jeffkbkim commented on code in PR #13639: URL: https://github.com/apache/kafka/pull/13639#discussion_r1204467377
########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. + */ + private final TimelineHashMap<String, Integer> serverAssignors; + + /** + * The number of subscribers per topic. + */ + private final TimelineHashMap<String, Integer> subscribedTopicNames; + + /** + * The metadata of the subscribed topics. Review Comment: nit: The metadata associated with each subscribed topic name ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. + */ + private final TimelineHashMap<String, Integer> serverAssignors; + + /** + * The number of subscribers per topic. + */ + private final TimelineHashMap<String, Integer> subscribedTopicNames; + + /** + * The metadata of the subscribed topics. + */ + private final TimelineHashMap<String, TopicMetadata> subscribedTopicMetadata; + + /** + * The assignment epoch. An assignment epoch smaller than the group epoch means + * that a new assignment is required. The assignment epoch is updated when a new + * assignment is installed. + */ + private final TimelineInteger assignmentEpoch; + + /** + * The target assignment. Review Comment: nit: The target assignment per member ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. + */ + private final TimelineHashMap<String, Integer> serverAssignors; + + /** + * The number of subscribers per topic. + */ + private final TimelineHashMap<String, Integer> subscribedTopicNames; + + /** + * The metadata of the subscribed topics. + */ + private final TimelineHashMap<String, TopicMetadata> subscribedTopicMetadata; + + /** + * The assignment epoch. An assignment epoch smaller than the group epoch means + * that a new assignment is required. The assignment epoch is updated when a new + * assignment is installed. + */ + private final TimelineInteger assignmentEpoch; + + /** + * The target assignment. + */ + private final TimelineHashMap<String, Assignment> assignments; + + /** + * The current partition epoch maps each topic-partitions to their current epoch where + * the epoch is the epoch of their owners. When a member revokes a partition, it removes + * itself from this map. When a member gets a partition, it adds itself to this map. + */ + private final TimelineHashMap<Uuid, TimelineHashMap<Integer, Integer>> currentPartitionEpoch; + + public ConsumerGroup( + SnapshotRegistry snapshotRegistry, + String groupId + ) { + this.snapshotRegistry = Objects.requireNonNull(snapshotRegistry); + this.groupId = Objects.requireNonNull(groupId); + this.state = new TimelineObject<>(snapshotRegistry, ConsumerGroupState.EMPTY); + this.groupEpoch = new TimelineInteger(snapshotRegistry); + this.members = new TimelineHashMap<>(snapshotRegistry, 0); + this.serverAssignors = new TimelineHashMap<>(snapshotRegistry, 0); + this.subscribedTopicNames = new TimelineHashMap<>(snapshotRegistry, 0); + this.subscribedTopicMetadata = new TimelineHashMap<>(snapshotRegistry, 0); + this.assignmentEpoch = new TimelineInteger(snapshotRegistry); + this.assignments = new TimelineHashMap<>(snapshotRegistry, 0); + this.currentPartitionEpoch = new TimelineHashMap<>(snapshotRegistry, 0); + } + + /** + * The type of this group. + * + * @return The group type (Consumer). + */ + @Override + public GroupType type() { + return GroupType.CONSUMER; + } + + /** + * The state of this group. + * + * @return The current state as a String. + */ + @Override + public String stateAsString() { + return state.get().toString(); + } + + /** + * The group id. + * + * @return The group id. + */ + @Override + public String groupId() { + return groupId; + } + + /** + * The state of this group. + * + * @return The current state. + */ + public ConsumerGroupState state() { + return state.get(); + } + + /** + * Returns the current group epoch. + * + * @return The group epoch. + */ + public int groupEpoch() { + return groupEpoch.get(); + } + + /** + * Sets the group epoch. + * + * @param groupEpoch The new group epoch. + */ + public void setGroupEpoch(int groupEpoch) { + this.groupEpoch.set(groupEpoch); + maybeUpdateGroupState(); + } + + /** + * Returns the current assignment epoch. + * + * @return The current assignment epoch. + */ + public int assignmentEpoch() { + return assignmentEpoch.get(); + } + + /** + * Sets