diff --git a/etc/emqx.conf b/etc/emqx.conf
index 308f59153..03c203321 100644
--- a/etc/emqx.conf
+++ b/etc/emqx.conf
@@ -445,6 +445,10 @@ log.file = emqx.log
 ## Default: No Limit
 #log.chars_limit = 8192
 
+## Log to single line
+## Value: boolean
+#log.single_line = true
+
 ## Enables the log rotation.
 ## With this enabled, new log files will be created when the current
 ## log file is full, max to `log.rotation.size` files will be created.
diff --git a/priv/emqx.schema b/priv/emqx.schema
index e5176ca56..d26b14e79 100644
--- a/priv/emqx.schema
+++ b/priv/emqx.schema
@@ -490,6 +490,12 @@ end}.
   {datatype, integer}
 ]}.
 
+%% @doc format logs in a single line.
+{mapping, "log.single_line", "kernel.logger", [
+  {default, true},
+  {datatype, {enum, [true, false]}}
+]}.
+
 {mapping, "log.rotation", "kernel.logger", [
   {default, on},
   {datatype, flag}
@@ -592,7 +598,8 @@ end}.
                      -1 -> unlimited;
                      V -> V
                  end,
-    Formatter = {emqx_logger_formatter,
+    SingleLine = cuttlefish:conf_get("log.single_line", Conf),
+    Formatter = {logger_formatter,
                   #{template =>
                       [time," [",level,"] ",
                        {clientid,
@@ -603,7 +610,9 @@ end}.
                               [peername," "],
                               []}]},
                        msg,"\n"],
-                    chars_limit => CharsLimit}},
+                    chars_limit => CharsLimit,
+                    single_line => SingleLine
+                   }},
     {BustLimitOn, {MaxBurstCount, TimeWindow}} =
         case string:tokens(cuttlefish:conf_get("log.burst_limit", Conf), ", ") of
             ["disabled"] -> {false, {20000, 1000}};
diff --git a/src/emqx_logger_formatter.erl b/src/emqx_logger_formatter.erl
deleted file mode 100644
index 2528a63b5..000000000
--- a/src/emqx_logger_formatter.erl
+++ /dev/null
@@ -1,363 +0,0 @@
-%%
-%% %CopyrightBegin%
-%%
-%% Copyright Ericsson AB 2013-2019. 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.
-%%
-%% %CopyrightEnd%
-%%
-
-%% This file is copied from lib/kernel/src/logger_formatter.erl, and
-%% modified for a more concise time format other than the default RFC3339.
-
--module(emqx_logger_formatter).
-
--export([format/2]).
-
--export([check_config/1]).
-
--define(DEFAULT_FORMAT_TEMPLATE_SINGLE, [time," ",level,": ",msg,"\n"]).
-
--define(FormatP, "~0tp").
-
--define(IS_STRING(String),
-        (is_list(String) orelse is_binary(String))).
-
-%%--------------------------------------------------------------------
-%% Types
-
--type(config() :: #{chars_limit => pos_integer() | unlimited,
-                    depth       => pos_integer() | unlimited,
-                    max_size    => pos_integer() | unlimited,
-                    report_cb   => logger:report_cb(),
-                    quit        => template()}).
-
--type(template() :: [metakey() | {metakey(),template(),template()} | string()]).
-
--type(metakey() :: atom() | [atom()]).
-
-%%--------------------------------------------------------------------
-%% API
-
--spec format(LogEvent,Config) -> unicode:chardata() when
-      LogEvent :: logger:log_event(),
-      Config :: config().
-format(#{level:=Level,msg:=Msg0,meta:=Meta},Config0)
-  when is_map(Config0) ->
-    Config = add_default_config(Config0),
-    Template = maps:get(template,Config),
-    {BT,AT0} = lists:splitwith(fun(msg) -> false; (_) -> true end, Template),
-    {DoMsg,AT} =
-        case AT0 of
-            [msg|Rest] -> {true,Rest};
-            _ ->{false,AT0}
-        end,
-    B = do_format(Level,Meta,BT,Config),
-    A = do_format(Level,Meta,AT,Config),
-    MsgStr =
-        if DoMsg ->
-                Config1 =
-                    case maps:get(chars_limit,Config) of
-                        unlimited ->
-                            Config;
-                        Size0 ->
-                            Size =
-                                case Size0 - string:length([B,A]) of
-                                    S when S>=0 -> S;
-                                    _ -> 0
-                                end,
-                            Config#{chars_limit=>Size}
-                    end,
-                format_msg(Msg0,Meta,Config1);
-           true ->
-                ""
-        end,
-    truncate([B,MsgStr,A],maps:get(max_size,Config)).
-
-do_format(Level,Data,[level|Format],Config) ->
-    [to_string(level,Level,Config)|do_format(Level,Data,Format,Config)];
-do_format(Level,Data,[{Key,IfExist,Else}|Format],Config) ->
-    String =
-        case value(Key,Data) of
-            {ok,Value} -> do_format(Level,Data#{Key=>Value},IfExist,Config);
-            error -> do_format(Level,Data,Else,Config)
-        end,
-    [String|do_format(Level,Data,Format,Config)];
-do_format(Level,Data,[Key|Format],Config)
-  when is_atom(Key) orelse
-       (is_list(Key) andalso is_atom(hd(Key))) ->
-    String =
-        case value(Key,Data) of
-            {ok,Value} -> to_string(Key,Value,Config);
-            error -> ""
-        end,
-    [String|do_format(Level,Data,Format,Config)];
-do_format(Level,Data,[Str|Format],Config) ->
-    [Str|do_format(Level,Data,Format,Config)];
-do_format(_Level,_Data,[],_Config) ->
-    [].
