%%--------------------------------------------------------------------
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1999-2009. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
%%----------------------------------------------------------------------
%% File : etrap_logmgr.erl
%% Purpose : Make it easier to use disk_log.
%%----------------------------------------------------------------------
-module(etrap_logmgr).
%%--------------- INCLUDES -----------------------------------
%% Local
-include_lib("ETraP_Common.hrl").
%%--------------- IMPORTS-------------------------------------
%%--------------- EXPORTS-------------------------------------
-export([start/1, stop/1, log_safe/2, log_lazy/2, get_next/2]).
%%------------------------------------------------------------
%% function : start
%% Arguments: LogName - name of the disk_log.
%% Returns :
%% Effect : creating linked log
%%------------------------------------------------------------
start(LogName) ->
case catch disk_log:open([{name, LogName},
{file, LogName},
{type, halt},
{size, infinity}]) of
{ok, LogName} ->
ok;
{error, Reason} ->
?tr_error_msg("Initiating internal log failed: ~p", [Reason]),
exit({error, Reason});
{repaired, LogName, {recovered, _Rec}, {badbytes, _Bad}} ->
ok;
Other ->
?tr_error_msg("Initiating internal log failed: ~p", [Other]),
exit({error, Other})
end.
%%------------------------------------------------------------
%% function : stop
%% Arguments: LogName - name of the disk_log.
%% Returns :
%% Effect :
%%------------------------------------------------------------
stop(LogName) ->
case catch disk_log:close(LogName) of
ok ->
ok;
{error, Reason} ->
?tr_error_msg("Stopping internal log failed: ~p", [Reason]),
{error, Reason};
Other ->
?tr_error_msg("Stopping internal log failed: ~p", [Other]),
{error, Other}
end.
%%------------------------------------------------------------
%% function : log_safe
%% Arguments: LogName - name of the disk_log. If 'dummy' is
%% used nothing should be logged. Reason, reuse code.
%% LogRecord - record to store in the log.
%% Returns :
%% Effect : Writes a logrecord and synchronizes to make sure
%% that the record is stored.
%%------------------------------------------------------------
log_safe(dummy, _) ->
ok;
log_safe(LogName, LogRecord) ->
case write_safe(LogName, LogRecord) of
ok ->
ok;
_ ->
%% We have to catch the exit because in some cases
%% it's not possible to abort action in the 2PC-protocol.
case catch start(LogName) of
ok ->
write_safe(LogName, LogRecord);
{'EXIT', Reason} ->
{error, Reason}
end
end.
write_safe(LogName, LogRecord) ->
case catch disk_log:log(LogName, LogRecord) of
ok -> % wrote to kernel successfully
case catch disk_log:sync(LogName) of
ok -> % Written to disk successfully
ok;
{error, Reason} ->
?tr_error_msg("Internal log write failed: ~p ~p",
[Reason, LogName]),
{error, Reason};
Other ->
?tr_error_msg("Internal log write failed: ~p ~p",
[Other, LogName]),
{error, Other}
end;
{error, Reason} ->
?tr_error_msg("Internal log write failed: ~p ~p", [Reason, LogName]),
{error, Reason};
Other ->
?tr_error_msg("Internal log write failed: ~p ~p", [Other, LogName]),
{error, Other}
end.
%%------------------------------------------------------------
%% function : log_lazy
%% Arguments: LogName - name of the disk_log. If 'dummy' is
%% used nothing should be logged. Reason, reuse code.
%% LogRecord - record to store in the log.
%% Returns :
%% Effect : Writes a logrecord. The record may be lost.
%%------------------------------------------------------------
log_lazy(dummy, _LogRecord) ->
ok;
log_lazy(LogName, LogRecord) ->
case write_lazy(LogName, LogRecord) of
ok ->
ok;
_ ->
%% We have to catch the exit because in some cases
%% it's not possible to abort action in the 2PC-protocol.
case catch start(LogName) of
ok ->
write_lazy(LogName, LogRecord);
{'EXIT', Reason} ->
{error, Reason}
end
end.
write_lazy(LogName, LogRecord) ->
case catch disk_log:log(LogName, LogRecord) of
ok ->
%% wrote to kernel successfully
ok;
{error, Reason} ->
%% Write to kernel failed with Reason
?tr_error_msg("Internal log write failed: ~p", [Reason]),
{error, Reason};
Other ->
%% unknown message received.
?tr_error_msg("Internal log write failed: ~p", [Other]),
{error, Other}
end.
%%------------------------------------------------------------
%% function : get_next
%% Arguments: LogName - name of the disk_log.
%% Cursor - place to read from.
%% Returns : {Cursor, LogRecs} - A cursor and up to N logrecords.
%% eof - the atom 'eof', indicating logfile empty.
%% {error, Reason} - error.
%% Effect :
%% Purpose : Used when performing a REDO scan
%%------------------------------------------------------------
get_next(LogName, Cursor) ->
case catch disk_log:chunk(LogName, Cursor, 1) of
{NewCursor, [Data]} ->
{Data, NewCursor};
eof ->
eof;
{error, Reason} ->
?tr_error_msg("Internal log '~p' read failed: ~p",
[LogName, Reason]),
exit({error, Reason});
_Other ->
?tr_error_msg("Internal log '~p' read failed: 'log_corrupt'", [LogName]),
exit({error, "log_corrupt"})
end.
%%--------------- END OF MODULE ------------------------------
