path: root/qpid/java/bdbstore/src/main/java/org/apache/qpid/server/store/berkeleydb/replication/ReplicatedEnvironmentFacade.java

/*
 *
 * 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.qpid.server.store.berkeleydb.replication;

import java.io.File;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicReference;

import org.apache.log4j.Logger;
import org.apache.qpid.AMQStoreException;
import org.apache.qpid.server.replication.ReplicationGroupListener;
import org.apache.qpid.server.store.berkeleydb.CoalescingCommiter;
import org.apache.qpid.server.store.berkeleydb.Committer;
import org.apache.qpid.server.store.berkeleydb.EnvironmentFacade;
import org.apache.qpid.server.store.berkeleydb.LoggingAsyncExceptionListener;
import org.apache.qpid.server.util.DaemonThreadFactory;

import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseConfig;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.Durability;
import com.sleepycat.je.Environment;
import com.sleepycat.je.EnvironmentConfig;
import com.sleepycat.je.EnvironmentFailureException;
import com.sleepycat.je.Transaction;
import com.sleepycat.je.rep.InsufficientLogException;
import com.sleepycat.je.rep.InsufficientReplicasException;
import com.sleepycat.je.rep.NetworkRestore;
import com.sleepycat.je.rep.NetworkRestoreConfig;
import com.sleepycat.je.rep.NodeState;
import com.sleepycat.je.rep.RepInternal;
import com.sleepycat.je.rep.ReplicatedEnvironment;
import com.sleepycat.je.rep.ReplicationConfig;
import com.sleepycat.je.rep.ReplicationGroup;
import com.sleepycat.je.rep.ReplicationMutableConfig;
import com.sleepycat.je.rep.ReplicationNode;
import com.sleepycat.je.rep.RestartRequiredException;
import com.sleepycat.je.rep.StateChangeEvent;
import com.sleepycat.je.rep.StateChangeListener;
import com.sleepycat.je.rep.util.DbPing;
import com.sleepycat.je.rep.util.ReplicationGroupAdmin;
import com.sleepycat.je.rep.utilint.ServiceDispatcher.ServiceConnectFailedException;
import com.sleepycat.je.rep.vlsn.VLSNRange;
import com.sleepycat.je.utilint.PropUtil;
import com.sleepycat.je.utilint.VLSN;

public class ReplicatedEnvironmentFacade implements EnvironmentFacade, StateChangeListener
{
    public static final String GROUP_CHECK_INTERVAL_PROPERTY_NAME = "qpid.bdb.ha.group_check_interval";
    public static final String MASTER_TRANSFER_TIMEOUT_PROPERTY_NAME = "qpid.bdb.ha.master_transfer_interval";
    public static final String DB_PING_SOCKET_TIMEOUT_PROPERTY_NAME = "qpid.bdb.ha.db_ping_socket_timeout";

    private static final Logger LOGGER = Logger.getLogger(ReplicatedEnvironmentFacade.class);

    private static final long DEFAULT_GROUP_CHECK_INTERVAL = 1000l;
    private static final int DEFAULT_MASTER_TRANSFER_TIMEOUT = 1000 * 60;
    private static final int DEFAULT_DB_PING_SOCKET_TIMEOUT = 1000;

    private static final long GROUP_CHECK_INTERVAL = Long.getLong(GROUP_CHECK_INTERVAL_PROPERTY_NAME, DEFAULT_GROUP_CHECK_INTERVAL);
    private static final int MASTER_TRANSFER_TIMEOUT = Integer.getInteger(MASTER_TRANSFER_TIMEOUT_PROPERTY_NAME, DEFAULT_MASTER_TRANSFER_TIMEOUT);
    private static final int DB_PING_SOCKET_TIMEOUT = Integer.getInteger(DB_PING_SOCKET_TIMEOUT_PROPERTY_NAME, DEFAULT_DB_PING_SOCKET_TIMEOUT);

    @SuppressWarnings("serial")
    private static final Map<String, String> REPCONFIG_DEFAULTS = Collections.unmodifiableMap(new HashMap<String, String>()
    {{
        /**
         * Parameter decreased as the 24h default may lead very large log files for most users.
         */
        put(ReplicationConfig.REP_STREAM_TIMEOUT, "1 h");
        /**
         * Parameter increased as the 5 s default may lead to spurious timeouts.
         */
        put(ReplicationConfig.REPLICA_ACK_TIMEOUT, "15 s");
        /**
         * Parameter increased as the 10 s default may lead to spurious timeouts.
         */
        put(ReplicationConfig.INSUFFICIENT_REPLICAS_TIMEOUT, "20 s");
        /**
         * Parameter increased as the 10 h default may cause user confusion.
         */
        put(ReplicationConfig.ENV_SETUP_TIMEOUT, "15 min");
        /**
         * Parameter changed from default true so we adopt immediately adopt the new behaviour early. False
         * is scheduled to become default after JE 5.0.48.
         */
        put(ReplicationConfig.PROTOCOL_OLD_STRING_ENCODING, Boolean.FALSE.toString());
        /**
         * Parameter decreased as a default 5min interval may lead to bigger data losses on Node
         * with NO_SYN durability in case if such Node crushes.
         */
        put(ReplicationConfig.LOG_FLUSH_TASK_INTERVAL, "1 min");

