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Posted to jira@kafka.apache.org by "dajac (via GitHub)" <gi...@apache.org> on 2023/04/06 09:08:42 UTC
[GitHub] [kafka] dajac commented on a diff in pull request #13476: KAFKA-14462; [4/N] Add GroupMetadataManager: ConsumerGroups Management, Members Management and Reconciliation Logic
dajac commented on code in PR #13476:
URL: https://github.com/apache/kafka/pull/13476#discussion_r1159506233
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group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java:
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@@ -0,0 +1,860 @@
+/*
+ * 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.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.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.consumer.ConsumerGroup;
+import org.apache.kafka.coordinator.group.consumer.ConsumerGroupMember;
+import org.apache.kafka.coordinator.group.consumer.ConsumerGroupMemberAssignment;
+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.apache.kafka.timeline.TimelineHashSet;
+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 stay 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 list of supported assignors.
+ */
+ 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 generic and consumer groups keyed by their subscribed topics.
+ */
+ private final TimelineHashMap<String, TimelineHashSet<Group>> groupsByTopicName;
+
+ /**
+ * 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.groupsByTopicName = 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.
+ *
+ * @return The Group removed.
+ */
+ private Group removeGroup(
+ String groupId
+ ) {
+ return 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 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.");
+ }
+ if (request.serverAssignor() != null && !assignors.containsKey(request.serverAssignor())) {
+ throw new UnsupportedAssignorException("ServerAssignor " + request.serverAssignor()
+ + " is not supported. Supported assignors: " + String.join(", ", assignors.keySet())
+ + ".");
+ }
+ } else {
+ throw new InvalidRequestException("MemberEpoch is invalid.");
+ }
+
+ if (request.subscribedTopicRegex() != null) {
+ throw new InvalidRequestException("SubscribedTopicRegex is not supported yet.");
+ }
+
+ if (request.clientAssignors() != null) {
+ // TODO We need to remove them from the request.
+ 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 client
+ * has a least of subset of them.
+ *
+ * @param ownedTopicPartitions The partitions provided by the client in the request.
+ * @param target The partitions that they client should have.
+ *
+ * @return A boolean indicating whether the owned partitions are a subset of 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 memberEpoch 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 memberEpoch,
+ List<ConsumerGroupHeartbeatRequestData.TopicPartitions> ownedTopicPartitions
+ ) {
+ if (memberEpoch > member.memberEpoch()) {
+ // The member has likely got a bump from another coordinator and this coordinator
+ // is stale. Return NOT_COORDINATOR to force the member to refresh its coordinator.
+ throw new NotCoordinatorException("The consumer group member has got a larger member "
+ + "epoch (" + memberEpoch + ") than the one known by this group coordinator ("
+ + member.memberEpoch() + ").");
+ } else if (memberEpoch < 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 (memberEpoch != member.previousMemberEpoch() || !isSubset(ownedTopicPartitions, member.assigned())) {
+ throw new FencedMemberEpochException("The consumer group member has an old member "
+ + "epoch. The member must abandon all its partitions and rejoin.");
+ }
+ }
+ }
+
+ private ConsumerGroupHeartbeatResponseData.Assignment createResponseAssignment(
+ ConsumerGroupMember member
+ ) {
+ ConsumerGroupHeartbeatResponseData.Assignment assignment = new ConsumerGroupHeartbeatResponseData.Assignment()
+ .setAssignedTopicPartitions(fromAssignmentMap(member.assigned()));
+
+ if (member.state() == ConsumerGroupMember.MemberState.ASSIGNING) {
+ assignment.setPendingTopicPartitions(fromAssignmentMap(member.assigning()));
+ }
+
+ 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.
+ *
+ * @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
+ ) {
+ List<Record> records = new ArrayList<>();
+ boolean createIfNotExists = memberEpoch == 0;
+
+ ConsumerGroup group = getOrMaybeCreateConsumerGroup(groupId, createIfNotExists);
+ throwIfConsumerGroupIsFull(group, memberId);
+
+ if (memberId.isEmpty()) memberId = Uuid.randomUuid().toString();
+ ConsumerGroupMember member = group.getOrMaybeCreateMember(memberId, createIfNotExists);
+ throwIfMemberEpochIsInvalid(member, memberEpoch, ownedTopicPartitions);
+
+ if (memberEpoch == 0) {
+ log.info("[GroupId " + groupId + "] Member " + memberId + " re-joins the consumer group.");
+ }
+
+ // Update the subscription part of the member if we received new values. If the member has
+ // changed, we write it to the log. If the subscribed topics have changed, we also recompute
+ // the subscription metadata.
+ 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(
+ updatedMember.memberId(),
+ updatedMember.subscribedTopicNames(),
+ topicsImage
+ );
+
+ if (!subscriptionMetadata.equals(group.subscriptionMetadata())) {
+ log.info("[GroupId " + groupId + "] Computed new subscription metadata: "
+ + subscriptionMetadata + ".");
+ records.add(newGroupSubscriptionMetadataRecord(groupId, subscriptionMetadata));
+ }
+
+ groupEpoch += 1;
Review Comment:
That's correct.
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