adds set_kind func for oc_trace

Author: castengo

src/oc_span.erl

@@ -32,6 +32,8 @@
 
          message_event/4,
 
+         set_kind/2,
+
          set_status/3]).
 
 -include("opencensus.hrl").
@@ -138,6 +140,16 @@ set_status(Code, Message, Span=#span{}) ->
 set_status(_, _, undefined) ->
     undefined.
 
+%%--------------------------------------------------------------------
+%% @doc
+%% Set Kind.
+%% @end
+%%--------------------------------------------------------------------
+-spec set_kind(Kind, Span) -> Span when Kind :: opencensus:span_kind(), Span :: maybe(opencensus:span()).
+set_kind(Kind, Span=#span{}) ->
+    Span#span{kind=Kind};
+set_kind(_, undefined) ->
+    undefined.
 
 %%--------------------------------------------------------------------
 %% @doc

test/oc_span_SUITE.erl

@@ -53,10 +53,13 @@ modifications(_Config) ->
     Span6 = oc_span:add_link(Link, Span5),
     ?assertEqual(undefined, oc_span:add_link(Link, undefined)),
 
-    ?assertEqual({error, no_report_buffer}, oc_span:finish_span(#span_ctx{}, Span6)),
+    Span7 = oc_span:set_kind(?SPAN_KIND_SERVER, Span6),
+    ?assertEqual(undefined, oc_span:set_kind(?SPAN_KIND_SERVER, undefined)),
+
+    ?assertEqual({error, no_report_buffer}, oc_span:finish_span(#span_ctx{}, Span7)),
 
     {ok, _} = application:ensure_all_started(opencensus),
-    ?assertEqual(true, oc_span:finish_span(#span_ctx{}, Span6)),
+    ?assertEqual(true, oc_span:finish_span(#span_ctx{}, Span7)),
     ?assertEqual(true, oc_span:finish_span(#span_ctx{}, undefined)),
 
     application:stop(opencensus).