        /**
         * Timeout to transit into UNKNOWN state if the majority is not available.
         * By default it is switched off.
         */
        put(ReplicationConfig.ENV_UNKNOWN_STATE_TIMEOUT, "5 s");
    }});

    public static final String TYPE = "BDB-HA";

    private final ReplicatedEnvironmentConfiguration _configuration;
    private final Durability _durability;
    private final Boolean _coalescingSync;
    private final String _prettyGroupNodeName;
    private final File _environmentDirectory;

    private final ExecutorService _environmentJobExecutor;
    private final ScheduledExecutorService _groupChangeExecutor;
    private final AtomicReference<State> _state = new AtomicReference<State>(State.OPENING);
    private final ConcurrentMap<String, DatabaseHolder> _databases = new ConcurrentHashMap<String, DatabaseHolder>();
    private final ConcurrentMap<String, RemoteReplicationNode> _remoteReplicationNodes = new ConcurrentHashMap<String, RemoteReplicationNode>();
    private final RemoteReplicationNodeFactory _remoteReplicationNodeFactory;
    private final AtomicReference<ReplicationGroupListener> _replicationGroupListener = new AtomicReference<ReplicationGroupListener>();
    private final AtomicReference<StateChangeListener> _stateChangeListener = new AtomicReference<StateChangeListener>();

    private volatile ReplicatedEnvironment _environment;
    private volatile long _joinTime;
    private volatile ReplicatedEnvironment.State _lastKnownEnvironmentState;

    public ReplicatedEnvironmentFacade(ReplicatedEnvironmentConfiguration configuration, RemoteReplicationNodeFactory remoteReplicationNodeFactory)
    {
        _environmentDirectory = new File(configuration.getStorePath());
        if (!_environmentDirectory.exists())
        {
            if (!_environmentDirectory.mkdirs())
            {
                throw new IllegalArgumentException("Environment path " + _environmentDirectory + " could not be read or created. "
                                                   + "Ensure the path is correct and that the permissions are correct.");
            }
        }

        _configuration = configuration;

        _durability = Durability.parse(_configuration.getDurability());
        _coalescingSync = _configuration.isCoalescingSync();
        _prettyGroupNodeName = _configuration.getGroupName() + ":" + _configuration.getName();

        // we relay on this executor being single-threaded as we need to restart and mutate the environment in one thread
        _environmentJobExecutor = Executors.newSingleThreadExecutor(new DaemonThreadFactory("Environment-" + _prettyGroupNodeName));
        _groupChangeExecutor = Executors.newScheduledThreadPool(Runtime.getRuntime().availableProcessors() + 1, new DaemonThreadFactory("Group-Change-Learner:" + _prettyGroupNodeName));

        _remoteReplicationNodeFactory = remoteReplicationNodeFactory;
        _groupChangeExecutor.scheduleWithFixedDelay(new GroupChangeLearner(), 0, GROUP_CHECK_INTERVAL, TimeUnit.MILLISECONDS);
        _groupChangeExecutor.schedule(new RemoteNodeStateLearner(), _remoteReplicationNodeFactory.getRemoteNodeMonitorInterval(), TimeUnit.MILLISECONDS);

        // create environment in a separate thread to avoid renaming of the current thread by JE
        _environment = createEnvironment(true);
        populateExistingRemoteReplicationNodes();
    }

    @Override
    public void commit(final Transaction tx) throws AMQStoreException
    {
        try
        {
            // Using commit() instead of commitNoSync() for the HA store to allow
            // the HA durability configuration to influence resulting behaviour.
            tx.commit();
        }
        catch (DatabaseException de)
        {
            throw handleDatabaseException("Got DatabaseException on commit, closing environment", de);
        }
    }

    @Override
    public void close()
    {
        if (_state.compareAndSet(State.OPENING, State.CLOSING) ||
                _state.compareAndSet(State.OPEN, State.CLOSING) ||
                _state.compareAndSet(State.RESTARTING, State.CLOSING) )
        {
            try
            {
                if (LOGGER.isDebugEnabled())
                {
                    LOGGER.debug("Closing replicated environment facade for " + _prettyGroupNodeName);
                }

                _environmentJobExecutor.shutdown();
                _groupChangeExecutor.shutdown();
                closeDatabases();
                closeEnvironment();
            }
            finally
            {
                _state.compareAndSet(State.CLOSING, State.CLOSED);
            }
        }
    }