-
-value(Key,Meta) when is_map_key(Key,Meta) ->
-    {ok,maps:get(Key,Meta)};
-value([Key|Keys],Meta) when is_map_key(Key,Meta) ->
-    value(Keys,maps:get(Key,Meta));
-value([],Value) ->
-    {ok,Value};
-value(_,_) ->
-    error.
-
-to_string(time,Time,Config) ->
-    format_time(Time,Config);
-to_string(mfa,MFA,Config) ->
-    format_mfa(MFA,Config);
-to_string(_,Value,Config) ->
-    to_string(Value,Config).
-
-to_string(X,_) when is_atom(X) ->
-    atom_to_list(X);
-to_string(X,_) when is_integer(X) ->
-    integer_to_list(X);
-to_string(X,_) when is_pid(X) ->
-    pid_to_list(X);
-to_string(X,_) when is_reference(X) ->
-    ref_to_list(X);
-to_string(X,_) when is_list(X) ->
-    case printable_list(lists:flatten(X)) of
-        true -> X;
-        _ -> io_lib:format(?FormatP,[X])
-    end;
-to_string(X,_) ->
-    io_lib:format(?FormatP,[X]).
-
-printable_list([]) ->
-    false;
-printable_list(X) ->
-    io_lib:printable_list(X).
-
-format_msg({string,Chardata},Meta,Config) ->
-    format_msg({"~ts",[Chardata]},Meta,Config);
-format_msg({report,_}=Msg,Meta,#{report_cb:=Fun}=Config)
-  when is_function(Fun,1); is_function(Fun,2) ->
-    format_msg(Msg,Meta#{report_cb=>Fun},maps:remove(report_cb,Config));
-format_msg({report,Report},#{report_cb:=Fun}=Meta,Config) when is_function(Fun,1) ->
-    try Fun(Report) of
-        {Format,Args} when is_list(Format), is_list(Args) ->
-            format_msg({Format,Args},maps:remove(report_cb,Meta),Config);
-        Other ->
-            format_msg({"REPORT_CB/1 ERROR: ~0tp; Returned: ~0tp",
-                        [Report,Other]},Meta,Config)
-    catch C:R:S ->
-            format_msg({"REPORT_CB/1 CRASH: ~0tp; Reason: ~0tp",
-                        [Report,{C,R,logger:filter_stacktrace(?MODULE,S)}]},Meta,Config)
-    end;
-format_msg({report,Report},#{report_cb:=Fun}=Meta,Config) when is_function(Fun,2) ->
-    try Fun(Report,maps:with([depth,chars_limit,single_line],Config)) of
-        Chardata when ?IS_STRING(Chardata) ->
-            try chardata_to_list(Chardata) % already size limited by report_cb
-            catch _:_ ->
-                    format_msg({"REPORT_CB/2 ERROR: ~0tp; Returned: ~0tp",
-                                [Report,Chardata]},Meta,Config)
-            end;
-        Other ->
-            format_msg({"REPORT_CB/2 ERROR: ~0tp; Returned: ~0tp",
-                        [Report,Other]},Meta,Config)
-    catch C:R:S ->
-            format_msg({"REPORT_CB/2 CRASH: ~0tp; Reason: ~0tp",
-                        [Report,{C,R,logger:filter_stacktrace(?MODULE,S)}]},
-                       Meta,Config)
-    end;
-format_msg({report,Report},Meta,Config) ->
-    format_msg({report,Report},
-               Meta#{report_cb=>fun logger:format_report/1},
-               Config);
-format_msg(Msg,_Meta,#{depth:=Depth,chars_limit:=CharsLimit}) ->
-    Opts = chars_limit_to_opts(CharsLimit),
-    do_format_msg(Msg, Depth, Opts).
-
-chars_limit_to_opts(unlimited) -> [];
-chars_limit_to_opts(CharsLimit) -> [{chars_limit,CharsLimit}].
-
-do_format_msg({Format0,Args},Depth,Opts) ->
-    try
-        Format1 = io_lib:scan_format(Format0, Args),
-        Format = reformat(Format1, Depth),
-        io_lib:build_text(Format,Opts)
-    catch C:R:S ->
-        FormatError = "FORMAT ERROR: ~0tp - ~0tp",
-        case Format0 of
-            FormatError ->
-                %% already been here - avoid failing cyclically
-                erlang:raise(C,R,S);
-            _ ->
-                do_format_msg({FormatError,[Format0,Args]},Depth,Opts)
-        end
-    end.
-
-reformat(Format,unlimited) ->
-    Format;
-reformat([#{control_char:=C}=M|T], Depth) when C =:= $p ->
-    [limit_depth(M#{width => 0}, Depth)|reformat(T, Depth)];
-reformat([#{control_char:=C}=M|T], Depth) when C =:= $P ->
-    [M#{width => 0}|reformat(T, Depth)];
-reformat([#{control_char:=C}=M|T], Depth) when C =:= $p; C =:= $w ->
-    [limit_depth(M, Depth)|reformat(T, Depth)];
-reformat([H|T], Depth) ->
-    [H|reformat(T, Depth)];
-reformat([], _) ->
-    [].
-
-limit_depth(M0, unlimited) ->
-    M0;
-limit_depth(#{control_char:=C0, args:=Args}=M0, Depth) ->
-    C = C0 - ($a - $A),				%To uppercase.
