Add retry handler support

sdk-workflows/pom.xml

@@ -47,7 +47,7 @@
     <dependency>
       <groupId>io.dapr</groupId>
       <artifactId>durabletask-client</artifactId>
-      <version>1.5.5</version>
+      <version>1.5.6</version>
     </dependency>
     <!--
     manually declare durabletask-client's jackson dependencies

sdk-workflows/src/main/java/io/dapr/workflows/WorkflowTaskOptions.java

@@ -16,13 +16,27 @@
 public class WorkflowTaskOptions {
 
   private final WorkflowTaskRetryPolicy retryPolicy;
+  private final WorkflowTaskRetryHandler retryHandler;
 
-  public WorkflowTaskOptions(WorkflowTaskRetryPolicy retryPolicy) {
+  public WorkflowTaskOptions(WorkflowTaskRetryPolicy retryPolicy, WorkflowTaskRetryHandler retryHandler) {
     this.retryPolicy = retryPolicy;
+    this.retryHandler = retryHandler;
+  }
+
+  public WorkflowTaskOptions(WorkflowTaskRetryPolicy retryPolicy) {
+    this(retryPolicy, null);
+  }
+
+  public WorkflowTaskOptions(WorkflowTaskRetryHandler retryHandler) {
+    this(null, retryHandler);
   }
 
   public WorkflowTaskRetryPolicy getRetryPolicy() {
     return retryPolicy;
   }
 
+  public WorkflowTaskRetryHandler getRetryHandler() {
+    return retryHandler;
+  }
+
 }

sdk-workflows/src/main/java/io/dapr/workflows/WorkflowTaskRetryContext.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2025 The Dapr Authors
+ * 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
+ *     http://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 io.dapr.workflows;
+
+import io.dapr.workflows.client.WorkflowFailureDetails;
+import io.dapr.workflows.runtime.DefaultWorkflowContext;
+
+import java.time.Duration;
+
+public class WorkflowTaskRetryContext {
+
+  private final DefaultWorkflowContext workflowContext;
+  private final int lastAttemptNumber;
+  private final WorkflowFailureDetails lastFailure;
+  private final Duration totalRetryTime;
+
+  /**
+   * Constructor for WorkflowTaskRetryContext.
+   *
+   * @param workflowContext The workflow context
+   * @param lastAttemptNumber The number of the previous attempt
+   * @param lastFailure The failure details from the most recent failure
+   * @param totalRetryTime The amount of time spent retrying
+   */
+  public WorkflowTaskRetryContext(
+          DefaultWorkflowContext workflowContext,
+          int lastAttemptNumber,
+          WorkflowFailureDetails lastFailure,
+          Duration totalRetryTime) {
+    this.workflowContext = workflowContext;
+    this.lastAttemptNumber = lastAttemptNumber;
+    this.lastFailure = lastFailure;
+    this.totalRetryTime = totalRetryTime;
+  }
+
+  /**
+   * Gets the context of the current workflow.
+   *
+   * <p>The workflow context can be used in retry handlers to schedule timers (via the
+   * {@link DefaultWorkflowContext#createTimer} methods) for implementing delays between retries. It can also be
+   * used to implement time-based retry logic by using the {@link DefaultWorkflowContext#getCurrentInstant} method.
+   *
+   * @return the context of the parent workflow
+   */
+  public DefaultWorkflowContext getWorkflowContext() {
+    return this.workflowContext;
+  }
+
+  /**
+   * Gets the details of the previous task failure, including the exception type, message, and callstack.
+   *
+   * @return the details of the previous task failure
+   */
+  public WorkflowFailureDetails getLastFailure() {
+    return this.lastFailure;
+  }
+
+  /**
+   * Gets the previous retry attempt number. This number starts at 1 and increments each time the retry handler
+   * is invoked for a particular task failure.
+   *
+   * @return the previous retry attempt number
+   */
+  public int getLastAttemptNumber() {
+    return this.lastAttemptNumber;
+  }
+
+  /**
+   * Gets the total amount of time spent in a retry loop for the current task.
+   *
+   * @return the total amount of time spent in a retry loop for the current task
+   */
+  public Duration getTotalRetryTime() {
+    return this.totalRetryTime;
+  }
+
+}

sdk-workflows/src/main/java/io/dapr/workflows/WorkflowTaskRetryHandler.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2025 The Dapr Authors
+ * 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
+ *     http://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 io.dapr.workflows;
+
+public interface WorkflowTaskRetryHandler {
+
+  /**
+   * Invokes retry handler logic. Return value indicates whether to continue retrying.
+   *
+   * @param retryContext The context of the retry
+   * @return {@code true} to continue retrying or {@code false} to stop retrying.
+   */
+  boolean handle(WorkflowTaskRetryContext retryContext);
+
+}

sdk-workflows/src/main/java/io/dapr/workflows/client/WorkflowFailureDetails.java

@@ -39,4 +39,14 @@ public interface WorkflowFailureDetails {
    */
   String getStackTrace();
 
