Add proto and remote tags to trace plugin (#4159)

* Add proto and client-ip trace tags
Signed-off-by: Adam Malcontenti-Wilson <amalcontenti-wilson@zendesk.com>

* Commit my own suggestion
Signed-off-by: Miek Gieben <miek@miek.nl>
Co-authored-by: Adam Malcontenti-Wilson <amalcontenti-wilson@zendesk.com>

plugin/trace/trace.go

@@ -25,9 +25,11 @@ import (
 )
 
 const (
-	tagName  = "coredns.io/name"
-	tagType  = "coredns.io/type"
-	tagRcode = "coredns.io/rcode"
+	tagName   = "coredns.io/name"
+	tagType   = "coredns.io/type"
+	tagRcode  = "coredns.io/rcode"
+	tagProto  = "coredns.io/proto"
+	tagRemote = "coredns.io/remote"
 )
 
 type trace struct {
@@ -107,6 +109,8 @@ func (t *trace) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg)
 
 	span.SetTag(tagName, req.Name())
 	span.SetTag(tagType, req.Type())
+	span.SetTag(tagProto, req.Proto())
+	span.SetTag(tagRemote, req.IP())
 	span.SetTag(tagRcode, rcode.ToString(rw.Rcode))
 
 	return status, err

plugin/trace/trace_test.go

@@ -88,6 +88,12 @@ func TestTrace(t *testing.T) {
 			if rootSpan.Tag(tagType) != req.Type() {
 				t.Errorf("Unexpected span tag: rootSpan.Tag(%v): want %v, got %v", tagType, req.Type(), rootSpan.Tag(tagType))
 			}
+			if rootSpan.Tag(tagProto) != req.Proto() {
+				t.Errorf("Unexpected span tag: rootSpan.Tag(%v): want %v, got %v", tagProto, req.Proto(), rootSpan.Tag(tagProto))
+			}
+			if rootSpan.Tag(tagRemote) != req.IP() {
+				t.Errorf("Unexpected span tag: rootSpan.Tag(%v): want %v, got %v", tagRemote, req.IP(), rootSpan.Tag(tagRemote))
+			}
 			if rootSpan.Tag(tagRcode) != rcode.ToString(tc.rcode) {
 				t.Errorf("Unexpected span tag: rootSpan.Tag(%v): want %v, got %v", tagRcode, rcode.ToString(tc.rcode), rootSpan.Tag(tagRcode))
 			}