EarlyReturn sample (Update-With-Start)

core/src/main/java/io/temporal/samples/earlyreturn/EarlyReturnClient.java

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+/*
+ *  Copyright (c) 2020 Temporal Technologies, Inc. All Rights Reserved
+ *
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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.temporal.samples.earlyreturn;
+
+import io.temporal.client.*;
+import io.temporal.serviceclient.WorkflowServiceStubs;
+
+public class EarlyReturnClient {
+  private static final String TASK_QUEUE = "EarlyReturnTaskQueue";
+  private static final String WORKFLOW_ID_PREFIX = "early-return-workflow-";
+
+  public static void main(String[] args) {
+    WorkflowClient client = setupWorkflowClient();
+    runWorkflowWithUpdateWithStart(client);
+  }
+
+  // Set up the WorkflowClient
+  public static WorkflowClient setupWorkflowClient() {
+    WorkflowServiceStubs service = WorkflowServiceStubs.newLocalServiceStubs();
+    return WorkflowClient.newInstance(service);
+  }
+
+  // Run workflow using 'updateWithStart'
+  private static void runWorkflowWithUpdateWithStart(WorkflowClient client) {
+    TransactionRequest txRequest =
+        new TransactionRequest(
+            "Bob", "Alice",
+            -1000); // Change this amount to a negative number to have initTransaction fail
+
+    WorkflowOptions options = buildWorkflowOptions();
+    TransactionWorkflow workflow = client.newWorkflowStub(TransactionWorkflow.class, options);
+
+    System.out.println("Starting workflow with UpdateWithStart");
+
+    UpdateWithStartWorkflowOperation<TxResult> updateOp =
+        UpdateWithStartWorkflowOperation.newBuilder(workflow::returnInitResult)
+            .setWaitForStage(WorkflowUpdateStage.COMPLETED) // Wait for update to complete
+            .build();
+
+    TxResult updateResult = null;
+    try {
+      WorkflowUpdateHandle<TxResult> updateHandle =
+          WorkflowClient.updateWithStart(workflow::processTransaction, txRequest, updateOp);
+
+      updateResult = updateHandle.getResultAsync().get();
+
+      System.out.println(
+          "Workflow initialized with result: "
+              + updateResult.getStatus()
+              + " (transactionId: "
+              + updateResult.getTransactionId()
+              + ")");
+
+      TxResult result = WorkflowStub.fromTyped(workflow).getResult(TxResult.class);
+      System.out.println(
+          "Workflow completed with result: "
+              + result.getStatus()
+              + " (transactionId: "
+              + result.getTransactionId()
+              + ")");
+    } catch (Exception e) {
+      System.err.println("Transaction initialization failed: " + e.getMessage());
+    }
+  }
+
+  // Build WorkflowOptions with task queue and unique ID
+  private static WorkflowOptions buildWorkflowOptions() {
+    return WorkflowOptions.newBuilder()
+        .setTaskQueue(TASK_QUEUE)
+        .setWorkflowId(WORKFLOW_ID_PREFIX + System.currentTimeMillis())
+        .build();
+  }
+}

core/src/main/java/io/temporal/samples/earlyreturn/EarlyReturnWorker.java

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+/*
+ *  Copyright (c) 2020 Temporal Technologies, Inc. All Rights Reserved
+ *
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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.temporal.samples.earlyreturn;
+
+import io.temporal.client.WorkflowClient;
+import io.temporal.worker.Worker;
+import io.temporal.worker.WorkerFactory;
+
+public class EarlyReturnWorker {
+  private static final String TASK_QUEUE = "EarlyReturnTaskQueue";
+
+  public static void main(String[] args) {
+    WorkflowClient client = EarlyReturnClient.setupWorkflowClient();
+    startWorker(client);
+  }
+
+  private static void startWorker(WorkflowClient client) {
+    WorkerFactory factory = WorkerFactory.newInstance(client);
+    Worker worker = factory.newWorker(TASK_QUEUE);
+
+    worker.registerWorkflowImplementationTypes(TransactionWorkflowImpl.class);
+    worker.registerActivitiesImplementations(new TransactionActivitiesImpl());
+
+    factory.start();
+    System.out.println("Worker started");
+  }
+}

core/src/main/java/io/temporal/samples/earlyreturn/README.md

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+### Early-Return Sample
+
+This sample demonstrates an early-return from a workflow.
+
+By utilizing Update-with-Start, a client can start a new workflow and synchronously receive 
+a response mid-workflow, while the workflow continues to run to completion.
+
+To run the sample, start the worker:
+```bash
+./gradlew -q execute -PmainClass=io.temporal.samples.earlyreturn.EarlyReturnWorker
+```
+
+Then, start the client:
+
+```bash
+./gradlew -q execute -PmainClass=io.temporal.samples.earlyreturn.EarlyReturnClient
+```
+
+* The client will start a workflow using Update-With-Start.
+* Update-With-Start will trigger an initialization step.
+* If the initialization step succeeds (default), intialization will return to the client with a transaction ID and the workflow will continue. The workflow will then complete and return the final result.
+* If the intitialization step fails (amount <= 0), the workflow will return to the client with an error message and the workflow will run an activity to cancel the transaction.
+
+To trigger a failed initialization, set the amount to <= 0 in the `EarlyReturnClient` class's `runWorkflowWithUpdateWithStart` method and re-run the client.

