jeffkbkim commented on code in PR #13644: URL: https://github.com/apache/kafka/pull/13644#discussion_r1185444113
########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/generic/GenericGroupMember.java: ########## @@ -0,0 +1,499 @@ +/** + * 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.common.message.JoinGroupResponseData; +import org.apache.kafka.common.message.SyncGroupResponseData; + +import java.util.Arrays; +import java.util.List; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; +import java.util.concurrent.CompletableFuture; +import java.util.stream.Collectors; + +/** + * This class encapsulates a generic group member's metadata. + * + * Member metadata contains the following: + * + * Heartbeat metadata: + * 1. negotiated heartbeat session timeout + * 2. timestamp of the latest heartbeat + * + * Protocol metadata: + * 1. the list of supported protocols (ordered by preference) + * 2. the metadata associated with each protocol + * + * In addition, it also contains the following state information: + * + * 1. Awaiting rebalance callback: when the group is in the prepare-rebalance state, + * its rebalance callback will be kept in the metadata if the + * member has sent the join group request + * 2. Awaiting sync callback: when the group is in the awaiting-sync state, its sync callback + * is kept in metadata until the leader provides the group assignment + * and the group transitions to stable + */ +public class GenericGroupMember { + + private static class MemberSummary { + private final String memberId; + private final Optional<String> groupInstanceId; + private final String clientId; + private final String clientHost; + private final byte[] metadata; + private final byte[] assignment; + + public MemberSummary(String memberId, + Optional<String> groupInstanceId, + String clientId, + String clientHost, + byte[] metadata, + byte[] assignment) { + + this.memberId = memberId; + this.groupInstanceId = groupInstanceId; + this.clientId = clientId; + this.clientHost = clientHost; + this.metadata = metadata; + this.assignment = assignment; + } + + public String memberId() { + return memberId; + } + + public Optional<String> getGroupInstanceId() { + return groupInstanceId; + } + + public String clientId() { + return clientId; + } + + public String clientHost() { + return clientHost; + } + + public byte[] metadata() { + return metadata; + } + + public byte[] assignment() { + return assignment; + } + + } + + /** + * The member id. + */ + private final String memberId; + + /** + * The group instance id. + */ + private final Optional<String> groupInstanceId; + + /** + * The client id. + */ + private final String clientId; + + /** + * The client host. + */ + private final String clientHost; + + /** + * The rebalance timeout in milliseconds. + */ + private final int rebalanceTimeoutMs; + + /** + * The session timeout in milliseconds. + */ + private final int sessionTimeoutMs; + + /** + * The protocol type. + */ + private final String protocolType; + + /** + * The list of supported protocols. + */ + private final List<Protocol> supportedProtocols; + + /** + * The assignment stored by the client assignor. + */ + private final byte[] assignment; + + /** + * The callback that is invoked once this member joins the group. + */ + private CompletableFuture<JoinGroupResponseData> awaitingJoinCallback = null; + + /** + * The callback that is invoked once this member completes the sync group phase. + */ + private CompletableFuture<SyncGroupResponseData> awaitingSyncCallback = null; + + /** + * Indicates whether the member is a new member of the group. + */ + private boolean isNew = false; + + /** + * This variable is used to track heartbeat completion through the delayed + * heartbeat purgatory. When scheduling a new heartbeat expiration, we set + * this value to `false`. Upon receiving the heartbeat (or any other event + * indicating the liveness of the client), we set it to `true` so that the + * delayed heartbeat can be completed. + */ + private boolean heartbeatSatisfied = false; + + + public GenericGroupMember( + String memberId, + Optional<String> groupInstanceId, + String clientId, + String clientHost, + int rebalanceTimeoutMs, + int sessionTimeoutMs, + String protocolType, + List<Protocol> supportedProtocols + ) { + this( + memberId, + groupInstanceId, + clientId, + clientHost, + rebalanceTimeoutMs, + sessionTimeoutMs, + protocolType, + supportedProtocols, + new byte[0] + ); + } + + public GenericGroupMember( + String memberId, + Optional<String> groupInstanceId, + String clientId, + String clientHost, + int rebalanceTimeoutMs, + int sessionTimeoutMs, + String protocolType, + List<Protocol> supportedProtocols, + byte[] assignment + ) { + this.memberId = memberId; + this.groupInstanceId = groupInstanceId; + this.clientId = clientId; + this.clientHost = clientHost; + this.rebalanceTimeoutMs = rebalanceTimeoutMs; + this.sessionTimeoutMs = sessionTimeoutMs; + this.protocolType = protocolType; + this.supportedProtocols = supportedProtocols; + this.assignment = assignment; + } + + /** + * @return true if the member is utilizing static membership, false otherwise. + */ + public boolean isStaticMember() { + return groupInstanceId.isPresent(); + } + + /** + * @return whether the member is awaiting join. + */ + public boolean isAwaitingJoin() { + return awaitingJoinCallback != null; + } + + /** + * @return whether the member is awaiting sync. + */ + public boolean isAwaitingSync() { + return awaitingSyncCallback != null; + } + + /** + * Get the metadata corresponding to the provided protocol. + */ + public byte[] metadata(String protocolName) { + Optional<Protocol> match = supportedProtocols.stream().filter(protocol -> + protocol.name().equals(protocolName)) + .findFirst(); + + if (match.isPresent()) { + return match.get().metadata(); + } else { + throw new IllegalArgumentException("Member does not support protocol " + + protocolName); + } + } + + /** + * The heartbeat is always considered satisfied when an existing member has made a + * successful join/sync group request during a rebalance. + * + * @return true if heartbeat was satisfied; false otherwise. + */ + public boolean hasSatisfiedHeartbeat() { + if (isNew) { + // New members can be expired while awaiting join, so we have to check this first + return heartbeatSatisfied; + } else if (isAwaitingJoin() || isAwaitingSync()) { + // Members that are awaiting a rebalance automatically satisfy expected heartbeats + return true; + } else { + // Otherwise, we require the next heartbeat + return heartbeatSatisfied; + } + } + + /** + * @param protocols list of protocols to match. + * @return true if the given list matches the member's list of supported protocols, + * false otherwise. + */ + public boolean matches(List<Protocol> protocols) { + return protocols.equals(this.supportedProtocols); + } + + /** + * @param protocolName the protocol name. + * @return MemberSummary object with metadata corresponding to the protocol name. + */ + public MemberSummary summary(String protocolName) { + return new MemberSummary( + memberId, + groupInstanceId, + clientId, + clientHost, + metadata(protocolName), + assignment + ); + } + + /** + * @return MemberSummary object with no metadata. + */ + public MemberSummary summaryNoMetadata() { + return new MemberSummary( + memberId, + groupInstanceId, + clientId, + clientHost, + new byte[0], + new byte[0] + ); + } + + /** + * Vote for one of the potential group protocols. This takes into account the protocol preference as + * indicated by the order of supported protocols and returns the first one also contained in the set + */ + public String vote(Set<String> candidates) { + Optional<Protocol> match = supportedProtocols.stream().filter(protocol -> + candidates.contains(protocol.name())).findFirst(); + + if (match.isPresent()) { + return match.get().name(); + } else { + throw new IllegalArgumentException("Member does not support any of the candidate protocols"); + } + } + + /** + * @param supportedProtocols list of supported protocols. + * @return a set of protocol names from the given list of supported protocols. + */ + public static Set<String> plainProtocolSet(List<Protocol> supportedProtocols) { + return supportedProtocols.stream().map(Protocol::name).collect(Collectors.toSet()); + } + + /** + * @return the member id. + */ + public String memberId() { + return memberId; + } + + /** + * @return the group instance id. + */ + public Optional<String> groupInstanceId() { + return groupInstanceId; + } + + /** + * @return the client id. + */ + public String clientId() { + return clientId; + } + + /** + * @return the client host. + */ + public String clientHost() { + return clientHost; + } + + /** + * @return the rebalance timeout in milliseconds. + */ + public int rebalanceTimeoutMs() { + return rebalanceTimeoutMs; + } + + /** + * @return the session timeout in milliseconds. + */ + public int sessionTimeoutMs() { + return sessionTimeoutMs; + } + + /** + * @return the protocol type. + */ + public String protocolType() { + return protocolType; + } + + /** + * @return the list of supported protocols. + */ + public List<Protocol> supportedProtocols() { + return supportedProtocols; + } + + /** + * @return the member's assignment. + */ + public byte[] assignment() { + return assignment; + } + + /** + * @return the awaiting join callback. + */ + public CompletableFuture<JoinGroupResponseData> awaitingJoinCallback() { + return awaitingJoinCallback; + } + + /** + * @param value the updated join callback. + */ + public void setAwaitingJoinCallback(CompletableFuture<JoinGroupResponseData> value) { + this.awaitingJoinCallback = value; + } + + /** + * @return the awaiting sync callback. + */ + public CompletableFuture<SyncGroupResponseData> awaitingSyncCallback() { + return awaitingSyncCallback; + } + + /** + * @param value the updated sync callback. + */ + public void setAwaitingSyncCallback(CompletableFuture<SyncGroupResponseData> value) { + this.awaitingSyncCallback = value; + } + + /** + * @return true if the member is new, false otherwise. + */ + public boolean isNew() { + return isNew; + } + + /** + * @param value true if the member is new, false otherwise. + */ + public void setIsNew(boolean value) { + this.isNew = value; + } + + /** + * @return true if the existing heartbeat was satisfied, false otherwise. + */ + public boolean heartBeatSatisfied() { + return heartbeatSatisfied; + } + + /** + * @param value whether the heartbeat was satisfied. + */ + public void setHeartBeatSatisfied(boolean value) { + this.heartbeatSatisfied = value; + } + + @Override + public String toString() { + return "GenericGroupMember(" + + "memberId='" + memberId + '\'' + + ", groupInstanceId='" + groupInstanceId + '\'' + + ", clientId='" + clientId + '\'' + + ", clientHost='" + clientHost + '\'' + + ", rebalanceTimeoutMs=" + rebalanceTimeoutMs + + ", sessionTimeoutMs=" + sessionTimeoutMs + + ", protocolType='" + protocolType + '\'' + + ", supportedProtocols=" + supportedProtocols + + ')'; + } + + @Override + public boolean equals(Object o) { + if (this == o) return true; + if (o == null || getClass() != o.getClass()) return false; + GenericGroupMember that = (GenericGroupMember) o; + + return memberId.equals(that.memberId) && + groupInstanceId.equals(that.groupInstanceId) && + clientId.equals(that.clientId) && + clientHost.equals(that.clientHost) && + rebalanceTimeoutMs == that.rebalanceTimeoutMs && + sessionTimeoutMs == that.sessionTimeoutMs && + protocolType.equals(that.protocolType) && + supportedProtocols.equals(that.supportedProtocols) && + Arrays.equals(assignment, that.assignment); + } + + @Override + public int hashCode() { + return Objects.hash( Review Comment: Wow, TIL we can generate this :) -- This is an automated message from the Apache Git Service. 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