refactor(pluglib): move `emqx_placeholder` to utils app

Also make user that existing code calls it directly.

apps/emqx_authn/src/emqx_authn_utils.erl

@@ -225,21 +225,19 @@ without_password(Credential, [Name | Rest]) ->
             without_password(Credential, Rest)
     end.
 
-urlencode_var({var, _} = Var, Value) ->
-    emqx_http_lib:uri_encode(handle_var(Var, Value));
 urlencode_var(Var, Value) ->
-    handle_var(Var, Value).
+    emqx_http_lib:uri_encode(handle_var(Var, Value)).
 
-handle_var({var, _Name}, undefined) ->
+handle_var(_Name, undefined) ->
     <<>>;
-handle_var({var, <<"peerhost">>}, PeerHost) ->
+handle_var([<<"peerhost">>], PeerHost) ->
     emqx_placeholder:bin(inet:ntoa(PeerHost));
 handle_var(_, Value) ->
     emqx_placeholder:bin(Value).
 
-handle_sql_var({var, _Name}, undefined) ->
+handle_sql_var(_Name, undefined) ->
     <<>>;
-handle_sql_var({var, <<"peerhost">>}, PeerHost) ->
+handle_sql_var([<<"peerhost">>], PeerHost) ->
     emqx_placeholder:bin(inet:ntoa(PeerHost));
 handle_sql_var(_, Value) ->
     emqx_placeholder:sql_data(Value).

apps/emqx_authz/src/emqx_authz_utils.erl

@@ -188,21 +188,19 @@ convert_client_var({dn, DN}) -> {cert_subject, DN};
 convert_client_var({protocol, Proto}) -> {proto_name, Proto};
 convert_client_var(Other) -> Other.
 
-urlencode_var({var, _} = Var, Value) ->
-    emqx_http_lib:uri_encode(handle_var(Var, Value));
 urlencode_var(Var, Value) ->
-    handle_var(Var, Value).
+    emqx_http_lib:uri_encode(handle_var(Var, Value)).
 
-handle_var({var, _Name}, undefined) ->
+handle_var(_Name, undefined) ->
     <<>>;
-handle_var({var, <<"peerhost">>}, IpAddr) ->
+handle_var([<<"peerhost">>], IpAddr) ->
     inet_parse:ntoa(IpAddr);
 handle_var(_Name, Value) ->
     emqx_placeholder:bin(Value).
 
-handle_sql_var({var, _Name}, undefined) ->
+handle_sql_var(_Name, undefined) ->
     <<>>;
-handle_sql_var({var, <<"peerhost">>}, IpAddr) ->
+handle_sql_var([<<"peerhost">>], IpAddr) ->
     inet_parse:ntoa(IpAddr);
 handle_sql_var(_Name, Value) ->
     emqx_placeholder:sql_data(Value).

apps/emqx_authz/test/emqx_authz_rule_SUITE.erl

@@ -81,7 +81,7 @@ t_compile(_) ->
                 {{127, 0, 0, 1}, {127, 0, 0, 1}, 32},
                 {{192, 168, 1, 0}, {192, 168, 1, 255}, 24}
             ]},
-            subscribe, [{pattern, [{var, {var, <<"clientid">>}}]}]},
+            subscribe, [{pattern, [{var, [<<"clientid">>]}]}]},
         emqx_authz_rule:compile(?SOURCE3)
     ),
 
@@ -99,14 +99,14 @@ t_compile(_) ->
                 {clientid, {re_pattern, _, _, _, _}}
             ]},
             publish, [
-                {pattern, [{var, {var, <<"username">>}}]}, {pattern, [{var, {var, <<"clientid">>}}]}
+                {pattern, [{var, [<<"username">>]}]}, {pattern, [{var, [<<"clientid">>]}]}
             ]},
         emqx_authz_rule:compile(?SOURCE5)
     ),
 
     ?assertEqual(
         {allow, {username, {eq, <<"test">>}}, publish, [
-            {pattern, [{str, <<"t/foo">>}, {var, {var, <<"username">>}}, {str, <<"boo">>}]}
+            {pattern, [{str, <<"t/foo">>}, {var, [<<"username">>]}, {str, <<"boo">>}]}
         ]},
         emqx_authz_rule:compile(?SOURCE6)
     ),

apps/emqx_bridge_cassandra/src/emqx_bridge_cassandra_connector.erl

@@ -273,10 +273,10 @@ proc_cql_params(
     %% assert
     _PreparedKey = maps:get(PreparedKey0, Prepares),
     Tokens = maps:get(PreparedKey0, ParamsTokens),
-    {PreparedKey0, assign_type_for_params(emqx_plugin_libs_rule:proc_sql(Tokens, Params))};
+    {PreparedKey0, assign_type_for_params(emqx_placeholder:proc_sql(Tokens, Params))};
 proc_cql_params(query, SQL, Params, _State) ->
-    {SQL1, Tokens} = emqx_plugin_libs_rule:preproc_sql(SQL, '?'),
-    {SQL1, assign_type_for_params(emqx_plugin_libs_rule:proc_sql(Tokens, Params))}.
+    {SQL1, Tokens} = emqx_placeholder:preproc_sql(SQL, '?'),
+    {SQL1, assign_type_for_params(emqx_placeholder:proc_sql(Tokens, Params))}.
 
 exec_cql_query(InstId, PoolName, Type, Async, PreparedKey, Data) when
     Type == query; Type == prepared_query
@@ -403,7 +403,7 @@ parse_prepare_cql(_) ->
     #{prepare_cql => #{}, params_tokens => #{}}.
 
 parse_prepare_cql([{Key, H} | T], Prepares, Tokens) ->
-    {PrepareSQL, ParamsTokens} = emqx_plugin_libs_rule:preproc_sql(H, '?'),
+    {PrepareSQL, ParamsTokens} = emqx_placeholder:preproc_sql(H, '?'),
     parse_prepare_cql(
         T, Prepares#{Key => PrepareSQL}, Tokens#{Key => ParamsTokens}
     );

apps/emqx_bridge_clickhouse/src/emqx_bridge_clickhouse_connector.erl

@@ -193,7 +193,7 @@ prepare_sql_templates(#{
     batch_value_separator := Separator
 }) ->
     InsertTemplate =
-        emqx_plugin_libs_rule:preproc_tmpl(Template),
+        emqx_placeholder:preproc_tmpl(Template),
     BulkExtendInsertTemplate =
         prepare_sql_bulk_extend_template(Template, Separator),
     #{
@@ -210,7 +210,7 @@ prepare_sql_bulk_extend_template(Template, Separator) ->
     %% Add separator before ValuesTemplate so that one can append it
     %% to an insert template
     ExtendParamTemplate = iolist_to_binary([Separator, ValuesTemplate]),
-    emqx_plugin_libs_rule:preproc_tmpl(ExtendParamTemplate).
+    emqx_placeholder:preproc_tmpl(ExtendParamTemplate).
 
 %% This function is similar to emqx_plugin_libs_rule:split_insert_sql/1 but can
 %% also handle Clickhouse's SQL extension for INSERT statments that allows the
@@ -363,7 +363,7 @@ on_query(
     transform_and_log_clickhouse_result(ClickhouseResult, ResourceID, SQL).
 
 get_sql(send_message, #{send_message_template := PreparedSQL}, Data) ->
-    emqx_plugin_libs_rule:proc_tmpl(PreparedSQL, Data);
+    emqx_placeholder:proc_tmpl(PreparedSQL, Data);
 get_sql(_, _, SQL) ->
     SQL.
 
