create noop channel primer

Change-Id: I8d4212aad0ca7613b6c33d69d925671a090d1609

Author: nicholsl

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

@@ -17,12 +17,12 @@
 
 import com.google.api.core.InternalApi;
 import com.google.api.core.SettableApiFuture;
-import com.google.api.gax.grpc.ChannelPrimer;
 import com.google.auth.Credentials;
 import com.google.bigtable.v2.BigtableGrpc;
 import com.google.bigtable.v2.InstanceName;
 import com.google.bigtable.v2.PingAndWarmRequest;
 import com.google.bigtable.v2.PingAndWarmResponse;
+import com.google.cloud.bigtable.gaxx.grpc.ChannelPrimer;
 import io.grpc.CallCredentials;
 import io.grpc.CallOptions;
 import io.grpc.ClientCall;

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

@@ -20,7 +20,6 @@
 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;
@@ -34,6 +33,7 @@
 import com.google.cloud.bigtable.data.v2.stub.metrics.MetricsProvider;
 import com.google.cloud.bigtable.data.v2.stub.metrics.NoopMetricsProvider;
 import com.google.cloud.bigtable.gaxx.grpc.BigtableTransportChannelProvider;
+import com.google.cloud.bigtable.gaxx.grpc.ChannelPrimer;
 import io.grpc.ManagedChannelBuilder;
 import io.grpc.opentelemetry.GrpcOpenTelemetry;
 import io.opentelemetry.api.OpenTelemetry;
@@ -122,7 +122,7 @@ public static BigtableClientContext create(EnhancedBigtableStubSettings settings
         setupCookieHolder(transportProvider);
       }
 
-      ChannelPrimer channelPrimer = NoOpChannelPrimer.create();
+      ChannelPrimer channelPrimer = (ChannelPrimer) NoOpChannelPrimer.create();
 
       // Inject channel priming if enabled
       if (builder.isRefreshingChannel()) {

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

@@ -17,8 +17,6 @@
 
 import com.google.api.core.InternalApi;
 import com.google.api.gax.grpc.ChannelFactory;
-import com.google.api.gax.grpc.ChannelPrimer;
-import com.google.cloud.bigtable.data.v2.stub.BigtableChannelPrimer;
 import com.google.cloud.bigtable.gaxx.grpc.ChannelPoolHealthChecker.ProbeResult;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
@@ -102,8 +100,7 @@ public static BigtableChannelPool create(
     this.channelPrimer = channelPrimer;
     Clock systemClock = Clock.systemUTC();
     this.channelPoolHealthChecker =
-        new ChannelPoolHealthChecker(
-            () -> entries.get(), (BigtableChannelPrimer) channelPrimer, executor, systemClock);
+        new ChannelPoolHealthChecker(() -> entries.get(), channelPrimer, executor, systemClock);
     this.channelPoolHealthChecker.start();
 
     ImmutableList.Builder<Entry> initialListBuilder = ImmutableList.builder();

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

@@ -18,7 +18,6 @@
 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;

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

@@ -16,8 +16,8 @@
 package com.google.cloud.bigtable.gaxx.grpc;
 
 import com.google.api.core.SettableApiFuture;
+import com.google.auto.value.AutoValue;
 import com.google.bigtable.v2.PingAndWarmResponse;
-import com.google.cloud.bigtable.data.v2.stub.BigtableChannelPrimer;
 import com.google.cloud.bigtable.gaxx.grpc.BigtableChannelPool.Entry;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableList;
@@ -37,42 +37,47 @@
 public class ChannelPoolHealthChecker {
 
   // Configuration constants
+  // Window_Duration is the duration over which we keep probe results
   private static final Duration WINDOW_DURATION = Duration.ofMinutes(5);
-  static final Duration PROBE_RATE = Duration.ofSeconds(30);
+  // Interval at which we probe channel health
+  static final Duration PROBE_INTERVAL = Duration.ofSeconds(30);
+  // Timeout deadline for a probe
   @VisibleForTesting static final Duration PROBE_DEADLINE = Duration.ofMillis(500);
+  // Minimum interval between new idle channel evictions
   private static final Duration MIN_EVICTION_INTERVAL = Duration.ofMinutes(10);
+  // Minimum number of probes that must be sent to a channel before it will be considered for
+  // eviction
   private static final int MIN_PROBES_FOR_EVALUATION = 4;
+  // Percentage of probes that must fail for a channel to be considered unhealthy
   private static final int SINGLE_CHANNEL_FAILURE_PERCENT_THRESHOLD = 60;
+  // "Circuitbreaker" - If this or a higher percentage of channels in a pool are bad, we will not
+  // evict any channels
   private static final int POOLWIDE_BAD_CHANNEL_CIRCUITBREAKER_PERCENT = 70;
 
   /** Inner class to represent the result of a single probe. */
-  static class ProbeResult {
-    final Instant startTime;
-    final boolean success;
+  @AutoValue
+  abstract static class ProbeResult {
+    abstract Instant startTime();
 
-    ProbeResult(Instant startTime, boolean success) {
-      this.startTime = startTime;
-      this.success = success;
-    }
+    abstract boolean isSuccessful();
 
