cadonna commented on code in PR #18676: URL: https://github.com/apache/kafka/pull/18676#discussion_r1937549560
########## group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/TopologyMetadata.java: ########## @@ -0,0 +1,115 @@ +/* + * 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.streams; + +import org.apache.kafka.coordinator.group.streams.assignor.TopologyDescriber; +import org.apache.kafka.coordinator.group.streams.topics.ConfiguredSubtopology; +import org.apache.kafka.coordinator.group.streams.topics.ConfiguredTopology; + +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.SortedMap; +import java.util.stream.Stream; + +/** + * The topology metadata class is used by the {@link org.apache.kafka.coordinator.group.streams.assignor.TaskAssignor} to get topic and + * partition metadata for the topology that the streams group using. + * + * @param topicMetadata The topic Ids mapped to their corresponding {@link TopicMetadata} object, which contains topic and partition + * metadata. + * @param topology The configured topology, containing subtopologies and internal topics. + */ +public record TopologyMetadata(Map<String, TopicMetadata> topicMetadata, ConfiguredTopology topology) implements TopologyDescriber { + + public TopologyMetadata { + topicMetadata = Objects.requireNonNull(Collections.unmodifiableMap(topicMetadata)); + Objects.requireNonNull(topology); + } + + /** + * Map of topic names to topic metadata. + * + * @return The map of topic Ids to topic metadata. + */ + @Override + public Map<String, TopicMetadata> topicMetadata() { + return this.topicMetadata; + } + + /** + * Checks whether the given subtopology is associated with a changelog topic. + * + * @param subtopologyId String identifying the subtopology. + * @throws IllegalStateException if the subtopology ID does not exist, or the topology is not configured. + * @return true if the subtopology is associated with a changelog topic, false otherwise. + */ + @Override + public boolean isStateful(String subtopologyId) { + final ConfiguredSubtopology subtopology = getSubtopologyOrFail(subtopologyId); + return !subtopology.stateChangelogTopics().isEmpty(); + } + + /** + * The list of subtopologies in the topology. + * + * @throws IllegalStateException if the topology is not configured. + * @return a list of subtopology IDs. + */ + @Override + public List<String> subtopologies() { + return getSubtopologiesOrFail().keySet().stream().toList(); + } + + /** + * The maximal number of input partitions among all source topics for the given subtopology. + * + * @param subtopologyId String identifying the subtopology. + * + * @throws IllegalStateException if the subtopology ID does not exist, or the topology is not configured, or the subtopology + * contains no source topics. + * @return The maximal number of input partitions among all source topics for the given subtopology. + */ + @Override + public int maxNumInputPartitions(String subtopologyId) { + final ConfiguredSubtopology subtopology = getSubtopologyOrFail(subtopologyId); + return Stream.concat( + subtopology.sourceTopics().stream(), + subtopology.repartitionSourceTopics().keySet().stream() + ).map(topic -> this.topicMetadata.get(topic).numPartitions()).max(Integer::compareTo).orElseThrow( + () -> new IllegalStateException("Subtopology does not contain any source topics") + ); + } + + private ConfiguredSubtopology getSubtopologyOrFail(String subtopologyId) { + final Map<String, ConfiguredSubtopology> subtopologies = getSubtopologiesOrFail(); + if (!subtopologies.containsKey(subtopologyId)) { + throw new IllegalStateException(String.format("Topology does not contain subtopology %s", subtopologyId)); + } + return subtopologies.get(subtopologyId); + } + + private Map<String, ConfiguredSubtopology> getSubtopologiesOrFail() { + final Optional<SortedMap<String, ConfiguredSubtopology>> subtopologies = topology.subtopologies(); + if (subtopologies.isEmpty()) { + throw new IllegalStateException("Topology is not configured"); + } Review Comment: Is there a reason, you cannot make this check at construction time? -- This is an automated message from the Apache Git Service. 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