-    M0#{control_char:=C,args:=Args++[Depth]}.
-
-chardata_to_list(Chardata) ->
-    case unicode:characters_to_list(Chardata,unicode) of
-        List when is_list(List) ->
-            List;
-        Error ->
-            throw(Error)
-    end.
-
-truncate(String,unlimited) ->
-    String;
-truncate(String,Size) ->
-    Length = string:length(String),
-    if Length>Size ->
-            case lists:reverse(lists:flatten(String)) of
-                [$\n|_] ->
-                    string:slice(String,0,Size-4)++"...\n";
-                _ ->
-                    string:slice(String,0,Size-3)++"..."
-            end;
-       true ->
-            String
-    end.
-
-%% Convert microseconds-timestamp into local datatime string in milliseconds
-format_time(SysTime,#{})
-  when is_integer(SysTime) ->
-    Ms = SysTime rem 1000000 div 1000,
-    {Date, _Time = {H, Mi, S}} = calendar:system_time_to_local_time(SysTime, microsecond),
-    format_time({Date, {H, Mi, S, Ms}}).
-format_time({{Y, M, D}, {H, Mi, S, Ms}}) ->
-    io_lib:format("~b-~2..0b-~2..0b ~2..0b:~2..0b:~2..0b.~3..0b", [Y, M, D, H, Mi, S, Ms]).
-
-format_mfa({M,F,A},_) when is_atom(M), is_atom(F), is_integer(A) ->
-    atom_to_list(M)++":"++atom_to_list(F)++"/"++integer_to_list(A);
-format_mfa({M,F,A},Config) when is_atom(M), is_atom(F), is_list(A) ->
-    format_mfa({M,F,length(A)},Config);
-format_mfa(MFA,Config) ->
-    to_string(MFA,Config).
-
-%% Ensure that all valid configuration parameters exist in the final
-%% configuration map
-add_default_config(Config0) ->
-    Default =
-        #{chars_limit=>unlimited,
-          error_logger_notice_header=>info},
-    MaxSize = get_max_size(maps:get(max_size,Config0,undefined)),
-    Depth = get_depth(maps:get(depth,Config0,undefined)),
-    add_default_template(maps:merge(Default,Config0#{max_size=>MaxSize,
-                                                     depth=>Depth})).
-
-add_default_template(#{template:=_}=Config) ->
-    Config;
-add_default_template(Config) ->
-    Config#{template=>?DEFAULT_FORMAT_TEMPLATE_SINGLE}.
-
-get_max_size(undefined) ->
-    unlimited;
-get_max_size(S) ->
-    max(10,S).
-
-get_depth(undefined) ->
-    error_logger:get_format_depth();
-get_depth(S) ->
-    max(5,S).
-
--spec check_config(Config) -> ok | {error,term()} when
-      Config :: config().
-check_config(Config) when is_map(Config) ->
-    do_check_config(maps:to_list(Config));
-check_config(Config) ->
-    {error,{invalid_formatter_config,?MODULE,Config}}.
-
-do_check_config([{Type,L}|Config]) when Type == chars_limit;
-                                        Type == depth;
-                                        Type == max_size ->
-    case check_limit(L) of
-        ok -> do_check_config(Config);
-        error -> {error,{invalid_formatter_config,?MODULE,{Type,L}}}
-    end;
-do_check_config([{error_logger_notice_header,ELNH}|Config]) when ELNH == info;
-                                                                 ELNH == notice ->
-    do_check_config(Config);
-do_check_config([{report_cb,RCB}|Config]) when is_function(RCB,1);
-                                               is_function(RCB,2) ->
-    do_check_config(Config);
-do_check_config([{template,T}|Config]) ->
-    case check_template(T) of
-        ok -> do_check_config(Config);
-        error -> {error,{invalid_formatter_template,?MODULE,T}}
-    end;
-
-do_check_config([C|_]) ->
-    {error,{invalid_formatter_config,?MODULE,C}};
-do_check_config([]) ->
-    ok.
-
-check_limit(L) when is_integer(L), L>0 ->
-    ok;
-check_limit(unlimited) ->
-    ok;
-check_limit(_) ->
-    error.
-
-check_template([Key|T]) when is_atom(Key) ->
-    check_template(T);
-check_template([Key|T]) when is_list(Key), is_atom(hd(Key)) ->
-    case lists:all(fun(X) when is_atom(X) -> true;
-                      (_) -> false
-                   end,
-                   Key) of
-        true ->
-            check_template(T);
-        false ->
-            error
-    end;
-check_template([{Key,IfExist,Else}|T])
-  when is_atom(Key) orelse
-       (is_list(Key) andalso is_atom(hd(Key))) ->
-    case check_template(IfExist) of
-        ok ->
-            case check_template(Else) of
-                ok ->
-                    check_template(T);
-                error ->
-                    error
-            end;
-        error ->
-            error
-    end;
-check_template([Str|T]) when is_list(Str) ->
-    case io_lib:printable_unicode_list(Str) of
-        true -> check_template(T);
-        false -> error
-    end;
-check_template([]) ->
-    ok;
-check_template(_) ->
-    error.
diff --git a/src/emqx_tracer.erl b/src/emqx_tracer.erl
index ef7e73a8d..02f735a75 100644
--- a/src/emqx_tracer.erl
+++ b/src/emqx_tracer.erl
@@ -31,7 +31,7 @@
 -type(trace_who() :: {clientid | topic, binary()}).
