| % 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. |
| |
| % todo |
| % - remove existance check on increment(), decrement() and record(). have |
| % modules initialize counters on startup. |
| |
| -module(couch_stats_collector). |
| |
| -behaviour(gen_server). |
| |
| -export([start/0, stop/0]). |
| -export([all/0, all/1, get/1, increment/1, decrement/1, record/2, clear/1]). |
| -export([track_process_count/1, track_process_count/2]). |
| |
| -export([init/1, terminate/2, code_change/3]). |
| -export([handle_call/3, handle_cast/2, handle_info/2]). |
| |
| -define(HIT_TABLE, stats_hit_table). |
| -define(ABS_TABLE, stats_abs_table). |
| |
| start() -> |
| gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). |
| |
| stop() -> |
| gen_server:call(?MODULE, stop). |
| |
| all() -> |
| ets:tab2list(?HIT_TABLE) ++ abs_to_list(). |
| |
| all(Type) -> |
| case Type of |
| incremental -> ets:tab2list(?HIT_TABLE); |
| absolute -> abs_to_list() |
| end. |
| |
| get(Key) -> |
| case ets:lookup(?HIT_TABLE, Key) of |
| [] -> |
| case ets:lookup(?ABS_TABLE, Key) of |
| [] -> |
| nil; |
| AbsVals -> |
| lists:map(fun({_, Value}) -> Value end, AbsVals) |
| end; |
| [{_, Counter}] -> |
| Counter |
| end. |
| |
| increment(Key) -> |
| Key2 = make_key(Key), |
| case catch ets:update_counter(?HIT_TABLE, Key2, 1) of |
| {'EXIT', {badarg, _}} -> |
| catch ets:insert(?HIT_TABLE, {Key2, 1}), |
| ok; |
| _ -> |
| ok |
| end. |
| |
| decrement(Key) -> |
| Key2 = make_key(Key), |
| case catch ets:update_counter(?HIT_TABLE, Key2, -1) of |
| {'EXIT', {badarg, _}} -> |
| catch ets:insert(?HIT_TABLE, {Key2, -1}), |
| ok; |
| _ -> ok |
| end. |
| |
| record(Key, Value) -> |
| catch ets:insert(?ABS_TABLE, {make_key(Key), Value}). |
| |
| clear(Key) -> |
| catch ets:delete(?ABS_TABLE, make_key(Key)). |
| |
| track_process_count(Stat) -> |
| track_process_count(self(), Stat). |
| |
| track_process_count(Pid, Stat) -> |
| MonitorFun = fun() -> |
| Ref = erlang:monitor(process, Pid), |
| receive {'DOWN', Ref, _, _, _} -> ok end, |
| couch_stats_collector:decrement(Stat) |
| end, |
| case (catch couch_stats_collector:increment(Stat)) of |
| ok -> spawn(MonitorFun); |
| _ -> ok |
| end. |
| |
| |
| init(_) -> |
| ets:new(?HIT_TABLE, [named_table, set, public]), |
| ets:new(?ABS_TABLE, [named_table, duplicate_bag, public]), |
| {ok, nil}. |
| |
| terminate(_Reason, _State) -> |
| ok. |
| |
| handle_call(stop, _, State) -> |
| {stop, normal, stopped, State}. |
| |
| handle_cast(foo, State) -> |
| {noreply, State}. |
| |
| handle_info(_Info, State) -> |
| {noreply, State}. |
| |
| code_change(_OldVersion, State, _Extra) -> |
| {ok, State}. |
| |
| |
| make_key({Module, Key}) when is_integer(Key) -> |
| {Module, list_to_atom(integer_to_list(Key))}; |
| make_key(Key) -> |
| Key. |
| |
| abs_to_list() -> |
| SortedKVs = lists:sort(ets:tab2list(?ABS_TABLE)), |
| lists:foldl(fun({Key, Val}, Acc) -> |
| case Acc of |
| [] -> |
| [{Key, [Val]}]; |
| [{Key, Prev} | Rest] -> |
| [{Key, [Val | Prev]} | Rest]; |
| Others -> |
| [{Key, [Val]} | Others] |
| end |
| end, [], SortedKVs). |