+  /**
+   * Checks whether the failure was caused by the provided exception class.
+   *
+   * @param exceptionClass the exception class to check
+   * @return {@code true} if the failure was caused by the provided exception class
+   */
+  default boolean isCausedBy(Class<? extends Exception> exceptionClass) {
+    throw new UnsupportedOperationException("This method is not implemented");
+  }
+
 }

sdk-workflows/src/main/java/io/dapr/workflows/runtime/DefaultWorkflowContext.java

@@ -14,13 +14,16 @@
 package io.dapr.workflows.runtime;
 
 import io.dapr.durabletask.CompositeTaskFailedException;
+import io.dapr.durabletask.RetryHandler;
 import io.dapr.durabletask.RetryPolicy;
 import io.dapr.durabletask.Task;
 import io.dapr.durabletask.TaskCanceledException;
 import io.dapr.durabletask.TaskOptions;
 import io.dapr.durabletask.TaskOrchestrationContext;
 import io.dapr.workflows.WorkflowContext;
 import io.dapr.workflows.WorkflowTaskOptions;
+import io.dapr.workflows.WorkflowTaskRetryContext;
+import io.dapr.workflows.WorkflowTaskRetryHandler;
 import io.dapr.workflows.WorkflowTaskRetryPolicy;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -228,22 +231,50 @@ public UUID newUuid() {
     return this.innerContext.newUUID();
   }
 
-  private static TaskOptions toTaskOptions(WorkflowTaskOptions options) {
+  private TaskOptions toTaskOptions(WorkflowTaskOptions options) {
     if (options == null) {
       return null;
     }
 
-    WorkflowTaskRetryPolicy workflowTaskRetryPolicy = options.getRetryPolicy();
-    RetryPolicy retryPolicy = new RetryPolicy(
-        workflowTaskRetryPolicy.getMaxNumberOfAttempts(),
-        workflowTaskRetryPolicy.getFirstRetryInterval()
-    );
+    RetryPolicy retryPolicy = null;
+    RetryHandler retryHandler = toRetryHandler(options.getRetryHandler());
 
-    retryPolicy.setBackoffCoefficient(workflowTaskRetryPolicy.getBackoffCoefficient());
-    if (workflowTaskRetryPolicy.getRetryTimeout() != null) {
-      retryPolicy.setRetryTimeout(workflowTaskRetryPolicy.getRetryTimeout());
+    if (options.getRetryPolicy() != null) {
+      WorkflowTaskRetryPolicy workflowTaskRetryPolicy = options.getRetryPolicy();
+      retryPolicy = new RetryPolicy(
+              workflowTaskRetryPolicy.getMaxNumberOfAttempts(),
+              workflowTaskRetryPolicy.getFirstRetryInterval()
+      );
+
+      retryPolicy.setBackoffCoefficient(workflowTaskRetryPolicy.getBackoffCoefficient());
+      if (workflowTaskRetryPolicy.getRetryTimeout() != null) {
+        retryPolicy.setRetryTimeout(workflowTaskRetryPolicy.getRetryTimeout());
+      }
+    }
+
+    return new TaskOptions(retryPolicy, retryHandler);
+  }
+
+  /**
+   * Converts a {@link WorkflowTaskRetryHandler} to a {@link RetryHandler}.
+   *
+   * @param workflowTaskRetryHandler The {@link WorkflowTaskRetryHandler} being converted
+   * @return A {@link RetryHandler}
+   */
+  private RetryHandler toRetryHandler(WorkflowTaskRetryHandler workflowTaskRetryHandler) {
+    if (workflowTaskRetryHandler == null) {
+      return null;
     }
 
-    return new TaskOptions(retryPolicy);
+    return retryContext -> {
+      WorkflowTaskRetryContext workflowRetryContext = new WorkflowTaskRetryContext(
+              this,
+              retryContext.getLastAttemptNumber(),
+              new DefaultWorkflowFailureDetails(retryContext.getLastFailure()),
+              retryContext.getTotalRetryTime()
+      );
+
+      return workflowTaskRetryHandler.handle(workflowRetryContext);
+    };
   }
 }

sdk-workflows/src/main/java/io/dapr/workflows/runtime/DefaultWorkflowFailureDetails.java

@@ -62,6 +62,17 @@ public String getStackTrace() {
     return workflowFailureDetails.getStackTrace();
   }
 