    @Override
    public AMQStoreException handleDatabaseException(String contextMessage, final DatabaseException dbe)
    {
        boolean restart = (dbe instanceof InsufficientReplicasException || dbe instanceof InsufficientReplicasException || dbe instanceof RestartRequiredException);
        if (restart)
        {
            tryToRestartEnvironment(dbe);
        }
        return new AMQStoreException(contextMessage, dbe);
    }

    private void tryToRestartEnvironment(final DatabaseException dbe)
    {
        if (_state.compareAndSet(State.OPEN, State.RESTARTING))
        {
            if (dbe != null && LOGGER.isDebugEnabled())
            {
                LOGGER.debug("Environment restarting due to exception " + dbe.getMessage(), dbe);
            }

            _environmentJobExecutor.execute(new Runnable()
            {
                @Override
                public void run()
                {
                    try
                    {
                        restartEnvironment();
                    }
                    catch (Exception e)
                    {
                        LOGGER.error("Exception on environment restart", e);
                    }
                }
            });

        }
        else
        {
            LOGGER.info("Cannot restart environment because of facade state: " + _state.get());
        }
    }

    @Override
    public void openDatabases(DatabaseConfig dbConfig, String... databaseNames)
    {
        if (_state.get() != State.OPEN)
        {
            throw new IllegalStateException("Environment facade is not in opened state");
        }

        if (!_environment.isValid())
        {
            throw new IllegalStateException("Environment is not valid");
        }

        if (_environment.getState() != ReplicatedEnvironment.State.MASTER)
        {
            throw new IllegalStateException("Databases can only be opened on Master node");
        }

        for (String databaseName : databaseNames)
        {
            _databases.put(databaseName, new DatabaseHolder(dbConfig));
        }
        for (String databaseName : databaseNames)
        {
            DatabaseHolder holder = _databases.get(databaseName);
            openDatabaseInternally(databaseName, holder);
        }
    }

    private void openDatabaseInternally(String databaseName, DatabaseHolder holder)
    {
        Database database = _environment.openDatabase(null, databaseName, holder.getConfig());
        holder.setDatabase(database);
    }

    @Override
    public Database getOpenDatabase(String name)
    {
        if (_state.get() != State.OPEN)
        {
            throw new IllegalStateException("Environment facade is not in opened state");
        }

        if (!_environment.isValid())
        {
            throw new IllegalStateException("Environment is not valid");
        }
        DatabaseHolder databaseHolder = _databases.get(name);
        if (databaseHolder == null)
        {
            throw new IllegalArgumentException("Database with name '" + name + "' has never been requested to be opened");
        }
        Database database = databaseHolder.getDatabase();
        if (database == null)
        {
            throw new IllegalArgumentException("Database with name '" + name + "' has not been opened");
        }
        return database;
    }

    @Override
    public String getStoreLocation()
    {
        return _environmentDirectory.getAbsolutePath();
    }

    @Override
    public void stateChange(final StateChangeEvent stateChangeEvent)
    {
        if (LOGGER.isInfoEnabled())
        {
            LOGGER.info("The node '" + _prettyGroupNodeName + "' state is " + stateChangeEvent.getState());
        }

        if (_state.get() != State.CLOSING && _state.get() != State.CLOSED)
        {
            _groupChangeExecutor.submit(new Runnable()
            {
                @Override
                public void run()
                {
                    stateChanged(stateChangeEvent);
                }
            });
        }
        else
        {
            if (LOGGER.isDebugEnabled())
            {
                LOGGER.debug("Ignoring the state environment change event as the environment facade for node '" + _prettyGroupNodeName
                        + "' is in state " + _state.get());
            }
        }
    }

    private void stateChanged(StateChangeEvent stateChangeEvent)
    {
        ReplicatedEnvironment.State state = stateChangeEvent.getState();

        if (state == ReplicatedEnvironment.State.REPLICA || state == ReplicatedEnvironment.State.MASTER)
        {
            if (_state.compareAndSet(State.OPENING, State.OPEN) || _state.compareAndSet(State.RESTARTING, State.OPEN))
            {
                LOGGER.info("The environment facade is in open state for node " + _prettyGroupNodeName);
                _joinTime = System.currentTimeMillis();
            }
        }

        if (state == ReplicatedEnvironment.State.MASTER)
        {
            reopenDatabases();
        }

        StateChangeListener listener = _stateChangeListener.get();
        if (listener != null)
        {
            listener.stateChange(stateChangeEvent);
        }

        if (_lastKnownEnvironmentState == ReplicatedEnvironment.State.MASTER && state == ReplicatedEnvironment.State.DETACHED && _state.get() == State.OPEN)
        {
            tryToRestartEnvironment(null);
        }
        _lastKnownEnvironmentState = state;
    }

    private void reopenDatabases()
    {
        DatabaseConfig pingDbConfig = new DatabaseConfig();
        pingDbConfig.setTransactional(true);
        pingDbConfig.setAllowCreate(true);

