[logger] Change timestamp from erlang:system_time to os:system_time

This is to align the timestamps with external logs.

7 files changed, 43 insertions, 13 deletions

diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
index df2d081d76..e6448e144e 100644
--- a/lib/kernel/doc/src/logger.xml
+++ b/lib/kernel/doc/src/logger.xml
@@ -190,7 +190,7 @@ logger:error("error happened because: ~p", [Reason]). % Without macro
 	<list>
 	  <item><c>pid  => self()</c></item>
 	  <item><c>gl   => group_leader()</c></item>
-	  <item><c>time => erlang:system_time(microsecond)</c></item>
+	  <item><c>time => logger:timestamp()</c></item>
 	</list>
 	<p>When a log macro is used, Logger also inserts location
 	  information:</p>
@@ -288,8 +288,8 @@ logger:error("error happened because: ~p", [Reason]). % Without macro
       <name name="timestamp"/>
       <desc>
 	<p>A timestamp produced
-	  with <seealso marker="erts:erlang#system_time-1">
-	    <c>erlang:system_time(microsecond)</c></seealso>.</p>
+	  with <seealso marker="#timestamp-0">
+	    <c>logger:timestamp()</c></seealso>.</p>
       </desc>
     </datatype>
   </datatypes>
@@ -1117,6 +1117,24 @@ logger:set_proxy_config(maps:merge(Old, Config)).
 	  a key-value list before formatting as such.</p>
       </desc>
     </func>
+
+    <func>
+      <name name="timestamp" arity="0" since="OTP @OTP-15625@"/>
+      <fsummary>Return a timestamp to insert in meta data for a log
+	event.</fsummary>
+      <desc>
+        <p>Return a timestamp that can be inserted as the <c>time</c>
+          field in the meta data for a log event. It is produced with
+	  <seealso marker="kernel:os#system_time-1">
+            <c>os:system_time(microsecond)</c></seealso>.</p>
+	<p>Notice that Logger automatically inserts a timestamp in the
+	  meta data unless it already exists. This function is
+	  exported for the rare case when the timestamp must be taken
+	  at a different point in time than when the log event is
+	  issued.</p>
+      </desc>
+    </func>
+
   </funcs>
 
   <section>
diff --git a/lib/kernel/src/code_server.erl b/lib/kernel/src/code_server.erl
index 1b4a67ecb7..68e1205301 100644
--- a/lib/kernel/src/code_server.erl
+++ b/lib/kernel/src/code_server.erl
@@ -1434,19 +1434,25 @@ all_loaded(Db) ->
 
 -spec error_msg(io:format(), [term()]) -> 'ok'.
 error_msg(Format, Args) ->
+    %% This is equal to calling logger:error/3 which we don't want to
+    %% do from code_server. We don't want to call logger:timestamp()
+    %% either.
     logger ! {log,error,Format,Args,
               #{pid=>self(),
                 gl=>group_leader(),
-                time=>erlang:system_time(microsecond),
+                time=>os:system_time(microsecond),
                 error_logger=>#{tag=>error}}},
     ok.
 
 -spec info_msg(io:format(), [term()]) -> 'ok'.
 info_msg(Format, Args) ->
+    %% This is equal to calling logger:info/3 which we don't want to
+    %% do from code_server. We don't want to call logger:timestamp()
+    %% either.
     logger ! {log,info,Format,Args,
               #{pid=>self(),
                 gl=>group_leader(),
-                time=>erlang:system_time(microsecond),
+                time=>os:system_time(microsecond),
                 error_logger=>#{tag=>info_msg}}},
     ok.
 
diff --git a/lib/kernel/src/logger.erl b/lib/kernel/src/logger.erl
index 7d36640f52..38bd2f481c 100644
--- a/lib/kernel/src/logger.erl
+++ b/lib/kernel/src/logger.erl
@@ -61,6 +61,7 @@
 -export([set_process_metadata/1, update_process_metadata/1,
          unset_process_metadata/0, get_process_metadata/0]).
 -export([i/0, i/1]).
+-export([timestamp/0]).
 
 %% Basic report formatting
 -export([format_report/1, format_otp_report/1]).
@@ -154,7 +155,8 @@
               filter_return/0,
               config_handler/0,
               formatter_config/0,
-              olp_config/0]).
+              olp_config/0,
+              timestamp/0]).
 
 %%%-----------------------------------------------------------------
 %%% API
@@ -354,6 +356,10 @@ internal_log(Level,Term) when is_atom(Level) ->
     erlang:display_string("Logger - "++ atom_to_list(Level) ++ ": "),
     erlang:display(Term).
 
