set parentSpanId as null in place of initializing it to UUID.zero

Author: Ashish Aggarwal

core/src/main/java/com/expedia/www/haystack/client/Tracer.java

@@ -267,8 +267,7 @@ public Scope startActive(boolean finishSpanOnClose) {
 
         protected SpanContext createNewContext() {
             UUID randomId = UUID.randomUUID();
-            UUID zero = new UUID(0l, 0l);
-            return createContext(randomId, randomId, zero, Collections.<String, String>emptyMap());
+            return createContext(randomId, randomId, null, Collections.emptyMap());
         }
 
         protected SpanContext createContext(UUID traceId, UUID spanId, UUID parentId, Map<String, String> baggage) {

core/src/main/java/com/expedia/www/haystack/client/dispatchers/formats/ProtoBufFormat.java

@@ -16,21 +16,20 @@
  */
 package com.expedia.www.haystack.client.dispatchers.formats;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.ObjectOutputStream;
-import java.util.stream.Collectors;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import com.expedia.open.tracing.Log;
 import com.expedia.open.tracing.Tag;
 import com.expedia.open.tracing.Tag.TagType;
 import com.expedia.www.haystack.client.LogData;
 import com.expedia.www.haystack.client.Span;
 import com.expedia.www.haystack.client.SpanContext;
 import com.google.protobuf.ByteString;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.util.stream.Collectors;
 
 public class ProtoBufFormat implements Format<com.expedia.open.tracing.Span> {
     private static final Logger LOGGER = LoggerFactory.getLogger(ProtoBufFormat.class);
@@ -41,36 +40,35 @@ public com.expedia.open.tracing.Span format(Span span) {
 
         SpanContext context = span.context();
         builder.setTraceId(context.getTraceId().toString())
-            .setSpanId(context.getSpanId().toString())
-            .setParentSpanId(context.getParentId().toString());
+                .setSpanId(context.getSpanId().toString());
 
-        builder.setServiceName(span.getServiceName())
-            .setOperationName(span.getOperatioName());
+        if (context.getParentId() != null) {
+            builder.setParentSpanId(context.getParentId().toString());
+        }
 
-        builder.setStartTime(span.getStartTime());
+        builder.setServiceName(span.getServiceName())
+                .setOperationName(span.getOperatioName())
+                .setStartTime(span.getStartTime());
 
         if (span.getDuration() != null) {
             builder.setDuration(span.getDuration());
         }
 
         builder.addAllLogs(span.getLogs().stream()
-                           .map(l -> buildLog(l))
-                           .collect(Collectors.toList()));
-
-        builder.addAllTags(span.getTags().entrySet().stream()
+                           .map(this::buildLog)
+                           .collect(Collectors.toList()))
+                .addAllTags(span.getTags().entrySet().stream()
                            .map(e -> buildTag(e.getKey(), e.getValue()))
-                           .collect(Collectors.toList()));
-
-        // add the baggage items as tags for now
-        builder.addAllTags(context.getBaggage().entrySet().stream()
+                           .collect(Collectors.toList()))
+                .addAllTags(context.getBaggage().entrySet().stream() // add the baggage items as tags for now
                            .map(e -> buildTag(e.getKey(), e.getValue()))
                            .collect(Collectors.toList()));
 
         return builder.build();
     }
 
-    protected Log buildLog(LogData log) {
-        Log.Builder builder = Log.newBuilder()
+    protected Log buildLog(final LogData log) {
+        final Log.Builder builder = Log.newBuilder()
             .setTimestamp(log.getTimestamp());
 
         if (log.getFields() != null ) {
@@ -87,7 +85,7 @@ protected Tag buildTag(String key, Object value) {
         if (value == null) {
             // just a message collected; adding an empty payload
             builder.setType(TagType.STRING);
-            builder.setVStr(new String());
+            builder.setVStr("");
         } else if (value instanceof String) {
             builder.setType(TagType.STRING);
             builder.setVStr((String) value);
@@ -103,8 +101,8 @@ protected Tag buildTag(String key, Object value) {
         } else {
             builder.setType(TagType.BINARY);
 
-            try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
-                try (ObjectOutputStream os = new ObjectOutputStream(out)) {
+            try (final ByteArrayOutputStream out = new ByteArrayOutputStream()) {
+                try (final ObjectOutputStream os = new ObjectOutputStream(out)) {
                     os.writeObject(value);
                     builder.setVBytes(ByteString.copyFrom(out.toByteArray()));
                 }

core/src/test/java/com/expedia/www/haystack/client/SpanPropagationTest.java

@@ -90,7 +90,7 @@ public void testActiveSpanIgnorePropagation() {
         Assert.assertEquals(0, secondSpan.getReferences().size());
         Assert.assertEquals(0, firstSpan.getReferences().size());
         Assert.assertNotEquals(firstSpan.context().getTraceId(), secondSpan.context().getTraceId());
-        Assert.assertEquals(new UUID(0l, 0l), secondSpan.context().getParentId());
+        Assert.assertNull(secondSpan.context().getParentId());
     }
 
     @Test
@@ -114,9 +114,9 @@ public void testActiveSpanPreSeeded() {
         Assert.assertEquals(parent.context().getSpanId(), child.context().getParentId());
 
         Assert.assertTrue(parent.getReferences().isEmpty());
-        Assert.assertEquals(new UUID(0l, 0l), parent.context().getParentId());
+        Assert.assertNull(parent.context().getParentId());
         Assert.assertTrue(active.getReferences().isEmpty());
-        Assert.assertEquals(new UUID(0l, 0l), active.context().getParentId());
+        Assert.assertNull(active.context().getParentId());
     }
 
     @Test

core/src/test/java/com/expedia/www/haystack/client/dispatchers/formats/ProtBufFormatTest.java

@@ -16,20 +16,19 @@
  */
 package com.expedia.www.haystack.client.dispatchers.formats;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-
-import org.junit.Assert;
-import org.junit.Before;
-import org.junit.Test;
-
 import com.expedia.open.tracing.Log;
 import com.expedia.open.tracing.Tag;
 import com.expedia.www.haystack.client.Span;
 import com.expedia.www.haystack.client.Tracer;
 import com.expedia.www.haystack.client.dispatchers.InMemoryDispatcher;
 import com.expedia.www.haystack.client.metrics.NoopMetricsRegistry;
 import com.google.common.collect.ImmutableMap;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
 public class ProtBufFormatTest {
     private Tracer tracer;
@@ -156,5 +155,4 @@ public void testSpanConversion() {
         // Tags + Baggage for now.
         assertEquals(2, protoSpan.getTagsCount());
     }
-
 }