Demogorgon314 commented on code in PR #19102: URL: https://github.com/apache/pulsar/pull/19102#discussion_r1061372645
########## pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerImpl.java: ########## @@ -0,0 +1,225 @@ +/* + * 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.pulsar.broker.loadbalance.extensions; + +import java.util.ArrayList; +import java.util.List; +import java.util.Optional; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.ThreadLocalRandom; +import lombok.Getter; +import lombok.extern.slf4j.Slf4j; +import org.apache.pulsar.broker.PulsarServerException; +import org.apache.pulsar.broker.PulsarService; +import org.apache.pulsar.broker.ServiceConfiguration; +import org.apache.pulsar.broker.loadbalance.BrokerFilterException; +import org.apache.pulsar.broker.loadbalance.extensions.channel.ServiceUnitStateChannel; +import org.apache.pulsar.broker.loadbalance.extensions.channel.ServiceUnitStateChannelImpl; +import org.apache.pulsar.broker.loadbalance.extensions.data.BrokerLookupData; +import org.apache.pulsar.broker.loadbalance.extensions.filter.BrokerFilter; +import org.apache.pulsar.broker.loadbalance.extensions.strategy.BrokerSelectionStrategy; +import org.apache.pulsar.common.naming.ServiceUnitId; +import org.apache.pulsar.common.util.collections.ConcurrentOpenHashMap; + +@Slf4j +public class ExtensibleLoadManagerImpl implements ExtensibleLoadManager { + + private PulsarService pulsar; + + private ServiceConfiguration conf; + + @Getter + private BrokerRegistry brokerRegistry; + + private ServiceUnitStateChannel serviceUnitStateChannel; + + @Getter + private LoadManagerContext context; + + @Getter + private final BrokerSelectionStrategy brokerSelectionStrategy; + + @Getter + private final List<BrokerFilter> brokerFilterPipeline; + + private boolean started = false; + + private final ConcurrentOpenHashMap<String, CompletableFuture<Optional<BrokerLookupData>>> + lookupRequests = ConcurrentOpenHashMap.<String, + CompletableFuture<Optional<BrokerLookupData>>>newBuilder() + .build(); + + /** + * Life cycle: Constructor -> initialize -> start -> close. + */ + public ExtensibleLoadManagerImpl() { + this.brokerFilterPipeline = new ArrayList<>(); + // TODO: Make brokerSelectionStrategy configurable. + this.brokerSelectionStrategy = (brokers, bundle, context) -> { + if (brokers.isEmpty()) { + return Optional.empty(); + } + return Optional.of(brokers.get(ThreadLocalRandom.current().nextInt(brokers.size()))); + }; + } + + public static boolean isLoadManagerExtensionEnabled(ServiceConfiguration conf) { + return ExtensibleLoadManagerImpl.class.getName().equals(conf.getLoadManagerClassName()); + } + + @Override + public synchronized void start() throws PulsarServerException { + if (this.started) { + return; + } + this.brokerRegistry = new BrokerRegistryImpl(pulsar); + this.serviceUnitStateChannel = new ServiceUnitStateChannelImpl(pulsar); + this.brokerRegistry.start(); + this.serviceUnitStateChannel.start(); + + // TODO: Start the load data store. + + this.context = LoadManagerContextImpl.builder() + .configuration(conf) + .brokerRegistry(brokerRegistry) + .brokerLoadDataStore(null) + .topBundleLoadDataStore(null).build(); + // TODO: Start load data reporter. + + // TODO: Start unload scheduler and bundle split scheduler + this.started = true; + } + + @Override + public synchronized void initialize(PulsarService pulsar) { + this.pulsar = pulsar; + this.conf = pulsar.getConfiguration(); + } + + @Override + public CompletableFuture<Optional<BrokerLookupData>> assign(Optional<ServiceUnitId> topic, + ServiceUnitId serviceUnit) { + + final String bundle = serviceUnit.toString(); + + CompletableFuture<Optional<BrokerLookupData>> future = lookupRequests.computeIfAbsent(bundle, k -> { + final CompletableFuture<Optional<String>> owner; + // Assign the bundle to channel owner if is internal topic, to avoid circular references. + if (topic.isPresent() && isInternalTopic(topic.get().toString())) { + owner = serviceUnitStateChannel.getChannelOwnerAsync(); + } else { + owner = serviceUnitStateChannel.getOwnerAsync(bundle).thenCompose(broker -> { + // If the bundle not assign yet, select and publish assign event to channel. + if (broker.isEmpty()) { + return this.selectAsync(serviceUnit).thenCompose(brokerOpt -> { + if (brokerOpt.isPresent()) { + log.info("Selected new owner broker: {} for bundle: {}.", brokerOpt.get(), bundle); + return serviceUnitStateChannel.publishAssignEventAsync(bundle, brokerOpt.get()) + .thenApply(Optional::of); + } else { + throw new IllegalStateException( + "Failed to select the new owner broker for bundle: " + bundle); + } + }); + } + // Already assigned, return it. + return CompletableFuture.completedFuture(broker); + }); + } + + return owner.thenCompose(broker -> { + if (broker.isEmpty()) { + String errorMsg = String.format( + "Failed to look up a broker registry:%s for bundle:%s", broker, bundle); + log.error(errorMsg); + throw new IllegalStateException(errorMsg); + } Review Comment: The caller handled this exception, see: https://github.com/apache/pulsar/blob/master/pulsar-broker/src/main/java/org/apache/pulsar/broker/lookup/TopicLookupBase.java#L315-L317 And in the old logic, it also throws the `IllegalStateException`, https://github.com/apache/pulsar/blob/master/pulsar-broker/src/main/java/org/apache/pulsar/broker/namespace/NamespaceService.java#L398-L400 -- This is an automated message from the Apache Git Service. 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