org.eclipse.aether.synccontext

Class RedissonSyncContextFactory

java.lang.Object

org.eclipse.aether.synccontext.RedissonSyncContextFactory

All Implemented Interfaces:

SyncContextFactory

@Named
 @Priority(value=2147483647)
 @Singleton
public class RedissonSyncContextFactory
extends Object
implements SyncContextFactory

A singleton factory to create synchronization contexts using Redisson's RReadWriteLock. It locks fine-grained with groupId, artifactId and version if required.

Note: This component is still considered to be experimental, use with caution!

Configuration

You can configure various aspects of this factory.

Redisson Client

To fully configure the Redisson client, this factory uses the following staggered approach:

1. If the property aether.syncContext.redisson.configFile is set and the file at that specific path does exist, load it otherwise an exception is thrown.
2. If no configuration file path is provided, load default from ${maven.conf}/maven-resolver-redisson.yaml, but ignore if it does not exist.
3. If no configuration file is available at all, Redisson is configured with a single server pointing to redis://localhost:6379 with client name maven-resolver.

Please note that an invalid confguration file results in an exception too.

Discrimination

You may freely use a single Redis instance to serve multiple Maven instances, on multiple hosts with shared or exclusive local repositories. Every sync context instance will generate a unique discriminator which identifies each host paired with the local repository currently accessed. The following staggered approach is used:

1. Determine hostname, if not possible use localhost.
2. If the property aether.syncContext.redisson.discriminator is set, use it and skip the remaining steps.
3. Concat hostname with the path of the local repository: ${hostname}:${maven.repo.local}.
4. Calculate the SHA-1 digest of this value. If that fails use the static digest of an empty string.

Key Composition

Each lock is assigned a unique key in the configured Redis instance which has the following pattern: maven:resolver:${discriminator}:${artifact|metadata}.

• ${artifact} will always resolve to artifact:${groupId}:${artifactId}:${baseVersion}.
• ${metadata} will resolve to one of metadata:${groupId}:${artifactId}:${version}, metadata:${groupId}:${artifactId}, metadata:${groupId}, metadata:.

Constructor Summary

Constructors

Constructor and Description
RedissonSyncContextFactory()

Method Summary

Modifier and Type	Method and Description
SyncContext	newInstance(RepositorySystemSession session, boolean shared) Creates a new synchronization context.
void	shutdown()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RedissonSyncContextFactory

public RedissonSyncContextFactory()

Method Detail

newInstance

public SyncContext newInstance(RepositorySystemSession session,
                               boolean shared)

Description copied from interface: SyncContextFactory

Creates a new synchronization context.

Specified by:

newInstance in interface SyncContextFactory

Parameters:

session - The repository session during which the context will be used, must not be null.

shared - A flag indicating whether access to the artifacts/metadata associated with the new context can be shared among concurrent readers or whether access needs to be exclusive to the calling thread.

Returns:

The synchronization context, never null.

See Also:

RepositorySystem.newSyncContext(RepositorySystemSession, boolean)

shutdown

@PreDestroy
public void shutdown()