 
 -define(TRACER, ?MODULE).
--define(FORMAT, {emqx_logger_formatter,
+-define(FORMAT, {logger_formatter,
                   #{template =>
                       [time, " [", level, "] ",
                        {clientid,
@@ -41,7 +41,9 @@
                           [{peername,
                               [peername, " "],
                               []}]},
-                       msg, "\n"]}}).
+                       msg, "\n"],
+                    single_line => true
+                   }}).
 -define(TOPIC_TRACE_ID(T), "trace_topic_"++T).
 -define(CLIENT_TRACE_ID(C), "trace_clientid_"++C).
 -define(TOPIC_TRACE(T), {topic, T}).
diff --git a/test/emqx_logger_formatter_SUITE.erl b/test/emqx_logger_formatter_SUITE.erl
deleted file mode 100644
index 3d7469dca..000000000
--- a/test/emqx_logger_formatter_SUITE.erl
+++ /dev/null
@@ -1,657 +0,0 @@
-%%
-%% %CopyrightBegin%
-%%
-%% Copyright Ericsson AB 2018. 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.
-%%
-%% %CopyrightEnd%
-%%
--module(emqx_logger_formatter_SUITE).
-
--compile(export_all).
--compile(nowarn_export_all).
-
--include_lib("eunit/include/eunit.hrl").
--include_lib("common_test/include/ct.hrl").
--include_lib("kernel/include/logger.hrl").
-
--define(TRY(X), my_try(fun() -> X end)).
-
-suite() ->
-    [{timetrap,{seconds,30}}].
-
-init_per_suite(Config) ->
-    Config.
-
-end_per_suite(_Config) ->
-    ok.
-
-init_per_group(_Group, Config) ->
-    Config.
-
-end_per_group(_Group, _Config) ->
-    ok.
-
-init_per_testcase(_TestCase, Config) ->
-    Config.
-
-end_per_testcase(Case, Config) ->
-    try apply(?MODULE,Case,[cleanup,Config])
-    catch error:undef -> ok
-    end,
-    ok.
-
-groups() ->
-    [].
-
-all() ->
-    [default,
-     single_line,
-     template,
-     format_msg,
-     report_cb,
-     max_size,
-     depth,
-     chars_limit,
-     format_mfa,
-     level_or_msg_in_meta,
-     faulty_log,
-     faulty_config,
-     faulty_msg,
-     check_config,
-     update_config].
-
-default(_Config) ->
-    String1 = format(info,{"~p",[term]},#{},#{}),
-    ct:log(String1),
-    ?assertMatch([_Date, _Time,"info:","term\n"], string:lexemes(String1," ")),
-
-    Time = timestamp(),
-    ExpectedTimestamp = default_time_format(Time),
-    String2 = format(info,{"~p",[term]},#{time=>Time},#{}),
-    ct:log("ExpectedTimestamp: ~p, got: ~p", [ExpectedTimestamp, String2]),
-    " info: term\n" = string:prefix(String2,ExpectedTimestamp),
-    ok.
-
-single_line(_Config) ->
-    Time = timestamp(),
-    ExpectedTimestamp = default_time_format(Time),
-    String1 = format(info,{"~p",[term]},#{time=>Time},#{}),
-    ct:log(String1),
-    ?assertMatch(" info: term\n", string:prefix(String1,ExpectedTimestamp)),
-
-    String2 = format(info,{"a:~n~p",[term]},#{time=>Time},#{}),
-    ct:log(String2),
-    ?assertMatch(" info: a:\nterm\n", string:prefix(String2,ExpectedTimestamp)),
-
-
-    Prefix =
-        "Some characters to fill the line ------------------------------------- ",
-    %% There would actually be newlines inside the
-    %% list and map.
-    String4 = format(info,{"~s~p~n~s~p~n",[Prefix,
-                                           lists:seq(1,10),
-                                           Prefix,
-                                           #{a=>map,with=>a,few=>accociations}]},
-                     #{time=>Time},
-                     #{}),
-    ct:log(String4),
-    match = re:run(String4,"\\[1,2,3,\n",[global,{capture,none}]),
-    {match,Match4} = re:run(String4,"=>\n",[global,{capture,all}]),
-    3 = length(Match4),
-
-    %% Test that big metadata fields do not get line breaks
-    String5 = format(info,"",
-                     #{mymeta=>lists:seq(1,100)},
-                     #{template=>[mymeta,"\n"]}),
-    ct:log(String5),
-    [_] = string:lexemes(String5,"\n"),
-    ok.
