[GitHub] metron pull request #1039: METRON-1588 Migrate storm-kafka-client to 1.2.1

[HeartSaVioR <gi...@git.apache.org>]

Github user HeartSaVioR commented on a diff in the pull request:

    https://github.com/apache/metron/pull/1039#discussion_r192273701
  
    --- Diff: metron-platform/metron-storm-kafka-override/src/main/java/org/apache/storm/kafka/spout/KafkaSpoutRetryExponentialBackoff.java ---
    @@ -0,0 +1,328 @@
    +/*
    + * 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.storm.kafka.spout;
    +
    +import org.apache.kafka.common.TopicPartition;
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import java.io.Serializable;
    +import java.util.Collection;
    +import java.util.Comparator;
    +import java.util.HashMap;
    +import java.util.HashSet;
    +import java.util.Iterator;
    +import java.util.Map;
    +import java.util.Set;
    +import java.util.TreeSet;
    +import java.util.concurrent.TimeUnit;
    +import org.apache.commons.lang.Validate;
    +import org.apache.kafka.clients.consumer.ConsumerRecord;
    +
    +/**
    + * Implementation of {@link KafkaSpoutRetryService} using the exponential backoff formula. The time of the nextRetry is set as follows:
    + * nextRetry = failCount == 1 ? currentTime + initialDelay : currentTime + delayPeriod*2^(failCount-1)    where failCount = 1, 2, 3, ...
    + * nextRetry = Min(nextRetry, currentTime + maxDelay)
    + */
    +public class KafkaSpoutRetryExponentialBackoff implements KafkaSpoutRetryService {
    --- End diff --
    
    I guess we don't strictly need to describe it to the NOTICE file, since it is pretty common for ASF project to pull file from another project, and modify it. Sometimes this brings complain in back channel, but if my understanding is right, it is just allowed from the ASLv2 license definition.
    
    In many cases people add the comment "the class is inspired by blabla..." if the file is modified. In other cases people don't describe the fact that the file is pulled from another project. I believe former would be nicer and it's the way to respect original author and project.
    
    So I'll add the comment in the class for now.
    
    @ottobackwards Please suggest which sentence is proper to add to NOTICE file. I'll follow your suggestion.


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