KAFKA-18311: Internal Topic Manager (5/5)

group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/TopicMetadata.java

@@ -0,0 +1,77 @@
+/*
+ * 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.common.Uuid;
+import org.apache.kafka.coordinator.group.generated.StreamsGroupPartitionMetadataValue;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Immutable topic metadata, representing the current state of a topic in the broker.
+ *
+ * @param id             The topic id.
+ * @param name           The topic name.
+ * @param numPartitions  The number of partitions.
+ * @param partitionRacks Map of every partition ID to a set of its rack IDs, if they exist. If rack information is unavailable for all
+ *                       partitions, this is an empty map.
+ */
+public record TopicMetadata(Uuid id, String name, int numPartitions, Map<Integer, Set<String>> partitionRacks) {
+
+    public TopicMetadata(
+        Uuid id,
+        String name,
+        int numPartitions,
+        Map<Integer, Set<String>> partitionRacks
+    ) {
+        this.id = Objects.requireNonNull(id);
+        if (Uuid.ZERO_UUID.equals(id)) {
+            throw new IllegalArgumentException("Topic id cannot be ZERO_UUID.");
+        }
+        this.name = Objects.requireNonNull(name);
+        if (name.isEmpty()) {
+            throw new IllegalArgumentException("Topic name cannot be empty.");
+        }
+        this.numPartitions = numPartitions;
+        if (numPartitions < 0) {
+            throw new IllegalArgumentException("Number of partitions cannot be negative.");
+        }
+        this.partitionRacks = Objects.requireNonNull(partitionRacks);
+    }
+
+    public static TopicMetadata fromRecord(
+        StreamsGroupPartitionMetadataValue.TopicMetadata record
+    ) {
+        // Converting the data type from a list stored in the record to a map for the topic metadata.
+        Map<Integer, Set<String>> partitionRacks = new HashMap<>();
+        for (StreamsGroupPartitionMetadataValue.PartitionMetadata partitionMetadata : record.partitionMetadata()) {
+            partitionRacks.put(
+                partitionMetadata.partition(),
+                Set.copyOf(partitionMetadata.racks())
+            );
+        }
+
+        return new TopicMetadata(
+            record.topicId(),
+            record.topicName(),
+            record.numPartitions(),
+            partitionRacks);
+    }
+}

group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/topics/ChangelogTopics.java

@@ -65,6 +65,8 @@ public ChangelogTopics(
     /**
      * Determines the number of partitions for each non-source changelog topic in the requested topology.
      *
+     * @throws IllegalStateException If a source topic does not have a partition count defined through topicPartitionCountProvider.
+     *
      * @return the map of all non-source changelog topics for the requested topology to their required number of partitions.
      */
     public Map<String, Integer> setup() {
@@ -94,7 +96,7 @@ public Map<String, Integer> setup() {
     private int getPartitionCountOrFail(String topic) {
         final OptionalInt topicPartitionCount = topicPartitionCountProvider.apply(topic);
         if (topicPartitionCount.isEmpty()) {
-            throw TopicConfigurationException.missingSourceTopics("No partition count for source topic " + topic);
+            throw new IllegalStateException("No partition count for source topic " + topic);
         }
         return topicPartitionCount.getAsInt();
     }

group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/topics/ConfiguredTopology.java

@@ -19,6 +19,7 @@
 import org.apache.kafka.common.message.CreateTopicsRequestData.CreatableTopic;
 import org.apache.kafka.common.message.StreamsGroupDescribeResponseData;
 
+import java.util.Collections;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
@@ -31,22 +32,26 @@
  * @param topologyEpoch               The epoch of the topology. Same as the topology epoch in the heartbeat request that last initialized
  *                                    the topology.
  * @param subtopologies               Contains the subtopologies that have been configured. This can be used by the task assignors, since it
- *                                    specifies the number of tasks available for every subtopology.
+ *                                    specifies the number of tasks available for every subtopology. Undefined if topology configuration
+ *                                    failed.
  * @param internalTopicsToBeCreated   Contains a list of internal topics that need to be created. This is used to create the topics in the
  *                                    broker.
  * @param topicConfigurationException If the topic configuration process failed, e.g. because expected topics are missing or have an
  *                                    incorrect number of partitions, this field will store the error that occurred, so that is can be
  *                                    reported back to the client.
  */
 public record ConfiguredTopology(int topologyEpoch,
-                                 Map<String, ConfiguredSubtopology> subtopologies,
+                                 Optional<Map<String, ConfiguredSubtopology>> subtopologies,
                                  Map<String, CreatableTopic> internalTopicsToBeCreated,
                                  Optional<TopicConfigurationException> topicConfigurationException) {
 
