dongnuo123 commented on code in PR #15798:
URL: https://github.com/apache/kafka/pull/15798#discussion_r1582397540
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group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupMetadataManager.java:
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@@ -1413,6 +1506,243 @@ 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> classicGroupJoinToConsumerGroup(
+ 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);
+
+ throwIfConsumerGroupIsFull(group, memberId);
+ throwIfClassicProtocolIsNotSupported(group, memberId,
request.protocolType(), protocols);
+ // 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) {
+ // A dynamic member (re-)joins.
+ throwIfRequiresKnownMemberId(groupId, memberId, isUnknownMember,
context);
+ newMemberCreated = !group.hasMember(memberId);
+ member = group.getOrMaybeCreateMember(memberId, true);
+ log.info("[GroupId {}] Member {} joins the consumer group.",
groupId, memberId);
+ updatedMemberBuilder = new ConsumerGroupMember.Builder(member);
+ } else {
+ 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());
+ removeMember(records, groupId, member.memberId());
+ log.info("[GroupId {}] Static member with unknown member
id and instance id {} re-joins the consumer group. " +
+ "Created a new member {} to replace the existing
member {}.", groupId, instanceId, memberId, member.memberId());
+ }
+ } else {
+ // Rejoining static member. Fence the static group with
unmatched member id.
+ throwIfStaticMemberIsUnknown(member, instanceId);
+ throwIfInstanceIdIsFenced(member, groupId, memberId,
instanceId);
+ 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();
+ final ConsumerPartitionAssignor.Subscription subscription =
deserializeSubscription(protocols);
+ final List<ConsumerGroupHeartbeatRequestData.TopicPartitions>
ownedTopicPartitions =
+ validateGenerationIdAndGetOwnedPartition(member, subscription);
+
+ // 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 = updateMemberSubscription(groupId, memberId,
member, updatedMember, records);
+ 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.
+
+ /**
+ * TODO:
+ * joinGroup - sync timeout
+ * syncGroup - (join timeout)
+ * heartbeat - (join timeout)
+ * => scheduleConsumerGroupRebalanceTimeout is not necessary
+ */
Review Comment:
Yes correct.
I'll make sure we remove all the the TODOs
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