-module(lager_rotator_default).
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-include_lib("kernel/include/file.hrl").
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-behaviour(lager_rotator_behaviour).
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-export([
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create_logfile/2, open_logfile/2, ensure_logfile/4, rotate_logfile/2
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]).
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-ifdef(TEST).
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-include_lib("eunit/include/eunit.hrl").
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-endif.
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create_logfile(Name, Buffer) ->
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open_logfile(Name, Buffer).
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open_logfile(Name, Buffer) ->
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case filelib:ensure_dir(Name) of
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ok ->
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Options = [append, raw] ++
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case Buffer of
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{Size, Interval} when is_integer(Interval), Interval >= 0, is_integer(Size), Size >= 0 ->
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[{delayed_write, Size, Interval}];
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_ -> []
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end,
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case file:open(Name, Options) of
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{ok, FD} ->
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case file:read_file_info(Name) of
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{ok, FInfo} ->
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Inode = FInfo#file_info.inode,
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{ok, {FD, Inode, FInfo#file_info.size}};
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X -> X
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end;
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Y -> Y
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end;
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Z -> Z
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end.
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ensure_logfile(Name, FD, Inode, Buffer) ->
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case file:read_file_info(Name) of
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{ok, FInfo} ->
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Inode2 = FInfo#file_info.inode,
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case Inode == Inode2 of
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true ->
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{ok, {FD, Inode, FInfo#file_info.size}};
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false ->
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%% delayed write can cause file:close not to do a close
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_ = file:close(FD),
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_ = file:close(FD),
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case open_logfile(Name, Buffer) of
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{ok, {FD2, Inode3, Size}} ->
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%% inode changed, file was probably moved and
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%% recreated
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{ok, {FD2, Inode3, Size}};
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Error ->
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Error
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end
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end;
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_ ->
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%% delayed write can cause file:close not to do a close
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_ = file:close(FD),
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_ = file:close(FD),
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case open_logfile(Name, Buffer) of
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{ok, {FD2, Inode3, Size}} ->
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%% file was removed
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{ok, {FD2, Inode3, Size}};
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Error ->
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Error
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end
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end.
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%% renames failing are OK
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rotate_logfile(File, 0) ->
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%% open the file in write-only mode to truncate/create it
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case file:open(File, [write]) of
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{ok, FD} ->
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file:close(FD),
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ok;
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Error ->
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Error
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end;
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rotate_logfile(File, 1) ->
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_ = file:rename(File, File++".0"),
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rotate_logfile(File, 0);
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rotate_logfile(File, Count) ->
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_ = file:rename(File ++ "." ++ integer_to_list(Count - 2), File ++ "." ++ integer_to_list(Count - 1)),
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rotate_logfile(File, Count - 1).
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-ifdef(TEST).
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rotate_file_test() ->
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RotCount = 10,
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TestDir = lager_util:create_test_dir(),
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TestLog = filename:join(TestDir, "rotation.log"),
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Outer = fun(N) ->
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?assertEqual(ok, file:write_file(TestLog, erlang:integer_to_list(N))),
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Inner = fun(M) ->
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File = lists:flatten([TestLog, $., erlang:integer_to_list(M)]),
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?assert(filelib:is_regular(File)),
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%% check the expected value is in the file
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Number = erlang:list_to_binary(integer_to_list(N - M - 1)),
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?assertEqual({ok, Number}, file:read_file(File))
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end,
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Count = erlang:min(N, RotCount),
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% The first time through, Count == 0, so the sequence is empty,
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% effectively skipping the inner loop so a rotation can occur that
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% creates the file that Inner looks for.
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% Don't shoot the messenger, it was worse before this refactoring.
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lists:foreach(Inner, lists:seq(0, Count-1)),
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rotate_logfile(TestLog, RotCount)
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end,
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lists:foreach(Outer, lists:seq(0, (RotCount * 2))),
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lager_util:delete_test_dir(TestDir).
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rotate_file_zero_count_test() ->
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%% Test that a rotation count of 0 simply truncates the file
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TestDir = lager_util:create_test_dir(),
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TestLog = filename:join(TestDir, "rotation.log"),
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?assertMatch(ok, rotate_logfile(TestLog, 0)),
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?assertNot(filelib:is_regular(TestLog ++ ".0")),
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?assertEqual(true, filelib:is_regular(TestLog)),
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?assertEqual(1, length(filelib:wildcard(TestLog++"*"))),
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%% assert the new file is 0 size:
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case file:read_file_info(TestLog) of
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{ok, FInfo} ->
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?assertEqual(0, FInfo#file_info.size);
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_ ->
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?assert(false)
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end,
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lager_util:delete_test_dir(TestDir).
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rotate_file_fail_test() ->
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TestDir = lager_util:create_test_dir(),
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TestLog = filename:join(TestDir, "rotation.log"),
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%% set known permissions on it
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os:cmd("chmod -R u+rwx " ++ TestDir),
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%% write a file
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file:write_file(TestLog, "hello"),
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%% hose up the permissions
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os:cmd("chmod -R u-w " ++ TestDir),
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?assertMatch({error, _}, rotate_logfile(TestLog, 10)),
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%% check we still only have one file, rotation.log
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?assertEqual([TestLog], filelib:wildcard(TestLog++"*")),
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?assert(filelib:is_regular(TestLog)),
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%% fix the permissions
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os:cmd("chmod -R u+w " ++ TestDir),
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?assertMatch(ok, rotate_logfile(TestLog, 10)),
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?assert(filelib:is_regular(TestLog ++ ".0")),
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?assertEqual(true, filelib:is_regular(TestLog)),
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?assertEqual(2, length(filelib:wildcard(TestLog++"*"))),
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%% assert the new file is 0 size:
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case file:read_file_info(TestLog) of
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{ok, FInfo} ->
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?assertEqual(0, FInfo#file_info.size);
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_ ->
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?assert(false)
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end,
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%% check that the .0 file now has the contents "hello"
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?assertEqual({ok, <<"hello">>}, file:read_file(TestLog++".0")),
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lager_util:delete_test_dir(TestDir).
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-endif.
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