s1gw_metrics: use lists:filter/2 to create counters/gauges

Change-Id: I5aa1ab8c95820e4e5e3233c92a6c1b8b3190a30c
---
M src/s1gw_metrics.erl
1 file changed, 9 insertions(+), 23 deletions(-)

diff --git a/src/s1gw_metrics.erl b/src/s1gw_metrics.erl
index 9f7b2e8..dceb477 100644
--- a/src/s1gw_metrics.erl
+++ b/src/s1gw_metrics.erl
@@ -98,29 +98,14 @@
 -type counter() :: [ctr | _].
 -type gauge() :: [gauge | _].
 
--spec new_ctr(counter()) -> ok.
-new_ctr(Name) ->
-    %%?LOG_INFO("New counter ~p", [Name]),
-    ok = exometer:new(Name, counter).
 
--spec new_ctrs(list(counter())) -> ok.
-new_ctrs([]) ->
-    ok;
-new_ctrs([Name | MoreNames]) ->
-    new_ctr(Name),
-    new_ctrs(MoreNames).
+-spec register_all(Type, List) -> Result
+    when Type :: exometer:type(),
+         List :: list(exometer:name()),
+         Result :: list(exometer:name()).
+register_all(Type, List) ->
+    lists:filter(fun(Name) -> exometer:new(Name, Type) =/= ok end, List).
 
--spec new_gauge(gauge()) -> ok.
-new_gauge(Name) ->
-    %%?LOG_INFO("New gauge ~p", [Name]),
-    ok = exometer:new(Name, gauge).
-
--spec new_gauges(list(gauge())) -> ok.
-new_gauges([]) ->
-    ok;
-new_gauges([Name | MoreNames]) ->
-    new_gauge(Name),
-    new_gauges(MoreNames).
 
 -spec get_current_value(counter() | gauge()) -> integer().
 get_current_value(Name) ->
@@ -128,14 +113,15 @@
     {ok, [{value, PrevVal}]} = Result,
     PrevVal.
 
+
 %% ------------------------------------------------------------------
 %% public API
 %% ------------------------------------------------------------------
 
 init() ->
     ?LOG_INFO("Initiating metrics"),
-    new_ctrs(?S1GW_COUNTERS),
-    new_gauges(?S1GW_GAUGES).
+    [] = register_all(counter, ?S1GW_COUNTERS),
+    [] = register_all(gauge, ?S1GW_GAUGES).
 
 %%%%%%%%%%%%%
 %% CTR APIs

