Allow poller scale-down on timeout when server supports autoscaling

temporal-sdk/src/main/java/io/temporal/internal/worker/ActivityWorker.java

@@ -26,6 +26,7 @@
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -48,6 +49,7 @@ final class ActivityWorker implements SuspendableWorker {
   private final GrpcRetryer grpcRetryer;
   private final GrpcRetryer.GrpcRetryerOptions replyGrpcRetryerOptions;
   private final TrackingSlotSupplier<ActivitySlotInfo> slotSupplier;
+  private final AtomicBoolean serverSupportsAutoscaling;
 
   public ActivityWorker(
       @Nonnull WorkflowServiceStubs service,
@@ -56,7 +58,8 @@ public ActivityWorker(
       double taskQueueActivitiesPerSecond,
       @Nonnull SingleWorkerOptions options,
       @Nonnull ActivityTaskHandler handler,
-      @Nonnull SlotSupplier<ActivitySlotInfo> slotSupplier) {
+      @Nonnull SlotSupplier<ActivitySlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.service = Objects.requireNonNull(service);
     this.namespace = Objects.requireNonNull(namespace);
     this.taskQueue = Objects.requireNonNull(taskQueue);
@@ -72,6 +75,7 @@ public ActivityWorker(
             DefaultStubServiceOperationRpcRetryOptions.INSTANCE, null);
 
     this.slotSupplier = new TrackingSlotSupplier<>(slotSupplier, this.workerMetricsScope);
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
   }
 
   @Override
@@ -106,6 +110,7 @@ public boolean start() {
                     service.getServerCapabilities()),
                 this.pollTaskExecutor,
                 pollerOptions,
+                serverSupportsAutoscaling.get(),
                 workerMetricsScope);
 
       } else {

temporal-sdk/src/main/java/io/temporal/internal/worker/AsyncPoller.java

@@ -29,6 +29,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
   private final List<PollTaskAsync<T>> asyncTaskPollers;
   private final PollerOptions pollerOptions;
   private final PollerBehaviorAutoscaling pollerBehavior;
+  private final boolean serverSupportsAutoscaling;
   private final Scope workerMetricsScope;
   private Throttler pollRateThrottler;
   private final Thread.UncaughtExceptionHandler uncaughtExceptionHandler =
@@ -42,13 +43,15 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
       PollTaskAsync<T> asyncTaskPoller,
       ShutdownableTaskExecutor<T> taskExecutor,
       PollerOptions pollerOptions,
+      boolean serverSupportsAutoscaling,
       Scope workerMetricsScope) {
     this(
         slotSupplier,
         slotReservationData,
         Collections.singletonList(asyncTaskPoller),
         taskExecutor,
         pollerOptions,
+        serverSupportsAutoscaling,
         workerMetricsScope);
   }
 
@@ -58,6 +61,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
       List<PollTaskAsync<T>> asyncTaskPollers,
       ShutdownableTaskExecutor<T> taskExecutor,
       PollerOptions pollerOptions,
+      boolean serverSupportsAutoscaling,
       Scope workerMetricsScope) {
     super(taskExecutor);
     Objects.requireNonNull(slotSupplier, "slotSupplier cannot be null");
@@ -78,6 +82,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
               + " is not supported for AsyncPoller. Only PollerBehaviorAutoscaling is supported.");
     }
     this.pollerBehavior = (PollerBehaviorAutoscaling) pollerOptions.getPollerBehavior();
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
     this.pollerOptions = pollerOptions;
     this.workerMetricsScope = workerMetricsScope;
   }
@@ -109,6 +114,7 @@ public boolean start() {
               pollerBehavior.getMinConcurrentTaskPollers(),
               pollerBehavior.getMaxConcurrentTaskPollers(),
               pollerBehavior.getInitialConcurrentTaskPollers(),
+              serverSupportsAutoscaling,
               (newTarget) -> {
                 log.debug(
                     "Updating maximum number of pollers for {} to: {}",

temporal-sdk/src/main/java/io/temporal/internal/worker/NexusWorker.java

@@ -30,6 +30,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -52,6 +53,7 @@ final class NexusWorker implements SuspendableWorker {
   private final GrpcRetryer grpcRetryer;
   private final GrpcRetryer.GrpcRetryerOptions replyGrpcRetryerOptions;
   private final TrackingSlotSupplier<NexusSlotInfo> slotSupplier;
+  private final AtomicBoolean serverSupportsAutoscaling;
   private final boolean forceOldFailureFormat;
 
   public NexusWorker(
@@ -61,7 +63,8 @@ public NexusWorker(
       @Nonnull SingleWorkerOptions options,
       @Nonnull NexusTaskHandler handler,
       @Nonnull DataConverter dataConverter,
-      @Nonnull SlotSupplier<NexusSlotInfo> slotSupplier) {
+      @Nonnull SlotSupplier<NexusSlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.service = Objects.requireNonNull(service);
     this.namespace = Objects.requireNonNull(namespace);
     this.taskQueue = Objects.requireNonNull(taskQueue);
@@ -77,6 +80,7 @@ public NexusWorker(
             DefaultStubServiceOperationRpcRetryOptions.INSTANCE, null);
 
