1 files changed, 43 insertions, 0 deletions
diff --git a/vendor/go.opencensus.io/trace/exemplar.go b/vendor/go.opencensus.io/trace/exemplar.go
new file mode 100644
index 000000000..416d80590
--- /dev/null
+++ b/vendor/go.opencensus.io/trace/exemplar.go
@@ -0,0 +1,43 @@
+// Copyright 2018, OpenCensus Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package trace
+
+import (
+	"context"
+	"encoding/hex"
+
+	"go.opencensus.io/exemplar"
+)
+
+func init() {
+	exemplar.RegisterAttachmentExtractor(attachSpanContext)
+}
+
+func attachSpanContext(ctx context.Context, a exemplar.Attachments) exemplar.Attachments {
+	span := FromContext(ctx)
+	if span == nil {
+		return a
+	}
+	sc := span.SpanContext()
+	if !sc.IsSampled() {
+		return a
+	}
+	if a == nil {
+		a = make(exemplar.Attachments)
+	}
+	a[exemplar.KeyTraceID] = hex.EncodeToString(sc.TraceID[:])
+	a[exemplar.KeySpanID] = hex.EncodeToString(sc.SpanID[:])
+	return a
+}