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%% The contents of this file are subject to the Mozilla Public License
%% Version 1.1 (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.mozilla.org/MPL/
%%
%% 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.
%%
%% The Original Code is RabbitMQ.
%%
%% The Initial Developers of the Original Code are LShift Ltd,
%% Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
%%
%% Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
%% Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
%% are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
%% Technologies LLC, and Rabbit Technologies Ltd.
%%
%% Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
%% Ltd. Portions created by Cohesive Financial Technologies LLC are
%% Copyright (C) 2007-2010 Cohesive Financial Technologies
%% LLC. Portions created by Rabbit Technologies Ltd are Copyright
%% (C) 2007-2010 Rabbit Technologies Ltd.
%%
%% All Rights Reserved.
%%
%% Contributor(s): ______________________________________.
%%
-module(rabbit_heartbeat).
-export([start_heartbeat_sender/3, start_heartbeat_receiver/3,
pause_monitor/1, resume_monitor/1]).
-include("rabbit.hrl").
%%----------------------------------------------------------------------------
-ifdef(use_specs).
-export_type([heartbeaters/0]).
-type(heartbeaters() :: rabbit_types:maybe({pid(), pid()})).
-spec(start_heartbeat_sender/3 ::
(pid(), rabbit_net:socket(), non_neg_integer()) ->
rabbit_types:ok(pid())).
-spec(start_heartbeat_receiver/3 ::
(pid(), rabbit_net:socket(), non_neg_integer()) ->
rabbit_types:ok(pid())).
-spec(pause_monitor/1 :: (heartbeaters()) -> 'ok').
-spec(resume_monitor/1 :: (heartbeaters()) -> 'ok').
-endif.
%%----------------------------------------------------------------------------
start_heartbeat_sender(_Parent, Sock, TimeoutSec) ->
%% the 'div 2' is there so that we don't end up waiting for nearly
%% 2 * TimeoutSec before sending a heartbeat in the boundary case
%% where the last message was sent just after a heartbeat.
heartbeater(
{Sock, TimeoutSec * 1000 div 2, send_oct, 0,
fun () ->
catch rabbit_net:send(
Sock, rabbit_binary_generator:build_heartbeat_frame()),
continue
end}).
start_heartbeat_receiver(Parent, Sock, TimeoutSec) ->
%% we check for incoming data every interval, and time out after
%% two checks with no change. As a result we will time out between
%% 2 and 3 intervals after the last data has been received.
heartbeater({Sock, TimeoutSec * 1000, recv_oct, 1, fun () ->
Parent ! timeout,
stop
end}).
pause_monitor(none) ->
ok;
pause_monitor({_Sender, Receiver}) ->
Receiver ! pause,
ok.
resume_monitor(none) ->
ok;
resume_monitor({_Sender, Receiver}) ->
Receiver ! resume,
ok.
%%----------------------------------------------------------------------------
heartbeater(Params) ->
{ok, proc_lib:spawn_link(fun () -> heartbeater(Params, {0, 0}) end)}.
heartbeater({Sock, TimeoutMillisec, StatName, Threshold, Handler} = Params,
{StatVal, SameCount}) ->
Recurse = fun (V) -> heartbeater(Params, V) end,
receive
pause ->
receive
resume ->
Recurse({0, 0});
Other ->
exit({unexpected_message, Other})
end;
Other ->
exit({unexpected_message, Other})
after TimeoutMillisec ->
case rabbit_net:getstat(Sock, [StatName]) of
{ok, [{StatName, NewStatVal}]} ->
if NewStatVal =/= StatVal ->
Recurse({NewStatVal, 0});
SameCount < Threshold ->
Recurse({NewStatVal, SameCount + 1});
true ->
case Handler() of
stop -> ok;
continue -> Recurse({NewStatVal, 0})
end
end;
{error, einval} ->
%% the socket is dead, most likely because the
%% connection is being shut down -> terminate
ok;
{error, Reason} ->
exit({cannot_get_socket_stats, Reason})
end
end.
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