dajac commented on code in PR #15721: URL: https://github.com/apache/kafka/pull/15721#discussion_r1568737120
########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java: ########## @@ -775,6 +777,126 @@ public ClassicGroup classicGroup( } } + public boolean validateOnlineDowngrade(ConsumerGroup consumerGroup, String memberId) { + if (!consumerGroupMigrationPolicy.isDowngradeEnabled()) { + log.info("Cannot downgrade consumer group {} to classic group because the online downgrade is disabled.", + consumerGroup.groupId()); + return false; + } else if (!consumerGroup.allMembersUseClassicProtocolExcept(memberId)) { + log.debug("Cannot downgrade consumer group {} to classic group because not all its members use the classic protocol.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() <= 1) { + log.info("Skip downgrading the consumer group {} to classic group because it's empty.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() - 1 > classicGroupMaxSize) { + log.info("Cannot downgrade consumer group {} to classic group because its group size is greater than classic group max size.", + consumerGroup.groupId()); + } + return true; + } + + public CompletableFuture<Void> convertToClassicGroup(ConsumerGroup consumerGroup, String leavingMemberId, List<Record> records) { + consumerGroup.createGroupTombstoneRecords(records); + ClassicGroup classicGroup; Review Comment: nit: Let's add an empty line before this one. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java: ########## @@ -775,6 +777,126 @@ public ClassicGroup classicGroup( } } + public boolean validateOnlineDowngrade(ConsumerGroup consumerGroup, String memberId) { + if (!consumerGroupMigrationPolicy.isDowngradeEnabled()) { + log.info("Cannot downgrade consumer group {} to classic group because the online downgrade is disabled.", + consumerGroup.groupId()); + return false; + } else if (!consumerGroup.allMembersUseClassicProtocolExcept(memberId)) { + log.debug("Cannot downgrade consumer group {} to classic group because not all its members use the classic protocol.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() <= 1) { + log.info("Skip downgrading the consumer group {} to classic group because it's empty.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() - 1 > classicGroupMaxSize) { + log.info("Cannot downgrade consumer group {} to classic group because its group size is greater than classic group max size.", + consumerGroup.groupId()); + } + return true; + } + + public CompletableFuture<Void> convertToClassicGroup(ConsumerGroup consumerGroup, String leavingMemberId, List<Record> records) { Review Comment: Does it need to be public? Let's add some javadoc please. ########## group-coordinator/src/test/java/org/apache/kafka/coordinator/group/GroupMetadataManagerTest.java: ########## @@ -9623,6 +10332,186 @@ public void testClassicGroupOnUnloadedCompletingRebalance() throws Exception { .setErrorCode(NOT_COORDINATOR.code()), pendingMemberSyncResult.syncFuture.get()); } + @ParameterizedTest + @ValueSource(booleans = {true, false}) + public void testLastClassicProtocolMemberLeavingConsumerGroup(boolean appendLogSuccessfully) { Review Comment: Should we also test the session expiration path and the rebalance expiration path? ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -998,4 +1094,232 @@ public ConsumerGroupDescribeResponseData.DescribedGroup asDescribedGroup( ); return describedGroup; } + + /** + * Create a new consumer group according to the given classic group. + * + * @param snapshotRegistry The SnapshotRegistry. + * @param metrics The GroupCoordinatorMetricsShard. + * @param classicGroup The converted classic group. + * @param topicsImage The TopicsImage for topic id and topic name conversion. + * @return The created ConsumerGruop. + */ + public static ConsumerGroup fromClassicGroup( + SnapshotRegistry snapshotRegistry, + GroupCoordinatorMetricsShard metrics, + ClassicGroup classicGroup, + TopicsImage topicsImage + ) { + String groupId = classicGroup.groupId(); + ConsumerGroup consumerGroup = new ConsumerGroup(snapshotRegistry, groupId, metrics); + consumerGroup.setGroupEpoch(classicGroup.generationId()); + consumerGroup.setTargetAssignmentEpoch(classicGroup.generationId()); + + classicGroup.allMembers().forEach(classicGroupMember -> { + ConsumerPartitionAssignor.Assignment assignment = ConsumerProtocol.deserializeAssignment( + ByteBuffer.wrap(classicGroupMember.assignment()) + ); + Map<Uuid, Set<Integer>> partitions = topicPartitionMapFromList(assignment.partitions(), topicsImage); + + ConsumerPartitionAssignor.Subscription subscription = ConsumerProtocol.deserializeSubscription( + ByteBuffer.wrap(classicGroupMember.metadata(classicGroup.protocolName().get())) + ); + + // The target assignment and the assigned partitions of each member are set based on the last + // assignment of the classic group. All the members are put in the Stable state. If the classic + // group was in Preparing Rebalance or Completing Rebalance states, the classic members are + // asked to rejoin the