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%%
%% Licensed to the Apache Software Foundation (ASF) under one
%% or more contributor license agreements. See the NOTICE file
%% distributed with this work for additional information
%% regarding copyright ownership. The ASF licenses this file
%% to you under the Apache License, Version 2.0 (the
%% "License"); you may not use this file except in compliance
%% with the License. You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing,
%% software distributed under the License is distributed on an
%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
%% KIND, either express or implied. See the License for the
%% specific language governing permissions and limitations
%% under the License.
%%
%%% Todo: this might be better off as a gen_server type of transport
%%% that handles stuff like group commit, similar to TFileTransport
%%% in cpp land
-module(thrift_disk_log_transport).
-behaviour(thrift_transport).
%% API
-export([new/2, new_transport_factory/2, new_transport_factory/3]).
%% thrift_transport callbacks
-export([read/2, write/2, force_flush/1, flush/1, close/1]).
%% state
-record(dl_transport, {log,
close_on_close = false,
sync_every = infinity,
sync_tref}).
%% Create a transport attached to an already open log.
%% If you'd like this transport to close the disk_log using disk_log:lclose()
%% when the transport is closed, pass a {close_on_close, true} tuple in the
%% Opts list.
new(LogName, Opts) when is_atom(LogName), is_list(Opts) ->
State = parse_opts(Opts, #dl_transport{log = LogName}),
State2 =
case State#dl_transport.sync_every of
N when is_integer(N), N > 0 ->
{ok, TRef} = timer:apply_interval(N, ?MODULE, force_flush, State),
State#dl_transport{sync_tref = TRef};
_ -> State
end,
thrift_transport:new(?MODULE, State2).
parse_opts([], State) ->
State;
parse_opts([{close_on_close, Bool} | Rest], State) when is_boolean(Bool) ->
State#dl_transport{close_on_close = Bool};
parse_opts([{sync_every, Int} | Rest], State) when is_integer(Int), Int > 0 ->
State#dl_transport{sync_every = Int}.
%%%% TRANSPORT IMPLENTATION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% disk_log_transport is write-only
read(_State, Len) ->
{error, no_read_from_disk_log}.
write(#dl_transport{log = Log}, Data) ->
disk_log:balog(Log, erlang:iolist_to_binary(Data)).
force_flush(#dl_transport{log = Log}) ->
error_logger:info_msg("~p syncing~n", [?MODULE]),
disk_log:sync(Log).
flush(#dl_transport{log = Log, sync_every = SE}) ->
case SE of
undefined -> % no time-based sync
disk_log:sync(Log);
_Else -> % sync will happen automagically
ok
end.
%% On close, close the underlying log if we're configured to do so.
close(#dl_transport{close_on_close = false}) ->
ok;
close(#dl_transport{log = Log}) ->
disk_log:lclose(Log).
%%%% FACTORY GENERATION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
new_transport_factory(Name, ExtraLogOpts) ->
new_transport_factory(Name, ExtraLogOpts, [{close_on_close, true},
{sync_every, 500}]).
new_transport_factory(Name, ExtraLogOpts, TransportOpts) ->
F = fun() -> factory_impl(Name, ExtraLogOpts, TransportOpts) end,
{ok, F}.
factory_impl(Name, ExtraLogOpts, TransportOpts) ->
LogOpts = [{name, Name},
{format, external},
{type, wrap} |
ExtraLogOpts],
Log =
case disk_log:open(LogOpts) of
{ok, Log} ->
Log;
{repaired, Log, Info1, Info2} ->
error_logger:info_msg("Disk log ~p repaired: ~p, ~p~n", [Log, Info1, Info2]),
Log
end,
new(Log, TransportOpts).
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