+-spec timestamp() -> timestamp().
+timestamp() ->
+    os:system_time(microsecond).
+
 %%%-----------------------------------------------------------------
 %%% Configuration
 -spec add_primary_filter(FilterId,Filter) -> ok | {error,term()} when
@@ -1129,7 +1135,7 @@ proc_meta() ->
 
 default(pid) -> self();
 default(gl) -> group_leader();
-default(time) -> erlang:system_time(microsecond).
+default(time) -> timestamp().
 
 %% Remove everything upto and including this module from the stacktrace
 filter_stacktrace(Module,[{Module,_,_,_}|_]) ->
diff --git a/lib/kernel/src/logger_h_common.erl b/lib/kernel/src/logger_h_common.erl
index e69f6de38d..4b5e0a7dd0 100644
--- a/lib/kernel/src/logger_h_common.erl
+++ b/lib/kernel/src/logger_h_common.erl
@@ -351,7 +351,7 @@ log_handler_info(Name, Format, Args, #{module:=Module,
             {ok,Conf} -> Conf;
             _ -> #{formatter=>{?DEFAULT_FORMATTER,?DEFAULT_FORMAT_CONFIG}}
         end,
-    Meta = #{time=>erlang:system_time(microsecond)},
+    Meta = #{time=>logger:timestamp()},
     Bin = log_to_binary(#{level => notice,
                           msg => {Format,Args},
                           meta => Meta}, Config),
diff --git a/lib/kernel/src/logger_simple_h.erl b/lib/kernel/src/logger_simple_h.erl
index fe181722f3..a0d51dba25 100644
--- a/lib/kernel/src/logger_simple_h.erl
+++ b/lib/kernel/src/logger_simple_h.erl
@@ -69,7 +69,7 @@ log(#{msg:=_,meta:=#{time:=_}}=Log,_Config) ->
                 do_log(
                   #{level=>error,
                     msg=>{report,{error,simple_handler_process_dead}},
-                    meta=>#{time=>erlang:system_time(microsecond)}}),
+                    meta=>#{time=>logger:timestamp()}}),
                 do_log(Log);
             _ ->
                 ?MODULE ! {log,Log}
@@ -129,7 +129,7 @@ drop_msg(0) ->
 drop_msg(N) ->
     [#{level=>info,
        msg=>{"Simple handler buffer full, dropped ~w messages",[N]},
-       meta=>#{time=>erlang:system_time(microsecond)}}].
+       meta=>#{time=>logger:timestamp()}}].
 
 %%%-----------------------------------------------------------------
 %%% Internal
diff --git a/lib/kernel/test/logger_SUITE.erl b/lib/kernel/test/logger_SUITE.erl
index 2dad651f9c..70bb775db8 100644
--- a/lib/kernel/test/logger_SUITE.erl
+++ b/lib/kernel/test/logger_SUITE.erl
@@ -899,14 +899,14 @@ process_metadata(_Config) ->
     undefined = logger:get_process_metadata(),
     {error,badarg} = ?TRY(logger:set_process_metadata(bad)),
     ok = logger:add_handler(h1,?MODULE,#{level=>notice,filter_default=>log}),
-    Time = erlang:system_time(microsecond),
+    Time = logger:timestamp(),
     ProcMeta = #{time=>Time,line=>0,custom=>proc},
     ok = logger:set_process_metadata(ProcMeta),
     S1 = ?str,
     ?LOG_NOTICE(S1,#{custom=>macro}),
     check_logged(notice,S1,#{time=>Time,line=>0,custom=>macro}),
 
-    Time2 = erlang:system_time(microsecond),
+    Time2 = logger:timestamp(),
     S2 = ?str,
     ?LOG_NOTICE(S2,#{time=>Time2,line=>1,custom=>macro}),
     check_logged(notice,S2,#{time=>Time2,line=>1,custom=>macro}),
diff --git a/lib/kernel/test/logger_formatter_SUITE.erl b/lib/kernel/test/logger_formatter_SUITE.erl
index 8c13f0f908..83e3e6c40a 100644
--- a/lib/kernel/test/logger_formatter_SUITE.erl
+++ b/lib/kernel/test/logger_formatter_SUITE.erl
@@ -867,7 +867,7 @@ my_try(Fun) ->
     try Fun() catch C:R:S -> {C,R,hd(S)} end.
 
 timestamp() ->
-    erlang:system_time(microsecond).
+    logger:timestamp().
 
 %% necessary?
 add_time(#{time:=_}=Meta) ->