group to re-trigger a rebalance or collect their assignments. + ConsumerGroupMember newMember = new ConsumerGroupMember.Builder(classicGroupMember.memberId()) + .setMemberEpoch(classicGroup.generationId()) + .setState(MemberState.STABLE) + .setPreviousMemberEpoch(classicGroup.generationId()) + .setInstanceId(classicGroupMember.groupInstanceId().orElse(null)) + .setRackId(subscription.rackId().orElse(null)) + .setRebalanceTimeoutMs(classicGroupMember.rebalanceTimeoutMs()) + .setClientId(classicGroupMember.clientId()) + .setClientHost(classicGroupMember.clientHost()) + .setSubscribedTopicNames(subscription.topics()) + .setAssignedPartitions(partitions) + .setSupportedClassicProtocols(classicGroupMember.supportedProtocols()) + .build(); + consumerGroup.updateTargetAssignment(newMember.memberId(), new Assignment(partitions)); + consumerGroup.updateMember(newMember); + }); + + return consumerGroup; + } + + /** + * Populate the record list with the records needed to create the given consumer group. + * + * @param records The list to which the new records are added. + */ + public void createConsumerGroupRecords( + List<Record> records + ) { + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newMemberSubscriptionRecord(groupId(), consumerGroupMember)) + ); + + records.add(RecordHelpers.newGroupEpochRecord(groupId(), groupEpoch())); + + members().forEach((consumerGroupMemberId, consumerGroupMember) -> + records.add(RecordHelpers.newTargetAssignmentRecord( + groupId(), + consumerGroupMemberId, + targetAssignment(consumerGroupMemberId).partitions() + )) + ); + + records.add(RecordHelpers.newTargetAssignmentEpochRecord(groupId(), groupEpoch())); + + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newCurrentAssignmentRecord(groupId(), consumerGroupMember)) + ); + } + + /** + * @return The map of topic id and partition set converted from the list of TopicPartition. + */ + private static Map<Uuid, Set<Integer>> topicPartitionMapFromList( + List<TopicPartition> partitions, + TopicsImage topicsImage + ) { + Map<Uuid, Set<Integer>> topicPartitionMap = new HashMap<>(); + partitions.forEach(topicPartition -> { + TopicImage topicImage = topicsImage.getTopic(topicPartition.topic()); + if (topicImage != null) { + topicPartitionMap + .computeIfAbsent(topicImage.id(), __ -> new HashSet<>()) + .add(topicPartition.partition()); + } + }); + return topicPartitionMap; + } + + /** + * Create a corresponding ClassicGroup and append the record for the creation for group downgrade. + * The member with leavingMemberId will not be converted to the new ClassicGroup as it's the last + * member using new consumer protocol that left and triggered the downgrade. + * + * @param leavingMemberId The member that will not be converted in the ClassicGroup. + * @param logContext The logContext to create the ClassicGroup. + * @param time The time to create the ClassicGroup. + * @param consumerGroupSessionTimeoutMs The consumerGroupSessionTimeoutMs. + * @param metadataImage The metadataImage. + * @param records The record list. + * @return The created ClassicGroup. + */ + public ClassicGroup toClassicGroup( + String leavingMemberId, + LogContext logContext, + Time time, + int consumerGroupSessionTimeoutMs, + MetadataImage metadataImage, + List<Record> records + ) { + ClassicGroup classicGroup = new ClassicGroup( + logContext, + groupId(), + ClassicGroupState.STABLE, + time, + metrics, + groupEpoch(), + Optional.ofNullable(ConsumerProtocol.PROTOCOL_TYPE), + Optional.empty(), + members().keySet().stream().filter(member -> !member.equals(leavingMemberId)).findAny(), Review Comment: I think that we could use `Optional.empty()` here because a leader will be picked when the members are added. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java: ########## @@ -775,6 +777,126 @@ public ClassicGroup classicGroup( } } + public boolean validateOnlineDowngrade(ConsumerGroup consumerGroup, String memberId) { + if (!consumerGroupMigrationPolicy.isDowngradeEnabled()) { + log.info("Cannot downgrade consumer group {} to classic group because the online downgrade is disabled.", + consumerGroup.groupId()); + return false; + } else if (!consumerGroup.allMembersUseClassicProtocolExcept(memberId)) { + log.debug("Cannot downgrade consumer group {} to classic group because not all its members use the classic protocol.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() <= 1) { + log.info("Skip downgrading the consumer group {} to classic group because it's empty.