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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.controller.maintenance;
import com.yahoo.component.AbstractComponent;
import com.yahoo.config.provision.HostName;
import com.yahoo.config.provision.SystemName;
import com.yahoo.vespa.curator.Lock;
import com.yahoo.vespa.hosted.controller.Controller;
import java.time.Duration;
import java.time.Instant;
import java.util.EnumSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A maintainer is some job which runs at a fixed interval to perform some maintenance task in the controller.
*
* @author bratseth
*/
public abstract class Maintainer extends AbstractComponent implements Runnable {
protected static final Logger log = Logger.getLogger(Maintainer.class.getName());
private final Controller controller;
private final Duration maintenanceInterval;
private final JobControl jobControl;
private final ScheduledExecutorService service;
private final String name;
/** The systems in which this maintainer should run */
private final Set<SystemName> activeSystems;
public Maintainer(Controller controller, Duration interval, JobControl jobControl) {
this(controller, interval, jobControl, null, EnumSet.allOf(SystemName.class));
}
public Maintainer(Controller controller, Duration interval, JobControl jobControl, String name, Set<SystemName> activeSystems) {
if (interval.isNegative() || interval.isZero())
throw new IllegalArgumentException("Interval must be positive, but was " + interval);
this.controller = controller;
this.maintenanceInterval = interval;
this.jobControl = jobControl;
this.name = name;
this.activeSystems = Set.copyOf(activeSystems);
service = new ScheduledThreadPoolExecutor(1);
long delay = staggeredDelay(controller.curator().cluster(), controller.hostname(), controller.clock().instant(), interval);
service.scheduleAtFixedRate(this, delay, interval.toMillis(), TimeUnit.MILLISECONDS);
jobControl.started(name());
}
protected Controller controller() { return controller; }
@Override
public void run() {
try {
if ( ! activeSystems.contains(controller.system())) {
return;
}
if (jobControl.isActive(name())) {
try (Lock lock = jobControl.curator().lockMaintenanceJob(name())) {
maintain();
}
}
}
catch (TimeoutException e) {
// another controller instance is running this job at the moment; ok
}
catch (Throwable t) {
log.log(Level.WARNING, this + " failed. Will retry in " + maintenanceInterval.toMinutes() + " minutes", t);
}
}
@Override
public void deconstruct() {
this.service.shutdown();
}
/** Called once each time this maintenance job should run */
protected abstract void maintain();
public Duration maintenanceInterval() { return maintenanceInterval; }
public final String name() {
return name == null ? this.getClass().getSimpleName() : name;
}
/** Returns the name of this */
@Override
public final String toString() {
return name();
}
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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