dongnuo123 commented on code in PR #15798:
URL: https://github.com/apache/kafka/pull/15798#discussion_r1580240281
##########
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java:
##########
@@ -1092,6 +1097,86 @@ private void
throwIfStaticMemberIsUnknown(ConsumerGroupMember staticMember, Stri
}
}
+ /**
+ * Validates if the received classic member protocols are supported by the
group.
+ *
+ * @param group The ConsumerGroup.
+ * @param memberId The joining member id.
+ * @param protocolType The joining member protocol type.
+ * @param protocols The joining member protocol collection.
+ */
+ private void throwIfClassicProtocolIsNotSupported(
+ ConsumerGroup group,
+ String memberId,
+ String protocolType,
+ JoinGroupRequestProtocolCollection protocols
+ ) {
+ if (!group.supportsClassicProtocols(protocolType,
ClassicGroupMember.plainProtocolSet(protocols))) {
+ throw Errors.INCONSISTENT_GROUP_PROTOCOL.exception("Member " +
memberId + "'s protocols are not supported.");
+ }
+ }
+
+ /**
+ * Deserialize the subscription in JoinGroupRequestProtocolCollection.
+ * All the protocols have the same subscription, so the method picks a
random one.
+ *
+ * @param protocols The JoinGroupRequestProtocolCollection.
+ * @return The Subscription.
+ */
+ private static ConsumerPartitionAssignor.Subscription
deserializeSubscription(
+ JoinGroupRequestProtocolCollection protocols
+ ) {
+ try {
+ return ConsumerProtocol.deserializeSubscription(
+ ByteBuffer.wrap(protocols.stream().findAny().get().metadata())
+ );
+ } catch (SchemaException e) {
+ throw new IllegalStateException("Malformed embedded consumer
protocol.");
+ }
+ }
+
+ /**
+ * Validates the generation id and returns the owned partitions in the
JoinGroupRequest to a consumer group.
+ *
+ * @param member The joining member.
+ * @param subscription The Subscription.
+ * @return The owned partitions if valid, otherwise return null.
+ */
+ private List<ConsumerGroupHeartbeatRequestData.TopicPartitions>
validateGenerationIdAndGetOwnedPartition(
Review Comment:
I was wondering if we can put off checking generation id to sync group and
throw ILLEGAL_GENERATION there. The client will rejoin in such situation.
That's what we did in the classic protocol.
##########
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java:
##########
@@ -1336,6 +1422,233 @@ private
CoordinatorResult<ConsumerGroupHeartbeatResponseData, Record> consumerGr
return new CoordinatorResult<>(records, response);
}
+ /**
+ * Handle a JoinGroupRequest to a ConsumerGroup.
+ *
+ * @param group The group to join.
+ * @param context The request context.
+ * @param request The actual JoinGroup request.
+ * @param responseFuture The join group response future.
+ *
+ * @return The result that contains records to append if the join group
phase completes.
+ */
+ private CoordinatorResult<Void, Record> consumerGroupJoin(
+ ConsumerGroup group,
+ RequestContext context,
+ JoinGroupRequestData request,
+ CompletableFuture<JoinGroupResponseData> responseFuture
+ ) throws ApiException {
+ final long currentTimeMs = time.milliseconds();
+ final List<Record> records = new ArrayList<>();
+ final String groupId = request.groupId();
+ String memberId = request.memberId();
+ final String instanceId = request.groupInstanceId();
+ final JoinGroupRequestProtocolCollection protocols =
request.protocols();
+
+ final boolean isUnknownMember = memberId.equals(UNKNOWN_MEMBER_ID);
+ final ConsumerPartitionAssignor.Subscription subscription =
deserializeSubscription(protocols);
+ List<ConsumerGroupHeartbeatRequestData.TopicPartitions>
ownedTopicPartitions = null;
+
+ if (!validateClassicGroupSessionTimeout(memberId,
request.sessionTimeoutMs(), responseFuture)) {
+ return EMPTY_RESULT;
+ }
+ throwIfConsumerGroupIsFull(group, memberId);
+ // TODO: need to throw an exception if group is dead?
+
+ // Get or create the member.
+ if (isUnknownMember) memberId = Uuid.randomUuid().toString();
+ ConsumerGroupMember member;
+ ConsumerGroupMember.Builder updatedMemberBuilder;
+ boolean staticMemberReplaced = false;
+ boolean newMemberCreated = false;
+ if (instanceId == null) {
+ if (isUnknownMember &&
JoinGroupRequest.requiresKnownMemberId(context.apiVersion())) {
+ // If member id required, send back a response to call for
another join group request with allocated member id.