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() - 1 > classicGroupMaxSize) { + log.info("Cannot downgrade consumer group {} to classic group because its group size is greater than classic group max size.", + consumerGroup.groupId()); + } + return true; + } + + public CompletableFuture<Void> convertToClassicGroup(ConsumerGroup consumerGroup, String leavingMemberId, List<Record> records) { + consumerGroup.createGroupTombstoneRecords(records); + ClassicGroup classicGroup; + try { + classicGroup = consumerGroup.toClassicGroup( + leavingMemberId, + logContext, + time, + consumerGroupSessionTimeoutMs, + metadataImage, + records + ); + } catch (SchemaException e) { + log.warn("Cannot downgrade the consumer group " + consumerGroup.groupId() + ": fail to parse " + + "the Consumer Protocol " + ConsumerProtocol.PROTOCOL_TYPE + ".", e); + + throw new GroupIdNotFoundException(String.format("Cannot downgrade the classic group %s: %s.", + consumerGroup.groupId(), e.getMessage())); + } + + groups.put(consumerGroup.groupId(), classicGroup); + metrics.onClassicGroupStateTransition(null, classicGroup.currentState()); + + CompletableFuture<Void> appendFuture = new CompletableFuture<>(); + appendFuture.whenComplete((__, t) -> { + if (t == null) { + classicGroup.allMembers().forEach(member -> rescheduleClassicGroupMemberHeartbeat(classicGroup, member)); + prepareRebalance(classicGroup, String.format("Downgrade group %s.", classicGroup.groupId())); Review Comment: I am not sure to understand why we do this here. In my opinion, it is better to create all the state immediately. However, if t != null, I think that we need to revert changes made by `onClassicGroupStateTransition` at L821. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java: ########## @@ -775,6 +777,126 @@ public ClassicGroup classicGroup( } } + public boolean validateOnlineDowngrade(ConsumerGroup consumerGroup, String memberId) { + if (!consumerGroupMigrationPolicy.isDowngradeEnabled()) { + log.info("Cannot downgrade consumer group {} to classic group because the online downgrade is disabled.", + consumerGroup.groupId()); + return false; + } else if (!consumerGroup.allMembersUseClassicProtocolExcept(memberId)) { + log.debug("Cannot downgrade consumer group {} to classic group because not all its members use the classic protocol.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() <= 1) { + log.info("Skip downgrading the consumer group {} to classic group because it's empty.", + consumerGroup.groupId()); + return false; + } else if (consumerGroup.numMembers() - 1 > classicGroupMaxSize) { + log.info("Cannot downgrade consumer group {} to classic group because its group size is greater than classic group max size.", + consumerGroup.groupId()); + } + return true; + } + + public CompletableFuture<Void> convertToClassicGroup(ConsumerGroup consumerGroup, String leavingMemberId, List<Record> records) { + consumerGroup.createGroupTombstoneRecords(records); + ClassicGroup classicGroup; + try { + classicGroup = consumerGroup.toClassicGroup( Review Comment: I wonder if we should rather follower the same structure than we used in this other PR. I mean that we could have a static method in ClassicGroup and we could have a createClassicGroupRecords. What do you think? ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java: ########## @@ -1369,11 +1493,16 @@ private CoordinatorResult<ConsumerGroupHeartbeatResponseData, Record> consumerGr log.info("[GroupId {}] Static Member {} with instance id {} left the consumer group.", group.groupId(), memberId, instanceId); records = consumerGroupFenceMember(group, member); + if (validateOnlineDowngrade(group, memberId)) appendFuture = convertToClassicGroup(group, memberId, records); } } - return new CoordinatorResult<>(records, new ConsumerGroupHeartbeatResponseData() - .setMemberId(memberId) - .setMemberEpoch(memberEpoch)); + return new CoordinatorResult<>( Review Comment: Could we extract the code from both branches and have it here? ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -998,4 +1094,232 @@ public ConsumerGroupDescribeResponseData.DescribedGroup asDescribedGroup( ); return describedGroup; } + + /** + * Create a new consumer group according to the given classic group. + * + * @param snapshotRegistry The SnapshotRegistry. + * @param metrics The GroupCoordinatorMetricsShard. + * @param classicGroup The converted classic group. + * @param topicsImage The TopicsImage for topic id and topic name conversion. + * @return The created ConsumerGruop. + */ + public static ConsumerGroup fromClassicGroup( + SnapshotRegistry snapshotRegistry, + GroupCoordinatorMetricsShard metrics, + ClassicGroup classicGroup, + TopicsImage topicsImage + ) { + String groupId = classicGroup.groupId(); + ConsumerGroup consumerGroup = new ConsumerGroup(snapshotRegistry, groupId, metrics); + consumerGroup.setGroupEpoch(classicGroup.generationId()); + consumerGroup.setTargetAssignmentEpoch(classicGroup.generationId()); + + classicGroup.allMembers().forEach(classicGroupMember -> { + ConsumerPartitionAssignor.Assignment assignment = ConsumerProtocol.deserializeAssignment( + ByteBuffer.wrap(classicGroupMember.assignment()) + ); + Map<Uuid, Set<Integer>> partitions = topicPartitionMapFromList(assignment.partitions(), topicsImage); + + ConsumerPartitionAssignor.Subscription subscription = ConsumerProtocol.deserializeSubscription( + ByteBuffer.wrap(classicGroupMember.metadata(classicGroup.protocolName().get())) + ); + + // The target assignment and the assigned partitions of each member are set based on the last + // assignment of the classic group. All