-
-template(_Config) ->
-    Time = timestamp(),
-
-    Template1 = [msg],
-    String1 = format(info,{"~p",[term]},#{time=>Time},#{template=>Template1}),
-    ct:log(String1),
-    "term" = String1,
-
-    Template2 = [msg,unknown],
-    String2 = format(info,{"~p",[term]},#{time=>Time},#{template=>Template2}),
-    ct:log(String2),
-    "term" = String2,
-
-    Template3 = ["string"],
-    String3 = format(info,{"~p",[term]},#{time=>Time},#{template=>Template3}),
-    ct:log(String3),
-    "string" = String3,
-
-    Template4 = ["string\nnewline"],
-    String4 = format(info,{"~p",[term]},#{time=>Time},#{template=>Template4}),
-    ct:log(String4),
-    "string\nnewline" = String4,
-
-    Template5 = [],
-    String5 = format(info,{"~p",[term]},#{time=>Time},#{template=>Template5}),
-    ct:log(String5),
-    "" = String5,
-
-    Ref6 = erlang:make_ref(),
-    Meta6 = #{atom=>some_atom,
-              integer=>632,
-              list=>[list,"string",4321,#{},{tuple}],
-              mfa=>{mod,func,0},
-              pid=>self(),
-              ref=>Ref6,
-              string=>"some string",
-              time=>Time,
-              tuple=>{1,atom,"list"},
-              nested=>#{subkey=>subvalue}},
-    Template6 = lists:join(";",lists:sort(maps:keys(maps:remove(nested,Meta6))) ++
-                               [[nested,subkey]]),
-    String6 = format(info,{"~p",[term]},Meta6,#{template=>Template6}),
-    ct:log(String6),
-    SelfStr = pid_to_list(self()),
-    RefStr6 = ref_to_list(Ref6),
-    ListStr = "[list,\"string\",4321,#{},{tuple}]",
-    ExpectedTime6 = default_time_format(Time),
-    ["some_atom",
-     "632",
-     ListStr,
-     "mod:func/0",
-     SelfStr,
-     RefStr6,
-     "some string",
-     ExpectedTime6,
-     "{1,atom,\"list\"}",
-     "subvalue"] = string:lexemes(String6,";"),
-
-    Meta7 = #{time=>Time,
-              nested=>#{key1=>#{subkey1=>value1},
-                        key2=>value2}},
-    Template7 = lists:join(";",[nested,
-                                [nested,key1],
-                                [nested,key1,subkey1],
-                                [nested,key2],
-                                [nested,key2,subkey2],
-                                [nested,key3],
-                                [nested,key3,subkey3]]),
-    String7 = format(info,{"~p",[term]},Meta7,#{template=>Template7}),
-    ct:log(String7),
-    [MultipleKeysStr7,
-     "#{subkey1 => value1}",
-     "value1",
-     "value2",
-     "",
-     "",
-     ""] = string:split(String7,";",all),
-    %% Order of keys is not fixed
-    case MultipleKeysStr7 of
-        "#{key2 => value2,key1 => #{subkey1 => value1}}" -> ok;
-        "#{key1 => #{subkey1 => value1},key2 => value2}" -> ok;
-        _ -> ct:fail({full_nested_map_unexpected,MultipleKeysStr7})
-    end,
-
-    Meta8 = #{time=>Time,
-              nested=>#{key1=>#{subkey1=>value1},
-                        key2=>value2}},
-    Template8 =
-        lists:join(
-          ";",
-          [{nested,["exist:",nested],["noexist"]},
-           {[nested,key1],["exist:",[nested,key1]],["noexist"]},
-           {[nested,key1,subkey1],["exist:",[nested,key1,subkey1]],["noexist"]},
-           {[nested,key2],["exist:",[nested,key2]],["noexist"]},
-           {[nested,key2,subkey2],["exist:",[nested,key2,subkey2]],["noexist"]},
-           {[nested,key3],["exist:",[nested,key3]],["noexist"]},
-           {[nested,key3,subkey3],["exist:",[nested,key3,subkey3]],["noexist"]}]),
-    String8 = format(info,{"~p",[term]},Meta8,#{template=>Template8}),
-    ct:log(String8),
-    [MultipleKeysStr8,
-     "exist:#{subkey1 => value1}",
-     "exist:value1",
-     "exist:value2",
-     "noexist",
-     "noexist",
-     "noexist"] = string:split(String8,";",all),
-    %% Order of keys is not fixed
-    case MultipleKeysStr8 of
-        "exist:#{key2 => value2,key1 => #{subkey1 => value1}}" -> ok;
-        "exist:#{key1 => #{subkey1 => value1},key2 => value2}" -> ok;
-        _ -> ct:fail({full_nested_map_unexpected,MultipleKeysStr8})
-    end,
-
-    ok.
-
-format_msg(_Config) ->
-    Template = [msg],
-
-    String1 = format(info,{"~p",[term]},#{},#{template=>Template}),
-    ct:log(String1),
-    "term" = String1,
-
-    String2 = format(info,{"list",[term]},#{},#{template=>Template}),
-    ct:log(String2),
-    "FORMAT ERROR: \"list\" - [term]" = String2,
-
-    String3 = format(info,{report,term},#{},#{template=>Template}),
-    ct:log(String3),
-    "term" = String3,
-
-    String4 = format(info,{report,term},
-                     #{report_cb=>fun(_)-> {"formatted",[]} end},
-                     #{template=>Template}),
-    ct:log(String4),
-    "formatted" = String4,
-
-    String5 = format(info,{report,term},
-                     #{report_cb=>fun(_)-> faulty_return end},
-                     #{template=>Template}),
-    ct:log(String5),
-    "REPORT_CB/1 ERROR: term; Returned: faulty_return" = String5,
-
-    String6 = format(info,{report,term},
-                     #{report_cb=>fun(_)-> erlang:error(fun_crashed) end},
-                     #{template=>Template}),
-    ct:log(String6),
-    "REPORT_CB/1 CRASH: term; Reason: {error,fun_crashed,"++_ = String6,
-
-    String7 = format(info,{report,term},
-                     #{report_cb=>fun(_,_)-> ['not',a,string] end},
-                     #{template=>Template}),
-    ct:log(String7),
-    "REPORT_CB/2 ERROR: term; Returned: ['not',a,string]" = String7,
-
-    String8 = format(info,{report,term},
-                     #{report_cb=>fun(_,_)-> faulty_return end},
-                     #{template=>Template}),
-    ct:log(String8),
-    "REPORT_CB/2 ERROR: term; Returned: faulty_return" = String8,
-
-    String9 = format(info,{report,term},
-                     #{report_cb=>fun(_,_)-> erlang:error(fun_crashed) end},
-                     #{template=>Template}),
-    ct:log(String9),
-    "REPORT_CB/2 CRASH: term; Reason: {error,fun_crashed,"++_ = String9,
-
-    %% strings are not formatted
-    String10 = format(info,{string,"string"},
-                     #{report_cb=>fun(_)-> {"formatted",[]} end},
-                     #{template=>Template}),
-    ct:log(String10),
-    "string" = String10,
-
-    String11 = format(info,{string,['not',printable,list]},
-                     #{report_cb=>fun(_)-> {"formatted",[]} end},
-                     #{template=>Template}),
-    ct:log("~ts",[String11]), % avoiding ct_log crash
-    "FORMAT ERROR: \"~ts\" - [['not',printable,list]]" = String11,
-
-    String12 = format(info,{string,"string"},#{},#{template=>Template}),
-    ct:log(String12),
-    "string" = String12,
-
-    ok.
