jolshan commented on code in PR #13639: URL: https://github.com/apache/kafka/pull/13639#discussion_r1204494016
########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java: ########## @@ -0,0 +1,859 @@ +/* + * 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; + +import org.apache.kafka.common.Uuid; +import org.apache.kafka.common.errors.ApiException; +import org.apache.kafka.common.errors.FencedMemberEpochException; +import org.apache.kafka.common.errors.GroupIdNotFoundException; +import org.apache.kafka.common.errors.GroupMaxSizeReachedException; +import org.apache.kafka.common.errors.InvalidRequestException; +import org.apache.kafka.common.errors.NotCoordinatorException; +import org.apache.kafka.common.errors.UnknownServerException; +import org.apache.kafka.common.errors.UnsupportedAssignorException; +import org.apache.kafka.common.message.ConsumerGroupHeartbeatRequestData; +import org.apache.kafka.common.message.ConsumerGroupHeartbeatResponseData; +import org.apache.kafka.common.requests.RequestContext; +import org.apache.kafka.common.utils.LogContext; +import org.apache.kafka.coordinator.group.assignor.PartitionAssignor; +import org.apache.kafka.coordinator.group.assignor.PartitionAssignorException; +import org.apache.kafka.coordinator.group.consumer.Assignment; +import org.apache.kafka.coordinator.group.consumer.ConsumerGroup; +import org.apache.kafka.coordinator.group.consumer.ConsumerGroupMember; +import org.apache.kafka.coordinator.group.consumer.CurrentAssignmentBuilder; +import org.apache.kafka.coordinator.group.consumer.TargetAssignmentBuilder; +import org.apache.kafka.coordinator.group.consumer.TopicMetadata; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupCurrentMemberAssignmentKey; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupCurrentMemberAssignmentValue; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupMemberMetadataKey; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupMemberMetadataValue; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupMetadataKey; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupMetadataValue; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupPartitionMetadataKey; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupPartitionMetadataValue; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupTargetAssignmentMemberKey; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupTargetAssignmentMemberValue; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupTargetAssignmentMetadataKey; +import org.apache.kafka.coordinator.group.generated.ConsumerGroupTargetAssignmentMetadataValue; +import org.apache.kafka.image.TopicsImage; +import org.apache.kafka.timeline.SnapshotRegistry; +import org.apache.kafka.timeline.TimelineHashMap; +import org.slf4j.Logger; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.OptionalInt; +import java.util.Set; +import java.util.function.Function; +import java.util.stream.Collectors; + +import static org.apache.kafka.coordinator.group.RecordHelpers.newCurrentAssignmentRecord; +import static org.apache.kafka.coordinator.group.RecordHelpers.newCurrentAssignmentTombstoneRecord; +import static org.apache.kafka.coordinator.group.RecordHelpers.newGroupEpochRecord; +import static org.apache.kafka.coordinator.group.RecordHelpers.newGroupSubscriptionMetadataRecord; +import static org.apache.kafka.coordinator.group.RecordHelpers.newMemberSubscriptionRecord; +import static org.apache.kafka.coordinator.group.RecordHelpers.newMemberSubscriptionTombstoneRecord; +import static org.apache.kafka.coordinator.group.RecordHelpers.newTargetAssignmentTombstoneRecord; + +/** + * The GroupMetadataManager manages the metadata of all generic and consumer groups. It holds + * the hard and the soft state of the groups. This class has two kinds of methods: + * 1) The request handlers which handle the requests and generate a response and records to + * mutate the hard state. Those records will be written by the runtime and applied to the + * hard state via the replay methods. + * 2) The replay methods which apply records to the hard state. Those are used in the request + * handling as well as during the initial loading of the records from the partitions. + */ +public class GroupMetadataManager { + + public static class Builder { + private LogContext logContext = null; + private SnapshotRegistry snapshotRegistry = null; + private List<PartitionAssignor> assignors = null; + private TopicsImage topicsImage = null; + private int consumerGroupMaxSize = Integer.MAX_VALUE; + private int consumerGroupHeartbeatIntervalMs = 5000; + + Builder withLogContext(LogContext logContext) { + this.logContext = logContext; + return this; + } + + Builder withSnapshotRegistry(SnapshotRegistry snapshotRegistry) { + this.snapshotRegistry = snapshotRegistry; + return this; + } + + Builder withAssignors(List<PartitionAssignor> assignors) { + this.assignors = assignors; + return this; + } + + Builder withConsumerGroupMaxSize(int consumerGroupMaxSize) { + this.consumerGroupMaxSize = consumerGroupMaxSize; + return this; + } + + Builder withConsumerGroupHeartbeatInterval(int consumerGroupHeartbeatIntervalMs) { + this.consumerGroupHeartbeatIntervalMs = consumerGroupHeartbeatIntervalMs; + return this; + } + + Builder withTopicsImage(TopicsImage topicsImage) { + this.topicsImage = topicsImage; + return this; + } + + GroupMetadataManager build() { + if (logContext == null) logContext = new LogContext(); + if (snapshotRegistry == null) snapshotRegistry = new SnapshotRegistry(logContext); + if (topicsImage == null) topicsImage = TopicsImage.EMPTY; + + if (assignors == null || assignors.isEmpty()) { + throw new IllegalStateException("Assignors must be set before building."); + } + + return new GroupMetadataManager( + snapshotRegistry, + logContext, + assignors, + topicsImage, + consumerGroupMaxSize, + consumerGroupHeartbeatIntervalMs + ); + } + } + + /** + * The logger. + */ + private final Logger log; + + /** + * The snapshot registry. + */ + private final SnapshotRegistry snapshotRegistry; + + /** + * The supported partition assignors keyed by their name. + */ + private final Map<String, PartitionAssignor> assignors; + + /** + * The default assignor used. + */ + private final PartitionAssignor defaultAssignor; + + /** + * The generic and consumer groups keyed by their name. + */ + private final TimelineHashMap<String, Group> groups; + + /** + * The maximum number of members allowed in a single consumer group. + */ + private final int consumerGroupMaxSize; + + /** + * The heartbeat interval for consumer groups. + */ + private final int consumerGroupHeartbeatIntervalMs; + + /** + * The topics metadata (or image). + */ + private TopicsImage topicsImage; + + private GroupMetadataManager( + SnapshotRegistry snapshotRegistry, + LogContext logContext, + List<PartitionAssignor> assignors, + TopicsImage topicsImage, + int consumerGroupMaxSize, + int consumerGroupHeartbeatIntervalMs + ) { + this.log = logContext.logger(GroupMetadataManager.class); + this.snapshotRegistry = snapshotRegistry; + this.topicsImage = topicsImage; + this.assignors = assignors.stream().collect(Collectors.toMap(PartitionAssignor::name, Function.identity())); + this.defaultAssignor = assignors.get(0); + this.groups = new TimelineHashMap<>(snapshotRegistry, 0); + this.consumerGroupMaxSize = consumerGroupMaxSize; + this.consumerGroupHeartbeatIntervalMs = consumerGroupHeartbeatIntervalMs; + } + + /** + * Gets or maybe creates a consumer group. + * + * @param groupId The group id. + * @param createIfNotExists A boolean indicating whether the group should be + * created if it does not exist. + * + * @return A ConsumerGroup. + * @throws GroupIdNotFoundException if the group does not exist and createIfNotExists is false or + * if the group is not a consumer group. + * + * Package private for testing. + */ + ConsumerGroup getOrMaybeCreateConsumerGroup( + String groupId, + boolean createIfNotExists + ) throws GroupIdNotFoundException { + Group group = groups.get(groupId); + + if (group == null && !createIfNotExists) { + throw new GroupIdNotFoundException(String.format("Consumer group %s not found.", groupId)); + } + + if (group == null) { + ConsumerGroup consumerGroup = new