the assignment epoch. + * + * @param assignmentEpoch The new assignment epoch. + */ + public void setAssignmentEpoch(int assignmentEpoch) { + this.assignmentEpoch.set(assignmentEpoch); + maybeUpdateGroupState(); + } + + /** + * Gets or creates a member. + * + * @param memberId The member id. + * @param createIfNotExists Booleans indicating whether the member must be + * created if it does not exist. + * + * @return A ConsumerGroupMember. + */ + public ConsumerGroupMember getOrMaybeCreateMember( + String memberId, + boolean createIfNotExists + ) { + ConsumerGroupMember member = members.get(memberId); + if (member == null) { + if (!createIfNotExists) { + throw new UnknownMemberIdException(String.format("Member %s is not a member of group %s.", + memberId, groupId)); + } + member = new ConsumerGroupMember.Builder(memberId).build(); + members.put(memberId, member); + } + + return member; + } + + /** + * Updates the member. + * + * @param newMember The new member state. + */ + public void updateMember(ConsumerGroupMember newMember) { + if (newMember == null) { + throw new IllegalArgumentException("newMember cannot be null."); + } + ConsumerGroupMember oldMember = members.put(newMember.memberId(), newMember); + maybeUpdateSubscribedTopicNames(oldMember, newMember); + maybeUpdateServerAssignors(oldMember, newMember); + maybeUpdatePartitionEpoch(oldMember, newMember); + maybeUpdateGroupState(); + } + + /** + * Remove the member from the group. + * + * @param memberId The member id to remove. + */ + public void removeMember(String memberId) { + ConsumerGroupMember member = members.remove(memberId); + maybeRemovePartitionEpoch(member); + maybeUpdateGroupState(); + } + + /** + * Returns true if the member exists. + * + * @param memberId The member id. + * + * @return A boolean indicating whether the member exists or not. + */ + public boolean hasMember(String memberId) { + return members.containsKey(memberId); + } + + /** + * Returns the number of members in the group. + * + * @return The number of members. + */ + public int numMembers() { + return members.size(); + } + + /** + * Returns the members keyed by their id. + * + * @return An immutable Map containing all the members. + */ + public Map<String, ConsumerGroupMember> members() { + return Collections.unmodifiableMap(members); + } + + /** + * Returns the current target assignment of the member. Review Comment: nit: Returns the existing ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. Review Comment: nit: The number of members supporting each server assignor name. is more readable to me ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. + */ + private final TimelineHashMap<String, Integer> serverAssignors; + + /** + * The number of subscribers per topic. + */ + private final TimelineHashMap<String, Integer> subscribedTopicNames; + + /** + * The metadata of the subscribed topics. + */ + private final TimelineHashMap<String, TopicMetadata> subscribedTopicMetadata; + + /** + * The assignment epoch. An assignment epoch smaller than the group epoch means + * that a new assignment is required. The assignment epoch is updated when a new + * assignment is installed. + */ + private final TimelineInteger assignmentEpoch; + + /** + * The target assignment. + */ + private final TimelineHashMap<String, Assignment> assignments; + + /** + * The current partition epoch maps each topic-partitions to their current epoch where + * the epoch is the epoch of their owners. When a member revokes a partition, it removes + * itself from this map. When a member gets a partition, it adds itself to this map. Review Comment: nit: it removes its partition epochs from this map. When a member gets a partition, it adds the epoch to this map. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. + */ + private final TimelineHashMap<String, Integer> serverAssignors; + + /** + * The number of subscribers per topic. + */ + private final TimelineHashMap<String, Integer> subscribedTopicNames; + + /** + * The metadata of the subscribed topics. + */ + private final TimelineHashMap<String, TopicMetadata> subscribedTopicMetadata; + + /** + * The assignment epoch. An assignment epoch smaller than the group epoch means + * that a new assignment is required. The assignment epoch is updated when a new + * assignment is installed. + */ + private final TimelineInteger assignmentEpoch; + + /** + * The target assignment. + */ + private final TimelineHashMap<String, Assignment> assignments; + + /** + * The current partition epoch maps each topic-partitions to their current epoch where + * the epoch is the epoch of their owners. When a member revokes a partition, it removes + * itself from this map. When a member gets a partition, it adds itself to this map. + */ + private final TimelineHashMap<Uuid, TimelineHashMap<Integer, Integer>> currentPartitionEpoch; + + public ConsumerGroup( + SnapshotRegistry snapshotRegistry, + String groupId + ) { + this.snapshotRegistry = Objects.requireNonNull(snapshotRegistry); + this.groupId = Objects.requireNonNull(groupId); + this.state = new TimelineObject<>(snapshotRegistry, ConsumerGroupState.EMPTY); + this.groupEpoch = new TimelineInteger(snapshotRegistry); + this.members = new TimelineHashMap<>(snapshotRegistry, 0); + this.serverAssignors = new TimelineHashMap<>(snapshotRegistry, 0); + this.subscribedTopicNames = new TimelineHashMap<>(snapshotRegistry, 0); + this.subscribedTopicMetadata = new TimelineHashMap<>(snapshotRegistry, 0); + this.assignmentEpoch = new TimelineInteger(snapshotRegistry); + this.assignments = new TimelineHashMap<>(snapshotRegistry, 0); + this.currentPartitionEpoch = new TimelineHashMap<>(snapshotRegistry, 0); + } + + /** + * The type of this group. + * + * @return The group type (Consumer). + */ + @Override + public GroupType type() { + return GroupType.CONSUMER; + } + + /** + * The state of this group. + * + * @return The current state as a String. + */ + @Override + public String stateAsString() { + return state.get().toString(); + } + + /** + * The group id. + * + * @return The group id. + */ + @Override + public String groupId() { + return groupId; + } + + /** + * The state of this group. + * + * @return The current state. + */ + public ConsumerGroupState state() { + return state.get(); + } + + /** + * Returns the current group epoch. + * + * @return The group epoch. + */ + public int groupEpoch() { + return groupEpoch.get(); + } + + /** + * Sets the group epoch. + * + * @param groupEpoch The new group epoch. + */ + public void setGroupEpoch(int groupEpoch) { + this.groupEpoch.set(groupEpoch); + maybeUpdateGroupState(); + } + + /** + * Returns the current assignment epoch. + * + * @return The current assignment epoch. + */ + public int assignmentEpoch() { + return assignmentEpoch.get(); + } + + /** + * Sets the assignment epoch. + * + * @param assignmentEpoch The new assignment epoch. + */ + public void setAssignmentEpoch(int assignmentEpoch) { + this.assignmentEpoch.set(assignmentEpoch); + maybeUpdateGroupState(); + } + + /** + * Gets or creates a member. + * + * @param memberId The member id. + * @param createIfNotExists Booleans indicating whether the member must be + * created if it does not exist. + * + * @return A ConsumerGroupMember. + */ + public ConsumerGroupMember getOrMaybeCreateMember( + String memberId, + boolean createIfNotExists + ) { + ConsumerGroupMember member = members.get(memberId); + if (member == null) { + if (!createIfNotExists) { + throw new UnknownMemberIdException(String.format("Member %s is not a member of group %s.", + memberId, groupId)); + } + member = new ConsumerGroupMember.Builder(memberId).build(); + members.put(memberId, member); + } + + return member; + } + + /** + * Updates the member. + * + * @param newMember The new member state. + */ + public void updateMember(ConsumerGroupMember newMember) { + if (newMember == null) { + throw new IllegalArgumentException("newMember cannot be null."); + } + ConsumerGroupMember oldMember = members.put(newMember.memberId(), newMember); + maybeUpdateSubscribedTopicNames(oldMember, newMember); + maybeUpdateServerAssignors(oldMember, newMember); + maybeUpdatePartitionEpoch(oldMember, newMember); + maybeUpdateGroupState(); + } + + /** + * Remove the member from the group. + * + * @param memberId The member id to remove. + */ + public void removeMember(String memberId) { + ConsumerGroupMember member = members.remove(memberId); + maybeRemovePartitionEpoch(member); + maybeUpdateGroupState(); + } + + /** + * Returns true if the member exists. + * + * @param memberId The member id. + * + * @return