[Improvement-17057][Master] Check if the WorkflowGraph is a DAG at constructor

dolphinscheduler-master/src/main/java/org/apache/dolphinscheduler/server/master/engine/graph/WorkflowGraph.java

@@ -22,11 +22,13 @@
 import org.apache.dolphinscheduler.dao.entity.TaskDefinition;
 import org.apache.dolphinscheduler.dao.entity.WorkflowTaskRelation;
 
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Queue;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -42,6 +44,7 @@
     public WorkflowGraph(List<WorkflowTaskRelation> workflowTaskRelations, List<TaskDefinition> taskDefinitions) {
         checkNotNull(taskDefinitions, "taskDefinitions can not be null");
         checkNotNull(workflowTaskRelations, "taskDefinitions can not be null");
+        checkIfDAG(workflowTaskRelations, taskDefinitions);
         this.predecessors = new HashMap<>();
         this.successors = new HashMap<>();
 
@@ -64,6 +67,53 @@
         addTaskEdge(workflowTaskRelations);
     }
 
+    private void checkIfDAG(List<WorkflowTaskRelation> workflowTaskRelations, List<TaskDefinition> taskDefinitions) {
+        Map<Long, List<Long>> preTaskCodeMap = workflowTaskRelations
+                .stream()
+                .filter(relation -> relation.getPreTaskCode() > 0 && relation.getPostTaskCode() > 0)
+                .collect(Collectors.groupingBy(WorkflowTaskRelation::getPostTaskCode,
+                        Collectors.mapping(WorkflowTaskRelation::getPreTaskCode, Collectors.toList())));
+        Map<Long, List<Long>> postTaskCodeMap = workflowTaskRelations
+                .stream()
+                .filter(relation -> relation.getPreTaskCode() > 0 && relation.getPostTaskCode() > 0)
+                .collect(Collectors.groupingBy(WorkflowTaskRelation::getPreTaskCode,
+                        Collectors.mapping(WorkflowTaskRelation::getPostTaskCode, Collectors.toList())));
+
+        Map<Long, Integer> inDegreeCount = new HashMap<>();
+        for (TaskDefinition taskDefinition : taskDefinitions) {
+            List<Long> preTasks = preTaskCodeMap.get(taskDefinition.getCode());
+            inDegreeCount.put(taskDefinition.getCode(), preTasks == null ? 0 : preTasks.size());
+        }
+
+        Queue<Long> queue = new ArrayDeque<>();
+        for (Map.Entry<Long, Integer> entry : inDegreeCount.entrySet()) {
+            if (entry.getValue() == 0) {
+                queue.offer(entry.getKey());
+            }
+        }
+
+        Set<Long> sortedTaskCodes = new HashSet<>();
+        while (!queue.isEmpty()) {
+            Long taskCode = queue.poll();
+            sortedTaskCodes.add(taskCode);
+
+            List<Long> postCodes = postTaskCodeMap.get(taskCode);
+            if (postCodes == null) {
+                continue;
+            }
+            for (Long postCode : postCodes) {
+                inDegreeCount.put(postCode, inDegreeCount.get(postCode) - 1);
+                if (inDegreeCount.get(postCode) == 0) {
+                    queue.offer(postCode);
+                }
+            }
+        }
+
+        if (sortedTaskCodes.size() < taskDefinitions.size()) {
+            throw new IllegalArgumentException("The workflow task relation is not a DAG");
+        }
+    }
+
     @Override
     public List<String> getStartNodes() {
         return predecessors.entrySet()

dolphinscheduler-master/src/test/java/org/apache/dolphinscheduler/server/master/engine/graph/WorkflowGraphCheckIfDAGTest.java

