diff options
Diffstat (limited to 'apps/couch/src/couch_task_status.erl')
-rw-r--r-- | apps/couch/src/couch_task_status.erl | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/apps/couch/src/couch_task_status.erl b/apps/couch/src/couch_task_status.erl new file mode 100644 index 00000000..639515c7 --- /dev/null +++ b/apps/couch/src/couch_task_status.erl @@ -0,0 +1,123 @@ +% 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. + +-module(couch_task_status). +-behaviour(gen_server). + +% This module allows is used to track the status of long running tasks. +% Long running tasks register (add_task/3) then update their status (update/1) +% and the task and status is added to tasks list. When the tracked task dies +% it will be automatically removed the tracking. To get the tasks list, use the +% all/0 function + +-export([start_link/0, stop/0]). +-export([all/0, add_task/3, update/1, update/2, set_update_frequency/1]). + +-export([init/1, terminate/2, code_change/3]). +-export([handle_call/3, handle_cast/2, handle_info/2]). + +-import(couch_util, [to_binary/1]). + +-include("couch_db.hrl"). + + +start_link() -> + gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). + + +stop() -> + gen_server:cast(?MODULE, stop). + + +all() -> + gen_server:call(?MODULE, all). + + +add_task(Type, TaskName, StatusText) -> + put(task_status_update, {{0, 0, 0}, 0}), + Msg = { + add_task, + to_binary(Type), + to_binary(TaskName), + to_binary(StatusText) + }, + gen_server:call(?MODULE, Msg). + + +set_update_frequency(Msecs) -> + put(task_status_update, {{0, 0, 0}, Msecs * 1000}). + + +update(StatusText) -> + update("~s", [StatusText]). + +update(Format, Data) -> + {LastUpdateTime, Frequency} = get(task_status_update), + case timer:now_diff(Now = now(), LastUpdateTime) >= Frequency of + true -> + put(task_status_update, {Now, Frequency}), + Msg = ?l2b(io_lib:format(Format, Data)), + gen_server:cast(?MODULE, {update_status, self(), Msg}); + false -> + ok + end. + + +init([]) -> + % read configuration settings and register for configuration changes + ets:new(?MODULE, [ordered_set, protected, named_table]), + {ok, nil}. + + +terminate(_Reason,_State) -> + ok. + + +handle_call({add_task, Type, TaskName, StatusText}, {From, _}, Server) -> + case ets:lookup(?MODULE, From) of + [] -> + true = ets:insert(?MODULE, {From, {Type, TaskName, StatusText}}), + erlang:monitor(process, From), + {reply, ok, Server}; + [_] -> + {reply, {add_task_error, already_registered}, Server} + end; +handle_call(all, _, Server) -> + All = [ + [ + {type, Type}, + {task, Task}, + {status, Status}, + {pid, ?l2b(pid_to_list(Pid))} + ] + || + {Pid, {Type, Task, Status}} <- ets:tab2list(?MODULE) + ], + {reply, All, Server}. + + +handle_cast({update_status, Pid, StatusText}, Server) -> + [{Pid, {Type, TaskName, _StatusText}}] = ets:lookup(?MODULE, Pid), + true = ets:insert(?MODULE, {Pid, {Type, TaskName, StatusText}}), + {noreply, Server}; +handle_cast(stop, State) -> + {stop, normal, State}. + +handle_info({'DOWN', _MonitorRef, _Type, Pid, _Info}, Server) -> + %% should we also erlang:demonitor(_MonitorRef), ? + ets:delete(?MODULE, Pid), + {noreply, Server}. + + +code_change(_OldVsn, State, _Extra) -> + {ok, State}. + |