org.apache.druid.indexing.overlord.autoscaling.ScalingStats.java Source code

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Here is the source code for org.apache.druid.indexing.overlord.autoscaling.ScalingStats.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more 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, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.druid.indexing.overlord.autoscaling;

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonValue;
import com.google.common.collect.Lists;
import com.google.common.collect.MinMaxPriorityQueue;
import com.google.common.collect.Ordering;
import org.apache.druid.guice.annotations.PublicApi;
import org.apache.druid.java.util.common.DateTimes;
import org.joda.time.DateTime;

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 */
@PublicApi
public class ScalingStats {
    public enum EVENT {
        PROVISION, TERMINATE
    }

    private static final Comparator<ScalingEvent> COMPARATOR = new Ordering<ScalingEvent>() {
        @Override
        public int compare(ScalingEvent s1, ScalingEvent s2) {
            return s2.getTimestamp().compareTo(s1.getTimestamp());
        }
    }.nullsLast();

    private final Object lock = new Object();

    private final MinMaxPriorityQueue<ScalingEvent> recentEvents;

    public ScalingStats(int capacity) {
        if (capacity == 0) {
            this.recentEvents = MinMaxPriorityQueue.orderedBy(COMPARATOR).create();
        } else {
            this.recentEvents = MinMaxPriorityQueue.orderedBy(COMPARATOR).maximumSize(capacity).create();
        }
    }

    /**
     * This method is unused, but ScalingStats is {@link PublicApi}, so we cannot remove it.
     * TODO test this method (it will "count" as usage)
     */
    @SuppressWarnings("unused")
    public void addAll(ScalingStats stats) {
        synchronized (lock) {
            synchronized (stats.lock) {
                recentEvents.addAll(stats.recentEvents);
            }
        }
    }

    public void addProvisionEvent(AutoScalingData data) {
        synchronized (lock) {
            recentEvents.add(new ScalingEvent(data, DateTimes.nowUtc(), EVENT.PROVISION));
        }
    }

    public void addTerminateEvent(AutoScalingData data) {
        synchronized (lock) {
            recentEvents.add(new ScalingEvent(data, DateTimes.nowUtc(), EVENT.TERMINATE));
        }
    }

    @JsonValue
    public List<ScalingEvent> toList() {
        synchronized (lock) {
            List<ScalingEvent> retVal = Lists.newArrayList(recentEvents);
            Collections.sort(retVal, COMPARATOR);
            return retVal;
        }
    }

    public static class ScalingEvent {
        private final AutoScalingData data;
        private final DateTime timestamp;
        private final EVENT event;

        private ScalingEvent(AutoScalingData data, DateTime timestamp, EVENT event) {
            this.data = data;
            this.timestamp = timestamp;
            this.event = event;
        }

        @JsonProperty
        public AutoScalingData getData() {
            return data;
        }

        @JsonProperty
        public DateTime getTimestamp() {
            return timestamp;
        }

        @JsonProperty
        public EVENT getEvent() {
            return event;
        }

        @Override
        public String toString() {
            return "ScalingEvent{" + "data=" + data + ", timestamp=" + timestamp + ", event=" + event + '}';
        }
    }
}