     this.slotSupplier = new TrackingSlotSupplier<>(slotSupplier, this.workerMetricsScope);
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
     // Allow tests to force old format for backward compatibility testing
     String forceOldFormat = System.getProperty("temporal.nexus.forceOldFailureFormat");
     this.forceOldFailureFormat = "true".equalsIgnoreCase(forceOldFormat);
@@ -112,6 +116,7 @@ public boolean start() {
                     this.slotSupplier),
                 this.pollTaskExecutor,
                 pollerOptions,
+                serverSupportsAutoscaling.get(),
                 workerMetricsScope);
       } else {
         poller =
@@ -282,6 +287,7 @@ public Throwable wrapFailure(NexusTask task, Throwable failure) {
           "Failure processing nexus response: " + response.getRequest().toString(), failure);
     }
 
+    @SuppressWarnings("deprecation") // Uses deprecated operationError
     private void handleNexusTask(NexusTask task, Scope metricsScope) {
       PollNexusTaskQueueResponseOrBuilder pollResponse = task.getResponse();
       ByteString taskToken = pollResponse.getTaskToken();
@@ -374,6 +380,7 @@ private void logExceptionDuringResultReporting(
       }
     }
 
+    @SuppressWarnings("deprecation") // Uses deprecated setOperationError
     private Response getResponseForOldServer(Response response) {
       Response.Builder b = response.toBuilder();
       Failure failure = response.getStartOperation().getFailure();

temporal-sdk/src/main/java/io/temporal/internal/worker/PollScaleReportHandle.java

@@ -18,6 +18,7 @@ public class PollScaleReportHandle<T extends ScalingTask> implements Runnable {
   private final int maxPollerCount;
   private int targetPollerCount;
   private final Functions.Proc1<Integer> scaleCallback;
+  private final boolean serverSupportsAutoscaling;
   private boolean everSawScalingDecision;
   private int ingestedThisPeriod;
   private int ingestedLastPeriod;
@@ -27,18 +28,20 @@ public PollScaleReportHandle(
       int minPollerCount,
       int maxPollerCount,
       int initialPollerCount,
+      boolean serverSupportsAutoscaling,
       Functions.Proc1<Integer> scaleCallback) {
     this.minPollerCount = minPollerCount;
     this.maxPollerCount = maxPollerCount;
     this.targetPollerCount = initialPollerCount;
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
     this.scaleCallback = scaleCallback;
   }
 
   public synchronized void report(T task, Throwable e) {
     if (e != null) {
       // We want to avoid scaling down on errors if we have never seen a scaling decision
-      // since we might never scale up again.
-      if (!everSawScalingDecision) {
+      // and the server doesn't support autoscaling - otherwise we might never scale up again.
+      if (!everSawScalingDecision && !serverSupportsAutoscaling) {
         return;
       }
       if ((e instanceof StatusRuntimeException)) {
@@ -68,9 +71,10 @@ public synchronized void report(T task, Throwable e) {
         updateTarget((t -> t + deltaSuggestion));
       }
 
-    } else if (task == null && everSawScalingDecision) {
+    } else if (task == null && (everSawScalingDecision || serverSupportsAutoscaling)) {
       // We want to avoid scaling down on empty polls if the server has never made any
-      // scaling decisions - otherwise we might never scale up again.
+      // scaling decisions and doesn't support autoscaling - otherwise we might never scale
+      // up again.
       updateTarget((t) -> t - 1);
     }
   }

temporal-sdk/src/main/java/io/temporal/internal/worker/SyncActivityWorker.java

@@ -11,6 +11,8 @@
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -32,7 +34,8 @@ public SyncActivityWorker(
       String taskQueue,
       double taskQueueActivitiesPerSecond,
       SingleWorkerOptions options,
-      SlotSupplier<ActivitySlotInfo> slotSupplier) {
+      SlotSupplier<ActivitySlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.identity = options.getIdentity();
     this.namespace = namespace;
     this.taskQueue = taskQueue;
@@ -72,7 +75,8 @@ public SyncActivityWorker(
             taskQueueActivitiesPerSecond,
             options,
             taskHandler,
-            slotSupplier);
+            slotSupplier,
+            serverSupportsAutoscaling);
   }
 
   public void registerActivityImplementations(Object... activitiesImplementation) {

temporal-sdk/src/main/java/io/temporal/internal/worker/SyncNexusWorker.java

@@ -6,6 +6,8 @@
 import io.temporal.worker.tuning.SlotSupplier;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -23,7 +25,8 @@ public SyncNexusWorker(
       String namespace,
       String taskQueue,
       SingleWorkerOptions options,
-      SlotSupplier<NexusSlotInfo> slotSupplier) {
+      SlotSupplier<NexusSlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.identity = options.getIdentity();
     this.namespace = namespace;
     this.taskQueue = taskQueue;
@@ -43,7 +46,8 @@ public SyncNexusWorker(
             options,
             taskHandler,
             options.getDataConverter(),
-            slotSupplier);
+            slotSupplier,
+            serverSupportsAutoscaling);
   }
 
