Fix : moving instance_name logging to log entry label

google-cloud-logging/src/main/java/com/google/cloud/logging/MonitoredResourceUtil.java

@@ -19,8 +19,10 @@
 import com.google.cloud.MetadataConfig;
 import com.google.cloud.MonitoredResource;
 import com.google.cloud.ServiceOptions;
+import com.google.cloud.logging.LogEntry.Builder;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableMap;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -72,23 +74,23 @@ String getKey() {
     }
   }
 
+  private static final String APPENGINE_LABEL_PREFIX = "appengine.googleapis.com/";
+
   private static Map<String, Label[]> resourceTypeWithLabels;
 
   static {
     resourceTypeWithLabels =
         new ImmutableMap.Builder<String, Label[]>()
             .put(
                 Resource.GaeAppFlex.getKey(),
-                new Label[] {
-                  Label.InstanceName,
-                  Label.ModuleId,
-                  Label.VersionId,
-                  Label.InstanceId,
-                  Label.Zone
+                new Label[]{
+                    Label.ModuleId,
+                    Label.VersionId,
+                    Label.Zone
                 })
             .put(
                 Resource.GaeAppStandard.getKey(),
-                new Label[] {Label.AppId, Label.ModuleId, Label.VersionId})
+                new Label[] {Label.ModuleId, Label.VersionId})
             .put(Resource.Container.getKey(), new Label[] {Label.ClusterName, Label.Zone})
             .put(Resource.GceInstance.getKey(), new Label[] {Label.InstanceId, Label.Zone})
             .build();
@@ -193,18 +195,47 @@ private static String getAppEngineInstanceName() {
   }
 
   private static List<LoggingEnhancer> getEnhancers(Resource resourceType) {
-    List<LoggingEnhancer> enhancers;
+    List<LoggingEnhancer> enhancers = new ArrayList<>();
     switch (resourceType) {
       // Trace logging enhancer is supported on GAE Flex and Standard.
-      case GaeAppStandard:
       case GaeAppFlex:
-        enhancers = new ArrayList<>();
-        enhancers.add(new TraceLoggingEnhancer());
+        enhancers.add(new LabelLoggingEnhancer(
+            APPENGINE_LABEL_PREFIX, Collections.singletonList(Label.InstanceName)));
+        enhancers.add(new TraceLoggingEnhancer(APPENGINE_LABEL_PREFIX));
+        break;
+      case GaeAppStandard:
+        enhancers.add(new TraceLoggingEnhancer(APPENGINE_LABEL_PREFIX));
         break;
       default:
         enhancers = Collections.emptyList();
         break;
     }
     return enhancers;
   }
+
+  /**
+   *  Adds additional resource-based labels to log entries.
+   *  Labels that can be provided with {@link MonitoredResource.Builder#addLabel(String, String)}
+   *  are restricted to a supported set per resource.
+   *  @see <a href="https://cloud.google.com/logging/docs/api/v2/resource-list">Logging Labels</a>
+   */
+  private static class LabelLoggingEnhancer implements LoggingEnhancer {
+    String prefix;
+    List<Label> labels;
+
+    LabelLoggingEnhancer(String prefix, List<Label> labels) {
+      this.prefix = prefix != null ? prefix : "";
+      this.labels = labels;
+    }
+
+    @Override
+    public void enhanceLogEntry(Builder logEntry) {
+      for (Label label : labels) {
+        String labelValue = MonitoredResourceUtil.getValue(label);
+        if (labelValue != null) {
+          logEntry.addLabel(prefix + label.getKey(), labelValue);
+        }
+      }
+    }
+  }
 }

google-cloud-logging/src/main/java/com/google/cloud/logging/TraceLoggingEnhancer.java

@@ -19,6 +19,12 @@
 /* Adds tracing support for logging with thread-local trace ID tracking. */
 public class TraceLoggingEnhancer implements LoggingEnhancer {
 
+  private final String prefix;
+
+  public TraceLoggingEnhancer(String prefix) {
+    this.prefix = (prefix != null) ? prefix : "";
+  }
+
   private static final ThreadLocal<String> traceId = new ThreadLocal<>();
 
   /**
@@ -43,7 +49,7 @@ public static String getCurrentTraceId() {
   public void enhanceLogEntry(com.google.cloud.logging.LogEntry.Builder builder) {
     String traceId = getCurrentTraceId();
     if (traceId != null) {
-      builder.addLabel("trace_id", traceId);
+      builder.addLabel(prefix + "trace_id", traceId);
     }
   }
 }