the members are put in the Stable state. If the classic + // group was in Preparing Rebalance or Completing Rebalance states, the classic members are + // asked to rejoin the group to re-trigger a rebalance or collect their assignments. + ConsumerGroupMember newMember = new ConsumerGroupMember.Builder(classicGroupMember.memberId()) + .setMemberEpoch(classicGroup.generationId()) + .setState(MemberState.STABLE) + .setPreviousMemberEpoch(classicGroup.generationId()) + .setInstanceId(classicGroupMember.groupInstanceId().orElse(null)) + .setRackId(subscription.rackId().orElse(null)) + .setRebalanceTimeoutMs(classicGroupMember.rebalanceTimeoutMs()) + .setClientId(classicGroupMember.clientId()) + .setClientHost(classicGroupMember.clientHost()) + .setSubscribedTopicNames(subscription.topics()) + .setAssignedPartitions(partitions) + .setSupportedClassicProtocols(classicGroupMember.supportedProtocols()) + .build(); + consumerGroup.updateTargetAssignment(newMember.memberId(), new Assignment(partitions)); + consumerGroup.updateMember(newMember); + }); + + return consumerGroup; + } + + /** + * Populate the record list with the records needed to create the given consumer group. + * + * @param records The list to which the new records are added. + */ + public void createConsumerGroupRecords( + List<Record> records + ) { + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newMemberSubscriptionRecord(groupId(), consumerGroupMember)) + ); + + records.add(RecordHelpers.newGroupEpochRecord(groupId(), groupEpoch())); + + members().forEach((consumerGroupMemberId, consumerGroupMember) -> + records.add(RecordHelpers.newTargetAssignmentRecord( + groupId(), + consumerGroupMemberId, + targetAssignment(consumerGroupMemberId).partitions() + )) + ); + + records.add(RecordHelpers.newTargetAssignmentEpochRecord(groupId(), groupEpoch())); + + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newCurrentAssignmentRecord(groupId(), consumerGroupMember)) + ); + } + + /** + * @return The map of topic id and partition set converted from the list of TopicPartition. + */ + private static Map<Uuid, Set<Integer>> topicPartitionMapFromList( + List<TopicPartition> partitions, + TopicsImage topicsImage + ) { + Map<Uuid, Set<Integer>> topicPartitionMap = new HashMap<>(); + partitions.forEach(topicPartition -> { + TopicImage topicImage = topicsImage.getTopic(topicPartition.topic()); + if (topicImage != null) { + topicPartitionMap + .computeIfAbsent(topicImage.id(), __ -> new HashSet<>()) + .add(topicPartition.partition()); + } + }); + return topicPartitionMap; + } + + /** + * Create a corresponding ClassicGroup and append the record for the creation for group downgrade. + * The member with leavingMemberId will not be converted to the new ClassicGroup as it's the last + * member using new consumer protocol that left and triggered the downgrade. + * + * @param leavingMemberId The member that will not be converted in the ClassicGroup. + * @param logContext The logContext to create the ClassicGroup. + * @param time The time to create the ClassicGroup. + * @param consumerGroupSessionTimeoutMs The consumerGroupSessionTimeoutMs. + * @param metadataImage The metadataImage. + * @param records The record list. + * @return The created ClassicGroup. + */ + public ClassicGroup toClassicGroup( + String leavingMemberId, + LogContext logContext, + Time time, + int consumerGroupSessionTimeoutMs, + MetadataImage metadataImage, + List<Record> records + ) { + ClassicGroup classicGroup = new ClassicGroup( + logContext, + groupId(), + ClassicGroupState.STABLE, + time, + metrics, + groupEpoch(), + Optional.ofNullable(ConsumerProtocol.PROTOCOL_TYPE), + Optional.empty(), + members().keySet().stream().filter(member -> !member.equals(leavingMemberId)).findAny(), + Optional.of(time.milliseconds()) + ); + + members().forEach((memberId, member) -> { + if (!memberId.equals(leavingMemberId)) { + classicGroup.add( + new ClassicGroupMember( + memberId, + Optional.ofNullable(member.instanceId()), + member.clientId(), + member.clientHost(), + member.rebalanceTimeoutMs(), + consumerGroupSessionTimeoutMs, + ConsumerProtocol.PROTOCOL_TYPE, + member.supportedJoinGroupRequestProtocols(), Review Comment: This does not seem correct. The issue is that the stored protocols were stored when the group was converted so they are outdated here. I wonder whether we should generate them with the minimal informations (e.g. the subscribed topics). ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -998,4 +1094,232 @@ public ConsumerGroupDescribeResponseData.DescribedGroup asDescribedGroup( ); return describedGroup; } + + /** + * Create a new consumer group according to the given classic group. + * + * @param snapshotRegistry The SnapshotRegistry. + * @param metrics The GroupCoordinatorMetricsShard. + * @param classicGroup The converted classic group. + * @param topicsImage The TopicsImage for topic id and topic name conversion. + * @return The created ConsumerGruop. + */ + public static ConsumerGroup fromClassicGroup( + SnapshotRegistry snapshotRegistry, + GroupCoordinatorMetricsShard metrics, + ClassicGroup classicGroup, + TopicsImage topicsImage + ) { + String groupId = classicGroup.groupId(); + ConsumerGroup consumerGroup = new ConsumerGroup(snapshotRegistry, groupId, metrics); + consumerGroup.setGroupEpoch(classicGroup.generationId()); + consumerGroup.setTargetAssignmentEpoch(classicGroup.generationId()); + + classicGroup.allMembers().forEach(classicGroupMember -> { + ConsumerPartitionAssignor.Assignment assignment = ConsumerProtocol.deserializeAssignment( + ByteBuffer.wrap(classicGroupMember.assignment()) + ); + Map<Uuid, Set<Integer>> partitions = topicPartitionMapFromList(assignment.partitions(), topicsImage); + + ConsumerPartitionAssignor.Subscription subscription = ConsumerProtocol.deserializeSubscription( + ByteBuffer.wrap(classicGroupMember.metadata(classicGroup.protocolName().get())) + ); + + // The target assignment and the assigned partitions of each member are set based on the last + // assignment of the classic group. All the members are put in the Stable state. If the classic + // group was in Preparing Rebalance or Completing Rebalance states, the classic members are + // asked to rejoin the group to re-trigger a rebalance or collect their assignments. + ConsumerGroupMember newMember = new ConsumerGroupMember.Builder(classicGroupMember.memberId()) + .setMemberEpoch(classicGroup.generationId()) + .setState(MemberState.STABLE) + .setPreviousMemberEpoch(classicGroup.generationId()) + .setInstanceId(classicGroupMember.groupInstanceId().orElse(null)) + .setRackId(subscription.rackId().orElse(null)) + .setRebalanceTimeoutMs(classicGroupMember.rebalanceTimeoutMs()) + .setClientId(classicGroupMember.clientId()) + .setClientHost(classicGroupMember.clientHost()) + .setSubscribedTopicNames(subscription.topics()) + .setAssignedPartitions(partitions) + .setSupportedClassicProtocols(classicGroupMember.supportedProtocols()) + .build(); + consumerGroup.updateTargetAssignment(newMember.memberId(), new Assignment(partitions)); + consumerGroup.updateMember(newMember); + }); + + return consumerGroup; + } + + /** + * Populate the record list with the records needed to create the given consumer group. + * + * @param records The list to which the new records are added. + */ + public void createConsumerGroupRecords( + List<Record> records + ) { + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newMemberSubscriptionRecord(groupId(), consumerGroupMember)) + ); + + records.add(RecordHelpers.newGroupEpochRecord(groupId(), groupEpoch())); + + members().forEach((consumerGroupMemberId, consumerGroupMember) -> + records.add(RecordHelpers.newTargetAssignmentRecord( + groupId(), + consumerGroupMemberId, + targetAssignment(consumerGroupMemberId).partitions() + )) + ); + + records.add(RecordHelpers.newTargetAssignmentEpochRecord(groupId(), groupEpoch())); + + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newCurrentAssignmentRecord(groupId(), consumerGroupMember)) + ); + } + + /** + * @return The map of topic id and partition set converted from the list of TopicPartition. + */ + private static Map<Uuid, Set<Integer>> topicPartitionMapFromList( + List<TopicPartition> partitions, + TopicsImage topicsImage + ) { + Map<Uuid, Set<Integer>> topicPartitionMap = new HashMap<>(); + partitions.forEach(topicPartition -> { + TopicImage topicImage = topicsImage.getTopic(topicPartition.topic()); + if (topicImage != null) { + topicPartitionMap + .computeIfAbsent(topicImage.id(), __ -> new HashSet<>()) + .add(topicPartition.partition()); + } + }); + return topicPartitionMap; + } + + /** + * Create a corresponding ClassicGroup and append the record for the creation for group downgrade. + * The member with leavingMemberId will not be converted to the new ClassicGroup as it's the last + * member using new consumer protocol that left and triggered the downgrade. + * + * @param leavingMemberId The member that will not be converted in the ClassicGroup. + * @param logContext The logContext to create the ClassicGroup. + * @param time The time to create the ClassicGroup. + * @param consumerGroupSessionTimeoutMs The consumerGroupSessionTimeoutMs. + * @param metadataImage The metadataImage. + * @param records The record list. + * @return The created ClassicGroup. + */ + public ClassicGroup toClassicGroup( + String leavingMemberId, + LogContext logContext, + Time time, + int consumerGroupSessionTimeoutMs, + MetadataImage metadataImage, + List<Record> records + ) { + ClassicGroup classicGroup = new ClassicGroup( + logContext, + groupId(), + ClassicGroupState.STABLE, + time, + metrics, + groupEpoch(), + Optional.ofNullable(ConsumerProtocol.PROTOCOL_TYPE), + Optional.empty(), + members().keySet().stream().filter(member -> !member.equals(leavingMemberId)).findAny(), + Optional.of(time.milliseconds()) + ); + + members().forEach((memberId, member) -> { + if (!memberId.equals(leavingMemberId)) { + classicGroup.add( + new