-
-report_cb(_Config) ->
-    Template = [msg],
-    MetaFun = fun(_) -> {"meta_rcb",[]} end,
-    ConfigFun = fun(_) -> {"config_rcb",[]} end,
-    "term" = format(info,{report,term},#{},#{template=>Template}),
-    "meta_rcb" =
-        format(info,{report,term},#{report_cb=>MetaFun},#{template=>Template}),
-    "config_rcb" =
-        format(info,{report,term},#{},#{template=>Template,
-                                        report_cb=>ConfigFun}),
-    "config_rcb" =
-        format(info,{report,term},#{report_cb=>MetaFun},#{template=>Template,
-                                                          report_cb=>ConfigFun}),
-    ok.
-
-max_size(_Config) ->
-    Cfg = #{template=>[msg]},
-    "12345678901234567890" = format(info,{"12345678901234567890",[]},#{},Cfg),
-    %% application:set_env(kernel,logger_max_size,11),
-    %% "12345678901234567890" = % min value is 50, so this is not limited
-    %%     format(info,{"12345678901234567890",[]},#{},Cfg),
-    %% "12345678901234567890123456789012345678901234567..." = % 50
-    %%     format(info,
-    %%            {"123456789012345678901234567890123456789012345678901234567890",
-    %%             []},
-    %%            #{},
-    %%            Cfg),
-    %% application:set_env(kernel,logger_max_size,53),
-    %% "12345678901234567890123456789012345678901234567890..." = %53
-    %%     format(info,
-    %%            {"123456789012345678901234567890123456789012345678901234567890",
-    %%             []},
-    %%            #{},
-    %%            Cfg),
-    "123456789012..." =
-        format(info,{"12345678901234567890",[]},#{},Cfg#{max_size=>15}),
-    "12345678901234567890" =
-        format(info,{"12345678901234567890",[]},#{},Cfg#{max_size=>unlimited}),
-    %% Check that one newline at the end of the line is kept (if it exists)
-    "12345678901...\n" =
-        format(info,{"12345678901234567890\n",[]},#{},Cfg#{max_size=>15}),
-    "12345678901...\n" =
-        format(info,{"12345678901234567890",[]},#{},Cfg#{template=>[msg,"\n"],
-                                                         max_size=>15}),
-    ok.
-max_size(cleanup,_Config) ->
-    application:unset_env(kernel,logger_max_size),
-    ok.
-
-depth(_Config) ->
-    Template = [msg],
-    "[1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]" =
-        format(info,
-               {"~p",[[1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]]},
-               #{},
-               #{template=>Template}),
-    application:set_env(kernel,error_logger_format_depth,11),
-    "[1,2,3,4,5,6,7,8,9,0|...]" =
-        format(info,
-               {"~p",[[1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]]},
-               #{},
-               #{template=>Template}),
-    "[1,2,3,4,5,6,7,8,9,0,1,2|...]" =
-        format(info,
-               {"~p",[[1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]]},
-               #{},
-               #{template=>Template,
-                 depth=>13}),
-    "[1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]" =
-        format(info,
-               {"~p",[[1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0]]},
-               #{},
-               #{template=>Template,
-                 depth=>unlimited}),
-    ok.
-depth(cleanup,_Config) ->
-    application:unset_env(kernel,error_logger_format_depth),
-    ok.
