ZipkinV1 JSON Receiver: handle LOCAL_COMPONENT binary annotation (#373)

The LOCAL_COMPONENT key is used to express the "component or namespace of a local span" in Zipkin V1. This should be used as a fallback if other information is not available. Opportunistically adding equivalent test to Zipkin V1 Thrift that already handles LOCAL_COMPONENT.

Author: Paulo Janotti

translator/trace/testdata/zipkin_v1_local_component.json

@@ -0,0 +1,17 @@
+[
+    {
+        "traceId": "0ed2e63cbe71f5a8",
+        "name": "checkStock",
+        "id": "fe351a053fbcac1f",
+        "parentId": "0ed2e63cbe71f5a8",
+        "timestamp": 1544805927453923,
+        "duration": 3740,
+        "annotations": [],
+        "binaryAnnotations": [
+            {
+                "key": "lc",
+                "value": "myLocalComponent"
+            }
+        ]
+    }
+]

translator/trace/testdata/zipkin_v1_thrift_local_component.json

@@ -0,0 +1,18 @@
+[
+    {
+        "trace_id": 1068169210207794600,
+        "name": "checkStock",
+        "id": -129168404463703009,
+        "parent_id": 1068169210207794600,
+        "timestamp": 1544805927453923,
+        "duration": 3740,
+        "annotations": [],
+        "binary_annotations": [
+            {
+                "key": "lc",
+                "annotation_type": "STRING",
+                "value": "bXlMb2NhbENvbXBvbmVudA=="
+            }
+        ]
+    }
+]

translator/trace/zipkinv1_thrift_to_protospan_test.go

@@ -23,6 +23,29 @@ import (
 	"github.com/jaegertracing/jaeger/thrift-gen/zipkincore"
 )
 
+func TestZipkinThriftFallbackToLocalComponent(t *testing.T) {
+	blob, err := ioutil.ReadFile("./testdata/zipkin_v1_thrift_local_component.json")
+	if err != nil {
+		t.Fatalf("failed to load test data: %v", err)
+	}
+	var ztSpans []*zipkincore.Span
+	err = json.Unmarshal(blob, &ztSpans)
+	if err != nil {
+		t.Fatalf("failed to unmarshal json into zipkin v1 thrift: %v", err)
+	}
+
+	reqs, err := ZipkinV1ThriftBatchToOCProto(ztSpans)
+	if err != nil {
+		t.Fatalf("failed to translate zipkinv1 thrift to OC proto: %v", err)
+	}
+
+	got := reqs[0].Node.ServiceInfo.Name
+	const want = "myLocalComponent"
+	if got != want {
+		t.Fatalf("got %q for service name, want %q", got, want)
+	}
+}
+
 func TestZipkinV1ThriftToOCProto(t *testing.T) {
 	blob, err := ioutil.ReadFile("./testdata/zipkin_v1_thrift_single_batch.json")
 	if err != nil {

translator/trace/zipkinv1_to_protospan.go

@@ -25,6 +25,7 @@ import (
 	agenttracepb "github.com/census-instrumentation/opencensus-proto/gen-go/agent/trace/v1"
 	tracepb "github.com/census-instrumentation/opencensus-proto/gen-go/trace/v1"
 	"github.com/golang/protobuf/ptypes/timestamp"
+	"github.com/jaegertracing/jaeger/thrift-gen/zipkincore"
 	"github.com/pkg/errors"
 )
 
