opts)}.
@@ -305,7 +301,7 @@ unparse_deep(Term) ->
 
 %%
 
--spec lookup_var(var(), bindings()) ->
+-spec lookup_var(accessor(), bindings()) ->
     {ok, binding()} | {error, undefined}.
 lookup_var(Var, Value) when Var == ?PH_VAR_THIS orelse Var == [] ->
     {ok, Value};

apps/emqx_connector/src/emqx_connector_template_sql.erl

@@ -88,14 +88,14 @@ render_strict(Template, Bindings, Opts) ->
 %%     #{parameters => '$n'}
 %% ),
 %% Statement = <<"INSERT INTO table (id, name, age) VALUES ($1, $2, 42)">>,
-%% RowTemplate = [{var, [...]}, ...]
+%% RowTemplate = [{var, "...", [...]}, ...]
 %% ```
 -spec parse_prepstmt(unicode:chardata(), parse_opts()) ->
     {unicode:chardata(), row_template()}.
 parse_prepstmt(String, Opts) ->
     Template = emqx_connector_template:parse(String, maps:with(?TEMPLATE_PARSE_OPTS, Opts)),
     Statement = mk_prepared_statement(Template, Opts),
-    Placeholders = [Placeholder || Placeholder = {var, _} <- Template],
+    Placeholders = [Placeholder || Placeholder <- Template, element(1, Placeholder) == var],
     {Statement, Placeholders}.
 
 mk_prepared_statement(Template, Opts) ->
@@ -103,7 +103,7 @@ mk_prepared_statement(Template, Opts) ->
     {Statement, _} =
         lists:mapfoldl(
             fun
-                ({var, _}, Acc) ->
+                (Var, Acc) when element(1, Var) == var ->
                     mk_replace(ParameterFormat, Acc);
                 (String, Acc) ->
                     {String, Acc}

apps/emqx_connector/test/emqx_connector_template_SUITE.erl

@@ -47,7 +47,7 @@ t_render_var_trans(_) ->
     {String, Errors} = emqx_connector_template:render(
         Template,
         Bindings,
-        #{var_trans => fun(Name, _) -> "<" ++ lists:join($., Name) ++ ">" end}
+        #{var_trans => fun(Name, _) -> "<" ++ Name ++ ">" end}
     ),
     ?assertEqual(
         {<<"a:<a>,b:<b>,c:<c.prop>">>, []},
@@ -59,7 +59,7 @@ t_render_path(_) ->
     Template = emqx_connector_template:parse(<<"d.d1:${d.d1}">>),
     ?assertEqual(
         ok,
-        emqx_connector_template:validate([<<"d.d1">>], Template)
+        emqx_connector_template:validate(["d.d1"], Template)
     ),
     ?assertEqual(
         {<<"d.d1:hi">>, []},
@@ -70,8 +70,8 @@ t_render_custom_ph(_) ->
     Bindings = #{a => <<"a">>, b => <<"b">>},
     Template = emqx_connector_template:parse(<<"a:${a},b:${b}">>),
     ?assertEqual(
-        {error, [{[<<"b">>], disallowed}]},
+        {error, [{"b", disallowed}]},
-        emqx_connector_template:validate([<<"a">>], Template)
+        emqx_connector_template:validate(["a"], Template)
     ),
     ?assertEqual(
         <<"a:a,b:b">>,
@@ -81,7 +81,7 @@ t_render_custom_ph(_) ->
 t_render_this(_) ->
     Bindings = #{a => <<"a">>, b => [1, 2, 3]},
     Template = emqx_connector_template:parse(<<"this:${} / also:${.}">>),
-    ?assertEqual(ok, emqx_connector_template:validate([?PH_VAR_THIS], Template)),
+    ?assertEqual(ok, emqx_connector_template:validate(["."], Template)),
     ?assertEqual(
         % NOTE: order of the keys in the JSON object depends on the JSON encoder
         <<"this:{\"b\":[1,2,3],\"a\":\"a\"} / also:{\"b\":[1,2,3],\"a\":\"a\"}">>,
@@ -95,21 +95,21 @@ t_render_missing_bindings(_) ->
     ),
     ?assertEqual(
         {<<"a:,b:,c:,d:,e:">>, [
-            {[<<"no">>, <<"such_atom_i_swear">>], undefined},
+            {"no.such_atom_i_swear", undefined},
-            {[<<"d">>, <<"d1">>], undefined},
+            {"d.d1", undefined},
-            {[<<"c">>], undefined},
+            {"c", undefined},
-            {[<<"b">>], undefined},
+            {"b", undefined},
-            {[<<"a">>], undefined}
+            {"a", undefined}
         ]},
         render_string(Template, Bindings)
     ),
     ?assertError(
         [
-            {[<<"no">>, <<"such_atom_i_swear">>], undefined},
+            {"no.such_atom_i_swear", undefined},
-            {[<<"d">>, <<"d1">>], undefined},
+            {"d.d1", undefined},
-            {[<<"c">>], undefined},
+            {"c", undefined},
-            {[<<"b">>], undefined},
+            {"b", undefined},
-            {[<<"a">>], undefined}
+            {"a", undefined}
         ],
         render_strict_string(Template, Bindings)
     ).
@@ -256,10 +256,10 @@ t_render_cql(_) ->
 
 t_render_sql_custom_ph(_) ->
     {PrepareStatement, RowTemplate} =
-        emqx_connector_template_sql:parse_prepstmt(<<"a:${a},b:${b}">>, #{parameters => '$n'}),
+        emqx_connector_template_sql:parse_prepstmt(<<"a:${a},b:${b.c}">>, #{parameters => '$n'}),
     ?assertEqual(
-        {error, [{[<<"b">>], disallowed}]},
+        {error, [{"b.c", disallowed}]},
-        emqx_connector_template:validate([<<"a">>], RowTemplate)
+        emqx_connector_template:validate(["a"], RowTemplate)
     ),
     ?assertEqual(<<"a:$1,b:$2">>, bin(PrepareStatement)).
 
@@ -296,8 +296,8 @@ t_render_tmpl_deep(_) ->
     ),
 
     ?assertEqual(
-        {error, [{V, disallowed} || V <- [[<<"b">>], [<<"c">>]]]},
+        {error, [{V, disallowed} || V <- ["b", "c"]]},
-        emqx_connector_template:validate([<<"a">>], Template)
+        emqx_connector_template:validate(["a"], Template)
     ),
 
     ?assertEqual(

apps/emqx_rule_engine/src/emqx_rule_actions.erl

@@ -224,8 +224,8 @@ parse_user_properties(_) ->
     %% invalid, discard
     undefined.
 
-render_simple_var([{var, Name}], Data, Default) ->
+render_simple_var([{var, _Name, Accessor}], Data, Default) ->
-    case emqx_connector_template:lookup_var(Name, Data) of
+    case emqx_connector_template:lookup_var(Accessor, Data) of
         {ok, Var} -> Var;
         %% cannot find the variable from Data
         {error, _} -> Default