change trace.WithAttributes to append values instead of replacing (#315)

* change trace.WithAttributes to append values instead of replacing * improve doc
plantfansam · Nov 14, 2019 · 1fd93b2 · 1fd93b2
1 parent a228baf
commit 1fd93b2
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/api/trace/api.go b/api/trace/api.go
@@ -204,9 +204,10 @@ func WithStartTime(t time.Time) SpanOption {
 
 // WithAttributes sets attributes to span. These attributes provides additional
 // data about the span.
+// Multiple `WithAttributes` options appends the attributes preserving the order.
 func WithAttributes(attrs ...core.KeyValue) SpanOption {
 	return func(o *SpanOptions) {
-		o.Attributes = attrs
+		o.Attributes = append(o.Attributes, attrs...)
 	}
 }
 

diff --git a/sdk/trace/trace_test.go b/sdk/trace/trace_test.go
@@ -295,7 +295,11 @@ func TestStartSpanWithFollowsFrom(t *testing.T) {
 func TestSetSpanAttributesOnStart(t *testing.T) {
 	te := &testExporter{}
 	tp, _ := NewProvider(WithSyncer(te))
-	span := startSpan(tp, "StartSpanAttribute", apitrace.WithAttributes(key.String("key1", "value1")))
+	span := startSpan(tp,
+		"StartSpanAttribute",
+		apitrace.WithAttributes(key.String("key1", "value1")),
+		apitrace.WithAttributes(key.String("key2", "value2")),
+	)
 	got, err := endSpan(te, span)
 	if err != nil {
 		t.Fatal(err)
@@ -310,6 +314,7 @@ func TestSetSpanAttributesOnStart(t *testing.T) {
 		Name:         "StartSpanAttribute/span0",
 		Attributes: []core.KeyValue{
 			key.String("key1", "value1"),
+			key.String("key2", "value2"),
 		},
 		SpanKind:        apitrace.SpanKindInternal,
 		HasRemoteParent: true,