chore: Update Datastore implementation

Author: lqiu96

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

@@ -193,7 +193,7 @@ public Builder setDatabaseId(String databaseId) {
     }
 
     /**
-     * Sets the {@link DatastoreOpenTelemetryOptions} to be used for this Firestore instance.
+     * Sets the {@link DatastoreOpenTelemetryOptions} to be used for this Datastore instance.
      *
      * @param openTelemetryOptions The `DatastoreOpenTelemetryOptions` to use.
      */

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

@@ -18,26 +18,20 @@
 
 import com.google.api.gax.core.GaxProperties;
 import com.google.auth.Credentials;
-import com.google.common.base.Strings;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.common.AttributesBuilder;
 import io.opentelemetry.sdk.metrics.SdkMeterProvider;
 import io.opentelemetry.sdk.metrics.SdkMeterProviderBuilder;
 import io.opentelemetry.sdk.resources.Resource;
-import java.io.BufferedReader;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
 import java.lang.management.ManagementFactory;
-import java.lang.reflect.Method;
-import java.net.HttpURLConnection;
-import java.net.URL;
-import java.nio.charset.StandardCharsets;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 /**
@@ -62,86 +56,71 @@ public final class DatastoreBuiltInMetricsProvider {
   private static String location;
   private static final String DEFAULT_LOCATION = "global";
 
-  private SdkMeterProvider sdkMeterProvider;
-  private OpenTelemetry openTelemetry;
+  private final Map<String, String> cachedClientAttributes;
 
-  private DatastoreBuiltInMetricsProvider() {}
+  private DatastoreBuiltInMetricsProvider() {
+    cachedClientAttributes =
+        Collections.unmodifiableMap(buildClientAttributes());
+  }
+
+  private Map<String, String> buildClientAttributes() {
+    Map<String, String> attrs = new HashMap<>();
+    attrs.put(
+        TelemetryConstants.CLIENT_NAME_KEY.getKey(),
+        "datastore-java/" + GaxProperties.getLibraryVersion(getClass()));
+    attrs.put(TelemetryConstants.CLIENT_UID_KEY.getKey(), getDefaultTaskValue());
+    attrs.put(TelemetryConstants.SERVICE_KEY.getKey(), TelemetryConstants.SERVICE_VALUE);
+    return attrs;
+  }
 
   /**
-   * Returns a singleton {@link OpenTelemetry} instance for built-in metrics.
+   * Creates a new {@link OpenTelemetry} instance for a single Datastore client's built-in metrics.
+   *
+   * <p>Each call returns a dedicated {@link SdkMeterProvider} configured with the provided
+   * project's monitored resource attributes and a {@link DatastoreCloudMonitoringExporter}. A
+   * shutdown hook is registered to flush and close the provider when the JVM exits.
    *
-   * <p>This method initializes an {@link SdkMeterProvider} with a {@link
-   * DatastoreCloudMonitoringExporter} and the appropriate resource attributes. It also registers a
-   * shutdown hook to ensure metrics are flushed when the JVM exits.
+   * <p>Callers are responsible for holding the returned instance for the lifetime of their
+   * Datastore client; no caching is performed here.
    *
    * @param projectId the GCP project ID.
    * @param databaseId the Datastore database ID.
    * @param credentials the credentials to use for exporting metrics.
    * @param monitoringHost optional monitoring host override.
    * @param universeDomain the universe domain to use for monitoring.
-   * @return the {@link OpenTelemetry} instance, or {@code null} if it could not be created.
+   * @return a new {@link OpenTelemetry} instance, or {@code null} if it could not be created.
    */
-  public OpenTelemetry getOrCreateOpenTelemetry(
-      String projectId,
-      String databaseId,
+  @Nullable
+  public OpenTelemetry createOpenTelemetry(
+      @Nonnull String projectId,
+      @Nonnull String databaseId,
       @Nullable Credentials credentials,
       @Nullable String monitoringHost,
-      String universeDomain) {
+      @Nonnull String universeDomain) {
     try {
-      if (this.openTelemetry == null) {
-        SdkMeterProviderBuilder sdkMeterProviderBuilder = SdkMeterProvider.builder();
-        // Register Datastore-specific views and the PeriodicMetricReader.
-        DatastoreBuiltInMetricsView.registerBuiltinMetrics(
-            DatastoreCloudMonitoringExporter.create(
-                projectId, credentials, monitoringHost, universeDomain),
-            sdkMeterProviderBuilder);
-        // Configure the monitored resource attributes.
-        sdkMeterProviderBuilder.setResource(
-            Resource.create(createResourceAttributes(projectId, databaseId)));
-        this.sdkMeterProvider = sdkMeterProviderBuilder.build();
-        this.openTelemetry = new DatastoreOpenTelemetry(this.sdkMeterProvider);
-        // Ensure cleanup on shutdown.
-        Runtime.getRuntime().addShutdownHook(new Thread(this.sdkMeterProvider::close));
-      }
-      return this.openTelemetry;
+      SdkMeterProviderBuilder sdkMeterProviderBuilder = SdkMeterProvider.builder();
+      // Register Datastore-specific views and the PeriodicMetricReader.
+      DatastoreBuiltInMetricsView.registerBuiltinMetrics(
+          DatastoreCloudMonitoringExporter.create(
+              projectId, credentials, monitoringHost, universeDomain),
+          sdkMeterProviderBuilder);
+      // Configure the monitored resource attributes for this specific client.
+      sdkMeterProviderBuilder.setResource(
+          Resource.create(createResourceAttributes(projectId, databaseId)));
+      SdkMeterProvider sdkMeterProvider = sdkMeterProviderBuilder.build();
+      // Ensure cleanup on shutdown.
+      Runtime.getRuntime().addShutdownHook(new Thread(sdkMeterProvider::close));
+      return new DatastoreOpenTelemetry(sdkMeterProvider);
     } catch (IOException ex) {
       logger.log(
           Level.WARNING,
-          "Unable to get OpenTelemetry object for client side metrics, will skip exporting client"
-              + " side metrics",
+          "Unable to create OpenTelemetry instance for client side metrics, will skip exporting"
+              + " built-in metrics",
           ex);
       return null;
     }
   }
 
