From 9cc4abc36661afcccf91ce86de39aad30bd2fc3a Mon Sep 17 00:00:00 2001
From: "John R. Daily" <git@epep.us>
Date: Tue, 23 Jun 2015 16:10:03 -0400
Subject: [PATCH] Support _unsafe message levels that dodge trunc_io

---
 include/lager.hrl       | 25 +++++++++++++++----------
 src/lager_transform.erl | 19 +++++++++++++++++--
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/include/lager.hrl b/include/lager.hrl
index 124e17d..f9ddf99 100644
--- a/include/lager.hrl
+++ b/include/lager.hrl
@@ -22,6 +22,11 @@
 -define(LEVELS,
     [debug, info, notice, warning, error, critical, alert, emergency, none]).
 
+%% Use of these "functions" means that the argument list will not be
+%% truncated for safety
+-define(LEVELS_UNSAFE,
+    [debug_unsafe, info_unsafe, notice_unsafe, warning_unsafe, error_unsafe, critical_unsafe, alert_unsafe, emergency_unsafe]).
+
 -define(DEBUG, 128).
 -define(INFO, 64).
 -define(NOTICE, 32).
@@ -64,7 +69,7 @@
             Level,
             [{pid,Pid},{line,?LINE},{file,?FILE},{module,?MODULE}],
             [])}
-        )). 
+        )).
 
 %% FOR INTERNAL USE ONLY
 %% internal non-blocking logging call
@@ -102,14 +107,14 @@
 -endif.
 
 -record(lager_shaper, {
-		  %% how many messages per second we try to deliver
-		  hwm = undefined :: 'undefined' | pos_integer(),
-		  %% how many messages we've received this second
-		  mps = 0 :: non_neg_integer(),
-		  %% the current second
-		  lasttime = os:timestamp() :: erlang:timestamp(),
-		  %% count of dropped messages this second
-		  dropped = 0 :: non_neg_integer()
-		 }).
+                  %% how many messages per second we try to deliver
+                  hwm = undefined :: 'undefined' | pos_integer(),
+                  %% how many messages we've received this second
+                  mps = 0 :: non_neg_integer(),
+                  %% the current second
+                  lasttime = os:timestamp() :: erlang:timestamp(),
+                  %% count of dropped messages this second
+                  dropped = 0 :: non_neg_integer()
+                 }).
 
 -type lager_shaper() :: #lager_shaper{}.
diff --git a/src/lager_transform.erl b/src/lager_transform.erl
index eda84d1..1a1a681 100644
--- a/src/lager_transform.erl
+++ b/src/lager_transform.erl
@@ -89,7 +89,13 @@ transform_statement({call, Line, {remote, _Line1, {atom, _Line2, Module},
                     SinkName = list_to_atom(atom_to_list(Module) ++ "_event"),
                     do_transform(Line, SinkName, Function, Arguments0);
                 false ->
-                    Stmt
+                    case lists:member(Function, ?LEVELS_UNSAFE) of
+                        true ->
+                            SinkName = list_to_atom(atom_to_list(Module) ++ "_event"),
+                            do_transform(Line, SinkName, Function, Arguments0, unsafe);
+                        false ->
+                            Stmt
+                    end
             end;
         false ->
             list_to_tuple(transform_statement(tuple_to_list(Stmt), Sinks))
@@ -102,6 +108,9 @@ transform_statement(Stmt, _Sinks) ->
     Stmt.
 
 do_transform(Line, SinkName, Severity, Arguments0) ->
+    do_transform(Line, SinkName, Severity, Arguments0, safe).
+
+do_transform(Line, SinkName, Severity, Arguments0, Safety) ->
     SeverityAsInt=lager_util:level_to_num(Severity),
     DefaultAttrs0 = {cons, Line, {tuple, Line, [
                                                 {atom, Line, module}, {atom, Line, get(module)}]},
@@ -168,6 +177,12 @@ do_transform(Line, SinkName, Severity, Arguments0) ->
     LevelVar = make_varname("__Level", Line),
     TracesVar = make_varname("__Traces", Line),
     PidVar = make_varname("__Pid", Line),
+    LogFun = case Safety of
+                 safe ->
+                     do_log;
+                 unsafe ->
+                     do_log_unsafe
+             end,
     %% Wrap the call to lager:dispatch_log/6 in case that will avoid doing any work if this message is not elegible for logging
     %% See lager.erl (lines 89-100) for lager:dispatch_log/6
     %% case {whereis(Sink), whereis(?DEFAULT_SINK), lager_config:get({Sink, loglevel}, {?LOG_NONE, []})} of
@@ -205,7 +220,7 @@ do_transform(Line, SinkName, Severity, Arguments0) ->
                   [[{op, Line, 'orelse',
                     {op, Line, '/=', {op, Line, 'band', {var, Line, LevelVar}, {integer, Line, SeverityAsInt}}, {integer, Line, 0}},
                     {op, Line, '/=', {var, Line, TracesVar}, {nil, Line}}}]],
-                  [{call,Line,{remote, Line, {atom, Line, lager}, {atom, Line, do_log}},
+                  [{call,Line,{remote, Line, {atom, Line, lager}, {atom, Line, LogFun}},
                          [{atom,Line,Severity},
                           Meta,
                           Message,