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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.provision.maintenance;
import com.yahoo.component.AbstractComponent;
import com.yahoo.config.provision.HostName;
import com.yahoo.vespa.hosted.provision.NodeRepository;
import java.time.Duration;
import java.time.Instant;
import java.util.List;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A maintainer is some job which runs at a fixed rate to perform some maintenance task on the node repo.
*
* @author bratseth
*/
public abstract class Maintainer extends AbstractComponent implements Runnable {
protected final Logger log = Logger.getLogger(this.getClass().getName());
private final NodeRepository nodeRepository;
private final Duration interval;
private final JobControl jobControl;
private final ScheduledExecutorService service;
public Maintainer(NodeRepository nodeRepository, Duration interval, JobControl jobControl) {
this.nodeRepository = nodeRepository;
this.interval = interval;
this.jobControl = jobControl;
HostName hostname = HostName.from(com.yahoo.net.HostName.getLocalhost());
long delay = staggeredDelay(nodeRepository.database().cluster(), hostname, nodeRepository.clock().instant(), interval);
service = new ScheduledThreadPoolExecutor(1);
service.scheduleAtFixedRate(this, delay, interval.toMillis(), TimeUnit.MILLISECONDS);
jobControl.started(name());
}
/** Returns the node repository */
protected NodeRepository nodeRepository() { return nodeRepository; }
protected static Duration min(Duration a, Duration b) {
return a.toMillis() < b.toMillis() ? a : b;
}
/** Returns the interval at which this job is set to run */
protected Duration interval() { return interval; }
@Override
public void run() {
try {
if (jobControl.isActive(name()))
maintain();
} catch (Throwable e) {
log.log(Level.WARNING, this + " failed. Will retry in " + interval.toMinutes() + " minutes", e);
}
}
@Override
public void deconstruct() {
this.service.shutdown();
}
/** Returns the simple name of this job */
@Override
public final String toString() { return name(); }
/** Called once each time this maintenance job should run */
protected abstract void maintain();
private String name() { return this.getClass().getSimpleName(); }
static long staggeredDelay(List<HostName> cluster, HostName host, Instant now, Duration interval) {
if ( ! cluster.contains(host))
return interval.toMillis();
long offset = cluster.indexOf(host) * interval.toMillis() / cluster.size();
long timeUntilNextRun = Math.floorMod(offset - now.toEpochMilli(), interval.toMillis());
return timeUntilNextRun + interval.toMillis() / cluster.size();
}
}
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