DSL sample using Serverless Workflo spec

README.md

@@ -107,6 +107,8 @@ All tests are available under [src/test/java](https://github.com/temporalio/samp
 
 - [**Money Batch**](https://github.com/temporalio/samples-java/tree/master/src/main/java/io/temporal/samples/moneybatch): Demonstrates a situation where a single deposit should be initiated for multiple withdrawals. For example, a seller might want to be paid once per fixed number of transactions. This sample can be easily extended to perform a payment based on more complex criteria, such as at a specific time or an accumulated amount. The sample also demonstrates how to Signal the Workflow when it executes (*Signal with start*). If the Workflow is already executing, it just receives the Signal. If it is not executing, then the Workflow executes first, and then the Signal is delivered to it. *Signal with start* is a "lazy" way to execute Workflows when Signaling them.
 
+- [**Customer Application Approval DSL**](https://github.com/temporalio/samples-java/tree/master/src/main/java/io/temporal/samples/dsl): Demonstrates execution of a customer application approval workflow defined in a DSL (JSON or YAML)
+
 ### API demonstrations
 
 - [**Updatable Timer**](https://github.com/temporalio/samples-java/tree/master/src/main/java/io/temporal/samples/updatabletimer): Demonstrates the use of a helper class which relies on `Workflow.await` to implement a blocking sleep that can be updated at any moment.

build.gradle

@@ -36,6 +36,10 @@ dependencies {
     implementation group: 'io.cloudevents', name: 'cloudevents-core', version: '2.2.0'
     implementation group: 'io.cloudevents', name: 'cloudevents-api', version: '2.2.0'
     implementation group: 'io.cloudevents', name: 'cloudevents-json-jackson', version: '2.2.0'
+    implementation group: 'io.serverlessworkflow', name: 'serverlessworkflow-api', version: '3.0.0.Final'
+    implementation group: 'io.serverlessworkflow', name: 'serverlessworkflow-validation', version: '3.0.0.Final'
+    implementation group: 'io.serverlessworkflow', name: 'serverlessworkflow-spi', version: '3.0.0.Final'
+    implementation group: 'com.jayway.jsonpath', name: 'json-path', version: '2.6.0'
 
     testImplementation group: 'io.temporal', name: 'temporal-testing', version: '1.2.0'
     testImplementation group: 'io.temporal', name: 'temporal-testing-junit4', version: '1.2.0'
@@ -44,8 +48,6 @@ dependencies {
     testImplementation group: 'org.mockito', name: 'mockito-core', version: '3.12.4'
     testImplementation group: 'org.powermock', name: 'powermock-api-mockito2', version: '2.0.9'
 
-
-
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.0-M1'
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.0-M1'
     testCompileOnly 'junit:junit:4.13.2'
@@ -70,6 +72,8 @@ task execute(type: JavaExec) {
 
 license {
     header rootProject.file('license-header.txt')
+    exclude '**/*.json'
+    exclude '**/*.yml'
 }
 