ConsumerGroup(snapshotRegistry, groupId); + groups.put(groupId, consumerGroup); + return consumerGroup; + } else { + if (group.type() == Group.GroupType.CONSUMER) { + return (ConsumerGroup) group; + } else { + // We don't support upgrading/downgrading between protocols at the moment so + // we throw an exception if a group exists with the wrong type. + throw new GroupIdNotFoundException(String.format("Group %s is not a consumer group.", groupId)); + } + } + } + + /** + * Removes the group. + * + * @param groupId The group id. + */ + private void removeGroup( + String groupId + ) { + groups.remove(groupId); + } + + /** + * Validates the request. + * + * @param request The request to validate. + * + * @throws InvalidRequestException if the request is not valid. + * @throws UnsupportedAssignorException if the assignor is not supported. + */ + private void throwIfConsumerGroupHeartbeatRequestIsInvalid( + ConsumerGroupHeartbeatRequestData request + ) throws InvalidRequestException, UnsupportedAssignorException { + if (request.groupId().isEmpty()) { + throw new InvalidRequestException("GroupId can't be empty."); + } + + if (request.memberEpoch() > 0 || request.memberEpoch() == -1) { + if (request.memberId().isEmpty()) { + throw new InvalidRequestException("MemberId can't be empty."); + } + if (request.instanceId() != null) { + throw new InvalidRequestException("InstanceId should only be provided in first request."); + } + if (request.rackId() != null) { + throw new InvalidRequestException("RackId should only be provided in first request."); + } + } else if (request.memberEpoch() == 0) { + if (request.rebalanceTimeoutMs() == -1) { + throw new InvalidRequestException("RebalanceTimeoutMs must be provided in first request."); + } + if (request.topicPartitions() == null || !request.topicPartitions().isEmpty()) { + throw new InvalidRequestException("TopicPartitions must be empty when (re-)joining."); + } + if (request.subscribedTopicNames() == null || request.subscribedTopicNames().isEmpty()) { + throw new InvalidRequestException("SubscribedTopicNames must be set in first request."); + } + } else { + throw new InvalidRequestException("MemberEpoch is invalid."); + } + + if (request.serverAssignor() != null && !assignors.containsKey(request.serverAssignor())) { + throw new UnsupportedAssignorException("ServerAssignor " + request.serverAssignor() + + " is not supported. Supported assignors: " + String.join(", ", assignors.keySet()) + + "."); + } + + if (request.subscribedTopicRegex() != null) { + throw new InvalidRequestException("SubscribedTopicRegex is not supported yet."); + } + + if (request.clientAssignors() != null) { + throw new InvalidRequestException("Client side assignors are not supported yet."); + } + } + + /** + * Verifies that the partitions currently owned by the member (the ones set in the + * request) matches the ones that the member should own. It matches if the consumer + * only owns partitions which are in the assigned partitions. It does not match if + * it owns any other partitions. + * + * @param ownedTopicPartitions The partitions provided by the consumer in the request. + * @param target The partitions that the member should have. + * + * @return A boolean indicating whether the owned partitions are a subset or not. + */ + private boolean isSubset( + List<ConsumerGroupHeartbeatRequestData.TopicPartitions> ownedTopicPartitions, + Map<Uuid, Set<Integer>> target + ) { + if (ownedTopicPartitions == null) return false; + + for (ConsumerGroupHeartbeatRequestData.TopicPartitions topicPartitions : ownedTopicPartitions) { + Set<Integer> partitions = target.get(topicPartitions.topicId()); + if (partitions == null) return false; + for (Integer partitionId : topicPartitions.partitions()) { + if (!partitions.contains(partitionId)) return false; + } + } + + return true; + } + + /** + * Checks whether the consumer group can accept a new member or not based on the + * max group side defined. + * + * @param group The consumer group. + * @param memberId The member id. + * + * @throws GroupMaxSizeReachedException if the maximum capacity has been reached. + */ + private void throwIfConsumerGroupIsFull( + ConsumerGroup group, + String memberId + ) throws GroupMaxSizeReachedException { + // If the consumer group has reached its maximum capacity, the member is rejected if it is not + // already a member of the consumer group. + if (group.numMembers() >= consumerGroupMaxSize && (memberId.isEmpty() || !group.hasMember(memberId))) { + throw new GroupMaxSizeReachedException("The consumer group has reached its maximum capacity of " + + consumerGroupMaxSize + " members."); + } + } + + /** + * Validates the member epoch provided in the heartbeat request. + * + * @param member The consumer group member. + * @param receivedMemberEpoch The member epoch. + * @param ownedTopicPartitions The owned partitions. + * + * @throws NotCoordinatorException if the provided epoch is ahead of the epoch known + * by this coordinator. This suggests that the member + * got a higher epoch from another coordinator. + * @throws FencedMemberEpochException if the provided epoch is behind the epoch known + * by this coordinator. + */ + private void throwIfMemberEpochIsInvalid( + ConsumerGroupMember member, + int receivedMemberEpoch, + List<ConsumerGroupHeartbeatRequestData.TopicPartitions> ownedTopicPartitions + ) { + if (receivedMemberEpoch > member.memberEpoch()) { + throw new FencedMemberEpochException("The consumer group member has a greater member " + + "epoch (" + receivedMemberEpoch + ") than the one known by the group coordinator (" + + member.memberEpoch() + "). The member must abandon all its partitions and rejoin."); + } else if (receivedMemberEpoch < member.memberEpoch()) { + // If the member comes with the previous epoch and has a subset of the current assignment partitions, + // we accept it because the response with the bumped epoch may have been lost. + if (receivedMemberEpoch != member.previousMemberEpoch() || !isSubset(ownedTopicPartitions, member.assignedPartitions())) { + throw new FencedMemberEpochException("The consumer group member has a smaller member " + + "epoch (" + receivedMemberEpoch + ") than the one known by the group coordinator (" + + member.memberEpoch() + "). The member must abandon all its partitions and rejoin."); + } + } + } + + private ConsumerGroupHeartbeatResponseData.Assignment createResponseAssignment( + ConsumerGroupMember member + ) { + ConsumerGroupHeartbeatResponseData.Assignment assignment = new ConsumerGroupHeartbeatResponseData.Assignment() + .setAssignedTopicPartitions(fromAssignmentMap(member.assignedPartitions())); + + if (member.state() == ConsumerGroupMember.MemberState.ASSIGNING) { + assignment.setPendingTopicPartitions(fromAssignmentMap(member.partitionsPendingAssignment())); + } + + return assignment; + } + + private List<ConsumerGroupHeartbeatResponseData.TopicPartitions> fromAssignmentMap( + Map<Uuid, Set<Integer>> assignment + ) { + return assignment.entrySet().stream() + .map(keyValue -> new ConsumerGroupHeartbeatResponseData.TopicPartitions() + .setTopicId(keyValue.getKey()) + .setPartitions(new ArrayList<>(keyValue.getValue()))) + .collect(Collectors.toList()); + } + + private OptionalInt ofSentinel(int value) { + return value != -1 ? OptionalInt.of(value) : OptionalInt.empty(); + } + + /** + * Handles a regular heartbeat from a consumer group member. It mainly consists of + * three parts: + * 1) The member is created or updated. The group epoch is bumped if the member + * has been created or updated. + * 2) The target assignment for the consumer group is updated if the group epoch + * is larger than the current target assignment epoch. + * 3) The member's assignment is reconciled with the target assignment. + * + * @param groupId The group id from the request. + * @param memberId The member id from the request. + * @param memberEpoch The member epoch from the request. + * @param instanceId The instance id from the request or null. + * @param rackId The rack id from the request or null. + * @param rebalanceTimeoutMs The rebalance timeout from the request or -1. + * @param clientId The client id. + * @param clientHost The client host. + * @param subscribedTopicNames The list