        _databases.putIfAbsent(DatabasePinger.PING_DATABASE_NAME, new DatabaseHolder(pingDbConfig));

        for (Map.Entry<String, DatabaseHolder> entry : _databases.entrySet())
        {
            openDatabaseInternally(entry.getKey(), entry.getValue());
        }
    }

    public String getGroupName()
    {
        return (String)_configuration.getGroupName();
    }

    public String getNodeName()
    {
        return _configuration.getName();
    }

    public String getHostPort()
    {
        return (String)_configuration.getHostPort();
    }

    public String getHelperHostPort()
    {
        return (String)_configuration.getHelperHostPort();
    }

    public String getDurability()
    {
        return _durability.toString();
    }

    public boolean isCoalescingSync()
    {
        return _coalescingSync;
    }

    public String getNodeState()
    {
        if (_state.get() != State.OPEN)
        {
            return ReplicatedEnvironment.State.UNKNOWN.name();
        }
        ReplicatedEnvironment.State state = _environment.getState();
        return state.toString();
    }

    public void removeNodeFromGroup(final String nodeName)
    {
        createReplicationGroupAdmin().removeMember(nodeName);
    }

    public boolean isDesignatedPrimary()
    {
        if (_state.get() != State.OPEN)
        {
            throw new IllegalStateException("Environment facade is not opened");
        }
        return _environment.getRepMutableConfig().getDesignatedPrimary();
    }

    public Future<Void> setDesignatedPrimary(final boolean isPrimary)
    {
        if (LOGGER.isInfoEnabled())
        {
            LOGGER.info("Submitting a job to set designated primary on " + _prettyGroupNodeName + " to " + isPrimary);
        }

        return _environmentJobExecutor.submit(new Callable<Void>()
        {
            @Override
            public Void call()
            {
                setDesignatedPrimaryInternal(isPrimary);
                return null;
            }
        });
    }

    void setDesignatedPrimaryInternal(final boolean isPrimary)
    {
        try
        {
            final ReplicationMutableConfig oldConfig = _environment.getRepMutableConfig();
            final ReplicationMutableConfig newConfig = oldConfig.setDesignatedPrimary(isPrimary);
            _environment.setRepMutableConfig(newConfig);

            if (LOGGER.isInfoEnabled())
            {
                LOGGER.info("Node " + _prettyGroupNodeName + " successfully set designated primary : " + isPrimary);
            }
        }
        catch (Exception e)
        {
            LOGGER.error("Cannot set designated primary to " + isPrimary + " on node " + _prettyGroupNodeName, e);
        }
    }

    int getPriority()
    {
        if (_state.get() != State.OPEN)
        {
            throw new IllegalStateException("Environment facade is not opened");
        }
        ReplicationMutableConfig repConfig = _environment.getRepMutableConfig();
        return repConfig.getNodePriority();
    }

    public Future<Void> setPriority(final int priority)
    {
        if (LOGGER.isInfoEnabled())
        {
            LOGGER.info("Submitting a job to set priority on " + _prettyGroupNodeName + " to " + priority);
        }

        return _environmentJobExecutor.submit(new Callable<Void>()
        {
            @Override
            public Void call()
            {
                setPriorityInternal(priority);
                return null;
            }
        });
    }

    void setPriorityInternal(int priority)
    {
        try
        {
            final ReplicationMutableConfig oldConfig = _environment.getRepMutableConfig();
            final ReplicationMutableConfig newConfig = oldConfig.setNodePriority(priority);
            _environment.setRepMutableConfig(newConfig);

            if (LOGGER.isDebugEnabled())
            {
                LOGGER.debug("Node " + _prettyGroupNodeName + " priority has been changed to " + priority);
            }
        }
        catch (Exception e)
        {
            LOGGER.error("Cannot set priority to " + priority + " on node " + _prettyGroupNodeName, e);
        }
    }

    int getElectableGroupSizeOverride()
    {
        if (_state.get() != State.OPEN)
        {
            throw new IllegalStateException("Environment facade is not opened");
        }
        ReplicationMutableConfig repConfig = _environment.getRepMutableConfig();
        return repConfig.getElectableGroupSizeOverride();
    }

    public Future<Void> setElectableGroupSizeOverride(final int electableGroupOverride)
    {
        if (LOGGER.isInfoEnabled())
        {
            LOGGER.info("Submitting a job to set electable group override on " + _prettyGroupNodeName + " to " + electableGroupOverride);
        }

