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
|
% Licensed 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.
%
% This causes an OS process to spawned and it is notified every time a database
% is updated.
%
% The notifications are in the form of a the database name sent as a line of
% text to the OS processes stdout.
%
-module(couch_db_update_notifier_sup).
-behaviour(supervisor).
-export([start_link/0,init/1]).
start_link() ->
supervisor:start_link({local, couch_db_update_notifier_sup},
couch_db_update_notifier_sup, []).
init([]) ->
ok = couch_config:register(
fun("update_notification", Key, Value) -> reload_config(Key, Value) end
),
UpdateNotifierExes = couch_config:get("update_notification"),
{ok,
{{one_for_one, 10, 3600},
lists:map(fun({Name, UpdateNotifierExe}) ->
{Name,
{couch_db_update_notifier, start_link, [UpdateNotifierExe]},
permanent,
1000,
supervisor,
[couch_db_update_notifier]}
end, UpdateNotifierExes)}}.
%% @doc when update_notification configuration changes, terminate the process
%% for that notifier and start a new one with the updated config
reload_config(Id, Exe) ->
ChildSpec = {
Id,
{couch_db_update_notifier, start_link, [Exe]},
permanent,
1000,
supervisor,
[couch_db_update_notifier]
},
supervisor:terminate_child(couch_db_update_notifier_sup, Id),
supervisor:delete_child(couch_db_update_notifier_sup, Id),
supervisor:start_child(couch_db_update_notifier_sup, ChildSpec).
|
