add no op channel primer

Change-Id: I343b3dc44d12638be2af32398b6aaa8529c7ebfb

Author: nicholsl

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/BigtableChannelPrimer.java

@@ -41,7 +41,7 @@
 
 /**
  * A channel warmer that ensures that a Bigtable channel is ready to be used before being added to
- * the active {@link com.google.api.gax.grpc.ChannelPool}.
+ * the active {@link com.google.cloud.bigtable.gaxx.grpc.BigtableChannelPool}.
  *
  * <p>This implementation is subject to change in the future, but currently it will prime the
  * channel by sending a ReadRow request for a hardcoded, non-existent row key.

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/BigtableClientContext.java

@@ -20,6 +20,7 @@
 import com.google.api.gax.core.BackgroundResource;
 import com.google.api.gax.core.CredentialsProvider;
 import com.google.api.gax.core.FixedCredentialsProvider;
+import com.google.api.gax.grpc.ChannelPrimer;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.auth.Credentials;
@@ -121,7 +122,7 @@ public static BigtableClientContext create(EnhancedBigtableStubSettings settings
         setupCookieHolder(transportProvider);
       }
 
-      BigtableChannelPrimer channelPrimer = null;
+      ChannelPrimer channelPrimer = NoOpChannelPrimer.create();
 
       // Inject channel priming if enabled
       if (builder.isRefreshingChannel()) {

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/NoOpChannelPrimer.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.cloud.bigtable.data.v2.stub;
+
+import com.google.api.gax.grpc.ChannelPrimer;
+import io.grpc.ManagedChannel;
+
+public class NoOpChannelPrimer implements ChannelPrimer {
+  static NoOpChannelPrimer create() {
+    return new NoOpChannelPrimer();
+  }
+
+  NoOpChannelPrimer() {}
+
+  @Override
+  public void primeChannel(ManagedChannel managedChannel) {
+    // No op
+  }
+}

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/gaxx/grpc/BigtableChannelPool.java

@@ -17,7 +17,7 @@
 
 import com.google.api.core.InternalApi;
 import com.google.api.gax.grpc.ChannelFactory;
-import com.google.cloud.bigtable.data.v2.stub.BigtableChannelPrimer;
+import com.google.api.gax.grpc.ChannelPrimer;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
@@ -62,7 +62,7 @@ public class BigtableChannelPool extends ManagedChannel {
   private final BigtableChannelPoolSettings settings;
   private final ChannelFactory channelFactory;
 
-  @Nullable private final BigtableChannelPrimer channelPrimer;
+  private final ChannelPrimer channelPrimer;
   private final ScheduledExecutorService executor;
 
   private final Object entryWriteLock = new Object();
@@ -73,7 +73,7 @@ public class BigtableChannelPool extends ManagedChannel {
   public static BigtableChannelPool create(
       BigtableChannelPoolSettings settings,
       ChannelFactory channelFactory,
-      BigtableChannelPrimer channelPrimer)
+      ChannelPrimer channelPrimer)
       throws IOException {
     return new BigtableChannelPool(
         settings, channelFactory, channelPrimer, Executors.newSingleThreadScheduledExecutor());
@@ -90,7 +90,7 @@ public static BigtableChannelPool create(
   BigtableChannelPool(
       BigtableChannelPoolSettings settings,
       ChannelFactory channelFactory,
-      BigtableChannelPrimer channelPrimer,
+      ChannelPrimer channelPrimer,
       ScheduledExecutorService executor)
       throws IOException {
     this.settings = settings;

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/gaxx/grpc/BigtableTransportChannelProvider.java

@@ -18,19 +18,18 @@
 import com.google.api.core.InternalApi;
 import com.google.api.gax.grpc.ChannelFactory;
 import com.google.api.gax.grpc.ChannelPoolSettings;
+import com.google.api.gax.grpc.ChannelPrimer;
 import com.google.api.gax.grpc.GrpcTransportChannel;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
 import com.google.api.gax.rpc.TransportChannel;
 import com.google.api.gax.rpc.TransportChannelProvider;
 import com.google.auth.Credentials;
-import com.google.cloud.bigtable.data.v2.stub.BigtableChannelPrimer;
 import com.google.common.base.Preconditions;
 import io.grpc.ManagedChannel;
 import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
-import javax.annotation.Nullable;
 
 /**
  * An instance of TransportChannelProvider that provides a TransportChannel through a supplied
@@ -40,11 +39,11 @@
 public final class BigtableTransportChannelProvider implements TransportChannelProvider {
 
   private final InstantiatingGrpcChannelProvider delegate;
-  @Nullable private final BigtableChannelPrimer channelPrimer;
+  private final ChannelPrimer channelPrimer;
 
   private BigtableTransportChannelProvider(
       InstantiatingGrpcChannelProvider instantiatingGrpcChannelProvider,
-      BigtableChannelPrimer channelPrimer) {
+      ChannelPrimer channelPrimer) {
     delegate = Preconditions.checkNotNull(instantiatingGrpcChannelProvider);
     this.channelPrimer = channelPrimer;
   }
@@ -161,7 +160,7 @@ public TransportChannelProvider withCredentials(Credentials credentials) {
   /** Creates a BigtableTransportChannelProvider. */
   public static BigtableTransportChannelProvider create(
       InstantiatingGrpcChannelProvider instantiatingGrpcChannelProvider,
-      BigtableChannelPrimer channelPrimer) {
+      ChannelPrimer channelPrimer) {
     return new BigtableTransportChannelProvider(instantiatingGrpcChannelProvider, channelPrimer);
   }
 }