        return _environmentJobExecutor.submit(new Callable<Void>()
        {
            @Override
            public Void call()
            {
                setElectableGroupSizeOverrideInternal(electableGroupOverride);
                return null;
            }
        });
    }

    void setElectableGroupSizeOverrideInternal(int electableGroupOverride)
    {
        try
        {
            final ReplicationMutableConfig oldConfig = _environment.getRepMutableConfig();
            final ReplicationMutableConfig newConfig = oldConfig.setElectableGroupSizeOverride(electableGroupOverride);
            _environment.setRepMutableConfig(newConfig);

            if (LOGGER.isDebugEnabled())
            {
                LOGGER.debug("Node " + _prettyGroupNodeName + " electable group size override has been changed to " + electableGroupOverride);
            }
        }
        catch (Exception e)
        {
            LOGGER.error("Cannot set electable group size to " + electableGroupOverride + " on node " + _prettyGroupNodeName, e);
        }
    }


    public long getJoinTime()
    {
        return _joinTime ;
    }

    public long getLastKnownReplicationTransactionId()
    {
        if (_state.get() == State.OPEN)
        {
            VLSNRange range = RepInternal.getRepImpl(_environment).getVLSNIndex().getRange();
            VLSN lastTxnEnd = range.getLastTxnEnd();
            return lastTxnEnd.getSequence();
        }
        else
        {
            return -1L;
        }
    }

    public void transferMasterToSelfAsynchronously()
    {
        final String nodeName = getNodeName();
        transferMasterAsynchronously(nodeName);
    }

    public void transferMasterAsynchronously(final String nodeName)
    {
        _groupChangeExecutor.submit(new Runnable()
        {
            @Override
            public void run()
            {
                try
                {
                    ReplicationGroupAdmin admin = createReplicationGroupAdmin();
                    String newMaster = admin.transferMaster(Collections.singleton(nodeName), MASTER_TRANSFER_TIMEOUT, TimeUnit.MILLISECONDS, true);
                    if (LOGGER.isDebugEnabled())
                    {
                        LOGGER.debug("The mastership has been transfered to " + newMaster);
                    }
                }
                catch (DatabaseException e)
                {
                    LOGGER.warn("Exception on transfering the mastership to " + _prettyGroupNodeName
                            + " Master transfer timeout : " + MASTER_TRANSFER_TIMEOUT, e);
                }
            }
        });
    }

    public ReplicatedEnvironment getEnvironment()
    {
        return _environment;
    }

    public State getFacadeState()
    {
        return _state.get();
    }

    public void setReplicationGroupListener(ReplicationGroupListener replicationGroupListener)
    {
        if (_replicationGroupListener.compareAndSet(null, replicationGroupListener))
        {
            notifyExistingRemoteReplicationNodes(replicationGroupListener);
        }
        else
        {
            throw new IllegalStateException("ReplicationGroupListener is already set on " + _prettyGroupNodeName);
        }
    }

    public void setStateChangeListener(StateChangeListener stateChangeListener)
    {
        if (_stateChangeListener.compareAndSet(null, stateChangeListener))
        {
            _environment.setStateChangeListener(this);
        }
        else
        {
            throw new IllegalStateException("StateChangeListener is already set on " + _prettyGroupNodeName);
        }
    }

    private void populateExistingRemoteReplicationNodes()
    {
        ReplicationGroup group = _environment.getGroup();
        Set<ReplicationNode> nodes = new HashSet<ReplicationNode>(group.getElectableNodes());
        String localNodeName = getNodeName();

        for (ReplicationNode replicationNode : nodes)
        {
            String discoveredNodeName = replicationNode.getName();
            if (!discoveredNodeName.equals(localNodeName))
            {
                RemoteReplicationNode remoteNode = _remoteReplicationNodeFactory.create(replicationNode, this);

                _remoteReplicationNodes.put(replicationNode.getName(), remoteNode);
            }
        }
     }

    private void notifyExistingRemoteReplicationNodes(ReplicationGroupListener listener)
    {
        for (org.apache.qpid.server.model.ReplicationNode value : _remoteReplicationNodes.values())
        {
            listener.onReplicationNodeRecovered(value);
        }
    }

    private ReplicationGroupAdmin createReplicationGroupAdmin()
    {
        final Set<InetSocketAddress> helpers = new HashSet<InetSocketAddress>();
        for (RemoteReplicationNode node : _remoteReplicationNodes.values())
        {
            helpers.add(node.getReplicationNode().getSocketAddress());
        }

