Introducing a Noop task to allow for switch decision branches to have "no" tasks

Purpose:
When using Switch tasks in usecases where we want a consistent set of decision case branches across all workflows, but some workflows make use of a sub-set of all decision cases, then some decision cases will not have tasks. Because of the constraint to always have tasks in decision cases, this Noop task is required.
This task is a system task and autocompletes.

Author: Boyan Georgiev

common/src/main/java/com/netflix/conductor/common/metadata/tasks/TaskType.java

@@ -40,7 +40,8 @@ public enum TaskType {
     TERMINATE,
     KAFKA_PUBLISH,
     JSON_JQ_TRANSFORM,
-    SET_VARIABLE;
+    SET_VARIABLE,
+    NOOP;
 
     /**
      * TaskType constants representing each of the possible enumeration values. Motivation: to not
@@ -69,6 +70,7 @@ public enum TaskType {
     public static final String TASK_TYPE_JSON_JQ_TRANSFORM = "JSON_JQ_TRANSFORM";
     public static final String TASK_TYPE_SET_VARIABLE = "SET_VARIABLE";
     public static final String TASK_TYPE_FORK = "FORK";
+    public static final String TASK_TYPE_NOOP = "NOOP";
 
     private static final Set<String> BUILT_IN_TASKS = new HashSet<>();
 

core/src/main/java/com/netflix/conductor/core/execution/mapper/NoopTaskMapper.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2023 Netflix, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 com.netflix.conductor.core.execution.mapper;
+
+import java.util.List;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+import com.netflix.conductor.common.metadata.tasks.TaskType;
+import com.netflix.conductor.model.TaskModel;
+
+import static com.netflix.conductor.common.metadata.tasks.TaskType.*;
+
+@Component
+public class NoopTaskMapper implements TaskMapper {
+
+    public static final Logger logger = LoggerFactory.getLogger(NoopTaskMapper.class);
+
+    @Override
+    public String getTaskType() {
+        return TaskType.NOOP.name();
+    }
+
+    @Override
+    public List<TaskModel> getMappedTasks(TaskMapperContext taskMapperContext) {
+        logger.debug("TaskMapperContext {} in NoopTaskMapper", taskMapperContext);
+
+        TaskModel task = taskMapperContext.createTaskModel();
+        task.setTaskType(TASK_TYPE_NOOP);
+        task.setStartTime(System.currentTimeMillis());
+        task.setStatus(TaskModel.Status.IN_PROGRESS);
+        return List.of(task);
+    }
+}

core/src/main/java/com/netflix/conductor/core/execution/tasks/Noop.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2023 Netflix, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 com.netflix.conductor.core.execution.tasks;
+
+import org.springframework.stereotype.Component;
+
+import com.netflix.conductor.core.execution.WorkflowExecutor;
+import com.netflix.conductor.model.TaskModel;
+import com.netflix.conductor.model.WorkflowModel;
+
+import static com.netflix.conductor.common.metadata.tasks.TaskType.TASK_TYPE_NOOP;
+
+@Component(TASK_TYPE_NOOP)
+public class Noop extends WorkflowSystemTask {
+
+    public Noop() {
+        super(TASK_TYPE_NOOP);
+    }
+
+    @Override
+    public boolean execute(
+            WorkflowModel workflow, TaskModel task, WorkflowExecutor workflowExecutor) {
+        task.setStatus(TaskModel.Status.COMPLETED);
+        return true;
+    }
+}

core/src/test/java/com/netflix/conductor/core/execution/mapper/NoopTaskMapperTest.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2023 Netflix, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 com.netflix.conductor.core.execution.mapper;
+
+import java.util.List;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.netflix.conductor.common.metadata.tasks.TaskDef;
+import com.netflix.conductor.common.metadata.tasks.TaskType;
+import com.netflix.conductor.common.metadata.workflow.WorkflowDef;
+import com.netflix.conductor.common.metadata.workflow.WorkflowTask;
+import com.netflix.conductor.core.utils.IDGenerator;
+import com.netflix.conductor.model.TaskModel;
+import com.netflix.conductor.model.WorkflowModel;
+
+public class NoopTaskMapperTest {
+
+    @Test
+    public void getMappedTasks() {
+
+        WorkflowTask workflowTask = new WorkflowTask();
+        workflowTask.setType(TaskType.TASK_TYPE_NOOP);
+
+        String taskId = new IDGenerator().generate();
+
+        WorkflowDef workflowDef = new WorkflowDef();
+        WorkflowModel workflow = new WorkflowModel();
+        workflow.setWorkflowDefinition(workflowDef);
+
+        TaskMapperContext taskMapperContext =
+                TaskMapperContext.newBuilder()
+                        .withWorkflowModel(workflow)
+                        .withTaskDefinition(new TaskDef())
+                        .withWorkflowTask(workflowTask)
+                        .withRetryCount(0)
+                        .withTaskId(taskId)
+                        .build();
+
+        List<TaskModel> mappedTasks = new NoopTaskMapper().getMappedTasks(taskMapperContext);
+
+        Assert.assertNotNull(mappedTasks);
+        Assert.assertEquals(1, mappedTasks.size());
+        Assert.assertEquals(TaskType.TASK_TYPE_NOOP, mappedTasks.get(0).getTaskType());
+    }
+}

core/src/test/java/com/netflix/conductor/core/execution/tasks/TestNoop.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2023 Netflix, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 com.netflix.conductor.core.execution.tasks;
+
+import org.junit.Test;
+
+import com.netflix.conductor.core.execution.WorkflowExecutor;
+import com.netflix.conductor.model.TaskModel;
+import com.netflix.conductor.model.WorkflowModel;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+public class TestNoop {
+
+    private final WorkflowExecutor executor = mock(WorkflowExecutor.class);
+
+    @Test
+    public void should_do_nothing() {
+        WorkflowModel workflow = new WorkflowModel();
+        Noop noopTask = new Noop();
+        TaskModel task = new TaskModel();
+        noopTask.execute(workflow, task, executor);
+        assertEquals(TaskModel.Status.COMPLETED, task.getStatus());
+    }
+}