fix(gax-grpc): resolve merge conflicts with feat/channelpool-resizing

Author: lqiu96

sdk-platform-java/gax-java/gax-grpc/src/main/java/com/google/api/gax/grpc/ChannelPoolSettings.java

@@ -61,6 +61,10 @@ public abstract class ChannelPoolSettings {
   /** The maximum number of channels that can be added or removed at a time. */
   static final int DEFAULT_MAX_RESIZE_DELTA = 2;
 
+  // Arbitrary limit to prevent unbounded growth and protect server/client resources.
+  // Capping at 25 ensures we don't scale too aggressively in a single cycle.
+  private static final int MAX_ALLOWED_RESIZE_DELTA = 25;
+
   /**
    * Threshold to start scaling down the channel pool.
    *
@@ -100,6 +104,11 @@ public abstract class ChannelPoolSettings {
    * the pool better handle sudden bursts or spikes in requests by allowing it to scale up faster.
    * Regardless of this setting, the number of channels will never exceed {@link
    * #getMaxChannelCount()}.
+   *
+   * <p><b>Note:</b> This value cannot exceed {@value #MAX_ALLOWED_RESIZE_DELTA}.
+   *
+   * <p><b>Warning:</b> Higher values for resize delta may still result in performance degradation
+   * during spikes due to rapid scaling.
    */
   public abstract int getMaxResizeDelta();
 
@@ -208,6 +217,9 @@ public abstract static class Builder {
      * This acts as a rate limiter to prevent wild fluctuations. The pool resizes periodically
      * according to {@link #RESIZE_INTERVAL} (default 1 minute). During resizing, this value is
      * effectively capped by the bound configured via {@link #setMaxChannelCount}.
+     *
+     * <p><b>Warning:</b> Higher values for resize delta may still result in performance degradation
+     * during spikes due to rapid scaling.
      */
     public abstract Builder setMaxResizeDelta(int count);
 
@@ -232,6 +244,12 @@ public ChannelPoolSettings build() {
           s.getInitialChannelCount() > 0, "Initial channel count must be greater than 0");
       Preconditions.checkState(
           s.getMaxResizeDelta() > 0, "Max resize delta must be greater than 0");
+      Preconditions.checkState(
+          s.getMaxResizeDelta() <= MAX_ALLOWED_RESIZE_DELTA,
+          "Max resize delta cannot be greater than " + MAX_ALLOWED_RESIZE_DELTA);
+      Preconditions.checkState(
+          s.getMaxResizeDelta() <= s.getMaxChannelCount(),
+          "Max resize delta cannot be greater than max channel count");
       return s;
     }
   }

sdk-platform-java/gax-java/gax-grpc/src/test/java/com/google/api/gax/grpc/ChannelPoolTest.java

@@ -851,109 +851,10 @@ void testDoubleRelease() throws Exception {
   }
 
   @Test
-  void settingsValidationFailsWhenMinChannelsExceedsMaxChannels() {
+  void settingsValidationFailsWhenMaxResizeDeltaExceedsLimit() {
     ChannelPoolSettings.Builder builder =
-        ChannelPoolSettings.builder().setMinChannelCount(2).setMaxChannelCount(1);
-    Assertions.assertThrows(IllegalStateException.class, () -> builder.build());
-  }
-
-  @Test
-  void minChannelsClampedToMaxChannelCountUnderHighLoad() throws Exception {
-    ScheduledExecutorService executor = Mockito.mock(ScheduledExecutorService.class);
-    FixedExecutorProvider provider = FixedExecutorProvider.create(executor);
-
-    List<ManagedChannel> channels = new ArrayList<>();
-    ChannelFactory channelFactory = createMockChannelFactory(channels, null);
-
-    pool =
-        new ChannelPool(
-            ChannelPoolSettings.builder()
-                .setInitialChannelCount(1)
-                .setMinRpcsPerChannel(1)
-                .setMaxRpcsPerChannel(2)
-                .setMaxResizeDelta(10) // Allow large growth
-                .setMinChannelCount(1)
-                .setMaxChannelCount(5)
-                .build(),
-            channelFactory,
-            provider);
-    assertThat(pool.entries.get()).hasSize(1);
-
-    // Add 20 RPCs, which would require 10 channels (20/2)
-    // But max is 5
-    for (int i = 0; i < 20; i++) {
-      ClientCalls.futureUnaryCall(
-          pool.newCall(METHOD_RECOGNIZE, CallOptions.DEFAULT), Color.getDefaultInstance());
-    }
-
-    pool.resize();
-
-    // Should be clamped to maxChannelCount = 5
-    assertThat(pool.entries.get()).hasSize(5);
-  }
-
-  @Test
-  void resizeDampenedByMaxResizeDelta() throws Exception {
-    ScheduledExecutorService executor = Mockito.mock(ScheduledExecutorService.class);
-    FixedExecutorProvider provider = FixedExecutorProvider.create(executor);
-
-    List<ManagedChannel> channels = new ArrayList<>();
-    ChannelFactory channelFactory = createMockChannelFactory(channels, null);
-
-    pool =
-        new ChannelPool(
-            ChannelPoolSettings.builder()
-                .setInitialChannelCount(1)
-                .setMinRpcsPerChannel(1)
-                .setMaxRpcsPerChannel(2)
-                .setMaxResizeDelta(2) // Limit growth to 2 channels per cycle
-                .setMinChannelCount(1)
-                .setMaxChannelCount(10)
-                .build(),
-            channelFactory,
-            provider);
-    assertThat(pool.entries.get()).hasSize(1);
-
-    // Add 20 RPCs, which would require 10 channels (20/2)
-    // Desired delta is +9 (10 - 1)
-    // maxResizeDelta is 2, so it should be dampened to 2
-    for (int i = 0; i < 20; i++) {
-      ClientCalls.futureUnaryCall(
-          pool.newCall(METHOD_RECOGNIZE, CallOptions.DEFAULT), Color.getDefaultInstance());
-    }
-
-    pool.resize();
-
-    // Should be dampened to 1 + 2 = 3 channels
-    assertThat(pool.entries.get()).hasSize(3);
-  }
-
-  @Test
-  void maxChannelsClampedToMinChannelCountUnderLowLoad() throws Exception {
-    ScheduledExecutorService executor = Mockito.mock(ScheduledExecutorService.class);
-    FixedExecutorProvider provider = FixedExecutorProvider.create(executor);
-
-    List<ManagedChannel> channels = new ArrayList<>();
-    ChannelFactory channelFactory = createMockChannelFactory(channels, null);
-
-    pool =
-        new ChannelPool(
-            ChannelPoolSettings.builder()
-                .setInitialChannelCount(5)
-                .setMinRpcsPerChannel(1)
-                .setMaxRpcsPerChannel(2)
-                .setMinChannelCount(3)
-                .setMaxChannelCount(10)
-                .build(),
-            channelFactory,
-            provider);
-    assertThat(pool.entries.get()).hasSize(5);
-
-    // With no outstanding RPCs, the pool should want to shrink to 0
-    // But min is 3
-    pool.resize();
-
-    // Should be clamped to minChannelCount = 3
-    assertThat(pool.entries.get()).hasSize(3);
+        ChannelPoolSettings.builder().setMaxResizeDelta(26).setMaxChannelCount(30);
+    org.junit.jupiter.api.Assertions.assertThrows(
+        IllegalStateException.class, () -> builder.build());
   }
 }