Сбор статистики через триггеры #16

src/infra/stats_collector.erl

@@ -0,0 +1,133 @@
+-module(stats_collector).
+-behaviour(gen_server).
+
+-include("records.hrl").
+
+-export([start_link/0, get_stats/0, subscribe/0]).
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
+
+-define(FLUSH_INTERVAL, 300000).
+
+start_link() -> gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+get_stats()   -> gen_server:call(?MODULE, get_stats).
+subscribe()   -> gen_server:call(?MODULE, subscribe).
+
+init([]) ->
+  ets:new(stats_ets, [set, public, named_table, {keypos, 1}]),
+  erlang:send_after(?FLUSH_INTERVAL, self(), flush),
+  {ok, #{}}.
+
+handle_call(subscribe, _From, State) ->
+  mnesia:subscribe({table, event, simple}),
+  mnesia:subscribe({table, booking, simple}),
+  mnesia:subscribe({table, review, simple}),
+  {reply, ok, State};
+handle_call(get_stats, _From, State) ->
+  {reply, ets:tab2list(stats_ets), State};
+handle_call(_Msg, _From, State) ->
+  {reply, {error, unknown}, State}.
+
+handle_cast(_Msg, State) -> {noreply, State}.
+
+handle_info(flush, State) ->
+  flush_stats(),
+  erlang:send_after(?FLUSH_INTERVAL, self(), flush),
+  {noreply, State};
+handle_info({mnesia_table_event, {write, Record, _ActivityId}}, State) ->
+  Table = element(1, Record),
+  process_write(Table, Record, []),
+  {noreply, State};
+handle_info({write, Table, New, Old, _ActivityId}, State) ->
+  process_write(Table, New, Old),
+  {noreply, State};
+handle_info(_Info, State) -> {noreply, State}.
+
+terminate(_Reason, _State) -> ok.
+code_change(_OldVsn, State, _Extra) -> {ok, State}.
+
+ensure_counter(Key) ->
+  case ets:member(stats_ets, Key) of
+    false -> ets:insert(stats_ets, {Key, 0});
+    true -> ok
+  end.
+
+process_write(event, New, Old) ->
+  CId = element(#event.calendar_id, New),
+  StNew = element(#event.status, New),
+  StOld = if Old =:= [] -> []; true -> element(#event.status, Old) end,
+  if StNew =:= active, StOld =/= active ->
+    ensure_counter({events_created, CId}),
+    ets:update_counter(stats_ets, {events_created, CId}, {2, 1});
+    StNew =:= cancelled, StOld =/= cancelled ->
+      ensure_counter({events_cancelled, CId}),
+      ets:update_counter(stats_ets, {events_cancelled, CId}, {2, 1});
+    true -> ok
+  end;
+process_write(booking, New, Old) ->
+  EvId = element(#booking.event_id, New),
+  StNew = element(#booking.status, New),
+  StOld = if Old =:= [] -> []; true -> element(#booking.status, Old) end,
+  CId = case mnesia:dirty_read({event, EvId}) of
+          [#event{calendar_id = C}] -> C;
+          _ -> undefined
+        end,
+  if CId =/= undefined ->
+    if StNew =:= confirmed, StOld =/= confirmed ->
+      ensure_counter({bookings_confirmed, CId}),
+      ets:update_counter(stats_ets, {bookings_confirmed, CId}, {2, 1});
+      StNew =:= cancelled, StOld =/= cancelled ->
+        ensure_counter({bookings_cancelled, CId}),
+        ets:update_counter(stats_ets, {bookings_cancelled, CId}, {2, 1});
+      true -> ok
+    end,
+    if Old =:= [] ->
+      ensure_counter({bookings_created, CId}),
+      ets:update_counter(stats_ets, {bookings_created, CId}, {2, 1});
+      true -> ok
+    end;
+    true -> ok
+  end;
+process_write(review, New, Old) ->
+  CId = case element(#review.target_type, New) of
+          event ->
+            EvId = element(#review.target_id, New),
+            case mnesia:dirty_read({event, EvId}) of
+              [#event{calendar_id = C}] -> C;
+              _ -> undefined
+            end;
+          calendar ->
+            element(#review.target_id, New)
+        end,
+  Rating = element(#review.rating, New),
+  if CId =/= undefined ->
+    if Old =:= [] ->
+      ensure_counter({reviews_created, CId}),
+      ets:update_counter(stats_ets, {reviews_created, CId}, {2, 1}),
+      ensure_counter({reviews_sum, CId}),
+      ets:update_counter(stats_ets, {reviews_sum, CId}, {2, Rating}),
+      ensure_counter({reviews_count, CId}),
+      ets:update_counter(stats_ets, {reviews_count, CId}, {2, 1});
+      true ->
+        OldRating = element(#review.rating, Old),
+        if Rating =/= OldRating ->
+          ensure_counter({reviews_sum, CId}),
+          ets:update_counter(stats_ets, {reviews_sum, CId}, {2, Rating - OldRating});
+          true -> ok
+        end
+    end;
+    true -> ok
+  end;
+process_write(_, _, _) -> ok.
+
+flush_stats() ->
+  All = ets:tab2list(stats_ets),
+  lists:foreach(fun({{Metric, EntityId}, Value}) ->
+    mnesia:dirty_write(#stats{
+      id = list_to_binary(io_lib:format("~p_~p_~p", [Metric, EntityId, os:system_time(millisecond)])),
+      metric = Metric,
+      entity_id = EntityId,
+      value = Value,
+      timestamp = calendar:local_time()
+    })
+                end, All),
+  ets:match_delete(stats_ets, '_').