@@ -421,10 +421,10 @@ objects_to_sql(
     }
 ) ->
     %% Prepare INSERT-statement and the first row after VALUES
-    InsertStatementHead = emqx_plugin_libs_rule:proc_tmpl(InsertTemplate, FirstObject),
+    InsertStatementHead = emqx_placeholder:proc_tmpl(InsertTemplate, FirstObject),
     FormatObjectDataFunction =
         fun(Object) ->
-            emqx_plugin_libs_rule:proc_tmpl(BulkExtendInsertTemplate, Object)
+            emqx_placeholder:proc_tmpl(BulkExtendInsertTemplate, Object)
         end,
     InsertStatementTail = lists:map(FormatObjectDataFunction, RemainingObjects),
     CompleteStatement = erlang:iolist_to_binary([InsertStatementHead, InsertStatementTail]),

apps/emqx_bridge_dynamo/src/emqx_bridge_dynamo_connector.erl

@@ -200,7 +200,7 @@ parse_template(Config) ->
     parse_template(maps:to_list(Templates), #{}).
 
 parse_template([{Key, H} | T], Templates) ->
-    ParamsTks = emqx_plugin_libs_rule:preproc_tmpl(H),
+    ParamsTks = emqx_placeholder:preproc_tmpl(H),
     parse_template(
         T,
         Templates#{Key => ParamsTks}

apps/emqx_bridge_dynamo/src/emqx_bridge_dynamo_connector_client.erl

@@ -144,7 +144,7 @@ apply_template({Key, Msg} = Req, Templates) ->
         undefined ->
             Req;
         Template ->
-            {Key, emqx_plugin_libs_rule:proc_tmpl(Template, Msg)}
+            {Key, emqx_placeholder:proc_tmpl(Template, Msg)}
     end;
 %% now there is no batch delete, so
 %% 1. we can simply replace the `send_message` to `put`

apps/emqx_bridge_gcp_pubsub/src/emqx_bridge_gcp_pubsub_connector.erl

@@ -40,7 +40,7 @@
     connect_timeout := timer:time(),
     jwt_config := emqx_connector_jwt:jwt_config(),
     max_retries := non_neg_integer(),
-    payload_template := emqx_plugin_libs_rule:tmpl_token(),
+    payload_template := emqx_placeholder:tmpl_token(),
     pool_name := binary(),
     project_id := binary(),
     pubsub_topic := binary(),
@@ -104,7 +104,7 @@ on_start(
         connect_timeout => ConnectTimeout,
         jwt_config => JWTConfig,
         max_retries => MaxRetries,
-        payload_template => emqx_plugin_libs_rule:preproc_tmpl(PayloadTemplate),
+        payload_template => emqx_placeholder:preproc_tmpl(PayloadTemplate),
         pool_name => ResourceId,
         project_id => ProjectId,
         pubsub_topic => PubSubTopic,
@@ -294,7 +294,7 @@ encode_payload(_State = #{payload_template := PayloadTemplate}, Selected) ->
     Interpolated =
         case PayloadTemplate of
             [] -> emqx_utils_json:encode(Selected);
-            _ -> emqx_plugin_libs_rule:proc_tmpl(PayloadTemplate, Selected)
+            _ -> emqx_placeholder:proc_tmpl(PayloadTemplate, Selected)
         end,
     #{data => base64:encode(Interpolated)}.
 

apps/emqx_bridge_influxdb/src/emqx_bridge_influxdb_connector.erl

@@ -436,7 +436,7 @@ to_config([Item0 | Rest], Acc, Precision) ->
     Ts0 = maps:get(timestamp, Item0, undefined),
     {Ts, FromPrecision, ToPrecision} = preproc_tmpl_timestamp(Ts0, Precision),
     Item = #{
-        measurement => emqx_plugin_libs_rule:preproc_tmpl(maps:get(measurement, Item0)),
+        measurement => emqx_placeholder:preproc_tmpl(maps:get(measurement, Item0)),
         timestamp => Ts,
         precision => {FromPrecision, ToPrecision},
         tags => to_kv_config(maps:get(tags, Item0)),
@@ -458,18 +458,18 @@ preproc_tmpl_timestamp(Ts, Precision) when is_integer(Ts) ->
 preproc_tmpl_timestamp(Ts, Precision) when is_list(Ts) ->
     preproc_tmpl_timestamp(iolist_to_binary(Ts), Precision);
 preproc_tmpl_timestamp(<<?DEFAULT_TIMESTAMP_TMPL>> = Ts, Precision) ->
-    {emqx_plugin_libs_rule:preproc_tmpl(Ts), ms, Precision};
+    {emqx_placeholder:preproc_tmpl(Ts), ms, Precision};
 preproc_tmpl_timestamp(Ts, Precision) when is_binary(Ts) ->
     %% a placehold is in use. e.g. ${payload.my_timestamp}
     %% we can only hope it the value will be of the same precision in the configs
-    {emqx_plugin_libs_rule:preproc_tmpl(Ts), Precision, Precision}.
+    {emqx_placeholder:preproc_tmpl(Ts), Precision, Precision}.
 
 to_kv_config(KVfields) ->
     maps:fold(fun to_maps_config/3, #{}, proplists:to_map(KVfields)).
 
 to_maps_config(K, V, Res) ->
-    NK = emqx_plugin_libs_rule:preproc_tmpl(bin(K)),
-    NV = emqx_plugin_libs_rule:preproc_tmpl(bin(V)),
+    NK = emqx_placeholder:preproc_tmpl(bin(K)),
+    NV = emqx_placeholder:preproc_tmpl(bin(V)),
     Res#{NK => NV}.
 
 %% -------------------------------------------------------------------------------------------------
@@ -505,7 +505,7 @@ parse_batch_data(InstId, BatchData, SyntaxLines) ->
         fields := [{binary(), binary()}],
         measurement := binary(),
         tags := [{binary(), binary()}],
-        timestamp := emqx_plugin_libs_rule:tmpl_token() | integer(),
+        timestamp := emqx_placeholder:tmpl_token() | integer(),
         precision := {From :: ts_precision(), To :: ts_precision()}
     }
 ]) -> {ok, [map()]} | {error, term()}.
@@ -526,7 +526,7 @@ lines_to_points(Data, [#{timestamp := Ts} = Item | Rest], ResultPointsAcc, Error
     is_list(Ts)
 ->
     TransOptions = #{return => rawlist, var_trans => fun data_filter/1},
-    case parse_timestamp(emqx_plugin_libs_rule:proc_tmpl(Ts, Data, TransOptions)) of
+    case parse_timestamp(emqx_placeholder:proc_tmpl(Ts, Data, TransOptions)) of
         {ok, TsInt} ->
             Item1 = Item#{timestamp => TsInt},
             continue_lines_to_points(Data, Item1, Rest, ResultPointsAcc, ErrorPointsAcc);
@@ -573,7 +573,7 @@ line_to_point(
     {_, EncodedTags} = maps:fold(fun maps_config_to_data/3, {Data, #{}}, Tags),
     {_, EncodedFields} = maps:fold(fun maps_config_to_data/3, {Data, #{}}, Fields),
     maps:without([precision], Item#{
-        measurement => emqx_plugin_libs_rule:proc_tmpl(Measurement, Data),
+        measurement => emqx_placeholder:proc_tmpl(Measurement, Data),
         tags => EncodedTags,
         fields => EncodedFields,
         timestamp => maybe_convert_time_unit(Ts, Precision)
@@ -590,8 +590,8 @@ time_unit(ns) -> nanosecond.
 maps_config_to_data(K, V, {Data, Res}) ->
     KTransOptions = #{return => rawlist, var_trans => fun key_filter/1},
     VTransOptions = #{return => rawlist, var_trans => fun data_filter/1},
-    NK0 = emqx_plugin_libs_rule:proc_tmpl(K, Data, KTransOptions),
-    NV = emqx_plugin_libs_rule:proc_tmpl(V, Data, VTransOptions),
+    NK0 = emqx_placeholder:proc_tmpl(K, Data, KTransOptions),
+    NV = emqx_placeholder:proc_tmpl(V, Data, VTransOptions),
     case {NK0, NV} of
         {[undefined], _} ->
             {Data, Res};