+ log.info("Dynamic member with unknown member id joins group
{}. " +
+ "Created a new member id {} and requesting the member
to rejoin with this id.",
+ group.groupId(), memberId);
+
+ responseFuture.complete(new JoinGroupResponseData()
+ .setMemberId(memberId)
+ .setErrorCode(Errors.MEMBER_ID_REQUIRED.code())
+ );
+ return EMPTY_RESULT;
+ } else {
+ // A dynamic member (re-)joins.
+ throwIfClassicProtocolIsNotSupported(group, memberId,
request.protocolType(), protocols);
+ newMemberCreated = !group.hasMember(memberId);
+
+ member = group.getOrMaybeCreateMember(memberId, true);
+ if (!newMemberCreated) ownedTopicPartitions =
validateGenerationIdAndGetOwnedPartition(member, subscription);
+ log.info("[GroupId {}] Member {} joins the consumer group.",
groupId, memberId);
+ updatedMemberBuilder = new ConsumerGroupMember.Builder(member);
+ }
+ } else {
+ throwIfClassicProtocolIsNotSupported(group, memberId,
request.protocolType(), protocols);
+ member = group.staticMember(instanceId);
+ // A new static member joins or the existing static member rejoins.
+ if (isUnknownMember) {
+ newMemberCreated = true;
+ if (member == null) {
+ // New static member.
+ member = group.getOrMaybeCreateMember(memberId, true);
+ updatedMemberBuilder = new
ConsumerGroupMember.Builder(member);
+ log.info("[GroupId {}] Static member {} with instance id
{} joins the consumer group.", groupId, memberId, instanceId);
+ } else {
+ // Replace the current static member.
+ staticMemberReplaced = true;
+ updatedMemberBuilder = new
ConsumerGroupMember.Builder(memberId)
+ .setAssignedPartitions(member.assignedPartitions());
+ ownedTopicPartitions =
validateGenerationIdAndGetOwnedPartition(member, subscription);
+ removeMemberAndCancelTimers(records, group.groupId(),
member.memberId());
+ log.info("[GroupId {}] Static member {} with instance id
{} re-joins the consumer group.", groupId, memberId, instanceId);
+ }
+ } else {
+ // Rejoining static member. Fence the static group with
unmatched member id.
+ throwIfStaticMemberIsUnknown(member, instanceId);
+ throwIfInstanceIdIsFenced(member, groupId, memberId,
instanceId);
+
+ ownedTopicPartitions =
validateGenerationIdAndGetOwnedPartition(member, subscription);
+ updatedMemberBuilder = new ConsumerGroupMember.Builder(member);
+ log.info("[GroupId {}] Static member {} with instance id {}
re-joins the consumer group.", groupId, memberId, instanceId);
+ }
+ }
+
+ int groupEpoch = group.groupEpoch();
+ Map<String, TopicMetadata> subscriptionMetadata =
group.subscriptionMetadata();
+
+ // 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.
+ ConsumerGroupMember updatedMember = updatedMemberBuilder
+ .maybeUpdateInstanceId(Optional.ofNullable(instanceId))
+ .maybeUpdateRackId(subscription.rackId())
+
.maybeUpdateRebalanceTimeoutMs(ofSentinel(request.rebalanceTimeoutMs()))
+ .maybeUpdateServerAssignorName(Optional.empty())
+
.maybeUpdateSubscribedTopicNames(Optional.ofNullable(subscription.topics()))
+ .setClientId(context.clientId())
+ .setClientHost(context.clientAddress.toString())
+ .setSupportedClassicProtocols(protocols)
+ .build();
+
+ boolean bumpGroupEpoch = false;
+ if (!updatedMember.equals(member)) {
+ records.add(newMemberSubscriptionRecord(groupId, updatedMember));
+
+ if
(!updatedMember.subscribedTopicNames().equals(member.subscribedTopicNames())) {
+ log.info("[GroupId {}] Member {} updated its subscribed topics
to: {}.",
+ groupId, memberId, updatedMember.subscribedTopicNames());
+ bumpGroupEpoch = true;
+ }
+
+ if
(!updatedMember.subscribedTopicRegex().equals(member.subscribedTopicRegex())) {
+ log.info("[GroupId {}] Member {} updated its subscribed regex
to: {}.",
+ groupId, memberId, updatedMember.subscribedTopicRegex());
+ bumpGroupEpoch = true;
+ }
+ }
+
+ if (bumpGroupEpoch || group.hasMetadataExpired(currentTimeMs)) {
+ // The subscription metadata is updated in two cases:
+ // 1) The member has updated its subscriptions;
+ // 2) The refresh deadline has been reached.
