org.neo4j.cluster.client.ClusterJoin Maven / Gradle / Ivy
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/*
* Copyright (c) 2002-2016 "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
* On start it will try to join the cluster specified by the initial hosts. After start finishes it will have
* either joined an existing cluster or created a new one. On stop it will leave the cluster, but will fail
* and continue the stop after one minute.
*/
public class ClusterJoin
extends LifecycleAdapter
{
public interface Configuration
{
List getInitialHosts();
String getClusterName();
boolean isAllowedToCreateCluster();
long getClusterJoinTimeout();
}
private final Configuration config;
private final ProtocolServer protocolServer;
private final Log userLog;
private final Log messagesLog;
private Cluster cluster;
public ClusterJoin( Configuration config, ProtocolServer protocolServer, LogService logService )
{
this.config = config;
this.protocolServer = protocolServer;
this.userLog = logService.getUserLog( getClass() );
this.messagesLog = logService.getInternalLog( getClass() );
}
@Override
public void start() throws Throwable
{
cluster = protocolServer.newClient( Cluster.class );
joinByConfig();
}
@Override
public void stop()
{
final Semaphore semaphore = new Semaphore( 0 );
cluster.addClusterListener( new ClusterListener.Adapter()
{
@Override
public void leftCluster()
{
cluster.removeClusterListener( this );
semaphore.release();
}
} );
cluster.leave();
try
{
if ( !semaphore.tryAcquire( 60, TimeUnit.SECONDS ) )
{
messagesLog.info( "Unable to leave cluster, timeout" );
}
}
catch ( InterruptedException e )
{
Thread.interrupted();
messagesLog.warn( "Unable to leave cluster, interrupted", e );
}
}
private void joinByConfig() throws TimeoutException
{
List hosts = config.getInitialHosts();
cluster.addClusterListener( new UnknownJoiningMemberWarning( hosts ) );
if ( hosts == null || hosts.size() == 0 )
{
userLog.info( "No cluster hosts specified. Creating cluster %s", config.getClusterName() );
cluster.create( config.getClusterName() );
}
else
{
URI[] memberURIs = hosts.stream()
.map( member -> URI.create( "cluster://" + resolvePortOnlyHost( member ) ) )
.toArray( URI[]::new );
while ( true )
{
userLog.info( "Attempting to join cluster of %s", hosts.toString() );
Future clusterConfig =
cluster.join( this.config.getClusterName(), memberURIs );
try
{
ClusterConfiguration clusterConf =
config.getClusterJoinTimeout() > 0
? clusterConfig.get( config.getClusterJoinTimeout(), TimeUnit.MILLISECONDS )
: clusterConfig.get();
userLog.info( "Joined cluster: %s", clusterConf );
return;
}
catch ( InterruptedException e )
{
userLog.warn( "Could not join cluster, interrupted. Retrying..." );
}
catch ( ExecutionException e )
{
messagesLog.debug( "Could not join cluster " + this.config.getClusterName() );
if ( e.getCause() instanceof IllegalStateException )
{
throw (IllegalStateException) e.getCause();
}
if ( config.isAllowedToCreateCluster() )
{
// Failed to join cluster, create new one
userLog.info( "Could not join cluster of %s", hosts.toString() );
userLog.info( "Creating new cluster with name [%s]...", config.getClusterName() );
cluster.create( config.getClusterName() );
break;
}
userLog.warn( "Could not join cluster, timed out. Retrying..." );
}
}
}
}
private String resolvePortOnlyHost( HostnamePort host )
{
try
{
return host.toString( InetAddress.getLocalHost().getHostAddress() );
}
catch ( UnknownHostException e )
{
throw new RuntimeException( e );
}
}
private class UnknownJoiningMemberWarning extends ClusterListener.Adapter
{
private final List initialHosts;
private UnknownJoiningMemberWarning( List initialHosts )
{
this.initialHosts = initialHosts;
}
@Override
public void joinedCluster( InstanceId member, URI uri )
{
for ( HostnamePort host : initialHosts )
{
if ( host.matches( uri ) )
{
return;
}
}
messagesLog.info( "Member " + member + "(" + uri + ") joined cluster but was not part of initial hosts (" +
initialHosts + ")" );
}
@Override
public void leftCluster()
{
cluster.removeClusterListener( this );
}
}
}