apps/emqx_bridge_iotdb/src/emqx_bridge_iotdb_impl.erl

@@ -185,7 +185,7 @@ preproc_data(
             timestamp => maybe_preproc_tmpl(
                 maps:get(<<"timestamp">>, Data, <<"now">>)
             ),
-            measurement => emqx_plugin_libs_rule:preproc_tmpl(Measurement),
+            measurement => emqx_placeholder:preproc_tmpl(Measurement),
             data_type => DataType,
             value => maybe_preproc_tmpl(Value)
         }
@@ -203,7 +203,7 @@ preproc_data(_NoMatch, Acc) ->
     Acc.
 
 maybe_preproc_tmpl(Value) when is_binary(Value) ->
-    emqx_plugin_libs_rule:preproc_tmpl(Value);
+    emqx_placeholder:preproc_tmpl(Value);
 maybe_preproc_tmpl(Value) ->
     Value.
 
@@ -225,7 +225,7 @@ proc_data(PreProcessedData, Msg) ->
         ) ->
             #{
                 timestamp => iot_timestamp(TimestampTkn, Msg, Nows),
-                measurement => emqx_plugin_libs_rule:proc_tmpl(Measurement, Msg),
+                measurement => emqx_placeholder:proc_tmpl(Measurement, Msg),
                 data_type => DataType,
                 value => proc_value(DataType, ValueTkn, Msg)
             }
@@ -236,7 +236,7 @@ proc_data(PreProcessedData, Msg) ->
 iot_timestamp(Timestamp, _, _) when is_integer(Timestamp) ->
     Timestamp;
 iot_timestamp(TimestampTkn, Msg, Nows) ->
-    iot_timestamp(emqx_plugin_libs_rule:proc_tmpl(TimestampTkn, Msg), Nows).
+    iot_timestamp(emqx_placeholder:proc_tmpl(TimestampTkn, Msg), Nows).
 
 iot_timestamp(Timestamp, #{now_ms := NowMs}) when
     Timestamp =:= <<"now">>; Timestamp =:= <<"now_ms">>; Timestamp =:= <<>>
@@ -250,7 +250,7 @@ iot_timestamp(Timestamp, _) when is_binary(Timestamp) ->
     binary_to_integer(Timestamp).
 
 proc_value(<<"TEXT">>, ValueTkn, Msg) ->
-    case emqx_plugin_libs_rule:proc_tmpl(ValueTkn, Msg) of
+    case emqx_placeholder:proc_tmpl(ValueTkn, Msg) of
         <<"undefined">> -> null;
         Val -> Val
     end;
@@ -262,7 +262,7 @@ proc_value(Int, ValueTkn, Msg) when Int =:= <<"FLOAT">>; Int =:= <<"DOUBLE">> ->
     convert_float(replace_var(ValueTkn, Msg)).
 
 replace_var(Tokens, Data) when is_list(Tokens) ->
-    [Val] = emqx_plugin_libs_rule:proc_tmpl(Tokens, Data, #{return => rawlist}),
+    [Val] = emqx_placeholder:proc_tmpl(Tokens, Data, #{return => rawlist}),
     Val;
 replace_var(Val, _Data) ->
     Val.
@@ -410,8 +410,8 @@ device_id(Message, Payloads, State) ->
             %% [FIXME] there could be conflicting device-ids in the Payloads
             maps:get(<<"device_id">>, hd(Payloads), undefined);
         DeviceId ->
-            DeviceIdTkn = emqx_plugin_libs_rule:preproc_tmpl(DeviceId),
-            emqx_plugin_libs_rule:proc_tmpl(DeviceIdTkn, Message)
+            DeviceIdTkn = emqx_placeholder:preproc_tmpl(DeviceId),
+            emqx_placeholder:proc_tmpl(DeviceIdTkn, Message)
     end.
 
 handle_response({ok, 200, _Headers, Body} = Resp) ->

apps/emqx_bridge_kafka/src/emqx_bridge_kafka_impl_consumer.erl

@@ -68,7 +68,7 @@
     resource_id := resource_id(),
     topic_mapping := #{
         kafka_topic() := #{
-            payload_template := emqx_plugin_libs_rule:tmpl_token(),
+            payload_template := emqx_placeholder:tmpl_token(),
             mqtt_topic => emqx_types:topic(),
             qos => emqx_types:qos()
         }
@@ -82,7 +82,7 @@
     resource_id := resource_id(),
     topic_mapping := #{
         kafka_topic() := #{
-            payload_template := emqx_plugin_libs_rule:tmpl_token(),
+            payload_template := emqx_placeholder:tmpl_token(),
             mqtt_topic => emqx_types:topic(),
             qos => emqx_types:qos()
         }
@@ -536,7 +536,7 @@ convert_topic_mapping(TopicMappingList) ->
                 qos := QoS,
                 payload_template := PayloadTemplate0
             } = Fields,
-            PayloadTemplate = emqx_plugin_libs_rule:preproc_tmpl(PayloadTemplate0),
+            PayloadTemplate = emqx_placeholder:preproc_tmpl(PayloadTemplate0),
             Acc#{
                 KafkaTopic => #{
                     payload_template => PayloadTemplate,
@@ -559,7 +559,7 @@ render(FullMessage, PayloadTemplate) ->
                 emqx_plugin_libs_rule:bin(X)
         end
     },
-    emqx_plugin_libs_rule:proc_tmpl(PayloadTemplate, FullMessage, Opts).
+    emqx_placeholder:proc_tmpl(PayloadTemplate, FullMessage, Opts).
 
 encode(Value, none) ->
     Value;

apps/emqx_bridge_kafka/src/emqx_bridge_kafka_impl_producer.erl

@@ -240,7 +240,7 @@ compile_message_template(T) ->
     }.
 
 preproc_tmpl(Tmpl) ->
-    emqx_plugin_libs_rule:preproc_tmpl(Tmpl).
+    emqx_placeholder:preproc_tmpl(Tmpl).
 
 render_message(
     #{key := KeyTemplate, value := ValueTemplate, timestamp := TimestampTemplate}, Message
@@ -259,7 +259,7 @@ render(Template, Message) ->
         end,
         return => full_binary
     },
-    emqx_plugin_libs_rule:proc_tmpl(Template, Message, Opts).
+    emqx_placeholder:proc_tmpl(Template, Message, Opts).
 
 render_timestamp(Template, Message) ->
     try

apps/emqx_bridge_mqtt/src/emqx_bridge_mqtt_msg.erl

@@ -21,7 +21,7 @@
 
 -export_type([msgvars/0]).
 