-
-chars_limit(_Config) ->
-    FA = {"LoL: ~p~nL: ~p~nMap: ~p~n",
-                [lists:duplicate(10,lists:seq(1,100)),
-                 lists:seq(1,100),
-                 maps:from_list(lists:zip(lists:seq(1,100),
-                                          lists:duplicate(100,value)))]},
-    Meta = #{time=>timestamp()},
-    Template = [time," - ", msg, "\n"],
-    FC = #{template=>Template,
-           depth=>unlimited,
-           max_size=>unlimited,
-           chars_limit=>unlimited},
-    CL1 = 80,
-    String1 = format(info,FA,Meta,FC#{chars_limit=>CL1}),
-    L1 = string:length(String1),
-    ct:log("String1: ~p~nLength1: ~p~n",[lists:flatten(String1),L1]),
-    true = L1 > CL1,
-    true = L1 < CL1 + 15,
-
-    String2 = format(info,FA,Meta,FC#{chars_limit=>CL1,depth=>10}),
-    L2 = string:length(String2),
-    ct:log("String2: ~p~nLength2: ~p~n",[lists:flatten(String2),L2]),
-    String2 = String1,
-
-    CL3 = 200,
-    String3 = format(info,FA,Meta,FC#{chars_limit=>CL3}),
-    L3 = string:length(String3),
-    ct:log("String3: ~p~nLength3: ~p~n",[lists:flatten(String3),L3]),
-    true = L3 > CL3,
-    true = L3 < CL3 + 15,
-
-    String4 = format(info,FA,Meta,FC#{chars_limit=>CL3,depth=>10}),
-    L4 = string:length(String4),
-    ct:log("String4: ~p~nLength4: ~p~n",[lists:flatten(String4),L4]),
-    true = L4 > CL3,
-    true = L4 < CL3 + 15,
-
-    %% Test that max_size truncates the string which is limited by
-    %% depth and chars_limit
-    MS5 = 150,
-    String5 = format(info,FA,Meta,FC#{chars_limit=>CL3,depth=>10,max_size=>MS5}),
-    L5 = string:length(String5),
-    ct:log("String5: ~p~nLength5: ~p~n",[String5,L5]),
-    L5 = MS5,
-    true = lists:prefix(lists:sublist(String5,L5-4),String4),
-
-    %% Test that chars_limit limits string also
-    Str = "123456789012345678901234567890123456789012345678901234567890123456789",
-    CL6 = 80,
-    String6 = format(info,{string,Str},Meta,FC#{chars_limit=>CL6}),
-    L6 = string:length(String6),
-    ct:log("String6: ~p~nLength6: ~p~n",[String6,L6]),
-    L6 = CL6,
-
-    ok.
-
-format_mfa(_Config) ->
-    Template = [mfa],
-
-    Meta1 = #{mfa=>{mod,func,0}},
-    String1 = format(info,{"~p",[term]},Meta1,#{template=>Template}),
-    ct:log(String1),
-    "mod:func/0" = String1,
-
-    Meta2 = #{mfa=>{mod,func,[]}},
-    String2 = format(info,{"~p",[term]},Meta2,#{template=>Template}),
-    ct:log(String2),
-    "mod:func/0" = String2,
-
-    Meta3 = #{mfa=>"mod:func/0"},
-    String3 = format(info,{"~p",[term]},Meta3,#{template=>Template}),
-    ct:log(String3),
-    "mod:func/0" = String3,
-
-    Meta4 = #{mfa=>othermfa},
-    String4 = format(info,{"~p",[term]},Meta4,#{template=>Template}),
-    ct:log(String4),
-    "othermfa" = String4,
-
-    ok.
-
-level_or_msg_in_meta(_Config) ->
-    %% The template contains atoms to pick out values from meta,
-    %% or level/msg to add these from the log event. What if you have
-    %% a key named 'level' or 'msg' in meta and want to display
-    %% its value?
-    %% For now we simply ignore Meta on this and display the
-    %% actual level and msg from the log event.
-
-    Meta = #{level=>mylevel,
-                 msg=>"metamsg"},
-    Template = [level,";",msg],
-    String = format(info,{"~p",[term]},Meta,#{template=>Template}),
-    ct:log(String),
-    "info;term" = String, % so mylevel and "metamsg" are ignored
-    ok.
-
-faulty_log(_Config) ->
-    %% Unexpected log (should be type logger:log_event()) - print error
-    {error,
-     function_clause,
-     {emqx_logger_formatter,format,[_,_],_}} =
-        ?TRY(emqx_logger_formatter:format(unexp_log,#{})),
-    ok.
-
-faulty_config(_Config) ->
-    {error,
-     function_clause,
-     {emqx_logger_formatter,format,[_,_],_}} =
-        ?TRY(emqx_logger_formatter:format(#{level=>info,
-                                       msg=>{"~p",[term]},
-                                       meta=>#{time=>timestamp()}},
-                                     unexp_config)),
-    ok.
-
-faulty_msg(_Config) ->
-    {error,
-     function_clause,
-     {emqx_logger_formatter,_,_,_}} =
-        ?TRY(emqx_logger_formatter:format(#{level=>info,
-                                       msg=>term,
-                                       meta=>#{time=>timestamp()}},
-                                     #{})),
-    ok.
-
--define(cfgerr(X), {error,{invalid_formatter_config,emqx_logger_formatter,X}}).