   @Override

temporal-sdk/src/main/java/io/temporal/internal/worker/SyncWorkflowWorker.java

@@ -25,6 +25,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import org.slf4j.Logger;
@@ -68,7 +69,8 @@ public SyncWorkflowWorker(
       @Nonnull WorkflowThreadExecutor workflowThreadExecutor,
       @Nonnull EagerActivityDispatcher eagerActivityDispatcher,
       @Nonnull SlotSupplier<WorkflowSlotInfo> slotSupplier,
-      @Nonnull SlotSupplier<LocalActivitySlotInfo> laSlotSupplier) {
+      @Nonnull SlotSupplier<LocalActivitySlotInfo> laSlotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.identity = singleWorkerOptions.getIdentity();
     this.namespace = namespace;
     this.taskQueue = taskQueue;
@@ -122,7 +124,8 @@ public SyncWorkflowWorker(
             cache,
             taskHandler,
             eagerActivityDispatcher,
-            slotSupplier);
+            slotSupplier,
+            serverSupportsAutoscaling);
 
     // Exists to support Worker#replayWorkflowExecution functionality.
     // This handler has to be non-sticky to avoid evicting actual executions from the cache

temporal-sdk/src/main/java/io/temporal/internal/worker/WorkflowWorker.java

@@ -30,6 +30,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import org.slf4j.Logger;
@@ -54,6 +55,7 @@ final class WorkflowWorker implements SuspendableWorker {
   private final GrpcRetryer grpcRetryer;
   private final EagerActivityDispatcher eagerActivityDispatcher;
   private final TrackingSlotSupplier<WorkflowSlotInfo> slotSupplier;
+  private final AtomicBoolean serverSupportsAutoscaling;
 
   private PollTaskExecutor<WorkflowTask> pollTaskExecutor;
 
@@ -73,7 +75,8 @@ public WorkflowWorker(
       @Nonnull WorkflowExecutorCache cache,
       @Nonnull WorkflowTaskHandler handler,
       @Nonnull EagerActivityDispatcher eagerActivityDispatcher,
-      @Nonnull SlotSupplier<WorkflowSlotInfo> slotSupplier) {
+      @Nonnull SlotSupplier<WorkflowSlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.service = Objects.requireNonNull(service);
     this.namespace = Objects.requireNonNull(namespace);
     this.taskQueue = Objects.requireNonNull(taskQueue);
@@ -88,6 +91,7 @@ public WorkflowWorker(
     this.grpcRetryer = new GrpcRetryer(service.getServerCapabilities());
     this.eagerActivityDispatcher = eagerActivityDispatcher;
     this.slotSupplier = new TrackingSlotSupplier<>(slotSupplier, this.workerMetricsScope);
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
   }
 
   @Override
@@ -154,6 +158,7 @@ public boolean start() {
                 pollers,
                 this.pollTaskExecutor,
                 pollerOptions,
+                serverSupportsAutoscaling.get(),
                 workerMetricsScope);
       } else {
         PollerBehaviorSimpleMaximum pollerBehavior =

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

@@ -69,7 +69,8 @@ public final class Worker {
       boolean useStickyTaskQueue,
       WorkflowThreadExecutor workflowThreadExecutor,
       List<ContextPropagator> contextPropagators,
-      @Nonnull List<WorkerPlugin> plugins) {
+      @Nonnull List<WorkerPlugin> plugins,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
 
     Objects.requireNonNull(client, "client should not be null");
     this.plugins = Objects.requireNonNull(plugins, "plugins should not be null");
@@ -102,7 +103,8 @@ public final class Worker {
               taskQueue,
               this.options.getMaxTaskQueueActivitiesPerSecond(),
               activityOptions,
-              activitySlotSupplier);
+              activitySlotSupplier,
+              serverSupportsAutoscaling);
     }
 
     EagerActivityDispatcher eagerActivityDispatcher =
@@ -120,7 +122,13 @@ public final class Worker {
     attachMetricsToResourceController(taggedScope, nexusSlotSupplier);
 
     nexusWorker =
-        new SyncNexusWorker(client, namespace, taskQueue, nexusOptions, nexusSlotSupplier);
+        new SyncNexusWorker(
+            client,
+            namespace,
+            taskQueue,
+            nexusOptions,
+            nexusSlotSupplier,
+            serverSupportsAutoscaling);
 
     SingleWorkerOptions singleWorkerOptions =
         toWorkflowWorkerOptions(
@@ -158,7 +166,8 @@ public final class Worker {
             workflowThreadExecutor,
             eagerActivityDispatcher,
             workflowSlotSupplier,
-            localActivitySlotSupplier);
+            localActivitySlotSupplier,
+            serverSupportsAutoscaling);
   }
 
   /**