--type template() :: emqx_plugin_libs_rule:tmpl_token().
+-type template() :: emqx_placeholder:tmpl_token().
 
 -type msgvars() :: #{
     topic => template(),
@@ -48,7 +48,7 @@ parse(Conf) ->
 parse_field(Key, Conf, Acc) ->
     case Conf of
         #{Key := Val} when is_binary(Val) ->
-            Acc#{Key => emqx_plugin_libs_rule:preproc_tmpl(Val)};
+            Acc#{Key => emqx_placeholder:preproc_tmpl(Val)};
         #{Key := Val} ->
             Acc#{Key => Val};
         #{} ->

apps/emqx_bridge_pulsar/src/emqx_bridge_pulsar_impl_producer.erl

@@ -34,8 +34,8 @@
     value := binary()
 }.
 -type message_template() :: #{
-    key := emqx_plugin_libs_rule:tmpl_token(),
-    value := emqx_plugin_libs_rule:tmpl_token()
+    key := emqx_placeholder:tmpl_token(),
+    value := emqx_placeholder:tmpl_token()
 }.
 -type config() :: #{
     authentication := _,
@@ -421,7 +421,7 @@ compile_message_template(TemplateOpts) ->
     }.
 
 preproc_tmpl(Template) ->
-    emqx_plugin_libs_rule:preproc_tmpl(Template).
+    emqx_placeholder:preproc_tmpl(Template).
 
 render_message(
     Message, #{key := KeyTemplate, value := ValueTemplate}
@@ -439,7 +439,7 @@ render(Message, Template) ->
         end,
         return => full_binary
     },
-    emqx_plugin_libs_rule:proc_tmpl(Template, Message, Opts).
+    emqx_placeholder:proc_tmpl(Template, Message, Opts).
 
 get_producer_status(Producers) ->
     case pulsar_producers:all_connected(Producers) of

apps/emqx_bridge_rabbitmq/src/emqx_bridge_rabbitmq_connector.erl

@@ -225,7 +225,7 @@ on_start(
         {pool_size, PoolSize},
         {pool, InstanceID}
     ],
-    ProcessedTemplate = emqx_plugin_libs_rule:preproc_tmpl(PayloadTemplate),
+    ProcessedTemplate = emqx_placeholder:preproc_tmpl(PayloadTemplate),
     State = #{
         poolname => InstanceID,
         processed_payload_template => ProcessedTemplate,
@@ -547,7 +547,7 @@ is_send_message_atom(_) ->
 format_data([], Msg) ->
     emqx_utils_json:encode(Msg);
 format_data(Tokens, Msg) ->
-    emqx_plugin_libs_rule:proc_tmpl(Tokens, Msg).
+    emqx_placeholder:proc_tmpl(Tokens, Msg).
 
 handle_result({error, ecpool_empty}) ->
     {error, {recoverable_error, ecpool_empty}};

apps/emqx_bridge_rocketmq/src/emqx_bridge_rocketmq_connector.erl

@@ -102,7 +102,7 @@ on_start(
         emqx_schema:parse_servers(BinServers, ?ROCKETMQ_HOST_OPTIONS)
     ),
     ClientId = client_id(InstanceId),
-    TopicTks = emqx_plugin_libs_rule:preproc_tmpl(Topic),
+    TopicTks = emqx_placeholder:preproc_tmpl(Topic),
     #{acl_info := AclInfo} = ProducerOpts = make_producer_opts(Config),
     ClientCfg = #{acl_info => AclInfo},
     Templates = parse_template(Config),
@@ -240,7 +240,7 @@ parse_template(Config) ->
     parse_template(maps:to_list(Templates), #{}).
 
 parse_template([{Key, H} | T], Templates) ->
-    ParamsTks = emqx_plugin_libs_rule:preproc_tmpl(H),
+    ParamsTks = emqx_placeholder:preproc_tmpl(H),
     parse_template(
         T,
         Templates#{Key => ParamsTks}
@@ -249,7 +249,7 @@ parse_template([], Templates) ->
     Templates.
 
 get_topic_key({_, Msg}, TopicTks) ->
-    emqx_plugin_libs_rule:proc_tmpl(TopicTks, Msg);
+    emqx_placeholder:proc_tmpl(TopicTks, Msg);
 get_topic_key([Query | _], TopicTks) ->
     get_topic_key(Query, TopicTks).
 
@@ -258,14 +258,14 @@ apply_template({Key, Msg} = _Req, Templates) ->
         undefined ->
             emqx_utils_json:encode(Msg);
         Template ->
-            emqx_plugin_libs_rule:proc_tmpl(Template, Msg)
+            emqx_placeholder:proc_tmpl(Template, Msg)
     end;
 apply_template([{Key, _} | _] = Reqs, Templates) ->
     case maps:get(Key, Templates, undefined) of
         undefined ->
             [emqx_utils_json:encode(Msg) || {_, Msg} <- Reqs];
         Template ->
-            [emqx_plugin_libs_rule:proc_tmpl(Template, Msg) || {_, Msg} <- Reqs]
+            [emqx_placeholder:proc_tmpl(Template, Msg) || {_, Msg} <- Reqs]
     end.
 
 client_id(ResourceId) ->

apps/emqx_bridge_sqlserver/src/emqx_bridge_sqlserver_connector.erl

@@ -455,9 +455,7 @@ parse_sql_template([{Key, H} | T], BatchInsertTks) ->
                             Key =>
                                 #{
                                     ?BATCH_INSERT_PART => InsertSQL,
-                                    ?BATCH_PARAMS_TOKENS => emqx_plugin_libs_rule:preproc_tmpl(
-                                        Params
-                                    )
+                                    ?BATCH_PARAMS_TOKENS => emqx_placeholder:preproc_tmpl(Params)
                                 }
                         }
                     );
@@ -478,7 +476,7 @@ parse_sql_template([], BatchInsertTks) ->
 apply_template(
     {?ACTION_SEND_MESSAGE = _Key, _Msg} = Query, Templates
 ) ->
-    %% TODO: fix emqx_plugin_libs_rule:proc_tmpl/2
+    %% TODO: fix emqx_placeholder:proc_tmpl/2
     %% it won't add single quotes for string
     apply_template([Query], Templates);
 %% batch inserts

