[GitHub] [pulsar] gaoran10 commented on a diff in pull request #19102: [improve][broker] PIP-192: Implement extensible load manager

["gaoran10 (via GitHub)" <gi...@apache.org>]

gaoran10 commented on code in PR #19102:
URL: https://github.com/apache/pulsar/pull/19102#discussion_r1092767910


##########
pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerImpl.java:
##########
@@ -0,0 +1,232 @@
+/*
+ * 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.HashMap;
+import java.util.List;
+import java.util.Map;
+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();

Review Comment:
   Do we need to use the modifier synchronized?



##########
pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/BrokerRegistryImpl.java:
##########
@@ -0,0 +1,222 @@
+/*

Review Comment:
   +1, we'd better merge the PR #18810 first.



##########
pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerImpl.java:
##########
@@ -0,0 +1,223 @@
+/*
+ * 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.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.atomic.AtomicBoolean;
+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 List<BrokerFilter> brokerFilterPipeline;
+
+    private final AtomicBoolean started = new AtomicBoolean(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<>();
+        this.brokerSelectionStrategy = (brokers, bundle, context) -> {
+            if (brokers.isEmpty()) {
+                return Optional.empty();
+            }
+            return Optional.of(brokers.get(ThreadLocalRandom.current().nextInt(brokers.size())));
+        };
+    }
+
+    @Override
+    public void start() throws PulsarServerException {
+        if (this.started.get()) {
+            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.set(true);
+    }
+
+    @Override
+    public 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());
+                            } else {
+                                throw new IllegalStateException(
+                                        "Failed to discover(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);
+                }
+                return CompletableFuture.completedFuture(broker.get());
+            }).thenCompose(broker -> this.getBrokerRegistry().lookupAsync(broker).thenCompose(brokerLookupData -> {
+                if (brokerLookupData.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);
+                }
+                return CompletableFuture.completedFuture(brokerLookupData);
+            }));
+        });
+        future.whenComplete((r, t) -> lookupRequests.remove(bundle));
+        return future;
+    }
+
+    public CompletableFuture<Optional<String>> selectAsync(ServiceUnitId bundle) {
+        BrokerRegistry brokerRegistry = getBrokerRegistry();
+        return brokerRegistry.getAvailableBrokerLookupDataAsync()
+                .thenCompose(availableBrokers -> {
+                    // TODO: Support isolation policies
+                    LoadManagerContext context = this.getContext();
+
+                    // Filter out brokers that do not meet the rules.
+                    List<BrokerFilter> filterPipeline = getBrokerFilterPipeline();
+                    Map<String, BrokerLookupData> availableBrokerCandidates = new HashMap<>(availableBrokers);
+                    for (final BrokerFilter filter : filterPipeline) {
+                        try {
+                            filter.filter(availableBrokerCandidates, context);
+                        } catch (BrokerFilterException e) {
+                            availableBrokerCandidates = availableBrokers;
+                        }
+                    }
+                    if (availableBrokerCandidates.isEmpty()) {
+                        return CompletableFuture.completedFuture(Optional.empty());
+                    }
+                    ArrayList<String> candidateBrokers = new ArrayList<>(availableBrokerCandidates.keySet());

Review Comment:
   Maybe we can change the parameter type from`List<String>` to `Set<String>` for the method `BrokerSelectionStrategy#select`? The type of the collection is `String`, it shouldn't have repeated brokers.



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: commits-unsubscribe@pulsar.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org