ClassicGroupMember( + memberId, + Optional.ofNullable(member.instanceId()), + member.clientId(), + member.clientHost(), + member.rebalanceTimeoutMs(), + consumerGroupSessionTimeoutMs, + ConsumerProtocol.PROTOCOL_TYPE, + member.supportedJoinGroupRequestProtocols(), + null + ) + ); + } + }); + + classicGroup.setProtocolName(Optional.of(classicGroup.selectProtocol())); + classicGroup.setSubscribedTopics(classicGroup.computeSubscribedTopics()); + + Map<String, byte[]> assignments = new HashMap<>(); + + classicGroup.allMembers().forEach(classicGroupMember -> { + byte[] assignment = Utils.toArray(ConsumerProtocol.serializeAssignment( + new ConsumerPartitionAssignor.Assignment(ConsumerGroup.topicPartitionListFromMap( + targetAssignment().get(classicGroupMember.memberId()).partitions(), + metadataImage.topics() + )), + ConsumerProtocol.deserializeVersion( + ByteBuffer.wrap(classicGroupMember.metadata(classicGroup.protocolName().orElse(""))) + ) Review Comment: This one maybe worth a comment explaining why we need to use this version. ########## group-coordinator/src/test/java/org/apache/kafka/coordinator/group/GroupMetadataManagerTest.java: ########## @@ -9623,6 +10332,186 @@ public void testClassicGroupOnUnloadedCompletingRebalance() throws Exception { .setErrorCode(NOT_COORDINATOR.code()), pendingMemberSyncResult.syncFuture.get()); } + @ParameterizedTest + @ValueSource(booleans = {true, false}) + public void testLastClassicProtocolMemberLeavingConsumerGroup(boolean appendLogSuccessfully) { + String groupId = "group-id"; + String memberId1 = Uuid.randomUuid().toString(); + String memberId2 = Uuid.randomUuid().toString(); + + Uuid fooTopicId = Uuid.randomUuid(); + String fooTopicName = "foo"; + Uuid barTopicId = Uuid.randomUuid(); + String barTopicName = "bar"; + Uuid zarTopicId = Uuid.randomUuid(); + String zarTopicName = "zar"; + + MockPartitionAssignor assignor = new MockPartitionAssignor("range"); + + List<ConsumerGroupMemberMetadataValue.ClassicProtocol> protocols = Collections.singletonList( + new ConsumerGroupMemberMetadataValue.ClassicProtocol() + .setName("range") + .setMetadata(Utils.toArray(ConsumerProtocol.serializeSubscription(new ConsumerPartitionAssignor.Subscription( + Arrays.asList(fooTopicName, barTopicName), + null, + Arrays.asList( + new TopicPartition(fooTopicName, 0), + new TopicPartition(fooTopicName, 1), + new TopicPartition(fooTopicName, 2), + new TopicPartition(barTopicName, 0), + new TopicPartition(barTopicName, 1) + ) + )))) + ); + + ConsumerGroupMember member1 = new ConsumerGroupMember.Builder(memberId1) + .setState(MemberState.STABLE) + .setMemberEpoch(10) + .setPreviousMemberEpoch(9) + .setClientId("client") + .setClientHost("localhost/127.0.0.1") + .setSubscribedTopicNames(Arrays.asList("foo", "bar")) + .setServerAssignorName("range") + .setClassicMemberMetadata(new ConsumerGroupMemberMetadataValue.ClassicMemberMetadata() + .setSupportedProtocols(protocols)) + .setAssignedPartitions(mkAssignment( + mkTopicAssignment(fooTopicId, 0, 1, 2), + mkTopicAssignment(barTopicId, 0, 1))) + .build(); + ConsumerGroupMember member2 = new ConsumerGroupMember.Builder(memberId2) + .setState(MemberState.STABLE) + .setMemberEpoch(10) + .setPreviousMemberEpoch(9) + .setClientId("client") + .setClientHost("localhost/127.0.0.1") + // Use zar only here to ensure that metadata needs to be recomputed. + .setSubscribedTopicNames(Arrays.asList("foo", "bar", "zar")) + .setServerAssignorName("range") + .setAssignedPartitions(mkAssignment( + mkTopicAssignment(fooTopicId, 3, 4, 5), + mkTopicAssignment(barTopicId, 2))) + .build(); + + // Consumer group with two members. + // Member 1 uses the classic protocol and member 2 uses the consumer protocol. + GroupMetadataManagerTestContext context = new GroupMetadataManagerTestContext.Builder() + .withConsumerGroupMigrationPolicy(ConsumerGroupMigrationPolicy.DOWNGRADE) + .withAssignors(Collections.singletonList(assignor)) + .withMetadataImage(new MetadataImageBuilder() + .addTopic(fooTopicId, fooTopicName, 6) + .addTopic(barTopicId, barTopicName, 3) + .addTopic(zarTopicId, zarTopicName, 1) + .addRacks() + .build()) + .withConsumerGroup(new ConsumerGroupBuilder(groupId, 10) + .withMember(member1) + .withMember(member2) + .withAssignment(memberId1, mkAssignment( + mkTopicAssignment(fooTopicId, 0, 1, 2), + mkTopicAssignment(barTopicId, 0, 1))) + .withAssignment(memberId2, mkAssignment( + mkTopicAssignment(fooTopicId, 3, 4, 5), + mkTopicAssignment(barTopicId, 2))) + .withAssignmentEpoch(10)) + .build(); + + context.commit(); + ConsumerGroup consumerGroup = context.groupMetadataManager.consumerGroup(groupId); + + // Member 2 leaves the consumer group, triggering the downgrade. + CoordinatorResult<ConsumerGroupHeartbeatResponseData, Record> result = context.consumerGroupHeartbeat( + new ConsumerGroupHeartbeatRequestData() + .setGroupId(groupId) + .setMemberId(memberId2) + .setMemberEpoch(LEAVE_GROUP_MEMBER_EPOCH) + .setRebalanceTimeoutMs(5000) + .setSubscribedTopicNames(Arrays.asList("foo", "bar")) + .setTopicPartitions(Collections.emptyList())); + + + byte[] assignment = Utils.toArray(ConsumerProtocol.serializeAssignment(new