1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
%% 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).
-include("rabbit.hrl").
-export([start_heartbeat/3,
start_heartbeat_sender/2,
start_heartbeat_receiver/2]).
start_heartbeat(_Sup, _Sock, 0) ->
none;
start_heartbeat(Sup, Sock, TimeoutSec) ->
{ok, _Sender} =
supervisor:start_child(
Sup, {heartbeat_sender,
{?MODULE, start_heartbeat_sender, [Sock, TimeoutSec]},
permanent, ?MAX_WAIT, worker, [rabbit_heartbeat]}),
{ok, _Receiver} =
supervisor:start_child(
Sup, {heartbeat_receiver,
{?MODULE, start_heartbeat_receiver, [Sock, TimeoutSec]},
permanent, ?MAX_WAIT, worker, [rabbit_heartbeat]}),
ok.
start_heartbeat_sender(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.
{ok, proc_lib:spawn_link(
fun () -> heartbeater(Sock, TimeoutSec * 1000 div 2,
send_oct, 0,
fun () ->
catch rabbit_net:send(Sock, rabbit_binary_generator:build_heartbeat_frame()),
continue
end)
end)}.
start_heartbeat_receiver(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.
{ok, proc_lib:spawn_link(
fun () -> heartbeater(Sock, TimeoutSec * 1000,
recv_oct, 1,
fun () -> exit(timeout) end)
end)}.
%% Y-combinator, posted by Vladimir Sekissov to the Erlang mailing list
%% http://www.erlang.org/ml-archive/erlang-questions/200301/msg00053.html
y(X) ->
F = fun (P) -> X(fun (A) -> (P(P))(A) end) end,
F(F).
heartbeater(Sock, TimeoutMillisec, StatName, Threshold, Handler) ->
Heartbeat =
fun (F) ->
fun ({StatVal, SameCount}) ->
receive
Other -> exit({unexpected_message, Other})
after TimeoutMillisec ->
case rabbit_net:getstat(Sock, [StatName]) of
{ok, [{StatName, NewStatVal}]} ->
if NewStatVal =/= StatVal ->
F({NewStatVal, 0});
SameCount < Threshold ->
F({NewStatVal, SameCount + 1});
true ->
case Handler() of
stop -> ok;
continue -> F({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
end
end,
(y(Heartbeat))({0, 0}).
|
