From af3a2d79c4ff38bd72fc4e92d0900a1d925079a6 Mon Sep 17 00:00:00 2001
From: Daniil Fedotov <dfedotov@pivotal.io>
Date: Mon, 11 Jan 2016 13:03:18 +0000
Subject: [PATCH] API to explicitly call log rotation

---
 src/lager.erl              | 24 ++++++++++++++++++++++++
 src/lager_file_backend.erl |  8 ++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/lager.erl b/src/lager.erl
index 9e4b051..aa9e2b5 100644
--- a/src/lager.erl
+++ b/src/lager.erl
@@ -28,6 +28,7 @@
         log/3, log/4, log/5,
         log_unsafe/4,
         md/0, md/1,
+        rotate_file/1, rotate_sink/1, rotate_all/0,
         trace/2, trace/3, trace_file/2, trace_file/3, trace_file/4, trace_console/1, trace_console/2,
         list_all_sinks/0, clear_all_traces/0, stop_trace/1, stop_trace/3, status/0,
         get_loglevel/1, get_loglevel/2, set_loglevel/2, set_loglevel/3, set_loglevel/4, get_loglevels/1,
@@ -594,3 +595,26 @@ pr_stacktrace(Stacktrace) ->
 pr_stacktrace(Stacktrace, {Class, Reason}) ->
     lists:flatten(
         pr_stacktrace(Stacktrace) ++ "\n" ++ io_lib:format("~s:~p", [Class, Reason])).
+
+rotate_file(FileName) ->
+    Handlers = lager_config:global_get(handlers),
+    RotateHandlers = lists:filter(
+        fun ({{lager_file_backend, FN}, _, _}) ->
+                FN == FileName orelse 
+                lager_util:expand_path(FN) == lager_util:expand_path(FileName);
+            (_) -> false
+        end,
+        Handlers),
+    lager_file_backend:rotate_handlers(RotateHandlers).
+
+rotate_sink(Sink) ->
+    Handlers = lager_config:global_get(handlers),
+    RotateHandlers = lists:filter(
+        fun({_,_,S}) -> S == Sink; 
+           (_) -> false 
+        end, 
+        Handlers),
+    lager_file_backend:rotate_handlers(RotateHandlers).
+
+rotate_all() -> 
+    lager_file_backend:rotate_handlers(lager_config:global_get(handlers)).
\ No newline at end of file
diff --git a/src/lager_file_backend.erl b/src/lager_file_backend.erl
index 1c18dc4..658fc2b 100644
--- a/src/lager_file_backend.erl
+++ b/src/lager_file_backend.erl
@@ -42,6 +42,7 @@
 
 -export([init/1, handle_call/2, handle_event/2, handle_info/2, terminate/2,
         code_change/3]).
+-export([rotate_handlers/1, rotate_handler/1]).
 
 -export([config_to_id/1]).
 
@@ -401,6 +402,13 @@ schedule_rotation(Name, Date) ->
     erlang:send_after(lager_util:calculate_next_rotation(Date) * 1000, self(), {rotate, Name}),
     ok.
 
+rotate_handlers(Handlers) ->
+    [ rotate_handler(Handler) || Handler <- Handlers ].
+
+rotate_handler({{lager_file_backend, FileName}, Handler, _Sink}) ->
+    Handler ! {rotate, lager_util:expand_path(FileName)};
+rotate_handler(_) -> ok.
+
 -ifdef(TEST).
 
 get_loglevel_test() ->