/**
* This file is part of Graylog2.
*
* Graylog2 is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Graylog2 is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Graylog2. If not, see <http://www.gnu.org/licenses/>.
*/
package org.graylog2.indexer.rotation;
import com.google.inject.Inject;
import org.graylog2.Configuration;
import org.graylog2.plugin.Tools;
import org.graylog2.plugin.indexer.rotation.RotationStrategy;
import org.joda.time.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.Nonnull;
import javax.inject.Singleton;
import java.text.MessageFormat;
import static org.joda.time.DateTimeFieldType.*;
@Singleton
public class TimeBasedRotationStrategy implements RotationStrategy {
private static final Logger log = LoggerFactory.getLogger(TimeBasedRotationStrategy.class);
private final Period rotationPeriod;
private DateTime lastRotation;
private DateTime anchor;
@Inject
public TimeBasedRotationStrategy(Configuration configuration) {
this(configuration.getElasticSearchMaxTimePerIndex());
}
public TimeBasedRotationStrategy(Period rotationPeriod) {
this.rotationPeriod = rotationPeriod.normalizedStandard();
anchor = determineRotationPeriodAnchor(rotationPeriod);
lastRotation = null;
}
/**
* Determines the starting point ("anchor") for a period.
*
* To produce repeatable rotation points in time, the period is "snapped" to a "grid" of time.
* For example, an hourly index rotation would be anchored to the last full hour, instead of happening at whatever minute
* the first rotation was started.
*
* This "snapping" is done accordingly with the other parts of a period.
*
* For highly irregular periods (those that do not have a small zero component)
*
* @param period the rotation period
* @return the anchor DateTime to calculate rotation periods from
*/
protected static DateTime determineRotationPeriodAnchor(Period period) {
final Period normalized = period.normalizedStandard();
int years = normalized.getYears();
int months = normalized.getMonths();
int weeks = normalized.getWeeks();
int days = normalized.getDays();
int hours = normalized.getHours();
int minutes = normalized.getMinutes();
int seconds = normalized.getSeconds();
if (years == 0 && months == 0 && weeks == 0 && days == 0 && hours == 0 && minutes == 0 && seconds == 0) {
throw new IllegalArgumentException("Invalid rotation period specified");
}
// find the largest non-zero stride in the period. that's our anchor type. statement order matters here!
DateTimeFieldType largestStrideType = null;
if (seconds > 0) largestStrideType = secondOfMinute();
if (minutes > 0) largestStrideType = minuteOfHour();
if (hours > 0) largestStrideType = hourOfDay();
if (days > 0) largestStrideType = dayOfMonth();
if (weeks > 0) largestStrideType = weekOfWeekyear();
if (months > 0) largestStrideType = monthOfYear();
if (years > 0) largestStrideType = year();
if (largestStrideType == null) {
throw new IllegalArgumentException("Could not determine rotation stride length.");
}
final DateTime now = Tools.iso8601();
final DateTimeField field = largestStrideType.getField(now.getChronology());
final int periodValue = period.get(largestStrideType.getDurationType());
final long fieldValue = field.roundFloor(now.getMillis());
final int fieldValueInUnit = field.get(fieldValue);
final long difference = (fieldValueInUnit % periodValue);
final long newValue = field.add(fieldValue, -1 * difference);
return new DateTime(newValue, DateTimeZone.UTC);
}
@Nonnull
@Override
public Result shouldRotate(String ignored) {
// in case we could not determine the last time a time-based rotation was performed, always rotate immediately
final DateTime now = Tools.iso8601();
if (lastRotation == null) {
lastRotation = now;
anchor = determineRotationPeriodAnchor(rotationPeriod);
return new SimpleResult(true, "No known previous rotation time, forcing index rotation now.");
}
final DateTime nextRotation = anchor.plus(rotationPeriod);
if (nextRotation.isAfter(now)) {
return new SimpleResult(false, MessageFormat.format("Next rotation at {0}", nextRotation));
}
// determine new anchor (push it to within less then one period before now) in case we missed one or more periods
DateTime tmpAnchor;
int multiplicator = 0;
do {
tmpAnchor = anchor.withPeriodAdded(rotationPeriod, ++multiplicator);
} while (tmpAnchor.isBefore(now));
anchor = anchor.withPeriodAdded(rotationPeriod, multiplicator - 1);
lastRotation = now;
return new SimpleResult(true, MessageFormat.format("Rotation period {0} elapsed, next rotation at {1}", rotationPeriod, anchor));
}
private static class SimpleResult implements Result {
private final String message;
private final boolean rotate;
public SimpleResult(boolean rotate, String message) {
this.message = message;
this.rotate = rotate;
log.debug("{} because of: {}", rotate ? "Rotating" : "Not rotating", message);
}
@Override
public String getDescription() {
return message;
}
@Override
public boolean shouldRotate() {
return rotate;
}
}
}