apps/emqx_bridge_tdengine/src/emqx_bridge_tdengine_connector.erl

@@ -126,8 +126,8 @@ on_query(InstanceId, {query, SQL}, State) ->
     do_query(InstanceId, SQL, State);
 on_query(InstanceId, {Key, Data}, #{insert_tokens := InsertTksMap} = State) ->
     case maps:find(Key, InsertTksMap) of
-        {ok, Tokens} ->
-            SQL = emqx_plugin_libs_rule:proc_sql_param_str(Tokens, Data),
+        {ok, Tokens} when is_map(Data) ->
+            SQL = emqx_placeholder:proc_sql_param_str(Tokens, Data),
             do_query(InstanceId, SQL, State);
         _ ->
             {error, {unrecoverable_error, invalid_request}}
@@ -136,7 +136,7 @@ on_query(InstanceId, {Key, Data}, #{insert_tokens := InsertTksMap} = State) ->
 %% aggregate the batch queries to one SQL is a heavy job, we should put it in the worker process
 on_batch_query(
     InstanceId,
-    [{Key, _} | _] = BatchReq,
+    [{Key, _Data = #{}} | _] = BatchReq,
     #{batch_tokens := BatchTksMap, query_opts := Opts} = State
 ) ->
     case maps:find(Key, BatchTksMap) of
@@ -231,8 +231,8 @@ do_batch_insert(Conn, Tokens, BatchReqs, Opts) ->
 aggregate_query({InsertPartTks, ParamsPartTks}, BatchReqs) ->
     lists:foldl(
         fun({_, Data}, Acc) ->
-            InsertPart = emqx_plugin_libs_rule:proc_sql_param_str(InsertPartTks, Data),
-            ParamsPart = emqx_plugin_libs_rule:proc_sql_param_str(ParamsPartTks, Data),
+            InsertPart = emqx_placeholder:proc_sql_param_str(InsertPartTks, Data),
+            ParamsPart = emqx_placeholder:proc_sql_param_str(ParamsPartTks, Data),
             Values = maps:get(InsertPart, Acc, []),
             maps:put(InsertPart, [ParamsPart | Values], Acc)
         end,
@@ -260,12 +260,12 @@ parse_batch_prepare_sql([{Key, H} | T], InsertTksMap, BatchTksMap) ->
         {ok, select} ->
             parse_batch_prepare_sql(T, InsertTksMap, BatchTksMap);
         {ok, insert} ->
-            InsertTks = emqx_plugin_libs_rule:preproc_tmpl(H),
+            InsertTks = emqx_placeholder:preproc_tmpl(H),
             H1 = string:trim(H, trailing, ";"),
             case split_insert_sql(H1) of
                 [_InsertStr, InsertPart, _ValuesStr, ParamsPart] ->
-                    InsertPartTks = emqx_plugin_libs_rule:preproc_tmpl(InsertPart),
-                    ParamsPartTks = emqx_plugin_libs_rule:preproc_tmpl(ParamsPart),
+                    InsertPartTks = emqx_placeholder:preproc_tmpl(InsertPart),
+                    ParamsPartTks = emqx_placeholder:preproc_tmpl(ParamsPart),
                     parse_batch_prepare_sql(
                         T,
                         InsertTksMap#{Key => InsertTks},

apps/emqx_bridge_tdengine/test/emqx_bridge_tdengine_SUITE.erl

@@ -496,7 +496,7 @@ t_simple_sql_query(Config) ->
         ),
     case EnableBatch of
         true ->
-            ?assertEqual({error, {unrecoverable_error, batch_prepare_not_implemented}}, Result);
+            ?assertEqual({error, {unrecoverable_error, invalid_request}}, Result);
         false ->
             ?assertMatch({ok, #{<<"code">> := 0, <<"data">> := [[1]]}}, Result)
     end,
@@ -535,7 +535,7 @@ t_bad_sql_parameter(Config) ->
             2_000
         ),
 
-    ?assertMatch({error, #{<<"code">> := _}}, Result),
+    ?assertMatch({error, {unrecoverable_error, invalid_request}}, Result),
     ok.
 
 t_nasty_sql_string(Config) ->

apps/emqx_connector/src/emqx_connector_http.erl

@@ -464,8 +464,8 @@ preprocess_request(
     } = Req
 ) ->
     #{
-        method => emqx_plugin_libs_rule:preproc_tmpl(to_bin(Method)),
-        path => emqx_plugin_libs_rule:preproc_tmpl(Path),
+        method => emqx_placeholder:preproc_tmpl(to_bin(Method)),
+        path => emqx_placeholder:preproc_tmpl(Path),
         body => maybe_preproc_tmpl(body, Req),
         headers => wrap_auth_header(preproc_headers(Headers)),
         request_timeout => maps:get(request_timeout, Req, ?DEFAULT_REQUEST_TIMEOUT_MS),
@@ -477,8 +477,8 @@ preproc_headers(Headers) when is_map(Headers) ->
         fun(K, V, Acc) ->
             [
                 {
-                    emqx_plugin_libs_rule:preproc_tmpl(to_bin(K)),
-                    emqx_plugin_libs_rule:preproc_tmpl(to_bin(V))
+                    emqx_placeholder:preproc_tmpl(to_bin(K)),
+                    emqx_placeholder:preproc_tmpl(to_bin(V))
                 }
                 | Acc
             ]
@@ -490,8 +490,8 @@ preproc_headers(Headers) when is_list(Headers) ->
     lists:map(
         fun({K, V}) ->
             {
-                emqx_plugin_libs_rule:preproc_tmpl(to_bin(K)),
-                emqx_plugin_libs_rule:preproc_tmpl(to_bin(V))
+                emqx_placeholder:preproc_tmpl(to_bin(K)),
+                emqx_placeholder:preproc_tmpl(to_bin(V))
             }
         end,
         Headers
@@ -530,7 +530,7 @@ try_bin_to_lower(Bin) ->
 maybe_preproc_tmpl(Key, Conf) ->
     case maps:get(Key, Conf, undefined) of
         undefined -> undefined;
-        Val -> emqx_plugin_libs_rule:preproc_tmpl(Val)
+        Val -> emqx_placeholder:preproc_tmpl(Val)
     end.
 
 process_request(
@@ -544,8 +544,8 @@ process_request(
     Msg
 ) ->
     Conf#{
-        method => make_method(emqx_plugin_libs_rule:proc_tmpl(MethodTks, Msg)),
-        path => emqx_plugin_libs_rule:proc_tmpl(PathTks, Msg),
+        method => make_method(emqx_placeholder:proc_tmpl(MethodTks, Msg)),
+        path => emqx_placeholder:proc_tmpl(PathTks, Msg),
         body => process_request_body(BodyTks, Msg),
         headers => proc_headers(HeadersTks, Msg),
         request_timeout => ReqTimeout
@@ -554,14 +554,14 @@ process_request(
 process_request_body(undefined, Msg) ->
     emqx_utils_json:encode(Msg);
 process_request_body(BodyTks, Msg) ->
-    emqx_plugin_libs_rule:proc_tmpl(BodyTks, Msg).
+    emqx_placeholder:proc_tmpl(BodyTks, Msg).
 
 proc_headers(HeaderTks, Msg) ->
     lists:map(
         fun({K, V}) ->
             {
-                emqx_plugin_libs_rule:proc_tmpl(K, Msg),
-                emqx_plugin_libs_rule:proc_tmpl(emqx_secret:unwrap(V), Msg)
+                emqx_placeholder:proc_tmpl(K, Msg),
+                emqx_placeholder:proc_tmpl(emqx_secret:unwrap(V), Msg)
             }
         end,
         HeaderTks

apps/emqx_connector/src/emqx_connector_mysql.erl

@@ -344,7 +344,7 @@ parse_prepare_sql(Config) ->
     parse_prepare_sql(maps:to_list(SQL), #{}, #{}, #{}, #{}).
 
