| % 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, config_change/3]). |
| |
| start_link() -> |
| supervisor:start_link({local, couch_db_update_notifier_sup}, |
| couch_db_update_notifier_sup, []). |
| |
| init([]) -> |
| ok = couch_config:register(fun ?MODULE:config_change/3), |
| |
| 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 |
| config_change("update_notification", 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). |
| |