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ASF GitHub Bot commented on APEXMALHAR-2086: -------------------------------------------- Github user chinmaykolhatkar commented on a diff in the pull request: https://github.com/apache/apex-malhar/pull/298#discussion_r66693682 --- Diff: kafka/src/main/java/org/apache/apex/malhar/kafka/AbstractExactlyOnceKafkaOutputOperator.java --- @@ -0,0 +1,366 @@ +/** + * 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.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; +import static org.apache.kafka.clients.producer.ProducerConfig.ACKS_CONFIG; + +/** + * Kafka output operator with exactly once processing semantics under certain conditions., + * + * Requirement for Exactly Once: + * Every message within the Window is unique + * + * 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 Abstract Exactly Once Kafka Output(0.9.0) + * @category Messaging + * @tags output operator + * + * @since 3.5 --- End diff -- Can you remove @since? They'll get added during release time. > 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)