[Fix #1107] Adding workflow status change event

impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowApplication.java

@@ -70,6 +70,7 @@ public class WorkflowApplication implements AutoCloseable {
   private final EventConsumer<?, ?> eventConsumer;
   private final Collection<EventPublisher> eventPublishers;
   private final boolean lifeCycleCEPublishingEnabled;
+  private final boolean lifeCycleStatusChangeEnabled;
   private final WorkflowModelFactory modelFactory;
   private final WorkflowModelFactory contextFactory;
   private final WorkflowScheduler scheduler;
@@ -95,6 +96,7 @@ private WorkflowApplication(Builder builder) {
     this.eventConsumer = builder.eventConsumer;
     this.eventPublishers = builder.eventPublishers;
     this.lifeCycleCEPublishingEnabled = builder.lifeCycleCEPublishingEnabled;
+    this.lifeCycleStatusChangeEnabled = builder.lifeCycleStatusChangeEnabled;
     this.modelFactory = builder.modelFactory;
     this.contextFactory = builder.contextFactory;
     this.scheduler = builder.scheduler;
@@ -179,6 +181,7 @@ public SchemaValidator getValidator(SchemaInline inline) {
     private RuntimeDescriptorFactory descriptorFactory =
         () -> new RuntimeDescriptor("reference impl", "1.0.0_alpha", Collections.emptyMap());
     private boolean lifeCycleCEPublishingEnabled = true;
+    private boolean lifeCycleStatusChangeEnabled = true;
     private WorkflowModelFactory modelFactory;
     private WorkflowModelFactory contextFactory;
     private Map<String, WorkflowAdditionalObject<?>> additionalObjects = new HashMap<>();
@@ -224,6 +227,11 @@ public Builder disableLifeCycleCEPublishing() {
       return this;
     }
 
+    public Builder disableStatusChangePublishing() {
+      this.lifeCycleStatusChangeEnabled = false;
+      return this;
+    }
+
     public Builder withExecutorFactory(ExecutorServiceFactory executorFactory) {
       this.executorFactory = executorFactory;
       return this;
@@ -421,6 +429,10 @@ public boolean isLifeCycleCEPublishingEnabled() {
     return lifeCycleCEPublishingEnabled;
   }
 
+  public boolean isStatusChangePublishingEnabled() {
+    return lifeCycleStatusChangeEnabled;
+  }
+
   public WorkflowScheduler scheduler() {
     return scheduler;
   }

impl/core/src/main/java/io/serverlessworkflow/impl/WorkflowMutableInstance.java

@@ -23,6 +23,7 @@
 import io.serverlessworkflow.impl.lifecycle.WorkflowFailedEvent;
 import io.serverlessworkflow.impl.lifecycle.WorkflowResumedEvent;
 import io.serverlessworkflow.impl.lifecycle.WorkflowStartedEvent;
+import io.serverlessworkflow.impl.lifecycle.WorkflowStatusEvent;
 import io.serverlessworkflow.impl.lifecycle.WorkflowSuspendedEvent;
 import java.time.Instant;
 import java.util.Map;
@@ -38,7 +39,7 @@
 
 public class WorkflowMutableInstance implements WorkflowInstance {
 
-  protected final AtomicReference<WorkflowStatus> status;
+  private final AtomicReference<WorkflowStatus> status;
   protected final String id;
   protected final WorkflowModel input;
 
@@ -75,7 +76,7 @@ protected final CompletableFuture<WorkflowModel> startExecution(Runnable runnabl
     if (future != null) {
       return future;
     }
-    status.set(WorkflowStatus.RUNNING);
+    status(WorkflowStatus.RUNNING);
     runnable.run();
     future =
         TaskExecutorHelper.processTaskList(
@@ -106,7 +107,7 @@ private void whenCompleted(WorkflowModel result, Throwable ex) {
 
   private void handleException(Throwable ex) {
     if (!(ex instanceof CancellationException)) {
-      status.set(WorkflowStatus.FAULTED);
+      status(WorkflowStatus.FAULTED);
       publishEvent(
           workflowContext, l -> l.onWorkflowFailed(new WorkflowFailedEvent(workflowContext, ex)));
     }
@@ -120,7 +121,7 @@ private WorkflowModel whenSuccess(WorkflowModel node) {
             .map(f -> f.apply(workflowContext, null, node))
             .orElse(node);
     workflowContext.definition().outputSchemaValidator().ifPresent(v -> v.validate(output));
-    status.set(WorkflowStatus.COMPLETED);
+    status(WorkflowStatus.COMPLETED);
     publishEvent(
         workflowContext,
         l -> l.onWorkflowCompleted(new WorkflowCompletedEvent(workflowContext, output)));
@@ -177,7 +178,14 @@ public <T> T outputAs(Class<T> clazz) {
   }
 
   public void status(WorkflowStatus state) {
-    this.status.set(state);
+    WorkflowStatus prevState = this.status.getAndSet(state);
+    if (prevState != state) {
+      publishEvent(
+          workflowContext,
+          l ->
+              l.onWorkflowStatusChanged(
+                  new WorkflowStatusEvent(workflowContext, prevState, state)));
+    }
   }
 
   @Override
@@ -213,7 +221,7 @@ public boolean suspend() {
 
   protected final void internalSuspend() {
     suspended = new ConcurrentHashMap<>();
-    status.set(WorkflowStatus.SUSPENDED);
+    status(WorkflowStatus.SUSPENDED);
   }
 
