org.apache.pulsar.functions.instance.FunctionResultRouter Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* 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
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package org.apache.pulsar.functions.instance;
import com.google.common.annotations.VisibleForTesting;
import java.time.Clock;
import java.util.concurrent.ThreadLocalRandom;
import org.apache.pulsar.client.api.HashingScheme;
import org.apache.pulsar.client.api.Message;
import org.apache.pulsar.client.api.TopicMetadata;
import org.apache.pulsar.client.impl.RoundRobinPartitionMessageRouterImpl;
/**
* Router for routing function results.
*/
public class FunctionResultRouter extends RoundRobinPartitionMessageRouterImpl {
private static final FunctionResultRouter INSTANCE = new FunctionResultRouter();
public FunctionResultRouter() {
this(Math.abs(ThreadLocalRandom.current().nextInt()), Clock.systemUTC());
}
@VisibleForTesting
public FunctionResultRouter(int startPtnIdx, Clock clock) {
super(
HashingScheme.Murmur3_32Hash,
startPtnIdx,
true,
1,
clock);
}
public static FunctionResultRouter of() {
return INSTANCE;
}
@Override
public int choosePartition(Message msg, TopicMetadata metadata) {
// if key is specified, we should use key as routing;
// if key is not specified and no sequence id is provided, not an effectively-once publish, use the default
// round-robin routing.
if (msg.hasKey() || msg.getSequenceId() < 0) {
// TODO: the message key routing is problematic at this moment.
// https://github.com/apache/pulsar/pull/1029 is fixing that.
return super.choosePartition(msg, metadata);
}
// if there is no key and sequence id is provided, it is an effectively-once publish, we need to ensure
// for a given message it always go to one partition, so we use sequence id to do a deterministic routing.
return (int) (msg.getSequenceId() % metadata.numPartitions());
}
}