| % 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), |
| ?LOG_DEBUG("New task status for ~s: ~s",[TaskName, StatusText]), |
| 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}. |
| |