-check_config(_Config) ->
-    ok = emqx_logger_formatter:check_config(#{}),
-    ?cfgerr(bad) = emqx_logger_formatter:check_config(bad),
-
-    C1 = #{chars_limit => 1,
-           depth => 1,
-           max_size => 1,
-           report_cb => fun(R) -> {"~p",[R]} end,
-           template => []},
-    ok = emqx_logger_formatter:check_config(C1),
-
-    ok = emqx_logger_formatter:check_config(#{chars_limit => unlimited}),
-    ?cfgerr({chars_limit,bad}) =
-        emqx_logger_formatter:check_config(#{chars_limit => bad}),
-
-    ok = emqx_logger_formatter:check_config(#{depth => unlimited}),
-    ?cfgerr({depth,bad}) =
-        emqx_logger_formatter:check_config(#{depth => bad}),
-
-    ok = emqx_logger_formatter:check_config(#{max_size => unlimited}),
-    ?cfgerr({max_size,bad}) =
-        emqx_logger_formatter:check_config(#{max_size => bad}),
-
-    ok =
-        emqx_logger_formatter:check_config(#{report_cb => fun(_,_) -> "" end}),
-    ?cfgerr({report_cb,F}) =
-        emqx_logger_formatter:check_config(#{report_cb => F=fun(_,_,_) -> {"",[]} end}),
-    ?cfgerr({report_cb,bad}) =
-        emqx_logger_formatter:check_config(#{report_cb => bad}),
-
-    Ts = [[key],
-          [[key1,key2]],
-          [{key,[key],[]}],
-          [{[key1,key2],[[key1,key2]],["noexist"]}],
-          ["string"]],
-    [begin
-         ct:log("check template: ~p",[T]),
-         ok = emqx_logger_formatter:check_config(#{template => T})
-     end
-     || T <- Ts],
-
-    ETs = [bad,
-           [{key,bad}],
-           [{key,[key],bad}],
-           [{key,[key],"bad"}],
-           "bad",
-           [[key,$a,$b,$c]],
-           [[$a,$b,$c,key]]],
-    [begin
-         ct:log("check template: ~p",[T]),
-         {error,{invalid_formatter_template,emqx_logger_formatter,T}} =
-         emqx_logger_formatter:check_config(#{template => T})
-     end
-     || T <- ETs],
-    ok.
-
-%% Test that formatter config can be changed, and that the default
-%% template is updated accordingly
-update_config(_Config) ->
-    #{level := OldLevel} = logger:get_primary_config(),
-    logger:set_primary_config(level, debug),
-    {error,{not_found,?MODULE}} = logger:update_formatter_config(?MODULE,#{}),
-
-    logger:add_handler_filter(default,silence,{fun(_,_) -> stop end,ok}),
-    ok = logger:add_handler(?MODULE,?MODULE,#{formatter => {emqx_logger_formatter, #{chars_limit => unlimited}},
-                                              config => #{type => standard_io}}),
-    D = lists:seq(1,1000),
-    logger:notice("~p~n",[D]),
-    {Lines1,C1} = check_log(),
-    ct:log("lines1: ~p", [Lines1]),
-    ct:log("c1: ~p",[C1]),
-    [Line1 | _] = Lines1,
-    [_Date, WithOutDate1] = string:split(Line1," "),
-    [_, "notice: "++D1] = string:split(WithOutDate1," "),
-    ?assert(length(D1)<1000),
-    ?assertMatch(#{chars_limit := unlimited}, C1),
-
-    error_logger:error_msg("~p",[D]),
-    {Lines5,C5} = check_log(),
-    ct:log("Lines5: ~p", [Lines5]),
-    ct:log("c5: ~p",[C5]),
-    [Line5 | _] = Lines5,
-    [_Date, WithOutDate5] = string:split(Line5," "),
-    [_, "error: "++_D5] = string:split(WithOutDate5," "),
-
-    ?assertMatch({error,{invalid_formatter_config,bad}},
-        logger:update_formatter_config(?MODULE,bad)),
-    ?assertMatch({error,{invalid_formatter_config,emqx_logger_formatter,{depth,bad}}},
-        logger:update_formatter_config(?MODULE,depth,bad)),
-
-    logger:set_primary_config(level, OldLevel),
-    ok.
-
-update_config(cleanup,_Config) ->
-    _ = logger:remove_handler(?MODULE),
-    _ = logger:remove_handler_filter(default,silence),
-    ok.
-
-%%%-----------------------------------------------------------------
-%%% Internal
-format(Level,Msg,Meta,Config) ->
-    format(#{level=>Level,msg=>Msg,meta=>add_time(Meta)},Config).
-
-format(Log,Config) ->
-    lists:flatten(emqx_logger_formatter:format(Log,Config)).
-
-default_time_format(SysTime) when is_integer(SysTime) ->
-    Ms = SysTime rem 1000000 div 1000,
-    {Date, _Time = {H, Mi, S}} = calendar:system_time_to_local_time(SysTime, microsecond),
-    default_time_format({Date, {H, Mi, S, Ms}});
-default_time_format({{Y, M, D}, {H, Mi, S, Ms}}) ->
-    io_lib:format("~b-~2..0b-~2..0b ~2..0b:~2..0b:~2..0b.~3..0b", [Y, M, D, H, Mi, S, Ms]);
-default_time_format({{Y, M, D}, {H, Mi, S}}) ->
-    io_lib:format("~b-~2..0b-~2..0b ~2..0b:~2..0b:~2..0b", [Y, M, D, H, Mi, S]).
-
-integer(Str) ->
-    is_integer(list_to_integer(Str)).
-integer(Str,Max) ->
-    integer(Str,0,Max).
-integer(Str,Min,Max) ->
-    Int = list_to_integer(Str),
-    Int >= Min andalso Int =<Max.
-
-%%%-----------------------------------------------------------------
-%%% Called by macro ?TRY(X)
-my_try(Fun) ->
-    try Fun() catch C:R:S -> {C,R,hd(S)} end.
-
-timestamp() ->
-    erlang:system_time(microsecond).
-
-%% necessary?
-add_time(#{time:=_}=Meta) ->
-    Meta;
-add_time(Meta) ->
-    Meta#{time=>timestamp()}.
-
-%%%-----------------------------------------------------------------
-%%% handler callback
-log(Log,#{formatter:={M,C}}) ->
-    put(log,{M:format(Log,C),C}),
-    ok.
-
-check_log() ->
-    {S,C} = erase(log),
-    {string:lexemes(S,"\n"),C}.