| /* |
| * 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.service; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.ConcurrentSkipListMap; |
| import org.apache.pulsar.broker.service.BrokerServiceException.ConsumerAssignException; |
| import org.apache.pulsar.client.api.Range; |
| import org.apache.pulsar.common.util.FutureUtil; |
| |
| /** |
| * This is a consumer selector based fixed hash range. |
| * |
| * 1.Each consumer serves a fixed range of hash value |
| * 2.The whole range of hash value could be covered by all the consumers. |
| * 3.Once a consumer is removed, the left consumers could still serve the whole range. |
| * |
| * Initializing with a fixed hash range, by default 2 >> 15. |
| * First consumer added, hash range looks like: |
| * |
| * 0 -< 65536(consumer-1) |
| * |
| * Second consumer added, will find a biggest range to split: |
| * |
| * 0 -< 32768(consumer-2) -< 65536(consumer-1) |
| * |
| * While a consumer removed, The range for this consumer will be taken over |
| * by other consumer, consumer-2 removed: |
| * |
| * 0 -< 65536(consumer-1) |
| * |
| * In this approach use skip list map to maintain the hash range and consumers. |
| * |
| * Select consumer will return the ceiling key of message key hashcode % range size. |
| * |
| */ |
| public class HashRangeAutoSplitStickyKeyConsumerSelector implements StickyKeyConsumerSelector { |
| |
| private final int rangeSize; |
| |
| private final ConcurrentSkipListMap<Integer, Consumer> rangeMap; |
| private final Map<Consumer, Integer> consumerRange; |
| |
| public HashRangeAutoSplitStickyKeyConsumerSelector() { |
| this(DEFAULT_RANGE_SIZE); |
| } |
| |
| public HashRangeAutoSplitStickyKeyConsumerSelector(int rangeSize) { |
| if (rangeSize < 2) { |
| throw new IllegalArgumentException("range size must greater than 2"); |
| } |
| if (!is2Power(rangeSize)) { |
| throw new IllegalArgumentException("range size must be nth power with 2"); |
| } |
| this.rangeMap = new ConcurrentSkipListMap<>(); |
| this.consumerRange = new HashMap<>(); |
| this.rangeSize = rangeSize; |
| } |
| |
| @Override |
| public synchronized CompletableFuture<Void> addConsumer(Consumer consumer) { |
| if (rangeMap.isEmpty()) { |
| rangeMap.put(rangeSize, consumer); |
| consumerRange.put(consumer, rangeSize); |
| } else { |
| try { |
| splitRange(findBiggestRange(), consumer); |
| } catch (ConsumerAssignException e) { |
| return FutureUtil.failedFuture(e); |
| } |
| } |
| return CompletableFuture.completedFuture(null); |
| } |
| |
| @Override |
| public synchronized void removeConsumer(Consumer consumer) { |
| Integer removeRange = consumerRange.remove(consumer); |
| if (removeRange != null) { |
| if (removeRange == rangeSize && rangeMap.size() > 1) { |
| Map.Entry<Integer, Consumer> lowerEntry = rangeMap.lowerEntry(removeRange); |
| rangeMap.put(removeRange, lowerEntry.getValue()); |
| rangeMap.remove(lowerEntry.getKey()); |
| consumerRange.put(lowerEntry.getValue(), removeRange); |
| } else { |
| rangeMap.remove(removeRange); |
| } |
| } |
| } |
| |
| @Override |
| public Consumer select(int hash) { |
| if (!rangeMap.isEmpty()) { |
| int slot = hash % rangeSize; |
| return rangeMap.ceilingEntry(slot).getValue(); |
| } else { |
| return null; |
| } |
| } |
| |
| @Override |
| public Map<Consumer, List<Range>> getConsumerKeyHashRanges() { |
| Map<Consumer, List<Range>> result = new HashMap<>(); |
| int start = 0; |
| for (Map.Entry<Integer, Consumer> entry: rangeMap.entrySet()) { |
| result.computeIfAbsent(entry.getValue(), key -> new ArrayList<>()) |
| .add(Range.of(start, entry.getKey())); |
| start = entry.getKey() + 1; |
| } |
| return result; |
| } |
| |
| private int findBiggestRange() { |
| int slots = 0; |
| int busiestRange = rangeSize; |
| for (Entry<Integer, Consumer> entry : rangeMap.entrySet()) { |
| Integer lowerKey = rangeMap.lowerKey(entry.getKey()); |
| if (lowerKey == null) { |
| lowerKey = 0; |
| } |
| if (entry.getKey() - lowerKey > slots) { |
| slots = entry.getKey() - lowerKey; |
| busiestRange = entry.getKey(); |
| } |
| } |
| return busiestRange; |
| } |
| |
| private void splitRange(int range, Consumer targetConsumer) throws ConsumerAssignException { |
| Integer lowerKey = rangeMap.lowerKey(range); |
| if (lowerKey == null) { |
| lowerKey = 0; |
| } |
| if (range - lowerKey <= 1) { |
| throw new ConsumerAssignException("No more range can assigned to new consumer, assigned consumers " |
| + rangeMap.size()); |
| } |
| int splitRange = range - ((range - lowerKey) >> 1); |
| rangeMap.put(splitRange, targetConsumer); |
| consumerRange.put(targetConsumer, splitRange); |
| } |
| |
| private boolean is2Power(int num) { |
| if (num < 2) { |
| return false; |
| } |
| return (num & num - 1) == 0; |
| } |
| } |