Map http attributes to the stackdriver format, resolves #1153 (#1183)

(cherry picked from commit a1a6cf1)

Author: Sebruck

exporters/trace/stackdriver/src/main/java/io/opencensus/exporter/trace/stackdriver/StackdriverV2ExporterHandler.java

@@ -23,6 +23,7 @@
 import com.google.cloud.trace.v2.TraceServiceClient;
 import com.google.cloud.trace.v2.TraceServiceSettings;
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.io.BaseEncoding;
 import com.google.devtools.cloudtrace.v2.AttributeValue;
 import com.google.devtools.cloudtrace.v2.ProjectName;
@@ -77,6 +78,16 @@ final class StackdriverV2ExporterHandler extends SpanExporter.Handler {
           .setStringValue(toTruncatableStringProto(AGENT_LABEL_VALUE_STRING))
           .build();
 
+  private static final ImmutableMap<String, String> HTTP_ATTRIBUTE_MAPPING =
+      ImmutableMap.<String, String>builder()
+          .put("http.host", "/http/host")
+          .put("http.method", "/http/method")
+          .put("http.path", "/http/path")
+          .put("http.route", "/http/route")
+          .put("http.user_agent", "/http/user_agent")
+          .put("http.status_code", "/http/status_code")
+          .build();
+
   private final String projectId;
   private final TraceServiceClient traceServiceClient;
   private final ProjectName projectName;
@@ -222,11 +233,20 @@ private static Attributes.Builder toAttributesBuilderProto(
     Attributes.Builder attributesBuilder =
         Attributes.newBuilder().setDroppedAttributesCount(droppedAttributesCount);
     for (Map.Entry<String, io.opencensus.trace.AttributeValue> label : attributes.entrySet()) {
-      attributesBuilder.putAttributeMap(label.getKey(), toAttributeValueProto(label.getValue()));
+      attributesBuilder.putAttributeMap(
+          mapKey(label.getKey()), toAttributeValueProto(label.getValue()));
     }
     return attributesBuilder;
   }
 
+  private static String mapKey(String key) {
+    if (HTTP_ATTRIBUTE_MAPPING.containsKey(key)) {
+      return HTTP_ATTRIBUTE_MAPPING.get(key);
+    } else {
+      return key;
+    }
+  }
+
   private static Status toStatusProto(io.opencensus.trace.Status status) {
     Status.Builder statusBuilder = Status.newBuilder().setCode(status.getCanonicalCode().value());
     if (status.getDescription() != null) {

exporters/trace/stackdriver/src/test/java/io/opencensus/exporter/trace/stackdriver/StackdriverV2ExporterHandlerProtoTest.java

@@ -53,6 +53,7 @@
 
 @RunWith(JUnit4.class)
 public final class StackdriverV2ExporterHandlerProtoTest {
+
   private static final Credentials FAKE_CREDENTIALS =
       GoogleCredentials.newBuilder().setAccessToken(new AccessToken("fake", new Date(100))).build();
   // OpenCensus constants
@@ -141,7 +142,6 @@ public void generateSpan() {
             CHILD_SPAN_COUNT,
             status,
             endTimestamp);
-
     TimeEvent annotationTimeEvent1 =
         TimeEvent.newBuilder()
             .setAnnotation(
@@ -255,4 +255,55 @@ public void generateSpan() {
     assertThat(span.getChildSpanCount())
         .isEqualTo(Int32Value.newBuilder().setValue(CHILD_SPAN_COUNT).build());
   }
+
+  @Test
+  public void mapHttpAttributes() {
+    Map<String, io.opencensus.trace.AttributeValue> attributesMap =
+        new HashMap<String, io.opencensus.trace.AttributeValue>();
+
+    attributesMap.put("http.host", io.opencensus.trace.AttributeValue.stringAttributeValue("host"));
+    attributesMap.put(
+        "http.method", io.opencensus.trace.AttributeValue.stringAttributeValue("method"));
+    attributesMap.put("http.path", io.opencensus.trace.AttributeValue.stringAttributeValue("path"));
+    attributesMap.put(
+        "http.route", io.opencensus.trace.AttributeValue.stringAttributeValue("route"));
+    attributesMap.put(
+        "http.user_agent", io.opencensus.trace.AttributeValue.stringAttributeValue("user_agent"));
+    attributesMap.put(
+        "http.status_code", io.opencensus.trace.AttributeValue.longAttributeValue(200L));
+    SpanData.Attributes httpAttributes = SpanData.Attributes.create(attributesMap, 0);
+
+    SpanData spanData =
+        SpanData.create(
+            spanContext,
+            parentSpanId,
+            /* hasRemoteParent= */ true,
+            SPAN_NAME,
+            startTimestamp,
+            httpAttributes,
+            annotations,
+            networkEvents,
+            links,
+            CHILD_SPAN_COUNT,
+            status,
+            endTimestamp);
+
+    Span span = handler.generateSpan(spanData);
+    Map<String, AttributeValue> attributes = span.getAttributes().getAttributeMapMap();
+
+    assertThat(attributes).containsEntry("/http/host", toStringValue("host"));
+    assertThat(attributes).containsEntry("/http/method", toStringValue("method"));
+    assertThat(attributes).containsEntry("/http/path", toStringValue("path"));
+    assertThat(attributes).containsEntry("/http/route", toStringValue("route"));
+    assertThat(attributes).containsEntry("/http/user_agent", toStringValue("user_agent"));
+    assertThat(attributes)
+        .containsEntry("/http/status_code", AttributeValue.newBuilder().setIntValue(200L).build());
+  }
+
+  private static AttributeValue toStringValue(String value) {
+    return AttributeValue.newBuilder()
+        .setStringValue(
+            TruncatableString.newBuilder().setValue(value).setTruncatedByteCount(0).build())
+        .build();
+  }
 }