org.apache.hadoop.hdfs.LeaseRenewal.java Source code

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Here is the source code for org.apache.hadoop.hdfs.LeaseRenewal.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.hadoop.hdfs;

import java.io.IOException;
import java.net.SocketException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.protocol.FSConstants;
import org.apache.hadoop.ipc.Client;

public abstract class LeaseRenewal implements Runnable {
    public volatile boolean running;
    private final String clientName;
    private final Configuration conf;
    private final Log LOG = LogFactory.getLog(LeaseRenewal.class);

    public LeaseRenewal(String clientName, Configuration conf) {
        this.clientName = clientName;
        this.conf = conf;
        running = true;
    }

    /**
     * This method is called each time we need to renew the lease.
     * 
     * @throws IOException
     */
    protected abstract void renew() throws IOException;

    /**
     * This method is invoked when our LeaseRenewal thread is aborting.
     */
    protected abstract void abort();

    /**
     * Computes the renewal period for the lease.
     * 
     * @return the renewal period in ms
     */
    private long computeRenewalPeriod() {
        long hardLeaseLimit = conf.getLong(FSConstants.DFS_HARD_LEASE_KEY, FSConstants.LEASE_HARDLIMIT_PERIOD);
        long softLeaseLimit = conf.getLong(FSConstants.DFS_SOFT_LEASE_KEY, FSConstants.LEASE_SOFTLIMIT_PERIOD);
        long renewal = Math.min(hardLeaseLimit, softLeaseLimit) / 2;
        long hdfsTimeout = Client.getTimeout(conf);
        if (hdfsTimeout > 0) {
            renewal = Math.min(renewal, hdfsTimeout / 2);
        }
        return renewal;
    }

    private void renewalSleep() {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException ie) {
            if (LOG.isDebugEnabled()) {
                LOG.debug(this + " is interrupted.", ie);
            }
            // Shutdown lease renewal.
            running = false;
            return;
        }
    }

    public void closeRenewal() {
        running = false;
    }

    @Override
    public void run() {
        long lastRenewed = 0;
        int retries = 0;
        long renewal = computeRenewalPeriod();
        int maxRetries = conf.getInt("dfs.lease.renewal.retries", FSConstants.MAX_LEASE_RENEWAL_RETRIES);
        while (running && !Thread.interrupted()) {
            if (System.currentTimeMillis() - lastRenewed > renewal) {
                try {
                    renew();
                    lastRenewed = System.currentTimeMillis();
                    retries = 0;
                } catch (SocketException ie) {
                    retries++;
                    LOG.warn("Can't renew lease for " + clientName + " for a period of " + (renewal / 1000)
                            + " seconds because NameNode is not reachable. Retried " + retries + " out of "
                            + maxRetries, ie);
                    if (retries > maxRetries) {
                        LOG.warn("Can't renew lease for " + clientName + " for a period of " + (renewal / 1000)
                                + " seconds because NameNode is not reachable. Shutting down HDFS client...", ie);
                        abort();
                        break;
                    }
                } catch (IOException ie) {
                    LOG.warn("Problem renewing lease for " + clientName + " for a period of " + (renewal / 1000)
                            + " seconds. Will retry shortly...", ie);
                }
            }
            renewalSleep();
        }
    }
}