of subscribed topic names from the request + * of null. + * @param subscribedTopicRegex The regular expression based subscription from the + * request or null. + * @param assignorName The assignor name from the request or null. + * @param ownedTopicPartitions The list of owned partitions from the request or null. + * + * @return A Result containing the ConsumerGroupHeartbeat response and + * a list of records to update the state machine. + */ + private Result<ConsumerGroupHeartbeatResponseData> consumerGroupHeartbeat( + String groupId, + String memberId, + int memberEpoch, + String instanceId, + String rackId, + int rebalanceTimeoutMs, + String clientId, + String clientHost, + List<String> subscribedTopicNames, + String subscribedTopicRegex, + String assignorName, + List<ConsumerGroupHeartbeatRequestData.TopicPartitions> ownedTopicPartitions + ) throws ApiException { + List<Record> records = new ArrayList<>(); + + // Get or create the consumer group. + boolean createIfNotExists = memberEpoch == 0; + final ConsumerGroup group = getOrMaybeCreateConsumerGroup(groupId, createIfNotExists); + throwIfConsumerGroupIsFull(group, memberId); + + // Get or create the member. Note that member is the persisted member anytime + // in this method. + if (memberId.isEmpty()) memberId = Uuid.randomUuid().toString(); + final ConsumerGroupMember member = group.getOrMaybeCreateMember(memberId, createIfNotExists); + throwIfMemberEpochIsInvalid(member, memberEpoch, ownedTopicPartitions); + + if (memberEpoch == 0) { + log.info("[GroupId " + groupId + "] Member " + memberId + " re-joins the consumer group."); + } + + // 1. Create or update the member. If the member is new or has changed, a ConsumerGroupMemberMetadataValue + // record is written to the __consumer_offsets partition to persist the change. If the subscriptions have + // changed, the subscription metadata is updated and persisted by writing a ConsumerGroupPartitionMetadataValue + // record to the __consumer_offsets partition. Finally, the group epoch is bumped if the subscriptions have + // changed, and persisted by writing a ConsumerGroupMetadataValue record to the partition. + int groupEpoch = group.groupEpoch(); + Map<String, TopicMetadata> subscriptionMetadata = group.subscriptionMetadata(); + ConsumerGroupMember updatedMember = new ConsumerGroupMember.Builder(member) + .maybeUpdateInstanceId(Optional.ofNullable(instanceId)) + .maybeUpdateRackId(Optional.ofNullable(rackId)) + .maybeUpdateRebalanceTimeoutMs(ofSentinel(rebalanceTimeoutMs)) + .maybeUpdateServerAssignorName(Optional.ofNullable(assignorName)) + .maybeUpdateSubscribedTopicNames(Optional.ofNullable(subscribedTopicNames)) + .maybeUpdateSubscribedTopicRegex(Optional.ofNullable(subscribedTopicRegex)) + .setClientId(clientId) + .setClientHost(clientHost) + .build(); + + if (!updatedMember.equals(member)) { + records.add(newMemberSubscriptionRecord(groupId, updatedMember)); + + if (!updatedMember.subscribedTopicNames().equals(member.subscribedTopicNames())) { + log.info("[GroupId " + groupId + "] Member " + memberId + " updated its subscribed topics to: " + + updatedMember.subscribedTopicNames()); + + subscriptionMetadata = group.computeSubscriptionMetadata( + member, + updatedMember, + topicsImage + ); + + if (!subscriptionMetadata.equals(group.subscriptionMetadata())) { + log.info("[GroupId " + groupId + "] Computed new subscription metadata: " + + subscriptionMetadata + "."); + records.add(newGroupSubscriptionMetadataRecord(groupId, subscriptionMetadata)); + } + + groupEpoch += 1; + records.add(newGroupEpochRecord(groupId, groupEpoch)); + + log.info("[GroupId " + groupId + "] Bumped group epoch to " + groupEpoch + "."); + } + } + + // 2. Update the target assignment if the group epoch is larger than the target assignment epoch. The + // delta between the current and the new target assignment is persisted to the partition. + int targetAssignmentEpoch = group.assignmentEpoch(); + Assignment targetAssignment = group.targetAssignment(memberId); + if (groupEpoch > targetAssignmentEpoch) { + String preferredServerAssignor = group.preferredServerAssignor( + member, + updatedMember + ).orElse(defaultAssignor.name()); + + try { + TargetAssignmentBuilder.TargetAssignmentResult assignmentResult = + new TargetAssignmentBuilder(groupId, groupEpoch, assignors.get(preferredServerAssignor)) + .withMembers(group.members()) + .withSubscriptionMetadata(subscriptionMetadata) + .withTargetAssignment(group.targetAssignments()) + .addOrUpdateMember(memberId, updatedMember) + .build(); + + log.info("[GroupId " + groupId + "] Computed a new target assignment for epoch " + groupEpoch + ": " + + assignmentResult.targetAssignment() + "."); + + records.addAll(assignmentResult.records()); + targetAssignment = assignmentResult.targetAssignment().get(memberId); + targetAssignmentEpoch = groupEpoch; + } catch (PartitionAssignorException ex) { + String msg = "Failed to compute a new target assignment for epoch " + groupEpoch + ": " + ex + "."; + log.error("[GroupId " + groupId + "] " + msg); + throw new UnknownServerException(msg, ex); + } + } + + // 3. Reconcile the member's assignment with the target assignment. This is only required if + // the member is not stable or if a new target assignment has been installed. + boolean assignmentUpdated = false; + if (updatedMember.state() != ConsumerGroupMember.MemberState.STABLE || updatedMember.nextMemberEpoch() != targetAssignmentEpoch) { + ConsumerGroupMember prevMember = updatedMember; + updatedMember = new CurrentAssignmentBuilder(updatedMember) + .withTargetAssignment(targetAssignmentEpoch, targetAssignment) + .withCurrentPartitionEpoch(group::currentPartitionEpoch) + .withOwnedTopicPartitions(ownedTopicPartitions) + .build(); + + // Checking the reference is enough here because a new instance + // is created only when the state has changed. + if (updatedMember != prevMember) { + assignmentUpdated = true; + records.add(newCurrentAssignmentRecord(groupId, updatedMember)); + + log.info("[GroupId " + groupId + "] Member " + memberId + " transitioned from " + + member.currentAssignmentSummary() + " to " + updatedMember.currentAssignmentSummary() + "."); + + // TODO(dajac) Starts or restarts the timer for the revocation timeout. + } + } + + // TODO(dajac) Starts or restarts the timer for the session timeout. + + // Prepare the response. + ConsumerGroupHeartbeatResponseData response = new ConsumerGroupHeartbeatResponseData() + .setMemberId(updatedMember.memberId()) + .setMemberEpoch(updatedMember.memberEpoch()) + .setHeartbeatIntervalMs(consumerGroupHeartbeatIntervalMs); + + // The assignment is only provided in the following cases: + // 1. The member reported its owned partitions; + // 2. The member just joined or rejoined to group. This is signaled with epoch equals to zero; + // 3. The member's assignment has been updated. + if (ownedTopicPartitions != null || memberEpoch == 0 || assignmentUpdated) { + response.setAssignment(createResponseAssignment(updatedMember)); + } + + return new Result<>(records, response); + } + + /** + * Handles leave request from a consumer group member. + * @param groupId The group id from the request. + * @param memberId The member id from the request. + * + * @return A Result containing the ConsumerGroupHeartbeat response and + * a list of records to update the state machine. + */ + private Result<ConsumerGroupHeartbeatResponseData> consumerGroupLeave( + String groupId, + String memberId + ) throws ApiException { + List<Record> records = new ArrayList<>(); + + ConsumerGroup group = getOrMaybeCreateConsumerGroup(groupId, false); + ConsumerGroupMember member = group.getOrMaybeCreateMember(memberId, false); + + log.info("[GroupId " + groupId + "] Member " + memberId + " left the consumer group."); + + // Write tombstones for the member. The order matters here. + records.add(newCurrentAssignmentTombstoneRecord(groupId, memberId)); + records.add(newTargetAssignmentTombstoneRecord(groupId, memberId)); + records.add(newMemberSubscriptionTombstoneRecord(groupId, memberId)); + + // We update the subscription metadata without the leaving member. + Map<String, TopicMetadata> subscriptionMetadata = group.computeSubscriptionMetadata( + member, + null, + topicsImage + ); + + if (!subscriptionMetadata.equals(group.subscriptionMetadata())) { + log.info("[GroupId " + groupId + "] Computed new subscription metadata: " + + subscriptionMetadata + "."); + records.add(newGroupSubscriptionMetadataRecord(groupId, subscriptionMetadata)); + } + + // We bump the group epoch. + int groupEpoch = group.groupEpoch() + 1; + records.add(newGroupEpochRecord(groupId, groupEpoch)); + + return new Result<>(records, new ConsumerGroupHeartbeatResponseData() + .setMemberId(memberId) + .setMemberEpoch(-1) + ); + } + + /** + * Handles a ConsumerGroupHeartbeat request. + * + * @param context The request context. + * @param request The actual ConsumerGroupHeartbeat request. + * + * @return A Result containing the ConsumerGroupHeartbeat response and + * a list of records to update the state machine. + */ + public Result<ConsumerGroupHeartbeatResponseData> consumerGroupHeartbeat( + RequestContext context, + ConsumerGroupHeartbeatRequestData request + ) throws ApiException { + throwIfConsumerGroupHeartbeatRequestIsInvalid(request); + + if (request.memberEpoch() == -1) { + // -1 means that the member wants to leave the group. + return consumerGroupLeave( + request.groupId(), + request.memberId() + ); + } else { + // Otherwise, it is a regular heartbeat. + return consumerGroupHeartbeat( + request.groupId(), + request.memberId(), + request.memberEpoch(), + request.instanceId(), + request.rackId(), + request.rebalanceTimeoutMs(), + context.clientId(), + context.clientAddress.toString(), + request.subscribedTopicNames(), + request.subscribedTopicRegex(), + request.serverAssignor(), + request.topicPartitions() + ); + } + } + + /** + * Replays ConsumerGroupMemberMetadataKey/Value to update the hard state of + * the consumer group. It updates the subscription part of the member or + * delete the member. + * + * @param key A ConsumerGroupMemberMetadataKey key. + * @param value A ConsumerGroupMemberMetadataValue record. + */ + public void replay( + ConsumerGroupMemberMetadataKey key, + ConsumerGroupMemberMetadataValue value + ) { + String groupId = key.groupId(); + String memberId = key.memberId(); + + if (value != null) { + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, true); + ConsumerGroupMember oldMember = consumerGroup.getOrMaybeCreateMember(memberId, true); + consumerGroup.updateMember(new ConsumerGroupMember.Builder(oldMember) + .updateWith(value) + .build()); + } else { + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, false); + ConsumerGroupMember oldMember = consumerGroup.getOrMaybeCreateMember(memberId, false); + if (oldMember.memberEpoch() != -1) { + throw new IllegalStateException("Received a tombstone record to delete member " + memberId + + " but did not receive ConsumerGroupCurrentMemberAssignmentValue tombstone."); + } + if (consumerGroup.targetAssignments().containsKey(memberId)) { + throw new IllegalStateException("Received a tombstone record to delete member " + memberId + + " but did not receive ConsumerGroupTargetAssignmentMetadataValue tombstone."); + } + consumerGroup.removeMember(memberId); + } + } + + /** + * Replays ConsumerGroupMetadataKey/Value to update the hard state of + * the consumer group. It updates the group epoch of the consumer + * group or deletes the consumer group. + * + * @param key A ConsumerGroupMetadataKey key. + * @param value A ConsumerGroupMetadataValue record. + */ + public void replay( + ConsumerGroupMetadataKey key, + ConsumerGroupMetadataValue value + ) { + String groupId = key.groupId(); + + if (value != null) { + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, true); + consumerGroup.setGroupEpoch(value.epoch()); + } else { + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, false); + if (!consumerGroup.members().isEmpty()) { + throw new IllegalStateException("Received a tombstone record to delete group " + groupId + + " but the group still has " + consumerGroup.members().size() + " members."); + } + if (!consumerGroup.targetAssignments().isEmpty()) { + throw new IllegalStateException("Received a tombstone record to delete group " + groupId + + " but the