@@ -0,0 +1,222 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.dolphinscheduler.server.master.engine.graph;
+
+import org.apache.dolphinscheduler.dao.entity.TaskDefinition;
+import org.apache.dolphinscheduler.dao.entity.WorkflowTaskRelation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class WorkflowGraphCheckIfDAGTest {
+
+    private List<TaskDefinition> taskDefinitions;
+    private List<WorkflowTaskRelation> workflowTaskRelations;
+
+    @BeforeEach
+    public void setUp() {
+        taskDefinitions = new ArrayList<>();
+        workflowTaskRelations = new ArrayList<>();
+    }
+
+    @Test
+    public void checkIfDAGSingleTaskNoException() {
+        TaskDefinition taskDefinition = new TaskDefinition(1L, 1);
+        taskDefinitions.add(taskDefinition);
+
+        WorkflowTaskRelation relation = new WorkflowTaskRelation();
+        relation.setPreTaskCode(0);
+        relation.setPostTaskCode(1);
+        workflowTaskRelations.add(relation);
+
+        Assertions.assertDoesNotThrow(() -> new WorkflowGraph(workflowTaskRelations, taskDefinitions));
+    }
+
+    @Test
+    public void checkIfDAGSimpleDAGNoException() {
+        TaskDefinition task1 = new TaskDefinition(1L, 1);
+        task1.setName("task1");
+        TaskDefinition task2 = new TaskDefinition(2L, 1);
+        task2.setName("task2");
+        taskDefinitions.add(task1);
+        taskDefinitions.add(task2);
+
+        WorkflowTaskRelation relation = new WorkflowTaskRelation();
+        relation.setPreTaskCode(1L);
+        relation.setPreTaskVersion(1);
+        relation.setPostTaskCode(2L);
+        relation.setPostTaskVersion(1);
+        workflowTaskRelations.add(relation);
+
+        Assertions.assertDoesNotThrow(() -> new WorkflowGraph(workflowTaskRelations, taskDefinitions));
+    }
+
+    @Test
+    public void checkIfDAGCycleThrowsException() {
+        TaskDefinition task1 = new TaskDefinition(1L, 1);
+        TaskDefinition task2 = new TaskDefinition(2L, 1);
+        taskDefinitions.add(task1);
+        taskDefinitions.add(task2);
+
+        WorkflowTaskRelation relation1 = new WorkflowTaskRelation();
+        relation1.setPreTaskCode(1L);
+        relation1.setPreTaskVersion(1);
+        relation1.setPostTaskCode(2L);
+        relation1.setPostTaskVersion(1);
+        WorkflowTaskRelation relation2 = new WorkflowTaskRelation();
+        relation2.setPreTaskCode(2L);
+        relation2.setPreTaskVersion(1);
+        relation2.setPostTaskCode(1L);
+        relation2.setPostTaskVersion(1);
+        workflowTaskRelations.add(relation1);
+        workflowTaskRelations.add(relation2);
+
+        Assertions.assertThrows(IllegalArgumentException.class,
+                () -> new WorkflowGraph(workflowTaskRelations, taskDefinitions));
+    }
+
+    @Test
+    public void checkIfDAGMultipleZeroInDegreeNoException() {
+        TaskDefinition task1 = new TaskDefinition(1L, 1);
+        task1.setName("task1");
+        TaskDefinition task2 = new TaskDefinition(2L, 1);
+        task2.setName("task2");
+        TaskDefinition task3 = new TaskDefinition(3L, 1);
+        task3.setName("task3");
+        taskDefinitions.add(task1);
+        taskDefinitions.add(task2);
+        taskDefinitions.add(task3);
+
+        WorkflowTaskRelation relation1 = new WorkflowTaskRelation();
+        relation1.setPreTaskCode(1L);
+        relation1.setPreTaskVersion(1);
+        relation1.setPostTaskCode(2L);
+        relation1.setPostTaskVersion(1);
+        WorkflowTaskRelation relation2 = new WorkflowTaskRelation();
+        relation2.setPreTaskCode(1L);
+        relation2.setPreTaskVersion(1);
+        relation2.setPostTaskCode(3L);
+        relation2.setPostTaskVersion(1);
+        workflowTaskRelations.add(relation1);
+        workflowTaskRelations.add(relation2);
+
+        Assertions.assertDoesNotThrow(() -> new WorkflowGraph(workflowTaskRelations, taskDefinitions));
