fix(server): fix some issues of the distributed scheduler

Author: Tsukilc

hugegraph-server/hugegraph-core/src/main/java/org/apache/hugegraph/task/DistributedTaskScheduler.java

@@ -295,6 +295,12 @@ protected <V> void initTaskParams(HugeTask<V> task) {
         }
     }
 
+    /**
+     * Note: This method will update the status of the input task.
+     *
+     * @param task
+     * @param <V>
+     */
     @Override
     public <V> void cancel(HugeTask<V> task) {
         E.checkArgumentNotNull(task, "Task can't be null");
@@ -309,6 +315,9 @@ public <V> void cancel(HugeTask<V> task) {
         HugeTask<?> runningTask = this.runningTasks.get(task.id());
         if (runningTask != null) {
             boolean cancelled = runningTask.cancel(true);
+            if (cancelled) {
+                task.overwriteStatus(TaskStatus.CANCELLED);
+            }
             LOG.info("Cancel local running task '{}' result: {}", task.id(), cancelled);
             return;
         }
@@ -319,6 +328,8 @@ public <V> void cancel(HugeTask<V> task) {
         if (!this.updateStatus(task.id(), currentStatus, TaskStatus.CANCELLING)) {
             LOG.info("Failed to cancel task '{}', status may have changed from {}",
                      task.id(), currentStatus);
+        } else {
+            task.overwriteStatus(TaskStatus.CANCELLING);
         }
     }
 

hugegraph-server/hugegraph-test/src/main/java/org/apache/hugegraph/core/TaskCoreTest.java

@@ -29,7 +29,11 @@
 import org.apache.hugegraph.job.EphemeralJobBuilder;
 import org.apache.hugegraph.job.GremlinJob;
 import org.apache.hugegraph.job.JobBuilder;
-import org.apache.hugegraph.task.*;
+import org.apache.hugegraph.task.StandardTaskScheduler;
+import org.apache.hugegraph.task.HugeTask;
+import org.apache.hugegraph.task.TaskCallable;
+import org.apache.hugegraph.task.TaskScheduler;
+import org.apache.hugegraph.task.TaskStatus;
 import org.apache.hugegraph.testutil.Assert;
 import org.apache.hugegraph.testutil.Whitebox;
 import org.junit.Before;