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ASF GitHub Bot commented on APEXMALHAR-2086: -------------------------------------------- Github user siyuanh commented on a diff in the pull request: https://github.com/apache/apex-malhar/pull/298#discussion_r68181344 --- Diff: kafka/src/main/java/org/apache/apex/malhar/kafka/KafkaSinglePortExactlyOnceOutputOperator.java --- @@ -0,0 +1,369 @@ +/** + * 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.apex.malhar.kafka; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Properties; +import java.util.concurrent.ExecutionException; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.apex.malhar.lib.wal.FSWindowDataManager; +import org.apache.apex.malhar.lib.wal.WindowDataManager; + +import org.apache.kafka.clients.consumer.ConsumerRecord; +import org.apache.kafka.clients.consumer.ConsumerRecords; +import org.apache.kafka.clients.consumer.KafkaConsumer; +import org.apache.kafka.clients.producer.ProducerRecord; +import org.apache.kafka.common.PartitionInfo; +import org.apache.kafka.common.TopicPartition; + +import com.datatorrent.api.Context; +import com.datatorrent.api.DefaultInputPort; +import com.datatorrent.api.Operator; + +import static org.apache.kafka.clients.consumer.ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG; +import static org.apache.kafka.clients.consumer.ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG; +import static org.apache.kafka.clients.consumer.ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG; + +/** + * Kafka output operator with exactly once processing semantics under certain conditions., + * + * This operator uses *Key* to distinguish the messages written by particular instance of the Output operator. + * Operator users can only use *value* for storing the data. + * + * @displayName Single Port Exactly Once Kafka Output(0.9.0) + * @category Messaging + * @tags output operator + * + */ +@org.apache.hadoop.classification.InterfaceStability.Evolving +public class KafkaSinglePortExactlyOnceOutputOperator<T> extends AbstractKafkaOutputOperator<String, T> + implements Operator.CheckpointNotificationListener +{ + private transient String key; + private transient String appName; + private transient Integer operatorId; + private transient Long windowId; + private transient Map<T, Integer> partialWindowTuples = new HashMap<>(); + private transient KafkaConsumer consumer; + + private WindowDataManager windowDataManager = new FSWindowDataManager(); + private final int KAFKA_CONNECT_ATTEMPT = 10; + private final String KEY_SEPARATOR = "#"; + private final String KEY_SERIALIZER = "org.apache.kafka.common.serialization.StringDeserializer"; + private final String VALUE_SERIALIZER = "org.apache.kafka.common.serialization.StringDeserializer"; + + public final transient DefaultInputPort<T> inputPort = new DefaultInputPort<T>() + { + @Override + public void process(T tuple) + { + sendTuple(tuple); + } + }; + + @Override + public void setup(Context.OperatorContext context) + { + super.setup(context); + + this.operatorId = context.getId(); + this.windowDataManager.setup(context); + this.appName = context.getValue(Context.DAGContext.APPLICATION_NAME); + this.key = appName + KEY_SEPARATOR + (new Integer(operatorId)); + this.consumer = KafkaConsumerInit(); + } + + @Override + public void beginWindow(long windowId) + { + this.windowId = windowId; + + if (windowId == windowDataManager.getLargestRecoveryWindow()) { + rebuildPartialWindow(); + } + } + + @Override + public void checkpointed(long windowId) + { + } + + @Override + public void committed(long windowId) + { + try { + windowDataManager.deleteUpTo(operatorId, windowId); + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + @Override + public void beforeCheckpoint(long windowId) + { + } + + @Override + public void teardown() + { + consumer.close(); + super.teardown(); + } + + @Override + public void endWindow() + { + if (!partialWindowTuples.isEmpty() && windowId > windowDataManager.getLargestRecoveryWindow()) { + throw new RuntimeException("Violates Exactly once. Not all the tuples received after operator reset."); + } + + try { + this.windowDataManager.save(getPartitionsAndOffsets(), operatorId, windowId); + } catch (IOException e) { + throw new RuntimeException(e); + } catch (InterruptedException e) { + e.printStackTrace(); + } catch (ExecutionException e) { + e.printStackTrace(); + } + } + + public WindowDataManager getWindowDataManager() + { + return windowDataManager; + } + + public void setWindowDataManager(WindowDataManager windowDataManager) + { + this.windowDataManager = windowDataManager; + } + + private boolean doesKeyBelongsToThisInstance(Integer operatorId, String key) + { + String[] split = key.split(KEY_SEPARATOR); + + if (split.length != 2) { + return false; + } + + if ((Integer.parseInt(split[1]) == operatorId) && (split[0].equals(appName))) { + return true; + } + + return false; + } + + private boolean alreadyInKafka(T message) + { + if ( windowId <= windowDataManager.getLargestRecoveryWindow() ) { + return true; + } + + if (partialWindowTuples.containsKey(message)) { + + Integer val = partialWindowTuples.get(message); + + if ( val == 0 ) { + return false; + } else if ( val == 1 ) { + partialWindowTuples.remove(message); + } else { + partialWindowTuples.put(message, val - 1); + } + + return true; + } + + return false; + } + + private Map<Integer,Long> getPartitionsAndOffsets() throws ExecutionException, InterruptedException + { + List<PartitionInfo> partitionInfoList = consumer.partitionsFor(getTopic()); + List<TopicPartition> topicPartitionList = new java.util.ArrayList<>(); + + for ( PartitionInfo partitionInfo: partitionInfoList) { + topicPartitionList.add(new TopicPartition(getTopic(), partitionInfo.partition()) ); + } + + Map<Integer,Long> parttionsAndOffset = new HashMap<>(); + consumer.assign(topicPartitionList); + + for ( PartitionInfo partitionInfo: partitionInfoList) { + + try { + + TopicPartition topicPartition = new TopicPartition(getTopic(), partitionInfo.partition()); + consumer.seekToEnd(topicPartition); + parttionsAndOffset.put(partitionInfo.partition(), consumer.position(topicPartition)); + + } catch (Exception ex) { + throw new RuntimeException(ex); + } + } + + return parttionsAndOffset; + } + + private void rebuildPartialWindow() + { + logger.info("Rebuild the partial window after " + windowDataManager.getLargestRecoveryWindow()); + + Map<Integer,Long> storedOffsets = getStoredOffsets(); + Map<Integer,Long> currentOffsets = getCurrentOffsets(); + + if (storedOffsets == null || currentOffsets == null) { + logger.debug("No tuples found while building partial window " + windowDataManager.getLargestRecoveryWindow()); + return; + } + + List<TopicPartition> topicPartitions = new ArrayList<>(); + + for (Map.Entry<Integer,Long> entry: currentOffsets.entrySet()) { + + topicPartitions.add(new TopicPartition(getTopic(), entry.getKey())); + } + + consumer.assign(topicPartitions); + + for (Map.Entry<Integer,Long> entry: currentOffsets.entrySet()) { + + Long storedOffset = 0L; + Integer currentPartition = entry.getKey(); + Long currentOffset = entry.getValue(); + + if (storedOffsets.containsKey(currentPartition)) { + storedOffset = storedOffsets.get(currentPartition); + } + + if (storedOffset >= currentOffset) { + continue; + } + + consumer.seek(new TopicPartition(getTopic(), currentPartition), storedOffset); + + int kafkaAttempt = 0; + + while ( true ) { + + ConsumerRecords<String, String> consumerRecords = consumer.poll(100); + + if (consumerRecords.count() == 0) { + if (kafkaAttempt++ == KAFKA_CONNECT_ATTEMPT) { + break; + } + } else { + kafkaAttempt = 0; + } + + boolean crossedBoundary = false; + + for (ConsumerRecord consumerRecord : consumerRecords) { + + if (!doesKeyBelongsToThisInstance(operatorId, (String)consumerRecord.key())) { + continue; + } + + T value = (T)consumerRecord.value(); + + if ( partialWindowTuples.containsKey(value)) { + Integer count = partialWindowTuples.get(value); + partialWindowTuples.put(value, count + 1); + } else { + partialWindowTuples.put(value, 1); + } + + if (consumerRecord.offset() >= currentOffset) { + crossedBoundary = true; + break; + } + } + + if (crossedBoundary) { + break; + } + } + } + } + + private Map<Integer,Long> getCurrentOffsets() + { + Map<Integer, Long> currentOffsets; + + try { + currentOffsets = getPartitionsAndOffsets(); + } catch (ExecutionException e) { + throw new RuntimeException(e); + } catch (InterruptedException e) { + throw new RuntimeException(e); + } + + return currentOffsets; + } + + private Map<Integer,Long> getStoredOffsets() + { + Map<Integer,Long> storedOffsets; + + try { + storedOffsets = (Map<Integer,Long>)this.windowDataManager.load(operatorId, windowId); + } catch (IOException e) { + throw new RuntimeException(e); + } + + return storedOffsets; + } + + private KafkaConsumer KafkaConsumerInit() + { + Properties props = new Properties(); + + props.put(BOOTSTRAP_SERVERS_CONFIG, getProperties().get(BOOTSTRAP_SERVERS_CONFIG)); + props.put(KEY_DESERIALIZER_CLASS_CONFIG, KEY_SERIALIZER); + props.put(VALUE_DESERIALIZER_CLASS_CONFIG, VALUE_SERIALIZER); + + return new KafkaConsumer<>(props); + } + + protected void sendTuple(T tuple) + { + if ( alreadyInKafka(tuple) ) { + return; + } + + try { + getProducer().send(new ProducerRecord<>(getTopic(), key, tuple)).get(); --- End diff -- Use the send(ProducerRecord<K,V> record, Callback callback) method, In callback if there is any exception, you can simply throw exception to fail the operator. > Kafka Output Operator with Kafka 0.9 API > ---------------------------------------- > > Key: APEXMALHAR-2086 > URL: https://issues.apache.org/jira/browse/APEXMALHAR-2086 > Project: Apache Apex Malhar > Issue Type: New Feature > Reporter: Sandesh > Assignee: Sandesh > > Goal : 2 Operartors for Kafka Output > 1. Simple Kafka Output Operator > - Supports Atleast Once > - Expose most used producer properties as class properties > 2. Exactly Once Kafka Output ( Not possible in all the cases, will be > documented later ) > > Design for Exactly Once > Window Data Manager - Stores the Kafka partitions offsets. > Kafka Key - Used by the operator = AppID#OperatorId > During recovery. Partially written window is re-created using the following > approach: > Tuples between the largest recovery offsets and the current offset are > checked. Based on the key, tuples written by the other entities are > discarded. > Only tuples which are not in the recovered set are emitted. > Tuples needs to be unique within the window. > -- This message was sent by Atlassian JIRA (v6.3.4#6332)