ConsumerPartitionAssignor.Assignment(Arrays.asList( + new TopicPartition(fooTopicName, 0), new TopicPartition(fooTopicName, 1), new TopicPartition(fooTopicName, 2), + new TopicPartition(barTopicName, 0), new TopicPartition(barTopicName, 1) + )))); + Map<String, byte[]> assignments = new HashMap<String, byte[]>() { + { + put(memberId1, assignment); + } + }; + + ClassicGroup expectedClassicGroup = new ClassicGroup( + new LogContext(), + groupId, + STABLE, + context.time, + context.metrics, + 10, + Optional.ofNullable(ConsumerProtocol.PROTOCOL_TYPE), + Optional.ofNullable("range"), + Optional.ofNullable(memberId1), + Optional.of(context.time.milliseconds()) + ); + expectedClassicGroup.add( + new ClassicGroupMember( + memberId1, + Optional.ofNullable(member1.instanceId()), + member1.clientId(), + member1.clientHost(), + member1.rebalanceTimeoutMs(), + 45000, + ConsumerProtocol.PROTOCOL_TYPE, + member1.supportedJoinGroupRequestProtocols(), + assignment + ) + ); + + List<Record> expectedRecords = Arrays.asList( + RecordHelpers.newCurrentAssignmentTombstoneRecord(groupId, memberId2), + RecordHelpers.newTargetAssignmentTombstoneRecord(groupId, memberId2), + RecordHelpers.newMemberSubscriptionTombstoneRecord(groupId, memberId2), + // Subscription metadata is recomputed because zar is no longer there. + RecordHelpers.newGroupSubscriptionMetadataRecord(groupId, new HashMap<String, TopicMetadata>() { + { + put(fooTopicName, new TopicMetadata(fooTopicId, fooTopicName, 6, mkMapOfPartitionRacks(6))); + put(barTopicName, new TopicMetadata(barTopicId, barTopicName, 3, mkMapOfPartitionRacks(3))); + } + }), + RecordHelpers.newGroupEpochRecord(groupId, 11), + + RecordHelpers.newTargetAssignmentEpochTombstoneRecord(groupId), + RecordHelpers.newGroupSubscriptionMetadataTombstoneRecord(groupId), + RecordHelpers.newGroupEpochTombstoneRecord(groupId), + RecordHelpers.newGroupMetadataRecord(expectedClassicGroup, assignments, MetadataVersion.latestTesting()) + ); + + assertRecordsEquals(expectedRecords, result.records()); + + if (appendLogSuccessfully) { + ClassicGroup classicGroup = context.groupMetadataManager.getOrMaybeCreateClassicGroup(groupId, false); + + // Simulate a successful write to the log. + result.appendFuture().complete(null); + + ScheduledTimeout<Void, Record> timeout = context.timer.timeout( + classicGroupHeartbeatKey(groupId, memberId1)); + assertNotNull(timeout); + + // A new rebalance is triggered. + assertTrue(classicGroup.isInState(PREPARING_REBALANCE)); + } else { + // Simulate a failed write to the log. + result.appendFuture().completeExceptionally(new NotLeaderOrFollowerException()); + context.rollback(); + + ScheduledTimeout<Void, Record> timeout = context.timer.timeout( + classicGroupHeartbeatKey(groupId, memberId1)); + assertNull(timeout); + + // The group is reverted back to the consumer group. + assertEquals(consumerGroup, context.groupMetadataManager.consumerGroup(groupId)); + } Review Comment: We should also verify the metrics as we had code related the group conversion. ########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/consumer/ConsumerGroup.java: ########## @@ -998,4 +1094,232 @@ public ConsumerGroupDescribeResponseData.DescribedGroup asDescribedGroup( ); return describedGroup; } + + /** + * Create a new consumer group according to the given classic group. + * + * @param snapshotRegistry The SnapshotRegistry. + * @param metrics The GroupCoordinatorMetricsShard. + * @param classicGroup The converted classic group. + * @param topicsImage The TopicsImage for topic id and topic name conversion. + * @return The created ConsumerGruop. + */ + public static ConsumerGroup fromClassicGroup( + SnapshotRegistry snapshotRegistry, + GroupCoordinatorMetricsShard metrics, + ClassicGroup classicGroup, + TopicsImage topicsImage + ) { + String groupId = classicGroup.groupId(); + ConsumerGroup consumerGroup = new ConsumerGroup(snapshotRegistry, groupId, metrics); + consumerGroup.setGroupEpoch(classicGroup.generationId()); + consumerGroup.setTargetAssignmentEpoch(classicGroup.generationId()); + + classicGroup.allMembers().forEach(classicGroupMember -> { + ConsumerPartitionAssignor.Assignment assignment = ConsumerProtocol.deserializeAssignment( + ByteBuffer.wrap(classicGroupMember.assignment()) + ); + Map<Uuid, Set<Integer>> partitions = topicPartitionMapFromList(assignment.partitions(), topicsImage); + + ConsumerPartitionAssignor.Subscription subscription = ConsumerProtocol.deserializeSubscription( + ByteBuffer.wrap(classicGroupMember.metadata(classicGroup.protocolName().get())) + ); + + // The target assignment and the assigned partitions of each member are set based on the last + // assignment of the classic group. All the members are put in the Stable state. If the classic + // group was in Preparing Rebalance or Completing Rebalance states, the classic members are + // asked to rejoin the group to re-trigger a rebalance or collect their assignments. + ConsumerGroupMember newMember = new