   @Override
@@ -259,7 +267,7 @@ public CompletableFuture<TaskContext> suspendedCheck(TaskContext t) {
         suspended.put(suspendedTask, t);
         return suspendedTask;
       } else if (TaskExecutorHelper.isActive(status.get())) {
-        status.set(WorkflowStatus.RUNNING);
+        status(WorkflowStatus.RUNNING);
       }
     } finally {
       statusLock.unlock();
@@ -272,7 +280,7 @@ public boolean cancel() {
     try {
       statusLock.lock();
       if (TaskExecutorHelper.isActive(status.get())) {
-        status.set(WorkflowStatus.CANCELLED);
+        status(WorkflowStatus.CANCELLED);
         publishEvent(
             workflowContext,
             l -> l.onWorkflowCancelled(new WorkflowCancelledEvent(workflowContext)));

impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/WorkflowExecutionListener.java

@@ -43,6 +43,8 @@ default void onTaskResumed(TaskResumedEvent ev) {}
 
   default void onTaskRetried(TaskRetriedEvent ev) {}
 
+  default void onWorkflowStatusChanged(WorkflowStatusEvent ev) {}
+
   @Override
   default void close() {}
 }

impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/WorkflowStatusEvent.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification 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.serverlessworkflow.impl.lifecycle;
+
+import io.serverlessworkflow.impl.WorkflowContextData;
+import io.serverlessworkflow.impl.WorkflowStatus;
+
+public class WorkflowStatusEvent extends WorkflowEvent {
+
+  private final WorkflowStatus status;
+  private final WorkflowStatus prevStatus;
+
+  public WorkflowStatusEvent(
+      WorkflowContextData workflow, WorkflowStatus prevStatus, WorkflowStatus status) {
+    super(workflow);
+    this.status = status;
+    this.prevStatus = prevStatus;
+  }
+
+  public WorkflowStatus status() {
+    return status;
+  }
+
+  public WorkflowStatus previousStatus() {
+    return prevStatus;
+  }
+}

impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/ce/AbstractLifeCyclePublisher.java

@@ -41,6 +41,7 @@
 import io.serverlessworkflow.impl.lifecycle.WorkflowFailedEvent;
 import io.serverlessworkflow.impl.lifecycle.WorkflowResumedEvent;
 import io.serverlessworkflow.impl.lifecycle.WorkflowStartedEvent;
+import io.serverlessworkflow.impl.lifecycle.WorkflowStatusEvent;
 import io.serverlessworkflow.impl.lifecycle.WorkflowSuspendedEvent;
 import java.time.OffsetDateTime;
 import java.util.Collection;
@@ -63,6 +64,8 @@ public abstract class AbstractLifeCyclePublisher implements WorkflowExecutionLis
   private static final String WORKFLOW_RESUMED = "io.serverlessworkflow.workflow.resumed.v1";
   private static final String WORKFLOW_FAULTED = "io.serverlessworkflow.workflow.faulted.v1";
   private static final String WORKFLOW_CANCELLED = "io.serverlessworkflow.workflow.cancelled.v1";
+  private static final String WORKFLOW_STATUS_CHANGED =
+      "io.serverlessworkflow.workflow.status-changed.v1";
 
   public static Collection<String> getLifeCycleTypes() {
     return Set.of(
@@ -78,7 +81,8 @@ public static Collection<String> getLifeCycleTypes() {
         WORKFLOW_SUSPENDED,
         WORKFLOW_RESUMED,
         WORKFLOW_FAULTED,
-        WORKFLOW_CANCELLED);
+        WORKFLOW_CANCELLED,
+        WORKFLOW_STATUS_CHANGED);
   }
 
   @Override
@@ -263,6 +267,23 @@ public void onWorkflowFailed(WorkflowFailedEvent event) {
                 .build());
   }
 
+  @Override
+  public void onWorkflowStatusChanged(WorkflowStatusEvent event) {
+    if (appl(event).isStatusChangePublishingEnabled()) {
+      publish(
+          event,
+          ev ->
+              builder()
+                  .withData(
+                      cloudEventData(
+                          new WorkflowStatusCEDataEvent(
+                              id(ev), ref(ev), ev.eventDate(), ev.status().toString()),
+                          this::convert))
+                  .withType(WORKFLOW_STATUS_CHANGED)
+                  .build());
+    }
+  }
+
   protected byte[] convert(WorkflowStartedCEData data) {
     return convertToBytes(data);
   }
@@ -315,10 +336,14 @@ protected byte[] convert(TaskResumedCEData data) {
     return convertToBytes(data);
   }
 
+  protected byte[] convert(WorkflowStatusCEDataEvent data) {
+    return convertToBytes(data);
+  }
+
   protected abstract <T> byte[] convertToBytes(T data);
 
   protected <T extends WorkflowEvent> void publish(T ev, Function<T, CloudEvent> ceFunction) {
-    WorkflowApplication appl = ev.workflowContext().definition().application();
+    WorkflowApplication appl = appl(ev);
     if (appl.isLifeCycleCEPublishingEnabled()) {
       publish(appl, ceFunction.apply(ev));
     }
@@ -342,6 +367,10 @@ private static CloudEventBuilder builder() {
         .withTime(OffsetDateTime.now());
   }
 
+  private static WorkflowApplication appl(WorkflowEvent ev) {
+    return ev.workflowContext().definition().application();
+  }
+
   private static String id(WorkflowEvent ev) {
     return ev.workflowContext().instanceData().id();
   }

impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/ce/WorkflowStatusCEDataEvent.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification 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.serverlessworkflow.impl.lifecycle.ce;
+
+import java.time.OffsetDateTime;
+
+public record WorkflowStatusCEDataEvent(
+    String name, WorkflowDefinitionCEData definition, OffsetDateTime updatetAt, String status) {}