-    public boolean isSuccessful() {
-      return success;
+    static ProbeResult create(Instant startTime, boolean success) {
+      return new AutoValue_ChannelPoolHealthChecker_ProbeResult(startTime, success);
     }
   }
 
-  // Class fields
   private final Supplier<ImmutableList<Entry>> entrySupplier;
   private Instant lastEviction;
   private ScheduledExecutorService executor;
 
-  private BigtableChannelPrimer channelPrimer;
+  private ChannelPrimer channelPrimer;
 
   private final Clock clock;
 
   /** Constructor for the pool health checker. */
   public ChannelPoolHealthChecker(
       Supplier<ImmutableList<Entry>> entrySupplier,
-      BigtableChannelPrimer channelPrimer,
+      ChannelPrimer channelPrimer,
       ScheduledExecutorService executor,
       Clock clock) {
     this.entrySupplier = entrySupplier;
@@ -84,18 +89,18 @@ public ChannelPoolHealthChecker(
 
   void start() {
     Duration initialDelayProbe =
-        Duration.ofMillis(ThreadLocalRandom.current().nextLong(PROBE_RATE.toMillis()));
+        Duration.ofMillis(ThreadLocalRandom.current().nextLong(PROBE_INTERVAL.toMillis()));
     executor.scheduleAtFixedRate(
         this::runProbes,
         initialDelayProbe.toMillis(),
-        PROBE_RATE.toMillis(),
+        PROBE_INTERVAL.toMillis(),
         TimeUnit.MILLISECONDS);
     Duration initialDelayDetect =
-        Duration.ofMillis(ThreadLocalRandom.current().nextLong(PROBE_RATE.toMillis()));
+        Duration.ofMillis(ThreadLocalRandom.current().nextLong(PROBE_INTERVAL.toMillis()));
     executor.scheduleAtFixedRate(
         this::detectAndRemoveOutlierEntries,
         initialDelayDetect.toMillis(),
-        PROBE_RATE.toMillis(),
+        PROBE_INTERVAL.toMillis(),
         TimeUnit.MILLISECONDS);
   }
 
@@ -127,7 +132,7 @@ void onComplete(
     } catch (Exception e) {
       success = false;
     }
-    addProbeResult(entry, new ProbeResult(startTime, success));
+    addProbeResult(entry, ProbeResult.create(startTime, success));
   }
 
   @VisibleForTesting
@@ -144,7 +149,7 @@ void addProbeResult(Entry entry, ProbeResult result) {
   void pruneHistoryFor(Entry entry) {
     Instant windowStart = clock.instant().minus(WINDOW_DURATION);
     while (!entry.probeHistory.isEmpty()
-        && entry.probeHistory.peek().startTime.isBefore(windowStart)) {
+        && entry.probeHistory.peek().startTime().isBefore(windowStart)) {
       ProbeResult removedResult = entry.probeHistory.poll();
       if (removedResult.isSuccessful()) {
         entry.successfulProbesInWindow.decrementAndGet();
@@ -157,8 +162,6 @@ void pruneHistoryFor(Entry entry) {
   /** Checks if a single entry is currently healthy based on its probe history. */
   @VisibleForTesting
   boolean isEntryHealthy(Entry entry) {
-    pruneHistoryFor(entry); // Ensure window is current before calculation
-
     int failedProbes = entry.failedProbesInWindow.get();
     int totalProbes = failedProbes + entry.successfulProbesInWindow.get();
 
@@ -178,10 +181,6 @@ boolean isEntryHealthy(Entry entry) {
   @Nullable
   @VisibleForTesting
   Entry findOutlierEntry() {
-    if (lastEviction.plus(WINDOW_DURATION).isAfter(clock.instant())) {
-      return null;
-    }
-
     List<Entry> unhealthyEntries =
         this.entrySupplier.get().stream()
             .peek(this::pruneHistoryFor)

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

@@ -0,0 +1,13 @@
+package com.google.cloud.bigtable.gaxx.grpc;
+
+import com.google.api.core.InternalApi;
+import com.google.api.core.SettableApiFuture;
+import com.google.bigtable.v2.PingAndWarmResponse;
+import io.grpc.ManagedChannel;
+
+@InternalApi("For internal use by google-cloud-java clients only")
+public interface ChannelPrimer {
+  void primeChannel(ManagedChannel var1);
+
+  SettableApiFuture<PingAndWarmResponse> sendPrimeRequestsAsync(ManagedChannel var1);
+}

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/gaxx/grpc/ChannelPoolHealthCheckerTest.java

@@ -113,7 +113,7 @@ public void testOnComplete_cancellationIsFailure() {
   @Test
   public void testPruning_removesOldProbesAndCounters() {
     Entry entry = createTestEntry();
-    healthChecker.addProbeResult(entry, new ProbeResult(mockClock.instant(), false));
+    healthChecker.addProbeResult(entry, ProbeResult.create(mockClock.instant(), false));
     assertThat(entry.failedProbesInWindow.get()).isEqualTo(1);
 
     Instant newTime = mockClock.instant().plus(Duration.ofMinutes(6));

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/gaxx/grpc/HealthChecker.java

@@ -0,0 +1,22 @@
+/*
+ * 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.gaxx.grpc;
+
+public interface HealthChecker {
+  void start();
+
+  void stop();
+}