A boolean indicating whether the member exists or not. + */ + public boolean hasMember(String memberId) { + return members.containsKey(memberId); + } + + /** + * Returns the number of members in the group. + * + * @return The number of members. + */ + public int numMembers() { + return members.size(); + } + + /** + * Returns the members keyed by their id. + * + * @return An immutable Map containing all the members. + */ + public Map<String, ConsumerGroupMember> members() { + return Collections.unmodifiableMap(members); + } + + /** + * Returns the current target assignment of the member. + * + * @return The ConsumerGroupMemberAssignment or an EMPTY one if it does not + * exist. + */ + public Assignment targetAssignment(String memberId) { + return assignments.getOrDefault(memberId, Assignment.EMPTY); + } + + /** + * Updates target assignment of a member. + * + * @param memberId The member id. + * @param newTargetAssignment The new target assignment. + */ + public void updateTargetAssignment(String memberId, Assignment newTargetAssignment) { + assignments.put(memberId, newTargetAssignment); + } + + /** + * Removes the target assignment of a member. + * + * @param memberId The member id. + */ + public void removeTargetAssignment(String memberId) { + assignments.remove(memberId); + } + + /** + * Returns the target assignments for the entire group keyed by member id. + * + * @return An immutable Map containing all the target assignments. + */ + public Map<String, Assignment> targetAssignments() { + return Collections.unmodifiableMap(assignments); + } + + /** + * Returns the current epoch of a partition or -1 if the partition + * does not have one. + * + * @param topicId The topic id. + * @param partitionId The partition id. + * + * @return The epoch or -1. + */ + public int currentPartitionEpoch( + Uuid topicId, int partitionId + ) { + Map<Integer, Integer> partitions = currentPartitionEpoch.get(topicId); + if (partitions == null) { + return -1; + } else { + return partitions.getOrDefault(partitionId, -1); + } + } + + /** + * Compute the preferred (server side) assignor for the group while + * taking into account the updated member. The computation relies + * on {{@link ConsumerGroup#serverAssignors}} persisted structure + * but it does not update it. + * + * @param oldMember The old member. + * @param newMember The new member. + * + * @return An Optional containing the preferred assignor. + */ + public Optional<String> preferredServerAssignor( + ConsumerGroupMember oldMember, + ConsumerGroupMember newMember + ) { + // Copy the current count and update it. + Map<String, Integer> counts = new HashMap<>(this.serverAssignors); + maybeUpdateServerAssignors(counts, oldMember, newMember); + + return counts.entrySet().stream() + .max(Map.Entry.comparingByValue()) + .map(Map.Entry::getKey); + } + + /** + * Returns the subscription metadata for all the topics whose + * members are subscribed to. + * + * @return An immutable Map containing the subscription metadata. + */ + public Map<String, TopicMetadata> subscriptionMetadata() { + return Collections.unmodifiableMap(subscribedTopicMetadata); + } + + /** + * Updates the subscription metadata. This replaces the previous one. + * + * @param subscriptionMetadata The new subscription metadata. + */ + public void setSubscriptionMetadata( + Map<String, TopicMetadata> subscriptionMetadata + ) { + this.subscribedTopicMetadata.clear(); + this.subscribedTopicMetadata.putAll(subscriptionMetadata); + } + + /** + * Computes the subscription metadata based on the current subscription and + * an updated member. + * + * @param oldMember The old member. + * @param newMember The new member. + * @param topicsImage The topic metadata. + * + * @return The new subscription metadata as an immutable Map. + */ + public Map<String, TopicMetadata> computeSubscriptionMetadata( + ConsumerGroupMember oldMember, + ConsumerGroupMember newMember, + TopicsImage topicsImage + ) { + // Copy and update the current subscriptions. + Map<String, Integer> subscribedTopicNames = new HashMap<>(this.subscribedTopicNames); + maybeUpdateSubscribedTopicNames(subscribedTopicNames, oldMember, newMember); + + // Create the topic metadata for each subscribed topic. + Map<String, TopicMetadata> newSubscriptionMetadata = new HashMap<>(subscribedTopicNames.size()); + subscribedTopicNames.forEach((topicName, count) -> { + TopicImage topicImage = topicsImage.getTopic(topicName); + if (topicImage != null) { Review Comment: do you think we should log something if topicImage == null? can both the topicsImage and/or subscribed topic names be outdated here? ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. + */ + private final TimelineHashMap<String, Integer> serverAssignors; + + /** + * The number of subscribers per topic. + */ + private final TimelineHashMap<String, Integer> subscribedTopicNames; + + /** + * The metadata of the subscribed topics. + */ + private final TimelineHashMap<String, TopicMetadata> subscribedTopicMetadata; + + /** + * The assignment epoch. An assignment epoch smaller than the group epoch means + * that a new assignment is required. The assignment epoch is updated when a new + * assignment is installed. + */ + private final TimelineInteger assignmentEpoch; + + /** + * The target assignment. + */ + private final TimelineHashMap<String, Assignment> assignments; + + /** + * The current partition epoch maps each topic-partitions to their current epoch where + * the epoch is the epoch of their owners. When a member revokes a partition, it removes + * itself from this map. When a member gets a partition, it adds itself to this map. + */ + private final TimelineHashMap<Uuid, TimelineHashMap<Integer, Integer>> currentPartitionEpoch; + + public ConsumerGroup( + SnapshotRegistry snapshotRegistry, + String groupId + ) { + this.snapshotRegistry = Objects.requireNonNull(snapshotRegistry); + this.groupId = Objects.requireNonNull(groupId); + this.state = new TimelineObject<>(snapshotRegistry, ConsumerGroupState.EMPTY); + this.groupEpoch = new TimelineInteger(snapshotRegistry); + this.members = new TimelineHashMap<>(snapshotRegistry, 0); Review Comment: for this line and the following couple lines, does expected size of 0 create a hash table with size 1 as it's a power of 2? i'm confused because the expected size intuitively should not be 0. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -0,0 +1,633 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.coordinator.group.Group; +import org.apache.kafka.image.TopicImage; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.apache.kafka.timeline.TimelineInteger; +import org.apache.kafka.timeline.TimelineObject; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; + +/** + * A Consumer Group. All the metadata in this class are backed by + * records in the __consumer_offsets partitions. + */ +public class ConsumerGroup implements Group { + + public enum ConsumerGroupState { + EMPTY("empty"), + ASSIGNING("assigning"), + RECONCILING("reconciling"), + STABLE("stable"), + DEAD("dead"); + + private final String name; + + ConsumerGroupState(String name) { + this.name = name; + } + + @Override + public String toString() { + return name; + } + } + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The group id. + */ + private final String groupId; + + /** + * The group state. + */ + private final TimelineObject<ConsumerGroupState> state; + + /** + * The group epoch. The epoch is incremented whenever the subscriptions + * are updated and it will trigger the computation of a new assignment + * for the group. + */ + private final TimelineInteger groupEpoch; + + /** + * The group members. + */ + private final TimelineHashMap<String, ConsumerGroupMember> members; + + /** + * The number of members per server assignor name. + */ + private final TimelineHashMap<String, Integer> serverAssignors; + + /** + * The number of subscribers per topic. + */ + private final TimelineHashMap<String, Integer> subscribedTopicNames; + + /** + * The metadata of the subscribed topics. + */ + private final TimelineHashMap<String, TopicMetadata> subscribedTopicMetadata; + + /** + * The assignment epoch. An assignment epoch smaller than the group epoch means + * that a new assignment is required. The assignment epoch is updated when a new + * assignment is installed. + */ + private final TimelineInteger assignmentEpoch; + + /** + * The target assignment. + */ + private final TimelineHashMap<String, Assignment> assignments; + + /** + * The current partition epoch maps each topic-partitions to their current epoch where + * the epoch is the epoch of their owners. When a member revokes a partition, it removes + * itself from this map. When a member gets a partition, it adds itself to this map. + */ + private final TimelineHashMap<Uuid, TimelineHashMap<Integer, Integer>> currentPartitionEpoch; + + public ConsumerGroup( + SnapshotRegistry snapshotRegistry, + String groupId + ) { + this.snapshotRegistry = Objects.requireNonNull(snapshotRegistry); + this.groupId = Objects.requireNonNull(groupId); + this.state = new TimelineObject<>(snapshotRegistry, ConsumerGroupState.EMPTY); + this.groupEpoch = new TimelineInteger(snapshotRegistry); + this.members = new TimelineHashMap<>(snapshotRegistry, 0); + this.serverAssignors = new TimelineHashMap<>(snapshotRegistry, 0); + this.subscribedTopicNames = new TimelineHashMap<>(snapshotRegistry, 0); + this.subscribedTopicMetadata = new TimelineHashMap<>(snapshotRegistry, 0); + this.assignmentEpoch = new TimelineInteger(snapshotRegistry); + this.assignments = new TimelineHashMap<>(snapshotRegistry, 0); + this.currentPartitionEpoch = new TimelineHashMap<>(snapshotRegistry, 0); + } + + /** + * The type of this group. + * + * @return The group type (Consumer). + */ + @Override + public GroupType type() { + return GroupType.CONSUMER; + } + + /** + * The state of this group. + * + * @return The current state as a String. + */ + @Override + public String stateAsString() { + return state.get().toString(); + } + + /** + * The group id. + * + * @return The group id. + */ + @Override + public String groupId() { + return groupId; + } + + /** + * The state of this group. + * + * @return The current state. + */ + public ConsumerGroupState state() { + return state.get(); + } + + /** + * Returns the current group epoch. Review Comment: I think justine or someone else may have mentioned in another PR but for getters, just having the `@return The current group epoch` makes more sense. i'm not sure if this line adds much value as well as for other getter methods ########## group-coordinator/src/test/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroupTest.java: ########## @@ -0,0 +1,500 @@ +/* + * 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.coordinator.group.consumer; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.UnknownMemberIdException; +import org.apache.kafka.common.utils.LogContext; +import org.apache.kafka.coordinator.group.GroupMetadataManagerTest; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.junit.jupiter.api.Test; + +import java.util.Arrays; +import java.util.Collections; +import java.util.Optional; + +import static org.apache.kafka.common.utils.Utils.mkEntry; +import static org.apache.kafka.common.utils.Utils.mkMap; +import static org.apache.kafka.coordinator.group.AssignmentTestUtil.mkAssignment; +import static org.apache.kafka.coordinator.group.AssignmentTestUtil.mkTopicAssignment; +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertFalse; +import static org.junit.jupiter.api.Assertions.assertThrows; +import static org.junit.jupiter.api.Assertions.assertTrue; + +public class ConsumerGroupTest { + + private ConsumerGroup createConsumerGroup(String groupId) { + SnapshotRegistry snapshotRegistry = new SnapshotRegistry(new LogContext()); + return new ConsumerGroup(snapshotRegistry, groupId); + } + + @Test + public void testGetOrCreateMember() { + ConsumerGroup consumerGroup = createConsumerGroup("foo"); + ConsumerGroupMember member; + + // Create a group. + member = consumerGroup.getOrMaybeCreateMember("member-id", true); + assertEquals("member-id", member.memberId()); + + // Get that group back. + member = consumerGroup.getOrMaybeCreateMember("member-id", false); + assertEquals("member-id", member.memberId()); + + assertThrows(UnknownMemberIdException.class, () -> + consumerGroup.getOrMaybeCreateMember("does-not-exist", false)); + } + + @Test + public void testUpdateMember() { + ConsumerGroup consumerGroup = createConsumerGroup("foo"); + ConsumerGroupMember member; + + member = consumerGroup.getOrMaybeCreateMember("member", true); + + member = new ConsumerGroupMember.Builder(member) + .setSubscribedTopicNames(Arrays.asList("foo", "bar")) + .build(); + + consumerGroup.updateMember(member); + + assertEquals(member, consumerGroup.getOrMaybeCreateMember("member", false)); + } + + @Test + public void testRemoveMember() { + ConsumerGroup consumerGroup = createConsumerGroup("foo"); + + consumerGroup.getOrMaybeCreateMember("member", true); + assertTrue(consumerGroup.hasMember("member")); + + consumerGroup.removeMember("member"); + assertFalse(consumerGroup.hasMember("member")); + + } + + @Test + public void testUpdatingMemberUpdatesPartitionEpoch() { + Uuid fooTopicId = Uuid.randomUuid(); + Uuid barTopicId = Uuid.randomUuid(); + Uuid zarTopicId = Uuid.randomUuid(); + + ConsumerGroup consumerGroup = createConsumerGroup("foo"); + ConsumerGroupMember member; + + member = new ConsumerGroupMember.Builder("member") + .setMemberEpoch(10) + .setAssignedPartitions(mkAssignment( + mkTopicAssignment(fooTopicId, 1, 2, 3))) + .setPartitionsPendingRevocation(mkAssignment( + mkTopicAssignment(barTopicId, 4, 5, 6))) + .setPartitionsPendingAssignment(mkAssignment( + mkTopicAssignment(zarTopicId, 7, 8, 9))) + .build(); + + consumerGroup.updateMember(member); + + assertEquals(10, consumerGroup.currentPartitionEpoch(fooTopicId, 1)); + assertEquals(10, consumerGroup.currentPartitionEpoch(fooTopicId, 2)); + assertEquals(10, consumerGroup.currentPartitionEpoch(fooTopicId, 3)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 4)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 5)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 6)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 7)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 8)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 9)); + + member = new ConsumerGroupMember.Builder(member) + .setMemberEpoch(10) + .setAssignedPartitions(mkAssignment( + mkTopicAssignment(barTopicId, 1, 2, 3))) + .setPartitionsPendingRevocation(mkAssignment( + mkTopicAssignment(zarTopicId, 4, 5, 6))) + .setPartitionsPendingAssignment(mkAssignment( + mkTopicAssignment(fooTopicId, 7, 8, 9))) + .build(); + + consumerGroup.updateMember(member); + + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 1)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 2)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 3)); + assertEquals(10, consumerGroup.currentPartitionEpoch(zarTopicId, 4)); + assertEquals(10, consumerGroup.currentPartitionEpoch(zarTopicId, 5)); + assertEquals(10, consumerGroup.currentPartitionEpoch(zarTopicId, 6)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(fooTopicId, 7)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(fooTopicId, 8)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(fooTopicId, 9)); + } + + @Test + public void testDeletingMemberRemovesPartitionEpoch() { + Uuid fooTopicId = Uuid.randomUuid(); + Uuid barTopicId = Uuid.randomUuid(); + Uuid zarTopicId = Uuid.randomUuid(); + + ConsumerGroup consumerGroup = createConsumerGroup("foo"); + ConsumerGroupMember member; + + member = new ConsumerGroupMember.Builder("member") + .setMemberEpoch(10) + .setAssignedPartitions(mkAssignment( + mkTopicAssignment(fooTopicId, 1, 2, 3))) + .setPartitionsPendingRevocation(mkAssignment( + mkTopicAssignment(barTopicId, 4, 5, 6))) + .setPartitionsPendingAssignment(mkAssignment( + mkTopicAssignment(zarTopicId, 7, 8, 9))) + .build(); + + consumerGroup.updateMember(member); + + assertEquals(10, consumerGroup.currentPartitionEpoch(fooTopicId, 1)); + assertEquals(10, consumerGroup.currentPartitionEpoch(fooTopicId, 2)); + assertEquals(10, consumerGroup.currentPartitionEpoch(fooTopicId, 3)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 4)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 5)); + assertEquals(10, consumerGroup.currentPartitionEpoch(barTopicId, 6)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 7)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 8)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 9)); + + consumerGroup.removeMember(member.memberId()); + + assertEquals(-1, consumerGroup.currentPartitionEpoch(barTopicId, 1)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(barTopicId, 2)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(barTopicId, 3)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 4)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 5)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(zarTopicId, 6)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(fooTopicId, 7)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(fooTopicId, 