Collect ra io stats

[#157193081]

Author: dcorbacho

src/rabbit_mgmt_external_stats.erl

@@ -340,7 +340,7 @@ format_mochiweb_option(_K, V) ->
 init([]) ->
     {ok, Interval}   = application:get_env(rabbit, collect_statistics_interval),
     State = #state{fd_total    = file_handle_cache:ulimit(),
-                   fhc_stats   = file_handle_cache_stats:get(),
+                   fhc_stats   = get_fhc_stats(),
                    node_owners = sets:new(),
                    interval    = Interval},
     %% We can update stats straight away as they need to be available
@@ -395,5 +395,13 @@ emit_node_node_stats(State = #state{node_owners = Owners}) ->
 update_state(State0) ->
     %% Store raw data, the average operation time is calculated during querying
     %% from the accumulated total
-    FHC = file_handle_cache_stats:get(),
+    FHC = get_fhc_stats(),
     State0#state{fhc_stats = FHC}.
+
+get_fhc_stats() ->
+    dict:to_list(dict:merge(fun(_, V1, V2) -> V1 + V2 end,
+                            dict:from_list(file_handle_cache_stats:get()),
+                            dict:from_list(get_ra_io_metrics()))).
+
+get_ra_io_metrics() ->
+    lists:sort(ets:tab2list(ra_io_metrics)).