-  /**
-   * Quick check to see if the application is running on GCP by querying the metadata server.
-   *
-   * <p>This is used to determine if we should enable built-in metrics by default.
-   *
-   * @return {@code true} if running on GCP, {@code false} otherwise.
-   */
-  public static boolean quickCheckIsRunningOnGcp() {
-    int timeout = 5000;
-    try {
-      URL url = new URL("http://metadata.google.internal/computeMetadata/v1/project/project-id");
-      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
-      connection.setConnectTimeout(timeout);
-      connection.setRequestProperty("Metadata-Flavor", "Google");
-      if (connection.getResponseCode() == 200
-          && ("Google").equals(connection.getHeaderField("Metadata-Flavor"))) {
-        InputStream input = connection.getInputStream();
-        try (BufferedReader reader =
-            new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
-          return !Strings.isNullOrEmpty(reader.readLine());
-        }
-      }
-    } catch (IOException ignore) {
-      // ignore
-    }
-    return false;
-  }
-
   /**
    * Detects the client's GCP location (region).
    *
@@ -179,30 +158,24 @@ Attributes createResourceAttributes(String projectId, String databaseId) {
   }
 
   /**
-   * Creates common client attributes for each metric data point.
+   * Returns common client attributes added to every exported metric data point.
    *
-   * <p>These attributes (client_name, client_uid) are added to every exported metric to identify
-   * the specific client instance.
+   * <p>The returned map is pre-computed at construction time and shared across all export calls,
+   * since {@code client_name}, {@code client_uid}, and {@code service} are stable for the lifetime
+   * of the process.
    *
-   * @return a map of client attributes.
+   * @return an unmodifiable map of client attributes.
    */
   public Map<String, String> createClientAttributes() {
-    Map<String, String> clientAttributes = new HashMap<>();
-    clientAttributes.put(
-        TelemetryConstants.CLIENT_NAME_KEY.getKey(),
-        "datastore-java/" + GaxProperties.getLibraryVersion(getClass()));
-    clientAttributes.put(TelemetryConstants.CLIENT_UID_KEY.getKey(), getDefaultTaskValue());
-    clientAttributes.put(TelemetryConstants.SERVICE_KEY.getKey(), TelemetryConstants.SERVICE_VALUE);
-    return clientAttributes;
+    return cachedClientAttributes;
   }
 
   /**
    * Generates a unique identifier for the {@code client_uid} metric field.
    *
-   * <p>The identifier is composed of a UUID, the process ID (PID), and the hostname to ensure
-   * uniqueness across different instances and restarts.
+   * <p>Uses {@code RuntimeMXBean.getName()} which typically returns {@code pid@hostname}.
    *
-   * @return a unique identifier string in the format UUID@PID@hostname.
+   * @return a unique identifier string.
    */
   private static String getDefaultTaskValue() {
     if (taskId == null) {
@@ -211,34 +184,6 @@ private static String getDefaultTaskValue() {
     return taskId;
   }
 