 // Executes most of the hello workflows as a sanity check

src/main/java/io/temporal/samples/dsl/DslWorkflowUtils.java

@@ -0,0 +1,163 @@
+/*
+ *  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.dsl;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.jayway.jsonpath.JsonPath;
+import io.serverlessworkflow.api.Workflow;
+import io.serverlessworkflow.api.interfaces.State;
+import io.serverlessworkflow.api.retry.RetryDefinition;
+import io.serverlessworkflow.api.states.EventState;
+import io.temporal.activity.ActivityOptions;
+import io.temporal.api.common.v1.WorkflowExecution;
+import io.temporal.client.WorkflowOptions;
+import io.temporal.client.WorkflowStub;
+import io.temporal.common.RetryOptions;
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.time.Duration;
+import java.util.List;
+
+/** Provides utility methods for dealing with DSL */
+public class DslWorkflowUtils {
+
+  // Default task queue name if not specified in dsl
+  public static final String DEFAULT_TASK_QUEUE_NAME = "defaultdsltaskqueue";
+
+  /** Set workflow options from DSL */
+  public static WorkflowOptions getWorkflowOptions(Workflow workflow) {
+    WorkflowOptions.Builder dslWorkflowOptionsBuilder = WorkflowOptions.newBuilder();
+
+    if (workflow.getId() != null) {
+      dslWorkflowOptionsBuilder.setWorkflowId(workflow.getId());
+    }
+
+    dslWorkflowOptionsBuilder.setTaskQueue(getTaskQueueFromDsl(workflow));
+
+    if (workflow.getTimeouts() != null
+        && workflow.getTimeouts().getWorkflowExecTimeout() != null
+        && workflow.getTimeouts().getWorkflowExecTimeout().getDuration() != null) {
+      dslWorkflowOptionsBuilder.setWorkflowExecutionTimeout(
+          Duration.parse(workflow.getTimeouts().getWorkflowExecTimeout().getDuration()));
+    }
+
+    if (workflow.getStart().getSchedule() != null
+        && workflow.getStart().getSchedule().getCron() != null) {
+      dslWorkflowOptionsBuilder.setCronSchedule(
+          workflow.getStart().getSchedule().getCron().getExpression());
+    }
+
+    return dslWorkflowOptionsBuilder.build();
+  }
+
+  /** Set Activity options from DSL */
+  public static ActivityOptions getActivityOptionsFromDsl(Workflow dslWorkflow) {
+    ActivityOptions.Builder dslActivityOptionsBuilder = ActivityOptions.newBuilder();
+    if (dslWorkflow.getTimeouts() != null
+        && dslWorkflow.getTimeouts().getActionExecTimeout() != null) {
+      dslActivityOptionsBuilder.setStartToCloseTimeout(
+          Duration.parse(dslWorkflow.getTimeouts().getActionExecTimeout()));
+    }
+
+    // In SW spec each action (activity) can define a specific retry
+    // For this demo we just use the globally defined one for all actions
+    if (dslWorkflow.getRetries() != null
+        && dslWorkflow.getRetries().getRetryDefs() != null
+        && dslWorkflow.getRetries().getRetryDefs().size() > 0) {
+      RetryDefinition retryDefinition = dslWorkflow.getRetries().getRetryDefs().get(0);
+      RetryOptions.Builder dslRetryOptionsBuilder = RetryOptions.newBuilder();
+      if (retryDefinition.getMaxAttempts() != null) {
+        dslRetryOptionsBuilder.setMaximumAttempts(
+            Integer.parseInt(retryDefinition.getMaxAttempts()));
+      }
+      dslRetryOptionsBuilder.setBackoffCoefficient(1.0);
+      if (retryDefinition.getDelay() != null) {
+        dslRetryOptionsBuilder.setInitialInterval(Duration.parse(retryDefinition.getDelay()));
+      }
+      if (retryDefinition.getMaxDelay() != null) {
+        dslRetryOptionsBuilder.setMaximumInterval(Duration.parse(retryDefinition.getMaxDelay()));
+      }
+    }
+
+    return dslActivityOptionsBuilder.build();
+  }
+
+  /** Read file and return contents as string */
+  public static String getFileAsString(String fileName) throws IOException {
+    File file = new File(Starter.class.getClassLoader().getResource(fileName).getFile());
+    return new String(Files.readAllBytes(file.toPath()), StandardCharsets.UTF_8);
+  }
+
+  /** Get the task queue from DSL */
+  public static String getTaskQueueFromDsl(Workflow workflow) {
+    if (workflow.getMetadata() != null
+        && workflow.getMetadata().size() > 0
+        && workflow.getMetadata().get("taskqueue") != null) {
+      return workflow.getMetadata().get("taskqueue");
+    } else {
+      return DEFAULT_TASK_QUEUE_NAME;
+    }
+  }
+
+  /** Start workflow execution depending on the DSL */
+  public static WorkflowExecution startWorkflow(
+      WorkflowStub workflowStub, Workflow dslWorkflow, JsonNode workflowInput) {
+    State startingDslWorkflowState = getStartingWorkflowState(dslWorkflow);
+    if (startingDslWorkflowState instanceof EventState) {
+      // This demo can parse only the first event
+      EventState eventState = (EventState) startingDslWorkflowState;
+      String eventName = eventState.getOnEvents().get(0).getEventRefs().get(0);
+      // send input data as signal data
+      return workflowStub.signalWithStart(
+          eventName, new Object[] {workflowInput}, new Object[] {Workflow.toJson(dslWorkflow)});
+    } else {
+      // directly send input data to workflow
+      return workflowStub.start(Workflow.toJson(dslWorkflow), workflowInput);
+    }
+  }
+
+  /** Returns the starting workflow state from DSL */
+  public static State getStartingWorkflowState(Workflow dslWorkflow) {
+    String start = dslWorkflow.getStart().getStateName();
+    for (State state : dslWorkflow.getStates()) {
+      if (state.getName().equals(start)) {
+        return state;
+      }
+    }
+    return null;
+  }
+
+  /** Returns the workflow state with the provided name or null */
+  public static State getWorkflowStateWithName(String name, Workflow dslWorkflow) {
+    for (State state : dslWorkflow.getStates()) {
+      if (state.getName().equals(name)) {
+        return state;
+      }
+    }
+    return null;
+  }
+
+  /** Evaluates a JsonPath expression to true/false, used for switch states data conditions */
+  public static boolean isTrueDataCondition(String condition, String jsonData) {
+    return JsonPath.parse(jsonData).read(condition, List.class).size() > 0;
+  }
+}

src/main/java/io/temporal/samples/dsl/DynamicDslActivities.java

@@ -0,0 +1,60 @@
+/*
+ *  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.dsl;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import io.temporal.activity.Activity;
+import io.temporal.activity.DynamicActivity;
+import io.temporal.common.converter.EncodedValues;
+
+public class DynamicDslActivities implements DynamicActivity {
+  @Override
+  public Object execute(EncodedValues args) {
+    // Get the activity type
+    String activityType = Activity.getExecutionContext().getInfo().getActivityType();
+    String actionName = args.get(0, String.class);
+    JsonNode workflowData = args.get(1, JsonNode.class);
+
+    try {
+      // Add a "actions" array to results to show what was executed
+      if (workflowData.get("actions") != null) {
+        ((ArrayNode) workflowData.get("actions")).add(actionName);
+      } else {
+        ((ObjectNode) workflowData).putArray("actions").add(actionName);
+      }
+
+      // Update the application status if we are approving / rejecting the customer
+      // This is for demo only, in real application this would come as result of the function
+      // invocation
+      if (activityType.equals("Invoke Approve Application Function")) {
+        ((ObjectNode) workflowData.get("customer")).put("applicationStatus", "APPROVED");
+      }
+      if (activityType.equals("Invoke Reject Application Function")) {
+        ((ObjectNode) workflowData.get("customer")).put("applicationStatus", "REJECTED");
+      }
+
+      return workflowData;
+    } catch (Exception e) {
+      throw Activity.wrap(e);
+    }
+  }
+}