        //TODO: refactor this into a method on LocalReplicationNode
        String hostPort = _configuration.getHostPort();
        String[] tokens = hostPort.split(":");
        helpers.add(new InetSocketAddress(tokens[0], Integer.parseInt(tokens[1])));

        return new ReplicationGroupAdmin(_configuration.getGroupName(), helpers);
    }

    private void closeEnvironment()
    {
        // Clean the log before closing. This makes sure it doesn't contain
        // redundant data. Closing without doing this means the cleaner may not
        // get a chance to finish.
        try
        {
            if (_environment.isValid())
            {
                _environment.cleanLog();
            }
        }
        finally
        {
            _environment.close();
            _environment = null;
        }
    }

    private void restartEnvironment()
    {
        LOGGER.info("Restarting environment");

        closeEnvironmentSafely();

        _environment = createEnvironment(false);

        if (_stateChangeListener.get() != null)
        {
            _environment.setStateChangeListener(this);
        }

        LOGGER.info("Environment is restarted");
    }

    private void closeEnvironmentSafely()
    {
        Environment environment = _environment;
        if (environment != null)
        {
            try
            {
                if (environment.isValid())
                {
                    try
                    {
                        closeDatabases();
                    }
                    catch(Exception e)
                    {
                        LOGGER.warn("Ignoring an exception whilst closing databases", e);
                    }
                }
                environment.close();
            }
            catch (EnvironmentFailureException efe)
            {
                LOGGER.warn("Ignoring an exception whilst closing environment", efe);
            }
        }
    }

    private void closeDatabases()
    {
        RuntimeException firstThrownException = null;
        for (Map.Entry<String, DatabaseHolder> entry : _databases.entrySet())
        {
            DatabaseHolder databaseHolder = entry.getValue();
            Database database = databaseHolder.getDatabase();
            if (database != null)
            {
                try
                {
                    if (LOGGER.isDebugEnabled())
                    {
                        LOGGER.debug("Closing database " + entry.getKey() + " on " + _prettyGroupNodeName);
                    }

                    database.close();
                }
                catch(RuntimeException e)
                {
                    LOGGER.error("Failed to close database on " + _prettyGroupNodeName, e);
                    if (firstThrownException == null)
                    {
                        firstThrownException = e;
                    }
                }
                finally
                {
                    databaseHolder.setDatabase(null);
                }
            }
        }
        if (firstThrownException != null)
        {
            throw firstThrownException;
        }
    }

    private ReplicatedEnvironment createEnvironment(boolean createEnvironmentInSeparateThread)
    {
        String groupName = _configuration.getGroupName();
        String helperHostPort = _configuration.getHelperHostPort();
        String hostPort = _configuration.getHostPort();
        Map<String, String> environmentParameters = _configuration.getParameters();
        Map<String, String> replicationEnvironmentParameters = _configuration.getReplicationParameters();
        boolean designatedPrimary = _configuration.isDesignatedPrimary();
        int priority = _configuration.getPriority();
        int quorumOverride = _configuration.getQuorumOverride();

        if (LOGGER.isInfoEnabled())
        {
            LOGGER.info("Creating environment");
            LOGGER.info("Environment path " + _environmentDirectory.getAbsolutePath());
            LOGGER.info("Group name " + groupName);
            LOGGER.info("Node name " + _configuration.getName());
            LOGGER.info("Node host port " + hostPort);
            LOGGER.info("Helper host port " + helperHostPort);
            LOGGER.info("Durability " + _durability);
            LOGGER.info("Coalescing sync " + _coalescingSync);
            LOGGER.info("Designated primary (applicable to 2 node case only) " + designatedPrimary);
            LOGGER.info("Node priority " + priority);
            LOGGER.info("Quorum override " + quorumOverride);
        }

        Map<String, String> replicationEnvironmentSettings = new HashMap<String, String>(REPCONFIG_DEFAULTS);
        if (replicationEnvironmentParameters != null && !replicationEnvironmentParameters.isEmpty())
        {
            replicationEnvironmentSettings.putAll(replicationEnvironmentParameters);
        }
        Map<String, String> environmentSettings = new HashMap<String, String>(EnvironmentFacade.ENVCONFIG_DEFAULTS);
        if (environmentParameters != null && !environmentParameters.isEmpty())
        {
            environmentSettings.putAll(environmentParameters);
        }

        ReplicationConfig replicationConfig = new ReplicationConfig(groupName, _configuration.getName(), hostPort);
        replicationConfig.setHelperHosts(helperHostPort);
        replicationConfig.setDesignatedPrimary(designatedPrimary);
        replicationConfig.setNodePriority(priority);
        replicationConfig.setElectableGroupSizeOverride(quorumOverride);

        for (Map.Entry<String, String> configItem : replicationEnvironmentSettings.entrySet())
        {
            if (LOGGER.isInfoEnabled())
            {
                LOGGER.info("Setting ReplicationConfig key " + configItem.getKey() + " to '" + configItem.getValue() + "'");
            }
            replicationConfig.setConfigParam(configItem.getKey(), configItem.getValue());
        }

