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author | Robert Newson <rnewson@apache.org> | 2011-05-17 11:15:14 +0000 |
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committer | Robert Newson <rnewson@apache.org> | 2011-05-17 11:15:14 +0000 |
commit | e8e4b0d293021fe90326a85828f3cfb087bf18b7 (patch) | |
tree | 986f544eac623ec23b769b36828894f93a173aa3 /1.1.x/src/couchdb/couch_event_sup.erl | |
parent | da6a5322b0b8084f434752060caa8be214c6f4fa (diff) |
tagging 1.1.0
git-svn-id: https://svn.apache.org/repos/asf/couchdb/tags/1.1.0@1104149 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to '1.1.x/src/couchdb/couch_event_sup.erl')
-rw-r--r-- | 1.1.x/src/couchdb/couch_event_sup.erl | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/1.1.x/src/couchdb/couch_event_sup.erl b/1.1.x/src/couchdb/couch_event_sup.erl new file mode 100644 index 00000000..07c48790 --- /dev/null +++ b/1.1.x/src/couchdb/couch_event_sup.erl @@ -0,0 +1,73 @@ +% 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. + +%% The purpose of this module is to allow event handlers to particpate in Erlang +%% supervisor trees. It provide a monitorable process that crashes if the event +%% handler fails. The process, when shutdown, deregisters the event handler. + +-module(couch_event_sup). +-behaviour(gen_server). + +-include("couch_db.hrl"). + +-export([start_link/3,start_link/4, stop/1]). +-export([init/1, terminate/2, handle_call/3, handle_cast/2, handle_info/2,code_change/3]). + +% +% Instead calling the +% ok = gen_event:add_sup_handler(error_logger, my_log, Args) +% +% do this: +% {ok, LinkedPid} = couch_event_sup:start_link(error_logger, my_log, Args) +% +% The benefit is the event is now part of the process tree, and can be +% started, restarted and shutdown consistently like the rest of the server +% components. +% +% And now if the "event" crashes, the supervisor is notified and can restart +% the event handler. +% +% Use this form to named process: +% {ok, LinkedPid} = couch_event_sup:start_link({local, my_log}, error_logger, my_log, Args) +% + +start_link(EventMgr, EventHandler, Args) -> + gen_server:start_link(couch_event_sup, {EventMgr, EventHandler, Args}, []). + +start_link(ServerName, EventMgr, EventHandler, Args) -> + gen_server:start_link(ServerName, couch_event_sup, {EventMgr, EventHandler, Args}, []). + +stop(Pid) -> + gen_server:cast(Pid, stop). + +init({EventMgr, EventHandler, Args}) -> + case gen_event:add_sup_handler(EventMgr, EventHandler, Args) of + ok -> + {ok, {EventMgr, EventHandler}}; + {stop, Error} -> + {stop, Error} + end. + +terminate(_Reason, _State) -> + ok. + +handle_call(_Whatever, _From, State) -> + {ok, State}. + +handle_cast(stop, State) -> + {stop, normal, State}. + +handle_info({gen_event_EXIT, _Handler, Reason}, State) -> + {stop, Reason, State}. + +code_change(_OldVsn, State, _Extra) -> + {ok, State}. |