target assignment still has " + consumerGroup.targetAssignments().size() + + " members."); + } + if (consumerGroup.assignmentEpoch() != -1) { + throw new IllegalStateException("Received a tombstone record to delete group " + groupId + + " but did not receive ConsumerGroupTargetAssignmentMetadataValue tombstone."); + } + removeGroup(groupId); + } + + } + + /** + * Replays ConsumerGroupPartitionMetadataKey/Value to update the hard state of + * the consumer group. It updates the subscription metadata of the consumer + * group. + * + * @param key A ConsumerGroupPartitionMetadataKey key. + * @param value A ConsumerGroupPartitionMetadataValue record. + */ + public void replay( + ConsumerGroupPartitionMetadataKey key, + ConsumerGroupPartitionMetadataValue value + ) { + String groupId = key.groupId(); + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, false); + + if (value != null) { + Map<String, TopicMetadata> subscriptionMetadata = new HashMap<>(); + value.topics().forEach(topicMetadata -> { + subscriptionMetadata.put(topicMetadata.topicName(), TopicMetadata.fromRecord(topicMetadata)); + }); + consumerGroup.setSubscriptionMetadata(subscriptionMetadata); + } else { + consumerGroup.setSubscriptionMetadata(Collections.emptyMap()); + } + } + + /** + * Replays ConsumerGroupTargetAssignmentMemberKey/Value to update the hard state of + * the consumer group. It updates the target assignment of the member or deletes it. + * + * @param key A ConsumerGroupTargetAssignmentMemberKey key. + * @param value A ConsumerGroupTargetAssignmentMemberValue record. + */ + public void replay( + ConsumerGroupTargetAssignmentMemberKey key, + ConsumerGroupTargetAssignmentMemberValue value + ) { + String groupId = key.groupId(); + String memberId = key.memberId(); + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, false); + + if (value != null) { + consumerGroup.updateTargetAssignment(memberId, Assignment.fromRecord(value)); + } else { + consumerGroup.removeTargetAssignment(memberId); + } + } + + /** + * Replays ConsumerGroupTargetAssignmentMetadataKey/Value to update the hard state of + * the consumer group. It updates the target assignment epoch or set it to -1 to signal + * that it has been deleted. + * + * @param key A ConsumerGroupTargetAssignmentMetadataKey key. + * @param value A ConsumerGroupTargetAssignmentMetadataValue record. + */ + public void replay( + ConsumerGroupTargetAssignmentMetadataKey key, + ConsumerGroupTargetAssignmentMetadataValue value + ) { + String groupId = key.groupId(); + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, false); + + if (value != null) { + consumerGroup.setAssignmentEpoch(value.assignmentEpoch()); + } else { + if (!consumerGroup.targetAssignments().isEmpty()) { + throw new IllegalStateException("Received a tombstone record to delete target assignment of " + groupId + + " but the assignment still has " + consumerGroup.targetAssignments().size() + " members."); + } + consumerGroup.setAssignmentEpoch(-1); + } + } + + /** + * Replays ConsumerGroupCurrentMemberAssignmentKey/Value to update the hard state of + * the consumer group. It updates the assignment of a member or deletes it. + * + * @param key A ConsumerGroupCurrentMemberAssignmentKey key. + * @param value A ConsumerGroupCurrentMemberAssignmentValue record. + */ + public void replay( + ConsumerGroupCurrentMemberAssignmentKey key, + ConsumerGroupCurrentMemberAssignmentValue value + ) { + String groupId = key.groupId(); + String memberId = key.memberId(); + ConsumerGroup consumerGroup = getOrMaybeCreateConsumerGroup(groupId, false); + ConsumerGroupMember oldMember = consumerGroup.getOrMaybeCreateMember(memberId, false); + + if (value != null) { + ConsumerGroupMember newMember = new ConsumerGroupMember.Builder(oldMember) + .updateWith(value) + .build(); + consumerGroup.updateMember(newMember); + } else { + ConsumerGroupMember newMember = new ConsumerGroupMember.Builder(oldMember) Review Comment: Yeah, I suppose I was meaning a method to add the sentinel values. But if it is only done here, maybe it is not useful. -- 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