core/src/main/java/io/temporal/samples/earlyreturn/Transaction.java

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+/*
+ *  Copyright (c) 2020 Temporal Technologies, Inc. All Rights Reserved
+ *
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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.temporal.samples.earlyreturn;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public final class Transaction {
+  private final String id;
+  private final String sourceAccount;
+  private final String targetAccount;
+  private final int amount;
+
+  @JsonCreator(mode = JsonCreator.Mode.PROPERTIES)
+  public Transaction(
+      @JsonProperty("id") String id,
+      @JsonProperty("sourceAccount") String sourceAccount,
+      @JsonProperty("targetAccount") String targetAccount,
+      @JsonProperty("amount") int amount) {
+    this.id = id;
+    this.sourceAccount = sourceAccount;
+    this.targetAccount = targetAccount;
+    this.amount = amount;
+  }
+
+  @JsonProperty("id")
+  public String getId() {
+    return id;
+  }
+
+  @JsonProperty("sourceAccount")
+  public String getSourceAccount() {
+    return sourceAccount;
+  }
+
+  @JsonProperty("targetAccount")
+  public String getTargetAccount() {
+    return targetAccount;
+  }
+
+  @JsonProperty("amount")
+  public int getAmount() {
+    return amount;
+  }
+
+  @Override
+  public String toString() {
+    return String.format(
+        "Transaction{id='%s', sourceAccount='%s', targetAccount='%s', amount=%d}",
+        id, sourceAccount, targetAccount, amount);
+  }
+}

core/src/main/java/io/temporal/samples/earlyreturn/TransactionActivities.java

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+/*
+ *  Copyright (c) 2020 Temporal Technologies, Inc. All Rights Reserved
+ *
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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.temporal.samples.earlyreturn;
+
+import io.temporal.activity.ActivityInterface;
+import io.temporal.activity.ActivityMethod;
+
+@ActivityInterface
+public interface TransactionActivities {
+  @ActivityMethod
+  Transaction initTransaction(TransactionRequest tx);
+
+  @ActivityMethod
+  void cancelTransaction(TransactionRequest txRequest);
+
+  @ActivityMethod
+  void completeTransaction(Transaction tx);
+}

core/src/main/java/io/temporal/samples/earlyreturn/TransactionActivitiesImpl.java

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+/*
+ *  Copyright (c) 2020 Temporal Technologies, Inc. All Rights Reserved
+ *
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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.temporal.samples.earlyreturn;
+
+import io.temporal.failure.ApplicationFailure;
+
+public class TransactionActivitiesImpl implements TransactionActivities {
+
+  @Override
+  public Transaction initTransaction(TransactionRequest txRequest) {
+    System.out.println("Initializing transaction");
+    sleep(500);
+    if (txRequest.getAmount() <= 0) {
+      System.out.println("Invalid amount: " + txRequest.getAmount());
+      throw ApplicationFailure.newNonRetryableFailure(
+          "Non-retryable Activity Failure: Invalid Amount", "InvalidAmount");
+    }
+    // Simulate transaction ID generation
+    String txId = "TXID" + String.format("%010d", (long) (Math.random() * 1_000_000_0000L));
+    Transaction tx =
+        new Transaction(
+            txId,
+            txRequest.getSourceAccount(),
+            txRequest.getTargetAccount(),
+            txRequest.getAmount());
+
+    sleep(500);
+    return tx;
+  }
+
+  @Override
+  public void cancelTransaction(TransactionRequest txRequest) {
+    System.out.println("Cancelling transaction");
+    sleep(300);
+    System.out.println("Transaction cancelled");
+  }
+
+  @Override
+  public void completeTransaction(Transaction tx) {
+    System.out.println(
+        "Sending $"
+            + tx.getAmount()
+            + " from "
+            + tx.getSourceAccount()
+            + " to "
+            + tx.getTargetAccount());
+    sleep(2000);
+    System.out.println("Transaction completed successfully");
+  }
+
+  private void sleep(long millis) {
+    try {
+      Thread.sleep(millis);
+    } catch (InterruptedException e) {
+      Thread.currentThread().interrupt();
+    }
+  }
+}