jeffkbkim commented on code in PR #13663: URL: https://github.com/apache/kafka/pull/13663#discussion_r1191303709
########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/generic/GenericGroup.java: ########## @@ -0,0 +1,998 @@ +/* + * 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.generic; + +import org.apache.kafka.clients.consumer.internals.ConsumerProtocol; +import org.apache.kafka.common.message.JoinGroupResponseData; +import org.apache.kafka.common.message.ListGroupsResponseData; +import org.apache.kafka.common.message.SyncGroupResponseData; +import org.apache.kafka.common.message.JoinGroupResponseData.JoinGroupResponseMember; +import org.apache.kafka.common.protocol.Errors; +import org.apache.kafka.common.protocol.types.SchemaException; +import org.apache.kafka.common.utils.LogContext; +import org.apache.kafka.common.utils.Time; +import org.apache.kafka.coordinator.group.Group; +import org.slf4j.Logger; + +import java.nio.ByteBuffer; +import java.util.Collection; +import java.util.Collections; +import java.util.Comparator; +import java.util.HashMap; +import java.util.HashSet; +import java.util.Iterator; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; +import java.util.UUID; +import java.util.concurrent.CompletableFuture; +import java.util.stream.Collectors; + +import static org.apache.kafka.coordinator.group.generic.GenericGroupState.COMPLETING_REBALANCE; +import static org.apache.kafka.coordinator.group.generic.GenericGroupState.DEAD; +import static org.apache.kafka.coordinator.group.generic.GenericGroupState.EMPTY; +import static org.apache.kafka.coordinator.group.generic.GenericGroupState.PREPARING_REBALANCE; + +/** + * + * This class holds metadata for a generic group where the + * member assignment is driven solely from the client side. + * + * The APIs members use to make changes to the group membership + * consist of JoinGroup, SyncGroup, and LeaveGroup. + */ +public class GenericGroup implements Group { + + /** + * Empty generation. + */ + public static final int NO_GENERATION = -1; + + /** + * Protocol with empty name. + */ + public static final String NO_PROTOCOL_NAME = ""; + + /** + * No leader. + */ + public static final String NO_LEADER = ""; + + /** + * Delimiter used to join a randomly generated UUID + * with a client id or a group instance id. + */ + private static final String MEMBER_ID_DELIMITER = "-"; + + /** + * The slf4j log context, used to create new loggers. + */ + private final LogContext logContext; + + /** + * The slf4j logger. + */ + private final Logger log; + + /** + * The group id. + */ + private final String groupId; + + /** + * The time. + */ + private final Time time; + + /** + * The current group state. + */ + private GenericGroupState state; + + /** + * The timestamp of when the group transitioned + * to its current state. + */ + private Optional<Long> currentStateTimestamp; + + /** + * The protocol type used for rebalance. + */ + private Optional<String> protocolType = Optional.empty(); + + /** + * The protocol name used for rebalance. + */ + private Optional<String> protocolName = Optional.empty(); + + /** + * The generation id. + */ + private int generationId = 0; + + /** + * The id of the group's leader. + */ + private Optional<String> leaderId = Optional.empty(); + + /** + * The members of the group. + */ + private final Map<String, GenericGroupMember> members = new HashMap<>(); + + /** + * The static members of the group. + */ + private final Map<String, String> staticMembers = new HashMap<>(); + + /** + * Members who have yet to (re)join the group + * during the join group phase. + */ + private final Set<String> pendingJoinMembers = new HashSet<>(); + + /** + * The number of members awaiting a join response. + */ + private int numMembersAwaitingJoinResponse = 0; + + /** + * Map of protocol names to the number of members that support them. + */ + private final Map<String, Integer> supportedProtocols = new HashMap<>(); + + /** + * Members who have yet to sync with the group + * during the sync group phase. + */ + private final Set<String> pendingSyncMembers = new HashSet<>(); + + /** + * The list of topics to which the group members are subscribed. + */ + private Optional<Set<String>> subscribedTopics = Optional.empty(); + + /** + * A flag to indiciate whether a new member was added. Used + * to further delay initial joins (new group). + */ + private boolean newMemberAdded = false; + + public GenericGroup( + LogContext logContext, + String groupId, + GenericGroupState initialState, + Time time + ) { + this.logContext = Objects.requireNonNull(logContext); + this.log = logContext.logger(GenericGroup.class); + this.groupId = Objects.requireNonNull(groupId); + this.state = Objects.requireNonNull(initialState); + this.time = Objects.requireNonNull(time); + this.currentStateTimestamp = Optional.of(time.milliseconds()); + } + + /** + * The type of this group. + * + * @return The group type (Generic). + */ + @Override + public GroupType type() { + return GroupType.GENERIC; + } + + /** + * The state of this group. + * + * @return The current state as a String. + */ + @Override + public String stateAsString() { + return this.state.toString(); + } + + /** + * @return the group id. + */ + public String groupId() { + return this.groupId; + } + + /** + * @return the generation id. + */ + public int generationId() { + return this.generationId; + } + + /** + * @return the protocol name. + */ + public Optional<String> protocolName() { + return this.protocolName; + } + + /** + * @return the protocol type. + */ + public Optional<String> protocolType() { + return this.protocolType; + } + + /** + * @return the current group state. + */ + public GenericGroupState currentState() { + return state; + } + + /** + * Compares the group's current state with the given state. + * + * @param groupState the state to match against. + * @return true if the state matches, false otherwise. + */ + public boolean isState(GenericGroupState groupState) { + return this.state == groupState; + } + + /** + * To identify whether the given member id is part of this group. + * + * @param memberId the given member id. + * @return true if the member is part of this group, false otherwise. + */ + public boolean hasMemberId(String memberId) { + return members.containsKey(memberId); + } + + /** + * Get the member metadata associated with the provided member id. + * + * @param memberId the member id. + * @return the member metadata if it exists, null otherwise. + */ + public GenericGroupMember member(String memberId) { + return members.get(memberId); + } + + /** + * @return the total number of members in this group. + */ + public int size() { + return members.size(); + } + + /** + * Used to identify whether the given member is the leader of this group. + * + * @param memberId the member id. + * @return true if the member is the leader, false otherwise. + */ + public boolean isLeader(String memberId) { + return leaderId.map(id -> id.equals(memberId)).orElse(false); + } + + /** + * @return the leader id or null if a leader does not exist. + */ + public String leaderOrNull() { + return leaderId.orElse(null); + } + + /** + * @return the current state timestamp. + */ + public long currentStateTimestampOrDefault() { + return currentStateTimestamp.orElse(-1L); + } + + /** + * @return whether the group is using the consumer protocol. + */ + public boolean isGenericGroup() { + return protocolType.map(type -> + type.equals(ConsumerProtocol.PROTOCOL_TYPE) + ).orElse(false); + } Review Comment: got it. this is from `def isConsumerGroup: Boolean = protocolType.contains(ConsumerProtocol.PROTOCOL_TYPE)` the naming is confusing because we both consumer and generic groups but a generic group can expect a group using the consumer protocol -- This is an automated message from the Apache Git Service. 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