 parse_prepare_sql([{Key, H} | _] = L, Prepares, Tokens, BatchInserts, BatchTks) ->
-    {PrepareSQL, ParamsTokens} = emqx_plugin_libs_rule:preproc_sql(H),
+    {PrepareSQL, ParamsTokens} = emqx_placeholder:preproc_sql(H),
     parse_batch_prepare_sql(
         L, Prepares#{Key => PrepareSQL}, Tokens#{Key => ParamsTokens}, BatchInserts, BatchTks
     );
@@ -363,7 +363,7 @@ parse_batch_prepare_sql([{Key, H} | T], Prepares, Tokens, BatchInserts, BatchTks
         {ok, insert} ->
             case emqx_plugin_libs_rule:split_insert_sql(H) of
                 {ok, {InsertSQL, Params}} ->
-                    ParamsTks = emqx_plugin_libs_rule:preproc_tmpl(Params),
+                    ParamsTks = emqx_placeholder:preproc_tmpl(Params),
                     parse_prepare_sql(
                         T,
                         Prepares,
@@ -389,7 +389,7 @@ proc_sql_params(TypeOrKey, SQLOrData, Params, #{params_tokens := ParamsTokens})
         undefined ->
             {SQLOrData, Params};
         Tokens ->
-            {TypeOrKey, emqx_plugin_libs_rule:proc_sql(Tokens, SQLOrData)}
+            {TypeOrKey, emqx_placeholder:proc_sql(Tokens, SQLOrData)}
     end.
 
 on_batch_insert(InstId, BatchReqs, InsertPart, Tokens, State) ->

apps/emqx_connector/src/emqx_connector_pgsql.erl

@@ -188,7 +188,7 @@ on_batch_query(
                     {error, {unrecoverable_error, batch_prepare_not_implemented}};
                 TokenList ->
                     {_, Datas} = lists:unzip(BatchReq),
-                    Datas2 = [emqx_plugin_libs_rule:proc_sql(TokenList, Data) || Data <- Datas],
+                    Datas2 = [emqx_placeholder:proc_sql(TokenList, Data) || Data <- Datas],
                     St = maps:get(BinKey, Sts),
                     case on_sql_query(InstId, PoolName, execute_batch, St, Datas2) of
                         {error, _Error} = Result ->
@@ -218,7 +218,7 @@ proc_sql_params(TypeOrKey, SQLOrData, Params, #{params_tokens := ParamsTokens})
         undefined ->
             {SQLOrData, Params};
         Tokens ->
-            {Key, emqx_plugin_libs_rule:proc_sql(Tokens, SQLOrData)}
+            {Key, emqx_placeholder:proc_sql(Tokens, SQLOrData)}
     end.
 
 on_sql_query(InstId, PoolName, Type, NameOrSQL, Data) ->
@@ -350,7 +350,7 @@ parse_prepare_sql(Config) ->
     parse_prepare_sql(maps:to_list(SQL), #{}, #{}).
 
 parse_prepare_sql([{Key, H} | T], Prepares, Tokens) ->
-    {PrepareSQL, ParamsTokens} = emqx_plugin_libs_rule:preproc_sql(H, '$n'),
+    {PrepareSQL, ParamsTokens} = emqx_placeholder:preproc_sql(H, '$n'),
     parse_prepare_sql(
         T, Prepares#{Key => PrepareSQL}, Tokens#{Key => ParamsTokens}
     );

apps/emqx_gateway_mqttsn/src/emqx_mqttsn_channel.erl

@@ -301,8 +301,8 @@ feedvar(Override, Packet, ConnInfo, ClientInfo) ->
     },
     maps:map(
         fun(_K, V) ->
-            Tokens = emqx_plugin_libs_rule:preproc_tmpl(V),
-            emqx_plugin_libs_rule:proc_tmpl(Tokens, Envs)
+            Tokens = emqx_placeholder:preproc_tmpl(V),
+            emqx_placeholder:proc_tmpl(Tokens, Envs)
         end,
         Override
     ).

apps/emqx_gateway_stomp/src/emqx_stomp_channel.erl

@@ -283,8 +283,8 @@ feedvar(Override, Packet, ConnInfo, ClientInfo) ->
     },
     maps:map(
         fun(_K, V) ->
-            Tokens = emqx_plugin_libs_rule:preproc_tmpl(V),
-            emqx_plugin_libs_rule:proc_tmpl(Tokens, Envs)
+            Tokens = emqx_placeholder:preproc_tmpl(V),
+            emqx_placeholder:proc_tmpl(Tokens, Envs)
         end,
         Override
     ).

apps/emqx_oracle/src/emqx_oracle.erl

@@ -168,7 +168,7 @@ on_batch_query(
                     {error, {unrecoverable_error, batch_prepare_not_implemented}};
                 TokenList ->
                     {_, Datas} = lists:unzip(BatchReq),
-                    Datas2 = [emqx_plugin_libs_rule:proc_sql(TokenList, Data) || Data <- Datas],
+                    Datas2 = [emqx_placeholder:proc_sql(TokenList, Data) || Data <- Datas],
                     St = maps:get(BinKey, Sts),
                     case
                         on_sql_query(InstId, PoolName, execute_batch, ?SYNC_QUERY_MODE, St, Datas2)
@@ -204,7 +204,7 @@ proc_sql_params(TypeOrKey, SQLOrData, Params, #{
                 undefined ->
                     {SQLOrData, Params};
                 Sql ->
-                    {Sql, emqx_plugin_libs_rule:proc_sql(Tokens, SQLOrData)}
+                    {Sql, emqx_placeholder:proc_sql(Tokens, SQLOrData)}
             end
     end.
 
@@ -305,7 +305,7 @@ parse_prepare_sql(Config) ->
     parse_prepare_sql(maps:to_list(SQL), #{}, #{}).
 
 parse_prepare_sql([{Key, H} | T], Prepares, Tokens) ->
-    {PrepareSQL, ParamsTokens} = emqx_plugin_libs_rule:preproc_sql(H, ':n'),
+    {PrepareSQL, ParamsTokens} = emqx_placeholder:preproc_sql(H, ':n'),
     parse_prepare_sql(
         T, Prepares#{Key => PrepareSQL}, Tokens#{Key => ParamsTokens}
     );

apps/emqx_plugin_libs/src/emqx_plugin_libs_rule.erl

@@ -19,17 +19,6 @@
 
 %% preprocess and process template string with place holders
 -export([
-    preproc_tmpl/1,
-    proc_tmpl/2,
-    proc_tmpl/3,
-    preproc_cmd/1,
-    proc_cmd/2,
-    proc_cmd/3,
-    preproc_sql/1,
-    preproc_sql/2,
-    proc_sql/2,
-    proc_sql_param_str/2,
-    proc_cql_param_str/2,
     split_insert_sql/1,
     detect_sql_type/1,
     proc_batch_sql/3,
@@ -61,68 +50,15 @@
 ]).
 
 -export([
-    now_ms/0,
     can_topic_match_oneof/2
 ]).
 