        EnvironmentConfig envConfig = new EnvironmentConfig();
        envConfig.setAllowCreate(true);
        envConfig.setTransactional(true);
        envConfig.setExceptionListener(new LoggingAsyncExceptionListener());
        envConfig.setDurability(_durability);

        for (Map.Entry<String, String> configItem : environmentSettings.entrySet())
        {
            if (LOGGER.isInfoEnabled())
            {
                LOGGER.info("Setting EnvironmentConfig key " + configItem.getKey() + " to '" + configItem.getValue() + "'");
            }
            envConfig.setConfigParam(configItem.getKey(), configItem.getValue());
        }

        if (createEnvironmentInSeparateThread)
        {
            return createEnvironmentInSeparateThread(_environmentDirectory, envConfig, replicationConfig);
        }
        else
        {
            return createEnvironment(_environmentDirectory, envConfig, replicationConfig);
        }
    }

    private ReplicatedEnvironment createEnvironmentInSeparateThread(final File environmentPathFile, final EnvironmentConfig envConfig,
            final ReplicationConfig replicationConfig)
    {
        Future<ReplicatedEnvironment> environmentFuture = _environmentJobExecutor.submit(new Callable<ReplicatedEnvironment>(){
            @Override
            public ReplicatedEnvironment call() throws Exception
            {
                String originalThreadName = Thread.currentThread().getName();
                try
                {
                    return createEnvironment(environmentPathFile, envConfig, replicationConfig);
                }
                finally
                {
                    Thread.currentThread().setName(originalThreadName);
                }
            }});

        long setUpTimeOutMillis = PropUtil.parseDuration(replicationConfig.getConfigParam(ReplicationConfig.ENV_SETUP_TIMEOUT));
        try
        {
            return environmentFuture.get(setUpTimeOutMillis, TimeUnit.MILLISECONDS);
        }
        catch (InterruptedException e)
        {
            Thread.currentThread().interrupt();
            throw new RuntimeException("Environment creation was interrupted", e);
        }
        catch (ExecutionException e)
        {
            throw new RuntimeException("Unexpected exception on environment creation", e.getCause());
        }
        catch (TimeoutException e)
        {
            throw new RuntimeException("JE environment has not been created in due time");
        }
    }

    private ReplicatedEnvironment createEnvironment(File environmentPathFile, EnvironmentConfig envConfig,
            final ReplicationConfig replicationConfig)
    {
        ReplicatedEnvironment environment = null;
        try
        {
            environment = new ReplicatedEnvironment(environmentPathFile, replicationConfig, envConfig);
        }
        catch (final InsufficientLogException ile)
        {
            LOGGER.info("InsufficientLogException thrown and so full network restore required", ile);
            NetworkRestore restore = new NetworkRestore();
            NetworkRestoreConfig config = new NetworkRestoreConfig();
            config.setRetainLogFiles(false);
            restore.execute(ile, config);
            environment = new ReplicatedEnvironment(environmentPathFile, replicationConfig, envConfig);
        }
        if (LOGGER.isInfoEnabled())
        {
            LOGGER.info("Environment is created for node " + _prettyGroupNodeName);
        }
        return environment;
    }

    @Override
    public Committer createCommitter(String name)
    {
        if (_coalescingSync)
        {
            return new CoalescingCommiter(name, this);
        }
        else
        {
            return Committer.IMMEDIATE_FUTURE_COMMITTER;
        }
    }

    public NodeState getRemoteNodeState(ReplicationNode repNode) throws IOException, ServiceConnectFailedException
    {
        if (repNode == null)
        {
            throw new IllegalArgumentException("Node cannot be null");
        }
        return new DbPing(repNode, (String)_configuration.getGroupName(), DB_PING_SOCKET_TIMEOUT).getNodeState();
    }

    // For testing only
    int getNumberOfElectableGroupMembers()
    {
        if (_state.get() != State.OPEN)
        {
            throw new IllegalStateException("Environment facade is not opened");
        }
        return _environment.getGroup().getElectableNodes().size();
    }

    private final class GroupChangeLearner implements Runnable
    {
        @Override
        public void run()
        {
            if (_state.get() == State.OPEN)
            {
                if (LOGGER.isDebugEnabled())
                {
                    LOGGER.debug("Checking for changes in the group " + _configuration.getGroupName() + " on node " + _configuration.getName());
                }

                try
                {
                    detectGroupChangesAndNotify();
                }
                catch(DatabaseException e)
                {
                    handleDatabaseException("Exception on replication group check", e);
                }
            }
        }

        private void detectGroupChangesAndNotify()
        {
            String groupName = _configuration.getGroupName();
            ReplicatedEnvironment env = _environment;
            ReplicationGroupListener replicationGroupListener = _replicationGroupListener.get();
            if (env != null)
            {
                ReplicationGroup group = env.getGroup();
                Set<ReplicationNode> nodes = new HashSet<ReplicationNode>(group.getElectableNodes());
                String localNodeName = getNodeName();

