From 4c2fc3924aa31d46e9a2903efd2fe1d148bbdcb4 Mon Sep 17 00:00:00 2001
From: Bartosz Zurkowski <zurkowski.bartosz@gmail.com>
Date: Mon, 6 Mar 2017 03:10:47 +0100
Subject: [PATCH] Reset behaviours counter after each metrics write

---
 src/mas_counter.erl    | 19 ++++++++++++++++++-
 src/mas_population.erl | 10 ++++++----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/mas_counter.erl b/src/mas_counter.erl
index 716a44d..4adfa78 100644
--- a/src/mas_counter.erl
+++ b/src/mas_counter.erl
@@ -8,7 +8,9 @@
 %%% API
 -export([new/1,
          new/2,
-         update/2]).
+         update/2,
+         reset/1,
+         reset/2]).
 
 %%%=============================================================================
 %%% API functions
@@ -36,3 +38,18 @@ new(Metrics, InitValue) ->
 update(DataPoints, Counter) ->
     Fun = fun ({K, V}, DictAcc) -> dict:update_counter(K, V, DictAcc) end,
     lists:foldl(Fun, Counter, DataPoints).
+
+%%------------------------------------------------------------------------------
+%% @doc Resets all metric values to zero.
+%% @end
+%%------------------------------------------------------------------------------
+reset(Counter) ->
+    reset(Counter, 0).
+
+%%------------------------------------------------------------------------------
+%% @doc Resets all metric values to provided value.
+%% @end
+%%------------------------------------------------------------------------------
+reset(Counter, Value) ->
+    Fun = fun(K, DictAcc) -> dict:store(K, Value, DictAcc) end,
+    lists:foldl(Fun, Counter, dict:fetch_keys(Counter)).
diff --git a/src/mas_population.erl b/src/mas_population.erl
index 59220a8..bda3b87 100644
--- a/src/mas_population.erl
+++ b/src/mas_population.erl
@@ -101,9 +101,8 @@ handle_info(process_population, State) ->
     self() ! process_population,
     {noreply, NewState};
 handle_info(update_metrics, State = #state{config = Config}) ->
-    update_metrics(State),
     schedule_metrics_update(Config),
-    {noreply, State};
+    {noreply, update_metrics(State)};
 handle_info(_Info, State) ->
     {noreply, State}.
 
@@ -240,7 +239,10 @@ schedule_metrics_update(#config{write_interval = WriteInterval}) ->
 %%------------------------------------------------------------------------------
 %% @private
 %%------------------------------------------------------------------------------
-update_metrics(#state{metrics = Metrics, behaviours_counter = Counter}) ->
+update_metrics(State) ->
+    #state{metrics = Metrics, behaviours_counter = Counter} = State,
     lists:foreach(fun(Metric = [_Pid, Behaviour]) ->
                       exometer:update(Metric, dict:fetch(Behaviour, Counter))
-                  end, Metrics).
+                  end, Metrics),
+    NewCounter = mas_counter:reset(Counter),
+    State#state{behaviours_counter = NewCounter}.