Github user GJL commented on a diff in the pull request:
https://github.com/apache/flink/pull/5215#discussion_r159225871
--- Diff:
flink-yarn/src/main/java/org/apache/flink/yarn/cli/YarnApplicationStatusMonitor.java
---
@@ -0,0 +1,101 @@
+/*
+ * 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.flink.yarn.cli;
+
+import org.apache.flink.runtime.clusterframework.ApplicationStatus;
+import org.apache.flink.runtime.concurrent.ScheduledExecutor;
+import org.apache.flink.util.Preconditions;
+
+import org.apache.hadoop.service.Service;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.api.records.ApplicationReport;
+import org.apache.hadoop.yarn.api.records.YarnApplicationState;
+import org.apache.hadoop.yarn.client.api.YarnClient;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Utility class which monitors the specified yarn application status
periodically.
+ */
+public class YarnApplicationStatusMonitor implements AutoCloseable {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(YarnApplicationStatusMonitor.class);
+
+ private static final long UPDATE_INTERVAL = 1000L;
+
+ private final YarnClient yarnClient;
+
+ private final ApplicationId yarnApplicationId;
+
+ private final ScheduledFuture<?> applicationStatusUpdateFuture;
+
+ private volatile ApplicationStatus applicationStatus;
+
+ public YarnApplicationStatusMonitor(
+ YarnClient yarnClient,
+ ApplicationId yarnApplicationId,
+ ScheduledExecutor scheduledExecutor) {
+ this.yarnClient = Preconditions.checkNotNull(yarnClient);
+ this.yarnApplicationId =
Preconditions.checkNotNull(yarnApplicationId);
+
+ applicationStatusUpdateFuture =
scheduledExecutor.scheduleWithFixedDelay(
+ this::updateApplicationStatus,
+ UPDATE_INTERVAL,
+ UPDATE_INTERVAL,
+ TimeUnit.MILLISECONDS);
+
+ applicationStatus = ApplicationStatus.UNKNOWN;
+ }
+
+ public ApplicationStatus getApplicationStatusNow() {
+ return applicationStatus;
+ }
+
+ @Override
+ public void close() throws Exception {
+ applicationStatusUpdateFuture.cancel(false);
--- End diff --
There is no need to declare `throws Exception` here because `cancel()` does
not throw any checked exceptions.
---
