org.apache.kafka.streams.processor.internals.assignment.StandbyTaskAssignmentUtils Maven / Gradle / Ivy
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* 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,
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package org.apache.kafka.streams.processor.internals.assignment;
import org.apache.kafka.streams.processor.TaskId;
import org.slf4j.Logger;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
import java.util.function.Function;
import static java.util.stream.Collectors.toMap;
final class StandbyTaskAssignmentUtils {
private StandbyTaskAssignmentUtils() {}
static ConstrainedPrioritySet createLeastLoadedPrioritySetConstrainedByAssignedTask(final Map clients) {
return new ConstrainedPrioritySet((client, t) -> !clients.get(client).hasAssignedTask(t),
client -> clients.get(client).assignedTaskLoad());
}
static void pollClientAndMaybeAssignAndUpdateRemainingStandbyTasks(final int numStandbyReplicas,
final Map clients,
final Map tasksToRemainingStandbys,
final ConstrainedPrioritySet standbyTaskClientsByTaskLoad,
final TaskId activeTaskId,
final Logger log) {
int numRemainingStandbys = tasksToRemainingStandbys.get(activeTaskId);
while (numRemainingStandbys > 0) {
final UUID client = standbyTaskClientsByTaskLoad.poll(activeTaskId);
if (client == null) {
break;
}
clients.get(client).assignStandby(activeTaskId);
numRemainingStandbys--;
standbyTaskClientsByTaskLoad.offer(client);
tasksToRemainingStandbys.put(activeTaskId, numRemainingStandbys);
}
if (numRemainingStandbys > 0) {
log.warn("Unable to assign {} of {} standby tasks for task [{}]. " +
"There is not enough available capacity. You should " +
"increase the number of application instances " +
"to maintain the requested number of standby replicas.",
numRemainingStandbys, numStandbyReplicas, activeTaskId);
}
}
static Map computeTasksToRemainingStandbys(final int numStandbyReplicas,
final Set statefulTaskIds) {
return statefulTaskIds.stream().collect(toMap(Function.identity(), t -> numStandbyReplicas));
}
}