Brought back the folsom histograms

I was wrong about how folsom compiles it's histograms.  While it is true
that there is support for windowed histograms, the default configuration
uses the entire dataset.

bin/compile_stats

@@ -69,9 +69,17 @@ update_elapsed_time(Metric, DField,
 write_elapsed_time_head(FH) ->
     io:format(FH, "type, timestamp, elapsed~n", []).
 
+metric_field(handshake_times) ->
+    #state.handshake_times;
+metric_field(message_latencies) ->
+    #state.message_latencies.
+
 write_elapsed_time(Metric, Start, End, State) ->    
-    FH = element(Metric, State),
+    FH = element(metric_field(Metric), State),
     Elapsed = timer:now_diff(End, Start),
+
+    folsom_metrics:notify({Metric, Elapsed}),
+
     io:format(FH, "\"~s\",~w,~w~n", 
               [State#state.type, timestamp(End), Elapsed]).
 
@@ -84,23 +92,23 @@ inc_count(Field, Counts) ->
     setelement(Field, Counts, Current + 1).
 
 reducer({Start, {ws_init, Pid}}, State) ->
-    State2 = update_elapsed_time(#state.handshake_times, 
+    State2 = update_elapsed_time(handshake_times, 
                                  #state.clients,
                                  Pid, Start, undefined, State),
     State2#state{counts=inc_count(#counts.clients, State#state.counts)};
 reducer({End, {ws_onopen, Pid}}, State) ->
-    State2 = update_elapsed_time(#state.handshake_times, 
+    State2 = update_elapsed_time(handshake_times, 
                                  #state.clients,
                                  Pid, undefined, End, State),
     State2#state{counts=inc_count(#counts.handshakes, State#state.counts)};
 reducer({Start, {send_message, Pid, Ref}}, State) ->
-    State2 = update_elapsed_time(#state.message_latencies, 
+    State2 = update_elapsed_time(message_latencies, 
                                  #state.messages,
                                  {Pid, Ref}, Start, undefined, State),
 
     State2#state{counts=inc_count(#counts.messages_sent, State#state.counts)};
 reducer({End, {recv_message, Pid, Ref}}, State) ->
-    State2 = update_elapsed_time(#state.message_latencies,
+    State2 = update_elapsed_time(message_latencies,
                                  #state.messages,
                                  {Pid, Ref}, undefined, End, State),
     State2#state{counts=inc_count(#counts.messages_recv, State#state.counts)};
@@ -121,32 +129,51 @@ reducer(E, State) ->
 
 main([Type, LogFile]) ->
     code:add_paths(["ebin",
+                    "deps/bear/ebin",
+                    "deps/folsom/ebin",
                     "deps/eleveldb/ebin"]),
 
+    application:start(folsom),
+
     {ok, HSFH} = file:open(filename:join(LogFile, "handshake_times.csv"),
                            [write]),
     {ok, MLFH} = file:open(filename:join(LogFile, "message_latencies.csv"),
                            [write]),
     {ok, CountsFH} = file:open(filename:join(LogFile, "counts.csv"),
                                [write]),
 
+    {ok, HistogramFH} = file:open(filename:join(LogFile, "histogram.config"),
+                                  [write]),
+
     write_stats_head(CountsFH),
     write_elapsed_time_head(HSFH),
     write_elapsed_time_head(MLFH),
 
+    folsom_metrics:new_histogram(handshake_times),
+    folsom_metrics:new_histogram(message_latencies),
+
     State = #state{type=Type,
                    clients=dict:new(),
                    messages=dict:new(),
                    handshake_times=HSFH,
                    message_latencies=MLFH},
-
     io:format("Aggregating stats~n", []),
     State2 = wsdemo_logger:foldl(fun reducer/2, State, LogFile),
+
+    HistogramData = [
+                     {handshake_times, 
+                      folsom_metrics:get_histogram_statistics(handshake_times)},
+                     {message_latencies,
+                      folsom_metrics:get_histogram_statistics(message_latencies)}
+                     ],
 
     write_stats(CountsFH, State2),
+    io:format(HistogramFH, "~w.", [{Type, HistogramData}]),
+
     ok = file:close(HSFH),
     ok = file:close(MLFH),
     ok = file:close(CountsFH),
+    ok = file:close(HistogramFH),
     ok;
 main(_) ->
     usage().