org.apache.flink.runtime.scheduler.DefaultSyncPreferredLocationsRetriever Maven / Gradle / Ivy
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* 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.flink.runtime.scheduler;
import org.apache.flink.runtime.scheduler.strategy.ExecutionVertexID;
import org.apache.flink.runtime.taskmanager.TaskManagerLocation;
import org.apache.flink.util.Preconditions;
import java.util.Collection;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
/**
* Synchronous version of {@link DefaultPreferredLocationsRetriever}.
*
* This class turns {@link DefaultPreferredLocationsRetriever} into {@link
* SyncPreferredLocationsRetriever}. The method {@link #getPreferredLocations(ExecutionVertexID,
* Set)} does not return {@link CompletableFuture} of preferred locations, it returns only locations
* which are available immediately. This behaviour is achieved by wrapping the original {@link
* InputsLocationsRetriever} with {@link AvailableInputsLocationsRetriever} and hence making it
* synchronous without blocking. As {@link StateLocationRetriever} is already synchronous, the
* overall location retrieval becomes synchronous without blocking.
*/
class DefaultSyncPreferredLocationsRetriever implements SyncPreferredLocationsRetriever {
private final PreferredLocationsRetriever asyncPreferredLocationsRetriever;
DefaultSyncPreferredLocationsRetriever(
StateLocationRetriever stateLocationRetriever,
InputsLocationsRetriever inputsLocationsRetriever) {
this.asyncPreferredLocationsRetriever =
new DefaultPreferredLocationsRetriever(
stateLocationRetriever,
new AvailableInputsLocationsRetriever(inputsLocationsRetriever));
}
@Override
public Collection getPreferredLocations(
ExecutionVertexID executionVertexId, Set producersToIgnore) {
CompletableFuture> preferredLocationsFuture =
asyncPreferredLocationsRetriever.getPreferredLocations(
executionVertexId, producersToIgnore);
Preconditions.checkState(preferredLocationsFuture.isDone());
// it is safe to do the blocking call here
// as the underlying InputsLocationsRetriever returns only immediately available locations
return preferredLocationsFuture.join();
}
}