Added Rotator Behaviour Definition

src/lager_rotator_behaviour.erl

@@ -0,0 +1,18 @@
+-module(lager_rotator_behaviour).
+
+%% @doc Create a log file
+-callback(create_logfile(Name::list(), Buffer::{integer(), integer()} | any()) ->
+    {ok, {file:io_device(), integer(), integer()}} | {error, any()}).
+
+%% @doc Open a log file
+-callback(open_logfile(Name::list(), Buffer::{integer(), integer()} | any()) ->
+    {ok, {file:io_device(), integer(), integer()}} | {error, any()}).
+
+%% @doc Ensure reference to current target, could be rotated
+-callback(ensure_logfile(Name::list(), FD::file:io_device(), Inode::integer(),
+                         Buffer::{integer(), integer()} | any()) ->
+    {ok, {file:io_device(), integer(), integer()}} | {error, any()}).
+
+%% @doc Rotate the log file
+-callback(rotate_logfile(Name::list(), Count::integer()) ->
+    ok).

src/lager_util.erl

@@ -39,6 +39,8 @@
 
 -include("lager.hrl").
 
+-behaviour(lager_rotator_behaviour).
+
 levels() ->
     [debug, info, notice, warning, error, critical, alert, emergency, none].