Merge pull request #8 from esl/fix_app_metrics

Fix app metrics

Author: chrzaszcz

src/amoc_metrics.erl

@@ -2,7 +2,7 @@
 
 -behaviour(prometheus_collector).
 
--export([start/0, start_predefined_metrics/1, init/2]).
+-export([start/0, init/2]).
 -export([update_counter/1, update_counter/2, update_gauge/2, update_time/2]).
 -export([deregister_cleanup/1, collect_mf/2]).
 
@@ -20,13 +20,9 @@
 
 -spec start() -> boolean().
 start() ->
+    maybe_init_predefined_metrics(),
     maybe_add_exporter().
 
--spec start_predefined_metrics(atom()) -> any().
-start_predefined_metrics(App) ->
-    Preconfigured = application:get_env(App, predefined_metrics, []),
-    [init(Type, Name) || {Type, Name} <- lists:flatten(Preconfigured)].
-
 -spec init(type(), name()) -> ok.
 init(counters, Name) ->
     prometheus_counter:new([{name, Name}, {help, ""}]);
@@ -105,3 +101,9 @@ histogram_buckets(AccBuckets, Val) when Val > 0 ->
     histogram_buckets([Val | AccBuckets], Val bsr 1);
 histogram_buckets(AccBuckets, _Val) ->
     AccBuckets.
+
+-spec maybe_init_predefined_metrics() -> any().
+maybe_init_predefined_metrics() ->
+    {ok, App} = application:get_application(?MODULE),
+    Preconfigured = application:get_env(App, predefined_metrics, []),
+    [init(Type, Name) || {Type, Name} <- lists:flatten(Preconfigured)].