Disable eager activities if task queue rate limits is set (#2325)

Author: Quinn-With-Two-Ns

temporal-sdk/src/main/java/io/temporal/worker/WorkerOptions.java

@@ -220,6 +220,8 @@ public Builder setMaxConcurrentNexusExecutionSize(int maxConcurrentNexusExecutio
      * it to less than 1 if needed. For example, set the number to 0.1 means you want your activity
      * to be executed once every 10 seconds. This can be used to protect down stream services from
      * flooding. The zero value of this uses the default value. Default is unlimited.
+     *
+     * <p>Setting this value to a non-zero value will disable eager execution for activities.
      */
     public Builder setMaxTaskQueueActivitiesPerSecond(double maxTaskQueueActivitiesPerSecond) {
       this.maxTaskQueueActivitiesPerSecond = maxTaskQueueActivitiesPerSecond;
@@ -373,7 +375,8 @@ public Builder setStickyQueueScheduleToStartTimeout(Duration timeout) {
      * the workflow task back to this worker which is faster than non-eager which may be dispatched
      * to a separate worker.
      *
-     * <p>Defaults to false, meaning that eager activity execution is permitted
+     * <p>Defaults to false, meaning that eager activity execution is permitted. Unless you set
+     * MaxTaskQueueActivitiesPerSecond, then eager execution is disabled.
      */
     public Builder setDisableEagerExecution(boolean disableEagerExecution) {
       this.disableEagerExecution = disableEagerExecution;
@@ -685,7 +688,7 @@ private WorkerOptions(
     this.maxHeartbeatThrottleInterval = maxHeartbeatThrottleInterval;
     this.defaultHeartbeatThrottleInterval = defaultHeartbeatThrottleInterval;
     this.stickyQueueScheduleToStartTimeout = stickyQueueScheduleToStartTimeout;
-    this.disableEagerExecution = disableEagerExecution;
+    this.disableEagerExecution = maxTaskQueueActivitiesPerSecond > 0 ? true : disableEagerExecution;
     this.useBuildIdForVersioning = useBuildIdForVersioning;
     this.buildId = buildId;
     this.stickyTaskQueueDrainTimeout = stickyTaskQueueDrainTimeout;

temporal-sdk/src/test/java/io/temporal/worker/WorkerOptionsTest.java

@@ -164,4 +164,14 @@ public void throwsIfResourceControllerIsNotSame() {
                 localActivitySlotSupplier,
                 nexusSlotSupplier));
   }
+
+  @Test
+  public void verifyMaxTaskQueuePerSecondsDisablesEagerExecution() {
+    // Verify that by default eager execution is enabled
+    WorkerOptions w1 = WorkerOptions.newBuilder().build();
+    assertEquals(false, w1.isEagerExecutionDisabled());
+    // Verify that setting maxTaskQueueActivitiesPerSecond disables eager
+    WorkerOptions w2 = WorkerOptions.newBuilder().setMaxTaskQueueActivitiesPerSecond(2.0).build();
+    assertEquals(true, w2.isEagerExecutionDisabled());
+  }
 }