8)); + assertEquals(-1, consumerGroup.currentPartitionEpoch(fooTopicId, 9)); + } + + @Test + public void testGroupState() { + ConsumerGroup consumerGroup = createConsumerGroup("foo"); + assertEquals(ConsumerGroup.ConsumerGroupState.EMPTY, consumerGroup.state()); + + ConsumerGroupMember member1 = new ConsumerGroupMember.Builder("member1") + .setMemberEpoch(1) + .setPreviousMemberEpoch(0) + .setNextMemberEpoch(1) + .build(); + + consumerGroup.updateMember(member1); + consumerGroup.setGroupEpoch(1); + + assertEquals(ConsumerGroup.ConsumerGroupState.ASSIGNING, consumerGroup.state()); + + ConsumerGroupMember member2 = new ConsumerGroupMember.Builder("member2") + .setMemberEpoch(1) + .setPreviousMemberEpoch(0) + .setNextMemberEpoch(1) + .build(); + + consumerGroup.updateMember(member2); + consumerGroup.setGroupEpoch(2); + + assertEquals(ConsumerGroup.ConsumerGroupState.ASSIGNING, consumerGroup.state()); + + consumerGroup.setAssignmentEpoch(2); + + assertEquals(ConsumerGroup.ConsumerGroupState.RECONCILING, consumerGroup.state()); + + member1 = new ConsumerGroupMember.Builder(member1) + .setMemberEpoch(2) + .setPreviousMemberEpoch(1) + .setNextMemberEpoch(2) + .build(); + consumerGroup.updateMember(member1); + + assertEquals(ConsumerGroup.ConsumerGroupState.RECONCILING, consumerGroup.state()); + + member2 = new ConsumerGroupMember.Builder(member2) + .setMemberEpoch(2) + .setPreviousMemberEpoch(1) + .setNextMemberEpoch(2) + .build(); + consumerGroup.updateMember(member2); + + assertEquals(ConsumerGroup.ConsumerGroupState.STABLE, consumerGroup.state()); + + consumerGroup.removeMember("member1"); + consumerGroup.removeMember("member2"); + + assertEquals(ConsumerGroup.ConsumerGroupState.EMPTY, consumerGroup.state()); + } + + @Test + public void testPreferredServerAssignor() { + ConsumerGroup consumerGroup = createConsumerGroup("foo"); + + ConsumerGroupMember member1 = new ConsumerGroupMember.Builder("member1") + .setServerAssignorName("range") + .build(); + ConsumerGroupMember member2 = new ConsumerGroupMember.Builder("member2") + .setServerAssignorName("range") + .build(); + ConsumerGroupMember member3 = new ConsumerGroupMember.Builder("member3") + .setServerAssignorName("uniform") + .build(); + + assertEquals( + Optional.empty(), + consumerGroup.preferredServerAssignor(null, null) + ); + + assertEquals( + Optional.of("range"), + consumerGroup.preferredServerAssignor(null, member1) + ); + + consumerGroup.updateMember(member1); + + assertEquals( + Optional.of("range"), + consumerGroup.preferredServerAssignor(null, null) + ); + + assertEquals( + Optional.empty(), + consumerGroup.preferredServerAssignor(member1, null) + ); + + assertEquals( + Optional.of("range"), + consumerGroup.preferredServerAssignor(null, member2) + ); + + consumerGroup.updateMember(member2); + + assertEquals( + Optional.of("range"), + consumerGroup.preferredServerAssignor(null, null) + ); + + consumerGroup.updateMember(member3); + + assertEquals( + Optional.of("range"), + consumerGroup.preferredServerAssignor(null, null) + ); + + // Members without assignors + ConsumerGroupMember updatedMember1 = new ConsumerGroupMember.Builder("member1") + .setServerAssignorName(null) + .build(); + ConsumerGroupMember updatedMember2 = new ConsumerGroupMember.Builder("member2") + .setServerAssignorName(null) + .build(); + ConsumerGroupMember updatedMember3 = new ConsumerGroupMember.Builder("member3") + .setServerAssignorName(null) + .build(); + + + Optional<String> assignor = consumerGroup.preferredServerAssignor(member1, updatedMember1); + assertTrue(assignor.equals(Optional.of("range")) || assignor.equals(Optional.of("uniform"))); + + consumerGroup.updateMember(updatedMember1); + + assignor = consumerGroup.preferredServerAssignor(member1, updatedMember1); + assertTrue(assignor.equals(Optional.of("range")) || assignor.equals(Optional.of("uniform"))); Review Comment: after updating member 1 in L315, we have ``` range: 1 uniform: 1 ``` in serverAssignors. preferredServerAssignor() in L317 decrements "range" so the copy should have ``` range: 0 uniform: 1 ``` shouldn't this be `assertTrue(assignor.equals(Optional.of("uniform")));`? -- This is an automated message from the Apache Git Service. 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