ConsumerGroupMember.Builder(classicGroupMember.memberId()) + .setMemberEpoch(classicGroup.generationId()) + .setState(MemberState.STABLE) + .setPreviousMemberEpoch(classicGroup.generationId()) + .setInstanceId(classicGroupMember.groupInstanceId().orElse(null)) + .setRackId(subscription.rackId().orElse(null)) + .setRebalanceTimeoutMs(classicGroupMember.rebalanceTimeoutMs()) + .setClientId(classicGroupMember.clientId()) + .setClientHost(classicGroupMember.clientHost()) + .setSubscribedTopicNames(subscription.topics()) + .setAssignedPartitions(partitions) + .setSupportedClassicProtocols(classicGroupMember.supportedProtocols()) + .build(); + consumerGroup.updateTargetAssignment(newMember.memberId(), new Assignment(partitions)); + consumerGroup.updateMember(newMember); + }); + + return consumerGroup; + } + + /** + * Populate the record list with the records needed to create the given consumer group. + * + * @param records The list to which the new records are added. + */ + public void createConsumerGroupRecords( + List<Record> records + ) { + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newMemberSubscriptionRecord(groupId(), consumerGroupMember)) + ); + + records.add(RecordHelpers.newGroupEpochRecord(groupId(), groupEpoch())); + + members().forEach((consumerGroupMemberId, consumerGroupMember) -> + records.add(RecordHelpers.newTargetAssignmentRecord( + groupId(), + consumerGroupMemberId, + targetAssignment(consumerGroupMemberId).partitions() + )) + ); + + records.add(RecordHelpers.newTargetAssignmentEpochRecord(groupId(), groupEpoch())); + + members().forEach((__, consumerGroupMember) -> + records.add(RecordHelpers.newCurrentAssignmentRecord(groupId(), consumerGroupMember)) + ); + } + + /** + * @return The map of topic id and partition set converted from the list of TopicPartition. + */ + private static Map<Uuid, Set<Integer>> topicPartitionMapFromList( + List<TopicPartition> partitions, + TopicsImage topicsImage + ) { + Map<Uuid, Set<Integer>> topicPartitionMap = new HashMap<>(); + partitions.forEach(topicPartition -> { + TopicImage topicImage = topicsImage.getTopic(topicPartition.topic()); + if (topicImage != null) { + topicPartitionMap + .computeIfAbsent(topicImage.id(), __ -> new HashSet<>()) + .add(topicPartition.partition()); + } + }); + return topicPartitionMap; + } + + /** + * Create a corresponding ClassicGroup and append the record for the creation for group downgrade. + * The member with leavingMemberId will not be converted to the new ClassicGroup as it's the last + * member using new consumer protocol that left and triggered the downgrade. + * + * @param leavingMemberId The member that will not be converted in the ClassicGroup. + * @param logContext The logContext to create the ClassicGroup. + * @param time The time to create the ClassicGroup. + * @param consumerGroupSessionTimeoutMs The consumerGroupSessionTimeoutMs. + * @param metadataImage The metadataImage. + * @param records The record list. + * @return The created ClassicGroup. + */ + public ClassicGroup toClassicGroup( + String leavingMemberId, + LogContext logContext, + Time time, + int consumerGroupSessionTimeoutMs, + MetadataImage metadataImage, + List<Record> records + ) { + ClassicGroup classicGroup = new ClassicGroup( + logContext, + groupId(), + ClassicGroupState.STABLE, + time, + metrics, + groupEpoch(), + Optional.ofNullable(ConsumerProtocol.PROTOCOL_TYPE), + Optional.empty(), + members().keySet().stream().filter(member -> !member.equals(leavingMemberId)).findAny(), + Optional.of(time.milliseconds()) + ); + + members().forEach((memberId, member) -> { + if (!memberId.equals(leavingMemberId)) { + classicGroup.add( + new ClassicGroupMember( + memberId, + Optional.ofNullable(member.instanceId()), + member.clientId(), + member.clientHost(), + member.rebalanceTimeoutMs(), + consumerGroupSessionTimeoutMs, + ConsumerProtocol.PROTOCOL_TYPE, + member.supportedJoinGroupRequestProtocols(), + null + ) + ); + } + }); + + classicGroup.setProtocolName(Optional.of(classicGroup.selectProtocol())); + classicGroup.setSubscribedTopics(classicGroup.computeSubscribedTopics()); + + Map<String, byte[]> assignments = new HashMap<>(); + + classicGroup.allMembers().forEach(classicGroupMember -> { + byte[] assignment = Utils.toArray(ConsumerProtocol.serializeAssignment( + new ConsumerPartitionAssignor.Assignment(ConsumerGroup.topicPartitionListFromMap( + targetAssignment().get(classicGroupMember.memberId()).partitions(), + metadataImage.topics() + )), + ConsumerProtocol.deserializeVersion( + ByteBuffer.wrap(classicGroupMember.metadata(classicGroup.protocolName().orElse(""))) + ) + )); + + classicGroupMember.setAssignment(assignment); + assignments.put(classicGroupMember.memberId(), assignment); + }); + + records.add(RecordHelpers.newGroupMetadataRecord( + classicGroup, assignments, metadataImage.features().metadataVersion())); Review Comment: nit: Style. ``` records.add(RecordHelpers.newGroupMetadataRecord( classicGroup, assignments, metadataImage.features().metadataVersion() )); ``` -- This is an automated message from the Apache Git Service. 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