tillrohrmann commented on a change in pull request #11473: [FLINK-16705] Ensure MiniCluster shutdown does not interfere with JobResult retrieval URL: https://github.com/apache/flink/pull/11473#discussion_r402431325
########## File path: flink-clients/src/main/java/org/apache/flink/client/program/PerJobMiniCluster.java ########## @@ -0,0 +1,182 @@ +/* + * 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.client.program; + +import org.apache.flink.api.common.JobExecutionResult; +import org.apache.flink.api.common.JobID; +import org.apache.flink.api.common.JobStatus; +import org.apache.flink.configuration.ConfigConstants; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.configuration.RestOptions; +import org.apache.flink.configuration.TaskManagerOptions; +import org.apache.flink.core.execution.JobClient; +import org.apache.flink.runtime.jobgraph.JobGraph; +import org.apache.flink.runtime.jobmaster.JobResult; +import org.apache.flink.runtime.minicluster.MiniCluster; +import org.apache.flink.runtime.minicluster.MiniClusterConfiguration; +import org.apache.flink.runtime.minicluster.RpcServiceSharing; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nullable; + +import java.util.Map; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.ExecutionException; +import java.util.function.Function; + +/** + * Starts a {@link MiniCluster} for every submitted job. + * This class guarantees to tear down the MiniCluster in case of normal or exceptional job completion. + * */ +public class PerJobMiniCluster { + + private static final Logger LOG = LoggerFactory.getLogger(PerJobMiniCluster.class); + + private final Configuration configuration; + private final Function<MiniClusterConfiguration, MiniCluster> miniClusterFactory; + + public PerJobMiniCluster() { + this(new Configuration()); + } + + public PerJobMiniCluster(Configuration configuration) { + this(configuration, MiniCluster::new); + } + + public PerJobMiniCluster(Configuration configuration, Function<MiniClusterConfiguration, MiniCluster> miniClusterFactory) { + this.configuration = configuration; + this.miniClusterFactory = miniClusterFactory; + } + + /** + * Starts a {@link MiniCluster} and submits a job. + */ + public CompletableFuture<JobClient> submitJob(JobGraph jobGraph) throws Exception { + MiniClusterConfiguration miniClusterConfig = getMiniClusterConfig(jobGraph.getMaximumParallelism()); + MiniCluster miniCluster = miniClusterFactory.apply(miniClusterConfig); + miniCluster.start(); + + return miniCluster + .submitJob(jobGraph) + .handle((result, throwable) -> { + if (throwable != null) { + try { + throw new RuntimeException("Error submitting job to MiniCluster.", throwable); + } finally { + shutDownCluster(miniCluster); + } + } + return new PerJobMiniClusterJobClient(result.getJobID(), miniCluster); + }); + } + + private MiniClusterConfiguration getMiniClusterConfig(int maximumParallelism) { + Configuration configuration = this.configuration.clone(); Review comment: Java's `Cloneable` mechanism has many problems. In a nutshell the problem is that it is fragile, dangerous and extralinguistic as it generates objects w/o calling the constructor. The only target it should be used on are arrays if I'm not mistaken. To name a few of the problems in detail: The `Cloneable` interface is a marker interface. Hence, before you call `clone` you actually need to make sure that the type implements `Cloneable`. But you can also call `clone` if it is not implemented. If a super class implements `Cloneable`, then it is hard for a subtype to not implement it. The only way is to throw an exception which the caller will only see at runtime. Even if you want to implement it, then you have to follow a quite fragile procedure. For example, in order to make it work with sub-types one always needs to call `super.clone()`. This is something we don't do in the implementation of `Configuration` and its subclasses. As a consequence, any new subclass of `Configuration` has to know that it must not call super.clone() in order to implement clone. If you implement `Cloneable`, then you cannot make your object immutable. A much simpler solution would be to offer copy constructors or static factory methods. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
