chore: Add comments for public methods for otel

Author: lqiu96

java-datastore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/DatastoreOpenTelemetryOptions.java

@@ -68,9 +68,9 @@ public boolean isMetricsEnabled() {
   /**
    * Returns whether built-in metrics should be exported to Google Cloud Monitoring.
    *
-   * <p>When enabled, client-side metrics are automatically exported to Google Cloud Monitoring using
-   * the Cloud Monitoring API. This is independent of the custom OpenTelemetry backend configured via
-   * {@link #getOpenTelemetry()}.
+   * <p>When enabled, client-side metrics are automatically exported to Google Cloud Monitoring
+   * using the Cloud Monitoring API. This is independent of the custom OpenTelemetry backend
+   * configured via {@link #getOpenTelemetry()}.
    *
    * @return {@code true} if built-in metrics export to Cloud Monitoring is enabled, {@code false}
    *     otherwise.

java-datastore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/telemetry/MetricsRecorder.java

@@ -94,6 +94,7 @@ static MetricsRecorder getInstance(@Nonnull DatastoreOptions datastoreOptions) {
         OpenTelemetry builtInOtel =
             DatastoreBuiltInMetricsProvider.INSTANCE.getOrCreateOpenTelemetry(
                 datastoreOptions.getProjectId(),
+                datastoreOptions.getDatabaseId(),
                 datastoreOptions.getCredentials(),
                 null,
                 datastoreOptions.getUniverseDomain());
@@ -126,5 +127,4 @@ static MetricsRecorder getInstance(@Nonnull DatastoreOptions datastoreOptions) {
     }
     return new CompositeMetricsRecorder(recorders);
   }
-
 }

java-datastore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/telemetry/TelemetryConstants.java

@@ -47,16 +47,17 @@ public class TelemetryConstants {
   // Monitored resource type for Cloud Monitoring
   public static final String DATASTORE_RESOURCE_TYPE = "firestore.googleapis.com/Database";
 
-  // Resource label keys
-  public static final String RESOURCE_KEY_RESOURCE_CONTAINER = "resource_container";
-  public static final String RESOURCE_KEY_LOCATION = "location";
-  public static final String RESOURCE_KEY_DATABASE_ID = "database_id";
+  // Resource label keys for firestore.googleapis.com/Database
+  public static final String RESOURCE_LABEL_PROJECT_ID = "project_id";
+  public static final String RESOURCE_LABEL_DATABASE_ID = "database_id";
+  public static final String RESOURCE_LABEL_LOCATION = "location";
   public static final Set<String> DATASTORE_RESOURCE_LABELS =
       ImmutableSet.of(
-          RESOURCE_KEY_RESOURCE_CONTAINER, RESOURCE_KEY_LOCATION, RESOURCE_KEY_DATABASE_ID);
+          RESOURCE_LABEL_PROJECT_ID, RESOURCE_LABEL_DATABASE_ID, RESOURCE_LABEL_LOCATION);
 
   // Resource attribute keys (used on OTel Resource)
   public static final AttributeKey<String> PROJECT_ID_KEY = AttributeKey.stringKey("project_id");
+  public static final AttributeKey<String> DATABASE_ID_KEY = AttributeKey.stringKey("database_id");
   public static final AttributeKey<String> LOCATION_ID_KEY = AttributeKey.stringKey("location");
 
   // Metric attribute keys (used on metric data points)

java-datastore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/telemetry/TelemetryUtils.java

@@ -74,7 +74,8 @@ public static void recordOperationMetrics(
       String methodName,
       String status) {
     if (methodName != null
-        && !TelemetryConstants.Transport.GRPC.getTransport()
+        && !TelemetryConstants.Transport.GRPC
+            .getTransport()
             .equals(TelemetryConstants.getTransportName(datastoreOptions.getTransportOptions()))) {
       Map<String, String> attributes = buildMetricAttributes(datastoreOptions, methodName, status);
       metricsRecorder.recordOperationLatency(
@@ -110,7 +111,8 @@ public static <T> Callable<T> attemptMetricsCallable(
         status = DatastoreException.extractStatusCode(e);
         throw e;
       } finally {
-        if (!TelemetryConstants.Transport.GRPC.getTransport()
+        if (!TelemetryConstants.Transport.GRPC
+            .getTransport()
             .equals(TelemetryConstants.getTransportName(datastoreOptions.getTransportOptions()))) {
           Map<String, String> attributes =
               buildMetricAttributes(datastoreOptions, methodName, status);