org.neo4j.kernel.ha.backup.HaBackupProvider.java Source code

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Here is the source code for org.neo4j.kernel.ha.backup.HaBackupProvider.java

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/**
 * Copyright (c) 2002-2012 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j 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.neo4j.kernel.ha.backup;

import java.net.URI;
import java.net.URISyntaxException;

import org.apache.zookeeper.KeeperException;
import org.neo4j.backup.BackupExtensionService;
import org.neo4j.com.ComException;
import org.neo4j.helpers.Args;
import org.neo4j.helpers.Pair;
import org.neo4j.helpers.Service;
import org.neo4j.kernel.configuration.ConfigurationDefaults;
import org.neo4j.kernel.ha.HaSettings;
import org.neo4j.kernel.ha.zookeeper.Machine;
import org.neo4j.kernel.ha.zookeeper.ZooKeeperClusterClient;

@Service.Implementation(BackupExtensionService.class)
public final class HaBackupProvider extends BackupExtensionService {
    // The server address is <host>:<port>
    private static final String ServerAddressFormat = "ha://%s:%d";

    public HaBackupProvider() {
        super("ha");
    }

    @Override
    public URI resolve(URI address, Args args) {
        String master = null;
        try {
            System.out.println("Asking coordinator service at '" + address + "' for master");

            // At first HaConfig.CONFIG_KEY_CLUSTER_NAME was used
            String clusterName = args.get(HaSettings.cluster_name.name(), null);
            // but then later on -cluster was also added because it looks much nicer.
            if (clusterName == null) {
                clusterName = args.get("cluster",
                        ConfigurationDefaults.getDefault(HaSettings.cluster_name, HaSettings.class));
            }
            master = getMasterServerInCluster(address.getSchemeSpecificPart().substring(2), clusterName); // skip the "//" part
            System.out.println("Found master '" + master + "' in cluster");
        } catch (ComException e) {
            throw e;
        } catch (RuntimeException e) {
            if (e.getCause() instanceof KeeperException) {
                KeeperException zkException = (KeeperException) e.getCause();
                System.out.println("Couldn't connect to '" + address + "', " + zkException.getMessage());
            }
            throw e;
        }
        URI toReturn = null;
        try {
            toReturn = new URI(master);
        } catch (URISyntaxException e) {
            // no way
        }
        return toReturn;
    }

    private static String getMasterServerInCluster(String from, String clusterName) {
        ZooKeeperClusterClient clusterClient = new ZooKeeperClusterClient(from, clusterName);
        Pair<String, Integer> masterServer = null;
        try {
            clusterClient.waitForSyncConnected();
            Machine master = clusterClient.getMaster();
            masterServer = master.getServer();
            if (masterServer != null) {
                int backupPort = clusterClient.getBackupPort(master.getMachineId());
                return String.format(ServerAddressFormat, masterServer.first(), backupPort);
            }
            throw new ComException("Master couldn't be found from cluster managed by " + from);
        } finally {
            clusterClient.shutdown();
        }
    }
}