+  /**
+   * Checks whether the failure was caused by the provided exception class.
+   *
+   * @param exceptionClass the exception class to check
+   * @return {@code true} if the failure was caused by the provided exception class
+   */
+  @Override
+  public boolean isCausedBy(Class<? extends Exception> exceptionClass) {
+    return workflowFailureDetails.isCausedBy(exceptionClass);
+  }
+
   @Override
   public String toString() {
     return workflowFailureDetails.toString();

sdk-workflows/src/test/java/io/dapr/workflows/DefaultWorkflowContextTest.java

@@ -14,6 +14,9 @@
 package io.dapr.workflows;
 
 import io.dapr.durabletask.CompositeTaskFailedException;
+import io.dapr.durabletask.FailureDetails;
+import io.dapr.durabletask.RetryContext;
+import io.dapr.durabletask.RetryHandler;
 import io.dapr.durabletask.Task;
 import io.dapr.durabletask.TaskCanceledException;
 import io.dapr.durabletask.TaskOptions;
@@ -35,10 +38,11 @@
 import java.util.List;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -278,7 +282,7 @@ public void callChildWorkflowWithName() {
   }
 
   @Test
-  public void callChildWorkflowWithOptions() {
+  public void callChildWorkflowWithRetryPolicy() {
     String expectedName = "TestActivity";
     String expectedInput = "TestInput";
     String expectedInstanceId = "TestInstanceId";
@@ -305,6 +309,90 @@ public void callChildWorkflowWithOptions() {
     assertEquals(retryPolicy.getMaxNumberOfAttempts(), taskOptions.getRetryPolicy().getMaxNumberOfAttempts());
     assertEquals(retryPolicy.getFirstRetryInterval(), taskOptions.getRetryPolicy().getFirstRetryInterval());
     assertEquals(Duration.ZERO, taskOptions.getRetryPolicy().getRetryTimeout());
+    assertNull(taskOptions.getRetryHandler());
+  }
+
+  @Test
+  public void callChildWorkflowWithRetryHandler() {
+    String expectedName = "TestActivity";
+    String expectedInput = "TestInput";
+    String expectedInstanceId = "TestInstanceId";
+
+    WorkflowTaskRetryHandler retryHandler = spy(new WorkflowTaskRetryHandler() {
+      @Override
+      public boolean handle(WorkflowTaskRetryContext retryContext) {
+        return true;
+      }
+    });
+
+    WorkflowTaskOptions executionOptions = new WorkflowTaskOptions(retryHandler);
+    ArgumentCaptor<TaskOptions> captor = ArgumentCaptor.forClass(TaskOptions.class);
+
+    context.callChildWorkflow(expectedName, expectedInput, expectedInstanceId, executionOptions, String.class);
+
+    verify(mockInnerContext, times(1))
+            .callSubOrchestrator(
+                    eq(expectedName),
+                    eq(expectedInput),
+                    eq(expectedInstanceId),
+                    captor.capture(),
+                    eq(String.class)
+            );
+
+    TaskOptions taskOptions = captor.getValue();
+
+    RetryHandler durableRetryHandler = taskOptions.getRetryHandler();
+    RetryContext retryContext = mock(RetryContext.class, invocationOnMock -> null);
+
+    durableRetryHandler.handle(retryContext);
+
+    verify(retryHandler, times(1)).handle(any());
+    assertNull(taskOptions.getRetryPolicy());
+  }
+
+  @Test
+  public void callChildWorkflowWithRetryPolicyAndHandler() {
+    String expectedName = "TestActivity";
+    String expectedInput = "TestInput";
+    String expectedInstanceId = "TestInstanceId";
+
+    WorkflowTaskRetryPolicy retryPolicy = WorkflowTaskRetryPolicy.newBuilder()
+            .setMaxNumberOfAttempts(1)
+            .setFirstRetryInterval(Duration.ofSeconds(10))
+            .build();
+
+    WorkflowTaskRetryHandler retryHandler = spy(new WorkflowTaskRetryHandler() {
+      @Override
+      public boolean handle(WorkflowTaskRetryContext retryContext) {
+        return true;
+      }
+    });
+
+    WorkflowTaskOptions executionOptions = new WorkflowTaskOptions(retryPolicy, retryHandler);
+    ArgumentCaptor<TaskOptions> captor = ArgumentCaptor.forClass(TaskOptions.class);
+
+    context.callChildWorkflow(expectedName, expectedInput, expectedInstanceId, executionOptions, String.class);
+
+    verify(mockInnerContext, times(1))
+            .callSubOrchestrator(
+                    eq(expectedName),
+                    eq(expectedInput),
+                    eq(expectedInstanceId),
+                    captor.capture(),
+                    eq(String.class)
+            );
+
+    TaskOptions taskOptions = captor.getValue();
+
+    RetryHandler durableRetryHandler = taskOptions.getRetryHandler();
+    RetryContext retryContext = mock(RetryContext.class, invocationOnMock -> null);
+
+    durableRetryHandler.handle(retryContext);
+
+    verify(retryHandler, times(1)).handle(any());
+    assertEquals(retryPolicy.getMaxNumberOfAttempts(), taskOptions.getRetryPolicy().getMaxNumberOfAttempts());
+    assertEquals(retryPolicy.getFirstRetryInterval(), taskOptions.getRetryPolicy().getFirstRetryInterval());
+    assertEquals(Duration.ZERO, taskOptions.getRetryPolicy().getRetryTimeout());
   }
 
   @Test