--export_type([tmpl_token/0]).
-
 -compile({no_auto_import, [float/1]}).
 
 -type uri_string() :: iodata().
 
 -type tmpl_token() :: list({var, binary()} | {str, binary()}).
 
--type tmpl_cmd() :: list(tmpl_token()).
-
--type prepare_statement_key() :: binary().
-
-%% preprocess template string with place holders
--spec preproc_tmpl(binary()) -> tmpl_token().
-preproc_tmpl(Str) ->
-    emqx_placeholder:preproc_tmpl(Str).
-
--spec proc_tmpl(tmpl_token(), map()) -> binary().
-proc_tmpl(Tokens, Data) ->
-    emqx_placeholder:proc_tmpl(Tokens, Data).
-
--spec proc_tmpl(tmpl_token(), map(), map()) -> binary() | list().
-proc_tmpl(Tokens, Data, Opts) ->
-    emqx_placeholder:proc_tmpl(Tokens, Data, Opts).
-
--spec preproc_cmd(binary()) -> tmpl_cmd().
-preproc_cmd(Str) ->
-    emqx_placeholder:preproc_cmd(Str).
-
--spec proc_cmd([tmpl_token()], map()) -> binary() | list().
-proc_cmd(Tokens, Data) ->
-    emqx_placeholder:proc_cmd(Tokens, Data).
--spec proc_cmd([tmpl_token()], map(), map()) -> list().
-proc_cmd(Tokens, Data, Opts) ->
-    emqx_placeholder:proc_cmd(Tokens, Data, Opts).
-
-%% preprocess SQL with place holders
--spec preproc_sql(Sql :: binary()) -> {prepare_statement_key(), tmpl_token()}.
-preproc_sql(Sql) ->
-    emqx_placeholder:preproc_sql(Sql).
-
--spec preproc_sql(Sql :: binary(), ReplaceWith :: '?' | '$n' | ':n') ->
-    {prepare_statement_key(), tmpl_token()}.
-preproc_sql(Sql, ReplaceWith) ->
-    emqx_placeholder:preproc_sql(Sql, ReplaceWith).
-
--spec proc_sql(tmpl_token(), map()) -> list().
-proc_sql(Tokens, Data) ->
-    emqx_placeholder:proc_sql(Tokens, Data).
-
--spec proc_sql_param_str(tmpl_token(), map()) -> binary().
-proc_sql_param_str(Tokens, Data) ->
-    emqx_placeholder:proc_sql_param_str(Tokens, Data).
-
--spec proc_cql_param_str(tmpl_token(), map()) -> binary().
-proc_cql_param_str(Tokens, Data) ->
-    emqx_placeholder:proc_cql_param_str(Tokens, Data).
-
 %% SQL = <<"INSERT INTO \"abc\" (c1,c2,c3) VALUES (${1}, ${1}, ${1})">>
 -spec split_insert_sql(binary()) -> {ok, {InsertSQL, Params}} | {error, atom()} when
     InsertSQL :: binary(),
@@ -169,7 +105,7 @@ detect_sql_type(SQL) ->
 proc_batch_sql(BatchReqs, InsertPart, Tokens) ->
     ValuesPart = erlang:iolist_to_binary(
         lists:join($,, [
-            proc_sql_param_str(Tokens, Msg)
+            emqx_placeholder:proc_sql_param_str(Tokens, Msg)
          || {_, Msg} <- BatchReqs
         ])
     ),
@@ -353,9 +289,6 @@ number_to_list(Int) when is_integer(Int) ->
 number_to_list(Float) when is_float(Float) ->
     float_to_list(Float, [{decimals, 10}, compact]).
 
-now_ms() ->
-    erlang:system_time(millisecond).
-
 can_topic_match_oneof(Topic, Filters) ->
     lists:any(
         fun(Fltr) ->

apps/emqx_rule_engine/src/emqx_rule_actions.erl

@@ -65,10 +65,10 @@ pre_process_action_args(
 ) ->
     Args#{
         preprocessed_tmpl => #{
-            topic => emqx_plugin_libs_rule:preproc_tmpl(Topic),
+            topic => emqx_placeholder:preproc_tmpl(Topic),
             qos => preproc_vars(QoS),
             retain => preproc_vars(Retain),
-            payload => emqx_plugin_libs_rule:preproc_tmpl(Payload),
+            payload => emqx_placeholder:preproc_tmpl(Payload),
             user_properties => preproc_user_properties(UserProperties)
         }
     };
@@ -110,7 +110,7 @@ republish(
         }
     }
 ) ->
-    Topic = emqx_plugin_libs_rule:proc_tmpl(TopicTks, Selected),
+    Topic = emqx_placeholder:proc_tmpl(TopicTks, Selected),
     Payload = format_msg(PayloadTks, Selected),
     QoS = replace_simple_var(QoSTks, Selected, 0),
     Retain = replace_simple_var(RetainTks, Selected, false),
@@ -189,7 +189,7 @@ safe_publish(RuleId, Topic, QoS, Flags, Payload, PubProps) ->
     emqx_metrics:inc_msg(Msg).
 
 preproc_vars(Data) when is_binary(Data) ->
-    emqx_plugin_libs_rule:preproc_tmpl(Data);
+    emqx_placeholder:preproc_tmpl(Data);
 preproc_vars(Data) ->
     Data.
 
@@ -201,13 +201,13 @@ preproc_user_properties(<<"${pub_props.'User-Property'}">>) ->
     ?ORIGINAL_USER_PROPERTIES;
 preproc_user_properties(<<"${", _/binary>> = V) ->
     %% use a variable
-    emqx_plugin_libs_rule:preproc_tmpl(V);
+    emqx_placeholder:preproc_tmpl(V);
 preproc_user_properties(_) ->
     %% invalid, discard
     undefined.
 
 replace_simple_var(Tokens, Data, Default) when is_list(Tokens) ->
-    [Var] = emqx_plugin_libs_rule:proc_tmpl(Tokens, Data, #{return => rawlist}),
+    [Var] = emqx_placeholder:proc_tmpl(Tokens, Data, #{return => rawlist}),
     case Var of
         %% cannot find the variable from Data
         undefined -> Default;
@@ -219,7 +219,7 @@ replace_simple_var(Val, _Data, _Default) ->
 format_msg([], Selected) ->
     emqx_utils_json:encode(Selected);
 format_msg(Tokens, Selected) ->
-    emqx_plugin_libs_rule:proc_tmpl(Tokens, Selected).
+    emqx_placeholder:proc_tmpl(Tokens, Selected).
 
 format_pub_props(UserPropertiesTks, Selected, Env) ->
     UserProperties =

apps/emqx_plugin_libs/src/emqx_placeholder.erl

@@ -46,7 +46,7 @@
     quote_mysql/1
 ]).
 
--include_lib("emqx/include/emqx_placeholder.hrl").
+-define(PH_VAR_THIS, '$this').
 
 -define(EX_PLACE_HOLDER, "(\\$\\{[a-zA-Z0-9\\._]+\\})").
 
@@ -55,7 +55,7 @@
 %% Space and CRLF
 -define(EX_WITHE_CHARS, "\\s").
 
--type tmpl_token() :: list({var, binary()} | {str, binary()}).
+-type tmpl_token() :: list({var, ?PH_VAR_THIS | [binary()]} | {str, binary()}).
 