-  /**
-   * Returns the process ID.
-   *
-   * <p>Attempts to use {@code ProcessHandle} (Java 9+) and falls back to {@code RuntimeMXBean} for
-   * Java 8 compatibility.
-   *
-   * @return the PID as a string.
-   */
-  private static String getProcessId() {
-    try {
-      // Check if Java 9+ and ProcessHandle class is available
-      Class<?> processHandleClass = Class.forName("java.lang.ProcessHandle");
-      Method currentMethod = processHandleClass.getMethod("current");
-      Object processHandleInstance = currentMethod.invoke(null);
-      Method pidMethod = processHandleClass.getMethod("pid");
-      long pid = (long) pidMethod.invoke(processHandleInstance);
-      return Long.toString(pid);
-    } catch (Exception e) {
-      // Fallback to Java 8 method
-      final String jvmName = ManagementFactory.getRuntimeMXBean().getName();
-      if (jvmName != null && jvmName.contains("@")) {
-        return jvmName.split("@")[0];
-      } else {
-        return "unknown";
-      }
-    }
-  }
-
   /**
    * A simple {@link OpenTelemetry} implementation that only provides a {@link
    * io.opentelemetry.api.metrics.MeterProvider}.

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

@@ -92,7 +92,7 @@ static MetricsRecorder getInstance(@Nonnull DatastoreOptions datastoreOptions) {
         && !metricsDisabledViaEnv) {
       try {
         OpenTelemetry builtInOtel =
-            DatastoreBuiltInMetricsProvider.INSTANCE.getOrCreateOpenTelemetry(
+            DatastoreBuiltInMetricsProvider.INSTANCE.createOpenTelemetry(
                 datastoreOptions.getProjectId(),
                 datastoreOptions.getDatabaseId(),
                 datastoreOptions.getCredentials(),

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

@@ -34,10 +34,9 @@
 @InternalApi
 public class TelemetryConstants {
 
-  // TODO(lawrenceqiu): For now, use `custom.googleapis.com` until metrics can be written to
-  // datastore domain
+  // Datastore metrics are exported under the Firestore service domain. The `service` metric
+  // attribute is set to "datastore.googleapis.com" to distinguish Datastore traffic from Firestore.
   public static final String SERVICE_NAME = "firestore.googleapis.com";
-  static final String METER_NAME = "com.google.cloud.datastore";
 
   // Built-in metrics constants for Cloud Monitoring export
   public static final String METRIC_PREFIX = "firestore.googleapis.com/internal/client";

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

@@ -17,6 +17,7 @@
 package com.google.cloud.datastore.telemetry;
 
 import com.google.api.core.InternalApi;
+import com.google.api.gax.core.GaxProperties;
 import com.google.api.gax.rpc.StatusCode;
 import com.google.cloud.datastore.DatastoreException;
 import com.google.cloud.datastore.DatastoreOptions;
@@ -54,6 +55,9 @@ public static Map<String, String> buildMetricAttributes(
     attributes.put(
         TelemetryConstants.ATTRIBUTES_KEY_TRANSPORT,
         TelemetryConstants.getTransportName(datastoreOptions.getTransportOptions()));
+    attributes.put(
+        TelemetryConstants.ATTRIBUTES_KEY_LIBRARY_VERSION,
+        GaxProperties.getLibraryVersion(DatastoreOptions.class));
     return attributes;
   }
 

java-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/telemetry/DatastoreBuiltInMetricsProviderTest.java

@@ -44,16 +44,24 @@ public void testCreateClientAttributes() {
   }
 
   @Test
-  public void testGetOrCreateOpenTelemetry() {
+  public void testCreateOpenTelemetry_returnsNonNull() {
     OpenTelemetry otel =
-        DatastoreBuiltInMetricsProvider.INSTANCE.getOrCreateOpenTelemetry(
+        DatastoreBuiltInMetricsProvider.INSTANCE.createOpenTelemetry(
             PROJECT_ID, "test-db", null, null, "googleapis.com");
     assertThat(otel).isNotNull();
+  }
 
+  @Test
+  public void testCreateOpenTelemetry_eachCallReturnsDistinctInstance() {
+    OpenTelemetry otel1 =
+        DatastoreBuiltInMetricsProvider.INSTANCE.createOpenTelemetry(
+            PROJECT_ID, "test-db", null, null, "googleapis.com");
     OpenTelemetry otel2 =
-        DatastoreBuiltInMetricsProvider.INSTANCE.getOrCreateOpenTelemetry(
+        DatastoreBuiltInMetricsProvider.INSTANCE.createOpenTelemetry(
             PROJECT_ID, "test-db", null, null, "googleapis.com");
-    assertThat(otel2).isSameInstanceAs(otel);
+    assertThat(otel1).isNotNull();
+    assertThat(otel2).isNotNull();
+    assertThat(otel1).isNotSameInstanceAs(otel2);
   }
 
   @Test