                Map<String, org.apache.qpid.server.model.ReplicationNode> removalMap = new HashMap<String, org.apache.qpid.server.model.ReplicationNode>(_remoteReplicationNodes);
                for (ReplicationNode replicationNode : nodes)
                {
                    String discoveredNodeName = replicationNode.getName();
                    if (!discoveredNodeName.equals(localNodeName))
                    {
                        if (!_remoteReplicationNodes.containsKey(discoveredNodeName))
                        {
                            if (LOGGER.isDebugEnabled())
                            {
                                LOGGER.debug("Remote replication node added '" + replicationNode + "' to '" + groupName + "'");
                            }

                            RemoteReplicationNode remoteNode = _remoteReplicationNodeFactory.create(replicationNode, ReplicatedEnvironmentFacade.this);

                            _remoteReplicationNodes.put(discoveredNodeName, remoteNode);

                            if (replicationGroupListener != null)
                            {
                                replicationGroupListener.onReplicationNodeAddedToGroup(remoteNode);
                            }
                        }
                        else
                        {
                            removalMap.remove(discoveredNodeName);
                        }
                    }
                }

                if (!removalMap.isEmpty())
                {
                    for (Map.Entry<String, org.apache.qpid.server.model.ReplicationNode> replicationNodeEntry : removalMap.entrySet())
                    {
                        String replicationNodeName = replicationNodeEntry.getKey();
                        if (LOGGER.isDebugEnabled())
                        {
                            LOGGER.debug("Remote replication node removed '" + replicationNodeName + "' from '" + groupName + "'");
                        }
                        _remoteReplicationNodes.remove(replicationNodeName);
                        if (replicationGroupListener != null)
                        {
                            replicationGroupListener.onReplicationNodeRemovedFromGroup(replicationNodeEntry.getValue());
                        }
                    }
                }
            }
        }
    }

    private class RemoteNodeStateLearner implements Callable<Void>
    {
        private Map<String, String> _previousGroupState = Collections.emptyMap();
        @Override
        public Void call()
        {
            long remoteNodeMonitorInterval = _remoteReplicationNodeFactory.getRemoteNodeMonitorInterval();
            try
            {
                Set<Future<Void>> futures = new HashSet<Future<Void>>();
                for (final RemoteReplicationNode node : _remoteReplicationNodes.values())
                {
                    Future<Void> future = _groupChangeExecutor.submit(new Callable<Void>()
                    {
                        @Override
                        public Void call()
                        {
                            node.updateNodeState();
                            return null;
                        }
                    });
                    futures.add(future);
                }

                for (Future<Void> future : futures)
                {
                    try
                    {
                        future.get(remoteNodeMonitorInterval, TimeUnit.MILLISECONDS);
                    }
                    catch (InterruptedException e)
                    {
                        Thread.currentThread().interrupt();
                    }
                    catch (ExecutionException e)
                    {
                        LOGGER.warn("Cannot update node state for group " + _configuration.getGroupName(), e.getCause());
                    }
                    catch (TimeoutException e)
                    {
                        LOGGER.warn("Timeout whilst updating node state for group " + _configuration.getGroupName());
                        future.cancel(true);
                    }
                }

                if (ReplicatedEnvironment.State.MASTER == _environment.getState())
                {
                    Map<String, String> currentGroupState = new HashMap<String, String>();
                    for (final RemoteReplicationNode node : _remoteReplicationNodes.values())
                    {
                        currentGroupState.put(node.getName(), (String)node.getAttribute(org.apache.qpid.server.model.ReplicationNode.ROLE));
                    }
                    boolean stateChanged = !_previousGroupState.equals(currentGroupState);
                    _previousGroupState = currentGroupState;
                    if (stateChanged && State.OPEN == _state.get())
                    {
                        new DatabasePinger().pingDb(ReplicatedEnvironmentFacade.this);
                    }
                }
            }
            finally
            {
                _groupChangeExecutor.schedule(this, remoteNodeMonitorInterval, TimeUnit.MILLISECONDS);
            }
            return null;
        }
    }

    public static enum State
    {
        OPENING,
        OPEN,
        RESTARTING,
        CLOSING,
        CLOSED
    }

    private static class DatabaseHolder
    {
        private final DatabaseConfig _config;
        private Database _database;

        public DatabaseHolder(DatabaseConfig config)
        {
            _config = config;
        }

        public Database getDatabase()
        {
            return _database;
        }

        public void setDatabase(Database database)
        {
            _database = database;
        }

        public DatabaseConfig getConfig()
        {
            return _config;
        }

        @Override
        public String toString()
        {
            return "DatabaseHolder [_config=" + _config + ", _database=" + _database + "]";
        }

    }

}