cmccabe commented on a change in pull request #10753: URL: https://github.com/apache/kafka/pull/10753#discussion_r670134315
########## File path: metadata/src/main/java/org/apache/kafka/controller/PartitionReassignmentRevert.java ########## @@ -0,0 +1,105 @@ +/* + * 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.kafka.controller; + +import org.apache.kafka.common.errors.InvalidReplicaAssignmentException; +import org.apache.kafka.metadata.PartitionRegistration; +import org.apache.kafka.metadata.Replicas; + +import java.util.ArrayList; +import java.util.Set; +import java.util.List; +import java.util.Objects; + + +class PartitionReassignmentRevert { + private final List<Integer> replicas; + private final List<Integer> isr; + private final boolean unclean; + + PartitionReassignmentRevert(PartitionRegistration registration) { + // Figure out the replica list and ISR that we will have after reverting the + // reassignment. In general, we want to take out any replica that the reassignment + // was adding, but keep the ones the reassignment was removing. (But see the + // special case below.) + Set<Integer> adding = Replicas.toSet(registration.addingReplicas); + this.replicas = new ArrayList<>(registration.replicas.length); + this.isr = new ArrayList<>(registration.isr.length); + for (int i = 0; i < registration.isr.length; i++) { + int replica = registration.isr[i]; + if (!adding.contains(replica)) { + this.isr.add(replica); + } + } + for (int replica : registration.replicas) { + if (!adding.contains(replica)) { + this.replicas.add(replica); + } + } + if (isr.isEmpty()) { + // In the special case that all the replicas that are in the ISR are also + // contained in addingReplicas, we choose the first remaining replica and add + // it to the ISR. This is considered an unclean leader election. Therefore, + // calling code must check that unclean leader election is enabled before + // accepting the new ISR. + if (this.replicas.isEmpty()) { + // This should not be reachable, since it would require a partition + // starting with an empty replica set prior to the reassignment we are + // trying to revert. + throw new InvalidReplicaAssignmentException("Invalid replica " + + "assignment: addingReplicas contains all replicas."); + } + isr.add(replicas.get(0)); Review comment: It seems simpler to do it here because then we can reject the unclean case before creating the `PartitionChangeBuilder` -- 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. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
