gobblin.util.limiter.RateBasedLimiter.java Source code

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Here is the source code for gobblin.util.limiter.RateBasedLimiter.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 gobblin.util.limiter;

import java.io.Closeable;
import java.util.concurrent.TimeUnit;

import com.google.common.primitives.Ints;
import com.google.common.util.concurrent.RateLimiter;
import com.typesafe.config.Config;

import gobblin.annotation.Alias;

import lombok.Getter;

/**
 * An implementation of {@link Limiter} that limits the rate of some events. This implementation uses
 * Guava's {@link RateLimiter}.
 *
 * <p>
 *   {@link #acquirePermits(long)} is blocking and will always return {@link true} after the permits
 *   are successfully acquired (probably after being blocked for some amount of time). Permit refills
 *   are not supported in this implementation. Also {@link #acquirePermits(long)} only accepts input
 *   arguments that can be safely casted to an integer bounded by {@link Integer#MAX_VALUE}.
 * </p>
 *
 * @author Yinan Li
 */
public class RateBasedLimiter extends NonRefillableLimiter {

    @Alias(value = "qps")
    public static class Factory implements LimiterFactory {
        public static final String QPS_KEY = "qps";

        @Override
        public Limiter buildLimiter(Config config) {
            if (!config.hasPath(QPS_KEY)) {
                throw new RuntimeException("Missing key " + QPS_KEY);
            }
            return new RateBasedLimiter(config.getLong(QPS_KEY));
        }
    }

    private final RateLimiter rateLimiter;
    @Getter
    private double rateLimitPerSecond;

    public RateBasedLimiter(double rateLimit) {
        this(rateLimit, TimeUnit.SECONDS);
    }

    public RateBasedLimiter(double rateLimit, TimeUnit timeUnit) {
        this.rateLimitPerSecond = convertRate(rateLimit, timeUnit, TimeUnit.SECONDS);
        this.rateLimiter = RateLimiter.create(this.rateLimitPerSecond);
    }

    @Override
    public void start() {
        // Nothing to do
    }

    @Override
    public Closeable acquirePermits(long permits) throws InterruptedException {
        this.rateLimiter.acquire(Ints.checkedCast(permits));
        return NO_OP_CLOSEABLE;
    }

    @Override
    public void stop() {
        // Nothing to do
    }

    private static double convertRate(double originalRate, TimeUnit originalTimeUnit, TimeUnit targetTimeUnit) {
        return originalRate / targetTimeUnit.convert(1, originalTimeUnit);
    }
}