/**
* Copyright (C) 2013 Open WhisperSystems
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.whispersystems.textsecuregcm.limits;
import com.codahale.metrics.Meter;
import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.SharedMetricRegistries;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.whispersystems.textsecuregcm.controllers.RateLimitExceededException;
import org.whispersystems.textsecuregcm.util.Constants;
import org.whispersystems.textsecuregcm.util.SystemMapper;
import java.io.IOException;
import static com.codahale.metrics.MetricRegistry.name;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
public class RateLimiter {
private final Logger logger = LoggerFactory.getLogger(RateLimiter.class);
private final ObjectMapper mapper = SystemMapper.getMapper();
private final Meter meter;
private final JedisPool cacheClient;
private final String name;
private final int bucketSize;
private final double leakRatePerMillis;
public RateLimiter(JedisPool cacheClient, String name,
int bucketSize, double leakRatePerMinute)
{
MetricRegistry metricRegistry = SharedMetricRegistries.getOrCreate(Constants.METRICS_NAME);
this.meter = metricRegistry.meter(name(getClass(), name, "exceeded"));
this.cacheClient = cacheClient;
this.name = name;
this.bucketSize = bucketSize;
this.leakRatePerMillis = leakRatePerMinute / (60.0 * 1000.0);
}
public void validate(String key, int amount) throws RateLimitExceededException {
LeakyBucket bucket = getBucket(key);
if (bucket.add(amount)) {
setBucket(key, bucket);
} else {
meter.mark();
throw new RateLimitExceededException(key + " , " + amount);
}
}
public void validate(String key) throws RateLimitExceededException {
validate(key, 1);
}
private void setBucket(String key, LeakyBucket bucket) {
try (Jedis jedis = cacheClient.getResource()) {
String serialized = bucket.serialize(mapper);
jedis.setex(getBucketName(key), (int) Math.ceil((bucketSize / leakRatePerMillis) / 1000), serialized);
} catch (JsonProcessingException e) {
throw new IllegalArgumentException(e);
}
}
private LeakyBucket getBucket(String key) {
try (Jedis jedis = cacheClient.getResource()) {
String serialized = jedis.get(getBucketName(key));
if (serialized != null) {
return LeakyBucket.fromSerialized(mapper, serialized);
}
} catch (IOException e) {
logger.warn("Deserialization error", e);
}
return new LeakyBucket(bucketSize, leakRatePerMillis);
}
private String getBucketName(String key) {
return "leaky_bucket::" + name + "::" + key;
}
}