     public ConfiguredTopology {
         if (topologyEpoch < 0) {
             throw new IllegalArgumentException("Topology epoch must be non-negative.");
         }
+        if (topicConfigurationException.isEmpty() && subtopologies.isEmpty()) {
+            throw new IllegalArgumentException("Subtopologies must be present if topicConfigurationException is empty.");
+        }
         Objects.requireNonNull(subtopologies, "subtopologies can't be null");
         Objects.requireNonNull(internalTopicsToBeCreated, "internalTopicsToBeCreated can't be null");
         Objects.requireNonNull(topicConfigurationException, "topicConfigurationException can't be null");
@@ -59,9 +64,11 @@ public boolean isReady() {
     public StreamsGroupDescribeResponseData.Topology asStreamsGroupDescribeTopology() {
         return new StreamsGroupDescribeResponseData.Topology()
             .setEpoch(topologyEpoch)
-            .setSubtopologies(subtopologies.entrySet().stream().map(
-                entry -> entry.getValue().asStreamsGroupDescribeSubtopology(entry.getKey())
-            ).collect(Collectors.toList()));
+            .setSubtopologies(
+                subtopologies.map(stringConfiguredSubtopologyMap -> stringConfiguredSubtopologyMap.entrySet().stream().map(
+                    entry -> entry.getValue().asStreamsGroupDescribeSubtopology(entry.getKey())
+                ).collect(Collectors.toList())).orElse(Collections.emptyList())
+            );
     }
 
 }

group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/topics/CopartitionedTopicsEnforcer.java

@@ -48,8 +48,7 @@ public class CopartitionedTopicsEnforcer {
      * @param logContext                  The context for emitting log messages.
      * @param topicPartitionCountProvider Returns the number of partitions for a given topic, representing the current state of the broker
      *                                    as well as any partition number decisions that have already been made. In particular, we expect
-     *                                    the number of partitions for all repartition topics defined, even if they do not exist in the
-     *                                    broker yet.
+     *                                    the number of partitions for all topics in all co-partitions groups to be defined.
      */
     public CopartitionedTopicsEnforcer(final LogContext logContext,
                                        final Function<String, OptionalInt> topicPartitionCountProvider) {
@@ -65,15 +64,16 @@ public CopartitionedTopicsEnforcer(final LogContext logContext,
      *                                     client (in particular, when the user uses `repartition` in the DSL).
      * @param flexibleRepartitionTopics    The set of repartition topics whose partition count is flexible, and can be changed.
      *
-     * @throws TopicConfigurationException If source topics are missing, or there are topics in copartitionTopics that are not copartitioned
-     *                                     according to topicPartitionCountProvider.
+     * @throws IllegalStateException If the partition count for any topic in copartitionedTopics is not defined by
+     *                               topicPartitionCountProvider.
      *
      * @return A map from all repartition topics in copartitionedTopics to their updated partition counts.
      */
     public Map<String, Integer> enforce(final Set<String> copartitionedTopics,
                                         final Set<String> fixedRepartitionTopics,
                                         final Set<String> flexibleRepartitionTopics) throws StreamsInvalidTopologyException {
         if (copartitionedTopics.isEmpty()) {
+            log.debug("Ignoring unexpected empty copartitioned topics set.");
             return Collections.emptyMap();
         }
         final Map<String, Integer> returnedPartitionCounts = new HashMap<>();
@@ -85,16 +85,7 @@ public Map<String, Integer> enforce(final Set<String> copartitionedTopics,
 
         final Map<String, Integer> nonRepartitionTopicPartitions =
             copartitionedTopics.stream().filter(topic -> !repartitionTopicPartitionCounts.containsKey(topic))
-                .collect(Collectors.toMap(topic -> topic, topic -> {
-                    final OptionalInt topicPartitionCount = topicPartitionCountProvider.apply(topic);
-                    if (topicPartitionCount.isEmpty()) {
-                        final String str = String.format("Following topics are missing: [%s]", topic);
-                        log.error(str);
-                        throw TopicConfigurationException.missingSourceTopics(str);
-                    } else {
-                        return topicPartitionCount.getAsInt();
-                    }
-                }));
+                .collect(Collectors.toMap(topic -> topic, this::getPartitionCount));
 
         final int numPartitionsToUseForRepartitionTopics;
 
@@ -139,7 +130,7 @@ private int getPartitionCount(final String topicName) {
         if (partitions.isPresent()) {
             return partitions.getAsInt();
         } else {
-            throw new StreamsInvalidTopologyException("Number of partitions is not set for topic: " + topicName);
+            throw new IllegalStateException("Number of partitions is not set for topic: " + topicName);
         }
     }