Add gRPC-GCP extension options to SpannerOptions

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerOptions.java

@@ -48,6 +48,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import com.google.grpc.gcp.GcpManagedChannelOptions;
 import com.google.spanner.v1.ExecuteSqlRequest;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryOptions;
 import com.google.spanner.v1.SpannerGrpc;
@@ -104,6 +105,7 @@ public class SpannerOptions extends ServiceOptions<Spanner, SpannerOptions> {
   private final DatabaseAdminStubSettings databaseAdminStubSettings;
   private final Duration partitionedDmlTimeout;
   private final boolean useGrpcGcpExtension;
+  private final GcpManagedChannelOptions grpcGcpOptions;
   private final boolean autoThrottleAdministrativeRequests;
   private final boolean trackTransactionStarter;
   /**
@@ -559,6 +561,7 @@ private SpannerOptions(Builder builder) {
     }
     partitionedDmlTimeout = builder.partitionedDmlTimeout;
     useGrpcGcpExtension = builder.useGrpcGcpExtension;
+    grpcGcpOptions = builder.grpcGcpOptions;
     autoThrottleAdministrativeRequests = builder.autoThrottleAdministrativeRequests;
     trackTransactionStarter = builder.trackTransactionStarter;
     defaultQueryOptions = builder.defaultQueryOptions;
@@ -638,7 +641,8 @@ public static class Builder
     private DatabaseAdminStubSettings.Builder databaseAdminStubSettingsBuilder =
         DatabaseAdminStubSettings.newBuilder();
     private Duration partitionedDmlTimeout = Duration.ofHours(2L);
-    private boolean useGrpcGcpExtension = true;
+    private boolean useGrpcGcpExtension = false;
+    private GcpManagedChannelOptions grpcGcpOptions;
     private boolean autoThrottleAdministrativeRequests = false;
     private boolean trackTransactionStarter = false;
     private Map<DatabaseId, QueryOptions> defaultQueryOptions = new HashMap<>();
@@ -686,7 +690,8 @@ private Builder() {
       this.instanceAdminStubSettingsBuilder = options.instanceAdminStubSettings.toBuilder();
       this.databaseAdminStubSettingsBuilder = options.databaseAdminStubSettings.toBuilder();
       this.partitionedDmlTimeout = options.partitionedDmlTimeout;
-      this.useGrpcGcpExtension = useGrpcGcpExtension;
+      this.useGrpcGcpExtension = options.useGrpcGcpExtension;
+      this.grpcGcpOptions = options.grpcGcpOptions;
       this.autoThrottleAdministrativeRequests = options.autoThrottleAdministrativeRequests;
       this.trackTransactionStarter = options.trackTransactionStarter;
       this.defaultQueryOptions = options.defaultQueryOptions;
@@ -1003,11 +1008,26 @@ public Builder setHost(String host) {
       return this;
     }
 
+    /**
+     * Sets the preference for gRPC-GCP extension (default: false). When enabled the gRPC-GCP
+     * channel pool will be used.
+     */
     public Builder setUseGrpcGcpExtension(boolean useGrpcGcpExtension) {
       this.useGrpcGcpExtension = useGrpcGcpExtension;
       return this;
     }
 
+    /**
+     * Sets the options for gRPC-GCP extension. The metric registry and default Spanner metric
+     * labels will be added automatically.
+     *
+     * <p>Note that gRPC-GCP extension must be enabled first with {@code setUseGrpcGcpExtension}.
+     */
+    public Builder setGrpcGcpOptions(GcpManagedChannelOptions options) {
+      this.grpcGcpOptions = options;
+      return this;
+    }
+
     /**
      * Sets the host of an emulator to use. By default the value is read from an environment
      * variable. If the environment variable is not set, this will be <code>null</code>.
@@ -1112,6 +1132,10 @@ public boolean isUseGrpcGcpExtension() {
     return useGrpcGcpExtension;
   }
 
+  public GcpManagedChannelOptions getGrpcGcpOptions() {
+    return grpcGcpOptions;
+  }
+
   public boolean isAutoThrottleAdministrativeRequests() {
     return autoThrottleAdministrativeRequests;
   }