@@ -143,7 +144,10 @@ func zipkinV1ToOCSpan(zSpan *zipkinV1Span) (*tracepb.Span, *annotationParseResul
 	}
 
 	parsedAnnotations := parseZipkinV1Annotations(zSpan.Annotations)
-	attributes := zipkinV1BinAnnotationsToOCAttributes(zSpan.BinaryAnnotations)
+	attributes, localComponent := zipkinV1BinAnnotationsToOCAttributes(zSpan.BinaryAnnotations)
+	if parsedAnnotations.Endpoint.ServiceName == unknownServiceName && localComponent != "" {
+		parsedAnnotations.Endpoint.ServiceName = localComponent
+	}
 	var startTime, endTime *timestamp.Timestamp
 	if zSpan.Timestamp == 0 {
 		startTime = parsedAnnotations.EarlyAnnotationTime
@@ -171,13 +175,17 @@ func zipkinV1ToOCSpan(zSpan *zipkinV1Span) (*tracepb.Span, *annotationParseResul
 	return ocSpan, parsedAnnotations, nil
 }
 
-func zipkinV1BinAnnotationsToOCAttributes(binAnnotations []*binaryAnnotation) *tracepb.Span_Attributes {
+func zipkinV1BinAnnotationsToOCAttributes(binAnnotations []*binaryAnnotation) (attributes *tracepb.Span_Attributes, localComponent string) {
 	if len(binAnnotations) == 0 {
-		return nil
+		return nil, ""
 	}
 
+	var fallbackServiceName string
 	attributeMap := make(map[string]*tracepb.AttributeValue)
 	for _, binAnnotation := range binAnnotations {
+		if binAnnotation.Endpoint != nil && binAnnotation.Endpoint.ServiceName != "" {
+			fallbackServiceName = binAnnotation.Endpoint.ServiceName
+		}
 		pbAttrib := &tracepb.AttributeValue{}
 		if iValue, err := strconv.ParseInt(binAnnotation.Value, 10, 64); err == nil {
 			pbAttrib.Value = &tracepb.AttributeValue_IntValue{IntValue: iValue}
@@ -187,16 +195,29 @@ func zipkinV1BinAnnotationsToOCAttributes(binAnnotations []*binaryAnnotation) *t
 			// For now all else go to string
 			pbAttrib.Value = &tracepb.AttributeValue_StringValue{StringValue: &tracepb.TruncatableString{Value: binAnnotation.Value}}
 		}
-		attributeMap[binAnnotation.Key] = pbAttrib
+
+		key := binAnnotation.Key
+		if key == zipkincore.LOCAL_COMPONENT {
+			// TODO: (@pjanotti) add reference to OpenTracing and change related tags to use them
+			key = "component"
+			localComponent = binAnnotation.Value
+		}
+		attributeMap[key] = pbAttrib
 	}
 
 	if len(attributeMap) == 0 {
-		return nil
+		return nil, ""
+	}
+
+	if localComponent == "" && fallbackServiceName != "" {
+		localComponent = fallbackServiceName
 	}
 
-	return &tracepb.Span_Attributes{
+	attributes = &tracepb.Span_Attributes{
 		AttributeMap: attributeMap,
 	}
+
+	return attributes, localComponent
 }
 
 // annotationParseResult stores the results of examining the original annotations,

translator/trace/zipkinv1_to_protospan_test.go

@@ -131,6 +131,23 @@ func Test_hexTraceIDToOCTraceID(t *testing.T) {
 	}
 }
 
+func TestZipkinJSONFallbackToLocalComponent(t *testing.T) {
+	blob, err := ioutil.ReadFile("./testdata/zipkin_v1_local_component.json")
+	if err != nil {
+		t.Fatalf("failed to load test data: %v", err)
+	}
+	reqs, err := ZipkinV1JSONBatchToOCProto(blob)
+	if err != nil {
+		t.Fatalf("failed to translate zipkinv1 to OC proto: %v", err)
+	}
+
+	got := reqs[0].Node.ServiceInfo.Name
+	const want = "myLocalComponent"
+	if got != want {
+		t.Fatalf("got %q for service name, want %q", got, want)
+	}
+}
+
 func TestSingleJSONZipkinV1BatchToOCProto(t *testing.T) {
 	blob, err := ioutil.ReadFile("./testdata/zipkin_v1_single_batch.json")
 	if err != nil {