 -type tmpl_cmd() :: list(tmpl_token()).
 
@@ -123,11 +123,11 @@ proc_tmpl(Tokens, Data, Opts = #{return := rawlist}) ->
             ({str, Str}) ->
                 Str;
             ({var, Phld}) when is_function(Trans, 1) ->
-                Trans(get_phld_var(Phld, Data));
+                Trans(lookup_var(Phld, Data));
             ({var, Phld}) when is_function(Trans, 2) ->
-                Trans(Phld, get_phld_var(Phld, Data));
+                Trans(Phld, lookup_var(Phld, Data));
             ({var, Phld}) ->
-                get_phld_var(Phld, Data)
+                lookup_var(Phld, Data)
         end,
         Tokens
     ).
@@ -264,13 +264,35 @@ quote_mysql(Str) when is_binary(Str) ->
 quote_mysql(Str) ->
     quote_escape(Str, fun escape_mysql/1).
 
+lookup_var(Var, Value) when Var == ?PH_VAR_THIS orelse Var == [] ->
+    Value;
+lookup_var([Prop | Rest], Data) ->
+    case lookup(Prop, Data) of
+        {ok, Value} ->
+            lookup_var(Rest, Value);
+        {error, _} ->
+            undefined
+    end.
+
+lookup(Prop, Data) when is_binary(Prop) ->
+    case maps:get(Prop, Data, undefined) of
+        undefined ->
+            try
+                {ok, maps:get(binary_to_existing_atom(Prop, utf8), Data)}
+            catch
+                error:{badkey, _} ->
+                    {error, undefined};
+                error:badarg ->
+                    {error, undefined}
+            end;
+        Value ->
+            {ok, Value}
+    end.
+
 %%------------------------------------------------------------------------------
 %% Internal functions
 %%------------------------------------------------------------------------------
 
-get_phld_var(Phld, Data) ->
-    emqx_rule_maps:nested_get(Phld, Data).
-
 preproc_var_re(#{placeholders := PHs, strip_double_quote := true}) ->
     Res = [ph_to_re(PH) || PH <- PHs],
     QuoteRes = ["\"" ++ Re ++ "\"" || Re <- Res],
@@ -340,9 +362,8 @@ parse_nested(<<".", R/binary>>) ->
     parse_nested(R);
 parse_nested(Attr) ->
     case string:split(Attr, <<".">>, all) of
-        [<<>>] -> {var, ?PH_VAR_THIS};
-        [Attr] -> {var, Attr};
-        Nested -> {path, [{key, P} || P <- Nested]}
+        [<<>>] -> ?PH_VAR_THIS;
+        Nested -> Nested
     end.
 
 unwrap(<<"\"${", Val/binary>>, _StripDoubleQuote = true) ->

lib-ee/emqx_ee_connector/src/emqx_ee_connector_hstreamdb.erl

@@ -225,9 +225,9 @@ start_producer(
                 msg => "hstreamdb connector: producer started"
             }),
             EnableBatch = maps:get(enable_batch, Options, false),
-            Payload = emqx_plugin_libs_rule:preproc_tmpl(PayloadBin),
+            Payload = emqx_placeholder:preproc_tmpl(PayloadBin),
             OrderingKeyBin = maps:get(ordering_key, Options, <<"">>),
-            OrderingKey = emqx_plugin_libs_rule:preproc_tmpl(OrderingKeyBin),
+            OrderingKey = emqx_placeholder:preproc_tmpl(OrderingKeyBin),
             State = #{
                 client => Client,
                 producer => Producer,
@@ -254,8 +254,8 @@ start_producer(
     end.
 
 to_record(OrderingKeyTmpl, PayloadTmpl, Data) ->
-    OrderingKey = emqx_plugin_libs_rule:proc_tmpl(OrderingKeyTmpl, Data),
-    Payload = emqx_plugin_libs_rule:proc_tmpl(PayloadTmpl, Data),
+    OrderingKey = emqx_placeholder:proc_tmpl(OrderingKeyTmpl, Data),
+    Payload = emqx_placeholder:proc_tmpl(PayloadTmpl, Data),
     to_record(OrderingKey, Payload).
 
 to_record(OrderingKey, Payload) when is_binary(OrderingKey) ->

lib-ee/emqx_ee_connector/src/emqx_ee_connector_mongodb.erl

@@ -57,7 +57,7 @@ on_query(InstanceId, {send_message, Message0}, State) ->
         connector_state := ConnectorState
     } = State,
     NewConnectorState = ConnectorState#{
-        collection => emqx_plugin_libs_rule:proc_tmpl(CollectionTemplate, Message0)
+        collection => emqx_placeholder:proc_tmpl(CollectionTemplate, Message0)
     },
     Message = render_message(PayloadTemplate, Message0),
     Res = emqx_connector_mongo:on_query(InstanceId, {send_message, Message}, NewConnectorState),
@@ -76,7 +76,7 @@ on_get_status(InstanceId, _State = #{connector_state := ConnectorState}) ->
 preprocess_template(undefined = _PayloadTemplate) ->
     undefined;
 preprocess_template(PayloadTemplate) ->
-    emqx_plugin_libs_rule:preproc_tmpl(PayloadTemplate).
+    emqx_placeholder:preproc_tmpl(PayloadTemplate).
 
 render_message(undefined = _PayloadTemplate, Message) ->
     Message;
@@ -102,14 +102,14 @@ format_data(PayloadTks, Msg) ->
     case maps:size(PreparedTupleMap) of
         % If no tuples were found simply proceed with the json decoding and be done with it
         0 ->
-            emqx_utils_json:decode(emqx_plugin_libs_rule:proc_tmpl(PayloadTks, Msg), [return_maps]);
+            emqx_utils_json:decode(emqx_placeholder:proc_tmpl(PayloadTks, Msg), [return_maps]);
         _ ->
             % If tuples were found, replace the tuple values with the references created, run
             % the modified message through the json parser, and then at the end replace the
             % references with the actual tuple values.
             ProcessedMessage = replace_message_values_with_references(Msg, PreparedTupleMap),
             DecodedMap = emqx_utils_json:decode(
-                emqx_plugin_libs_rule:proc_tmpl(PayloadTks, ProcessedMessage), [return_maps]
+                emqx_placeholder:proc_tmpl(PayloadTks, ProcessedMessage), [return_maps]
             ),
             populate_map_with_tuple_values(PreparedTupleMap, DecodedMap)
     end.

lib-ee/emqx_ee_connector/src/emqx_ee_connector_redis.erl

@@ -126,13 +126,13 @@ process_batch_data(BatchData, CommandTemplate) ->
 proc_command_template(CommandTemplate, Msg) ->
     lists:map(
         fun(ArgTks) ->
-            emqx_plugin_libs_rule:proc_tmpl(ArgTks, Msg, #{return => full_binary})
+            emqx_placeholder:proc_tmpl(ArgTks, Msg, #{return => full_binary})
         end,
         CommandTemplate
     ).
 
 preproc_command_template(CommandTemplate) ->
     lists:map(
-        fun emqx_plugin_libs_rule:preproc_tmpl/1,
+        fun emqx_placeholder:preproc_tmpl/1,
         CommandTemplate
     ).