+ subscriptionMetadata = group.computeSubscriptionMetadata(
+ member,
+ updatedMember,
+ metadataImage.topics(),
+ metadataImage.cluster()
+ );
+
+ if (!subscriptionMetadata.equals(group.subscriptionMetadata())) {
+ log.info("[GroupId {}] Computed new subscription metadata:
{}.",
+ groupId, subscriptionMetadata);
+ bumpGroupEpoch = true;
+ records.add(newGroupSubscriptionMetadataRecord(groupId,
subscriptionMetadata));
+ }
+
+ if (bumpGroupEpoch) {
+ groupEpoch += 1;
+ records.add(newGroupEpochRecord(groupId, groupEpoch));
+ log.info("[GroupId {}] Bumped group epoch to {}.", groupId,
groupEpoch);
+ metrics.record(CONSUMER_GROUP_REBALANCES_SENSOR_NAME);
+ }
+
+ group.setMetadataRefreshDeadline(currentTimeMs +
consumerGroupMetadataRefreshIntervalMs, groupEpoch);
+ }
+
+ // 2. Update the target assignment if the group epoch is larger than
the target assignment epoch or a static member
+ // replaces an existing static member. The delta between the existing
and the new target assignment is persisted to the partition.
+ int targetAssignmentEpoch = group.assignmentEpoch();
+ Assignment targetAssignment = group.targetAssignment(memberId);
+ if (groupEpoch > targetAssignmentEpoch || staticMemberReplaced) {
+ String preferredServerAssignor =
group.computePreferredServerAssignor(
+ member,
+ updatedMember
+ ).orElse(defaultAssignor.name());
+ try {
+ TargetAssignmentBuilder assignmentResultBuilder =
+ new TargetAssignmentBuilder(groupId, groupEpoch,
assignors.get(preferredServerAssignor))
+ .withMembers(group.members())
+ .withStaticMembers(group.staticMembers())
+ .withSubscriptionMetadata(subscriptionMetadata)
+ .withTargetAssignment(group.targetAssignment())
+ .addOrUpdateMember(memberId, updatedMember);
+ TargetAssignmentBuilder.TargetAssignmentResult
assignmentResult;
+ // A new static member is replacing an older one with the same
subscriptions.
+ // We just need to remove the older member and add the newer
one. The new member should
+ // reuse the target assignment of the older member.
+ if (staticMemberReplaced) {
+ assignmentResult = assignmentResultBuilder
+ .removeMember(member.memberId())
+ .build();
+ } else {
+ assignmentResult = assignmentResultBuilder
+ .build();
+ }
+
+ log.info("[GroupId {}] Computed a new target assignment for
epoch {} with '{}' assignor: {}.",
+ groupId, groupEpoch, preferredServerAssignor,
assignmentResult.targetAssignment());
+
+ records.addAll(assignmentResult.records());
+ targetAssignment =
assignmentResult.targetAssignment().get(memberId);
+ targetAssignmentEpoch = groupEpoch;
+ } catch (PartitionAssignorException ex) {
+ String msg = String.format("Failed to compute a new target
assignment for epoch %d: %s",
+ groupEpoch, ex.getMessage());
+ log.error("[GroupId {}] {}.", groupId, msg);
+ throw new UnknownServerException(msg, ex);
+ }
+ }
+
+ // 3. Reconcile the member's assignment with the target assignment if
the member is not
+ // fully reconciled yet.
+ updatedMember = maybeReconcile(
+ groupId,
+ updatedMember,
+ group::currentPartitionEpoch,
+ targetAssignmentEpoch,
+ targetAssignment,
+ ownedTopicPartitions,
+ records
+ );
+
+ if (newMemberCreated) {
+ scheduleConsumerGroupSessionTimeout(groupId, memberId);
+ }
+
+ // TODO: what will happen to the client if the generation id in
response is 0?
+ responseFuture.complete(new JoinGroupResponseData()
+ .setMemberId(updatedMember.memberId())
+ .setGenerationId(updatedMember.memberEpoch())
+ .setProtocolType(ConsumerProtocol.PROTOCOL_TYPE)
+ .setProtocolName(protocols.stream().findAny().get().name())
Review Comment:
We have the validation in `throwIfClassicProtocolIsNotSupported`.
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