File 3511-Allow-metadata-and-ignore-to-be-computed-i... of Package erlang

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File 3511-Allow-metadata-and-ignore-to-be-computed-in-logger-f.patch of Package erlang

From 73f04748306e21e46b1f7c2c220bce0df2115d0e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@dashbit.co>
Date: Sat, 22 Aug 2020 19:47:50 +0200
Subject: [PATCH 1/2] Allow metadata and ignore to be computed in logger funs

This commit allows the logger metadata to be
computed lazily via the logger `msg_fun`.
The `msg_fun` itself can also return `ignore`.

These features are useful when computing the
metadata or if the message should be logged or
not is expensive and you want to do so only
after the log level match.
---
 lib/kernel/doc/src/logger.xml    |  6 +++++
 lib/kernel/src/logger.erl        | 42 ++++++++++++++++++++------------
 lib/kernel/test/logger_SUITE.erl | 10 ++++++++
 3 files changed, 43 insertions(+), 15 deletions(-)

diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
index 801a2c1193..2f2417690b 100644
--- a/lib/kernel/doc/src/logger.xml
+++ b/lib/kernel/doc/src/logger.xml
@@ -244,6 +244,12 @@ logger:error("error happened because: ~p", [Reason]). % Without macro
 	<p></p>
       </desc>
     </datatype>
+    <datatype>
+      <name name="msg_fun_return"/>
+      <desc>
+        <p></p>
+      </desc>
+    </datatype>
     <datatype>
       <name name="olp_config"/>
       <desc>
diff --git a/lib/kernel/src/logger.erl b/lib/kernel/src/logger.erl
index 167637b8b4..eadf15f108 100644
--- a/lib/kernel/src/logger.erl
+++ b/lib/kernel/src/logger.erl
@@ -86,9 +86,11 @@
 -type report_cb_config() :: #{depth       := pos_integer() | unlimited,
                               chars_limit := pos_integer() | unlimited,
                               single_line := boolean()}.
--type msg_fun() :: fun((term()) -> {io:format(),[term()]} |
-                                   report() |
-                                   unicode:chardata()).
+-type msg_fun() :: fun((term()) -> msg_fun_return() | {msg_fun_return(), metadata()}).
+-type msg_fun_return() :: {io:format(),[term()]} |
+                           report() |
+                           unicode:chardata() |
+                           ignore.
 -type metadata() :: #{pid    => pid(),
                       gl     => pid(),
                       time   => timestamp(),
@@ -1048,19 +1050,12 @@ do_log(Level,Msg,Meta) ->
              report() |
              unicode:chardata(),
       Meta :: metadata().
-log_allowed(Location,Level,{Fun,FunArgs},Meta) when is_function(Fun,1) ->
+log_allowed(Location,Level,{Fun,FunArgs}=FunCall,Meta) when is_function(Fun,1) ->
     try Fun(FunArgs) of
-        Msg={Format,Args} when ?IS_FORMAT(Format), is_list(Args) ->
-            log_allowed(Location,Level,Msg,Meta);
-        Report when ?IS_REPORT(Report) ->
-            log_allowed(Location,Level,Report,Meta);
-        String when ?IS_STRING(String) ->
-            log_allowed(Location,Level,String,Meta);
-        Other ->
-            log_allowed(Location,Level,
-                        {"LAZY_FUN ERROR: ~tp; Returned: ~tp",
-                         [{Fun,FunArgs},Other]},
-                        Meta)
+        {FunRes, #{} = FunMeta} ->
+            log_fun_allowed(Location, Level, FunRes, maps:merge(Meta, FunMeta), FunCall);
+        FunRes ->
+            log_fun_allowed(Location, Level, FunRes, Meta, FunCall)
     catch C:R ->
             log_allowed(Location,Level,
                         {"LAZY_FUN CRASH: ~tp; Reason: ~tp",
@@ -1083,6 +1078,23 @@ log_allowed(Location,Level,Msg,Meta0) when is_map(Meta0) ->
     end,
     do_log_allowed(Level,Msg,Meta,Tid,PrimaryConfig).
 
+log_fun_allowed(Location, Level, FunRes, Meta, FunCall) ->
+    case FunRes of
+        ignore ->
+            ok;
+        Msg={Format,Args} when ?IS_FORMAT(Format), is_list(Args) ->
+            log_allowed(Location,Level,Msg,Meta);
+        Report when ?IS_REPORT(Report) ->
+            log_allowed(Location,Level,Report,Meta);
+        String when ?IS_STRING(String) ->
+            log_allowed(Location,Level,String,Meta);
+        Other ->
+            log_allowed(Location,Level,
+                        {"LAZY_FUN ERROR: ~tp; Returned: ~tp",
+                         [FunCall,Other]},
+                        Meta)
+    end.
+
 do_log_allowed(Level,{Format,Args}=Msg,Meta,Tid,Config)
   when ?IS_LEVEL(Level),
        ?IS_FORMAT(Format),
diff --git a/lib/kernel/test/logger_SUITE.erl b/lib/kernel/test/logger_SUITE.erl
index 8513cf2936..d1e7b1a4fc 100644
--- a/lib/kernel/test/logger_SUITE.erl
+++ b/lib/kernel/test/logger_SUITE.erl
@@ -1341,6 +1341,16 @@ test_log_function(Level) ->
     logger:log(Level,F2=fun(x) -> erlang:error(fun_that_crashes) end,x,#{}),
     ok = check_logged(Level,"LAZY_FUN CRASH: ~tp; Reason: ~tp",
                       [{F2,x},{error,fun_that_crashes}],#{}),
+    logger:log(Level,fun(x) -> {{"~w: ~w ~w",[Level,fun_to_fa,meta]}, #{my=>override}} end,
+               x, #{my=>meta}),
+    ok = check_logged(Level,"~w: ~w ~w",[Level,fun_to_fa,meta],#{my=>override}),
+    logger:log(Level,fun(x) -> {#{Level=>fun_to_r,meta=>true}, #{my=>override}} end,
+               x, #{my=>meta}),
+    ok = check_logged(Level,#{Level=>fun_to_r,meta=>true},#{my=>override}),
+    logger:log(Level,fun(x) -> {<<"fun_to_s">>,#{my=>override}} end,x,#{my=>meta}),
+    ok = check_logged(Level,<<"fun_to_s">>,#{my=>override}),
+    logger:log(Level, fun(x) -> ignore end, x, #{}),
+    ok = check_no_log(),
     ok.
 
 test_macros(emergency=Level) ->
-- 
2.26.2

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File 3511-Allow-metadata-and-ignore-to-be-computed-in-logger-f.patch of Package erlang

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