Demogorgon314 commented on code in PR #18810: URL: https://github.com/apache/pulsar/pull/18810#discussion_r1053919039
########## pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/BrokerRegistryImpl.java: ########## @@ -0,0 +1,218 @@ +/* + * 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 com.google.common.annotations.VisibleForTesting; +import com.google.common.collect.Lists; +import java.util.ArrayList; +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.CompletionException; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.RejectedExecutionException; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.function.BiConsumer; +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.extensions.data.BrokerLookupData; +import org.apache.pulsar.common.util.FutureUtil; +import org.apache.pulsar.metadata.api.MetadataStoreException; +import org.apache.pulsar.metadata.api.Notification; +import org.apache.pulsar.metadata.api.NotificationType; +import org.apache.pulsar.metadata.api.coordination.LockManager; +import org.apache.pulsar.metadata.api.coordination.ResourceLock; + +/** + * The broker registry impl, base on the LockManager. + */ +@Slf4j +public class BrokerRegistryImpl implements BrokerRegistry { + + private static final String LOOKUP_DATA_PATH = "/loadbalance/brokers"; + + private final PulsarService pulsar; + + private final ServiceConfiguration conf; + + private final BrokerLookupData brokerLookupData; + + private final LockManager<BrokerLookupData> brokerLookupDataLockManager; + + private final String brokerZNodePath; + + private final String lookupServiceAddress; + + @VisibleForTesting + protected final Map<String, BrokerLookupData> brokerLookupDataMap; + + private final ScheduledExecutorService scheduler; + + private final List<BiConsumer<String, NotificationType>> listeners; + + private final AtomicBoolean registered; + + private volatile ResourceLock<BrokerLookupData> brokerLookupDataLock; + + public BrokerRegistryImpl(PulsarService pulsar) { + this.pulsar = pulsar; + this.conf = pulsar.getConfiguration(); + this.brokerLookupDataLockManager = pulsar.getCoordinationService().getLockManager(BrokerLookupData.class); + this.scheduler = pulsar.getLoadManagerExecutor(); + this.brokerLookupDataMap = new ConcurrentHashMap<>(); + this.listeners = new ArrayList<>(); + + this.registered = new AtomicBoolean(false); + this.lookupServiceAddress = pulsar.getAdvertisedAddress() + ":" + + conf.getWebServicePort().orElseGet(() -> conf.getWebServicePortTls().get()); + this.brokerZNodePath = LOOKUP_DATA_PATH + "/" + lookupServiceAddress; + this.brokerLookupData = new BrokerLookupData( + pulsar.getSafeWebServiceAddress(), + pulsar.getWebServiceAddressTls(), + pulsar.getBrokerServiceUrl(), + pulsar.getBrokerServiceUrlTls(), + pulsar.getAdvertisedListeners(), + pulsar.getProtocolDataToAdvertise(), + pulsar.getConfiguration().isEnablePersistentTopics(), + pulsar.getConfiguration().isEnableNonPersistentTopics(), + pulsar.getBrokerVersion()); + } + + @Override + public void start() { + pulsar.getLocalMetadataStore().registerListener(this::handleMetadataStoreNotification); + } + + @Override + public void register() { + if (registered.compareAndSet(false, true)) { + this.brokerLookupDataLock = + brokerLookupDataLockManager.acquireLock(brokerZNodePath, brokerLookupData).join(); + } + } + + @Override + public void unregister() throws MetadataStoreException { + if (registered.compareAndSet(true, false)) { + try { + brokerLookupDataLock.release().join(); + } catch (CompletionException e) { + throw MetadataStoreException.unwrap(e); + } + } + } + + @Override + public String getLookupServiceAddress() { + return this.lookupServiceAddress; + } + + @Override + public CompletableFuture<List<String>> getAvailableBrokersAsync() { + CompletableFuture<List<String>> future = new CompletableFuture<>(); + brokerLookupDataLockManager.listLocks(LOOKUP_DATA_PATH) Review Comment: > Unless necessary, we want to keep this path design for the following reasons. > >1. This path design change can further complicate version compatibility(uneasy to maintain the path design for different pulsar versions). >2. During version upgrade, if the shutdown is ungraceful, the new path design could incur two locks for the same >broker. However, currently, the restart will be blocked as the lingering lock will block it. Yes, I agree. I have the same concern after trying to implement the broker filter. > Here the readLock will return the up-to-date lock value (maximum 5 mins delay, except the first time) as the cache refreshes after 5mins, once the key-value is stored. > In this way, we can make this foreach non-blocking. When the readLock cache is initially empty, it will return the empty available broker set. In this case. the client should retry. Why don't we use a cache like the original implement? It will never block the client thread. -- This is an automated message from the Apache Git Service. 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