+    }
+
+    @Test
+    public void checkIfDAGComplexDAGNoException() {
+        TaskDefinition task1 = new TaskDefinition(1L, 1);
+        task1.setName("task1");
+        TaskDefinition task2 = new TaskDefinition(2L, 1);
+        task2.setName("task2");
+        TaskDefinition task3 = new TaskDefinition(3L, 1);
+        task3.setName("task3");
+        TaskDefinition task4 = new TaskDefinition(4L, 1);
+        task4.setName("task4");
+        taskDefinitions.add(task1);
+        taskDefinitions.add(task2);
+        taskDefinitions.add(task3);
+        taskDefinitions.add(task4);
+
+        WorkflowTaskRelation relation1 = new WorkflowTaskRelation();
+        relation1.setPreTaskCode(1L);
+        relation1.setPreTaskVersion(1);
+        relation1.setPostTaskCode(2L);
+        relation1.setPostTaskVersion(1);
+
+        WorkflowTaskRelation relation2 = new WorkflowTaskRelation();
+        relation2.setPreTaskCode(1L);
+        relation2.setPreTaskVersion(1);
+        relation2.setPostTaskCode(3L);
+        relation2.setPostTaskVersion(1);
+
+        WorkflowTaskRelation relation3 = new WorkflowTaskRelation();
+        relation3.setPreTaskCode(2L);
+        relation3.setPreTaskVersion(1);
+        relation3.setPostTaskCode(4L);
+        relation3.setPostTaskVersion(1);
+
+        WorkflowTaskRelation relation4 = new WorkflowTaskRelation();
+        relation4.setPreTaskCode(3L);
+        relation4.setPreTaskVersion(1);
+        relation4.setPostTaskCode(4L);
+        relation4.setPostTaskVersion(1);
+
+        workflowTaskRelations.add(relation1);
+        workflowTaskRelations.add(relation2);
+        workflowTaskRelations.add(relation3);
+        workflowTaskRelations.add(relation4);
+
+        Assertions.assertDoesNotThrow(() -> new WorkflowGraph(workflowTaskRelations, taskDefinitions));
+    }
+
+    @Test
+    public void checkIfDAGComplexDAGThrowsException() {
+        TaskDefinition task1 = new TaskDefinition(1L, 1);
+        TaskDefinition task2 = new TaskDefinition(2L, 1);
+        TaskDefinition task3 = new TaskDefinition(3L, 1);
+        TaskDefinition task4 = new TaskDefinition(4L, 1);
+        taskDefinitions.add(task1);
+        taskDefinitions.add(task2);
+        taskDefinitions.add(task3);
+        taskDefinitions.add(task4);
+
+        WorkflowTaskRelation relation1 = new WorkflowTaskRelation();
+        relation1.setPreTaskCode(1L);
+        relation1.setPreTaskVersion(1);
+        relation1.setPostTaskCode(2L);
+        relation1.setPostTaskVersion(1);
+
+        WorkflowTaskRelation relation2 = new WorkflowTaskRelation();
+        relation2.setPreTaskCode(1L);
+        relation2.setPreTaskVersion(1);
+        relation2.setPostTaskCode(3L);
+        relation2.setPostTaskVersion(1);
+
+        WorkflowTaskRelation relation3 = new WorkflowTaskRelation();
+        relation3.setPreTaskCode(2L);
+        relation3.setPreTaskVersion(1);
+        relation3.setPostTaskCode(4L);
+        relation3.setPostTaskVersion(1);
+
+        WorkflowTaskRelation relation4 = new WorkflowTaskRelation();
+        relation4.setPreTaskCode(3L);
+        relation4.setPreTaskVersion(1);
+        relation4.setPostTaskCode(4L);
+        relation4.setPostTaskVersion(1);
+
+        WorkflowTaskRelation relation5 = new WorkflowTaskRelation();
+        relation5.setPreTaskCode(4L);
+        relation5.setPreTaskVersion(1);
+        relation5.setPostTaskCode(3L);
+        relation5.setPostTaskVersion(1);
+
+        workflowTaskRelations.add(relation1);
+        workflowTaskRelations.add(relation2);
+        workflowTaskRelations.add(relation3);
+        workflowTaskRelations.add(relation4);
+        workflowTaskRelations.add(relation5);
+
+        Assertions.assertThrows(IllegalArgumentException.class,
+                () -> new WorkflowGraph(workflowTaskRelations, taskDefinitions));
+    }
+}