001package org.eclipse.aether.internal.impl.synccontext.named;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.eclipse.aether.RepositorySystemSession;
023import org.eclipse.aether.artifact.Artifact;
024import org.eclipse.aether.metadata.Metadata;
025import org.eclipse.aether.util.ConfigUtils;
026import org.eclipse.aether.util.StringDigestUtil;
027import org.slf4j.Logger;
028import org.slf4j.LoggerFactory;
029
030import java.io.File;
031import java.net.InetAddress;
032import java.net.UnknownHostException;
033import java.util.Collection;
034import java.util.Objects;
035
036import static java.util.stream.Collectors.toList;
037
038/**
039 * Wrapping {@link NameMapper}, that wraps another {@link NameMapper} and adds a "discriminator" as prefix, that
040 * makes lock names unique including the hostname and local repository (by default). The discriminator may be passed
041 * in via {@link RepositorySystemSession} or is automatically calculated based on the local hostname and repository
042 * path. The implementation retains order of collection elements as it got it from
043 * {@link NameMapper#nameLocks(RepositorySystemSession, Collection, Collection)} method.
044 * <p>
045 * The default setup wraps {@link GAVNameMapper}, but manually may be created any instance needed.
046 */
047public class DiscriminatingNameMapper implements NameMapper
048{
049    /**
050     * Configuration property to pass in discriminator
051     */
052    private static final String CONFIG_PROP_DISCRIMINATOR = "aether.syncContext.named.discriminating.discriminator";
053
054    /**
055     * Configuration property to pass in hostname
056     */
057    private static final String CONFIG_PROP_HOSTNAME = "aether.syncContext.named.discriminating.hostname";
058
059    private static final String DEFAULT_DISCRIMINATOR_DIGEST = "da39a3ee5e6b4b0d3255bfef95601890afd80709";
060
061    private static final String DEFAULT_HOSTNAME = "localhost";
062
063    private static final Logger LOGGER = LoggerFactory.getLogger( DiscriminatingNameMapper.class );
064
065    private final NameMapper delegate;
066
067    private final String hostname;
068
069    public DiscriminatingNameMapper( final NameMapper delegate )
070    {
071        this.delegate = Objects.requireNonNull( delegate );
072        this.hostname = getHostname();
073    }
074
075    @Override
076    public boolean isFileSystemFriendly()
077    {
078        return false; // uses ":" in produced lock names
079    }
080
081    @Override
082    public Collection<String> nameLocks( final RepositorySystemSession session,
083                                         final Collection<? extends Artifact> artifacts,
084                                         final Collection<? extends Metadata> metadatas )
085    {
086        String discriminator = createDiscriminator( session );
087        return delegate.nameLocks( session, artifacts, metadatas ).stream()
088                .map( s -> discriminator + ":" + s )
089                .collect( toList() );
090    }
091
092    private String getHostname()
093    {
094        try
095        {
096            return InetAddress.getLocalHost().getHostName();
097        }
098        catch ( UnknownHostException e )
099        {
100            LOGGER.warn( "Failed to get hostname, using '{}'", DEFAULT_HOSTNAME, e );
101            return DEFAULT_HOSTNAME;
102        }
103    }
104
105    private String createDiscriminator( final RepositorySystemSession session )
106    {
107        String discriminator = ConfigUtils.getString( session, null, CONFIG_PROP_DISCRIMINATOR );
108
109        if ( discriminator == null || discriminator.isEmpty() )
110        {
111            String hostname = ConfigUtils.getString( session, this.hostname, CONFIG_PROP_HOSTNAME );
112            File basedir = session.getLocalRepository().getBasedir();
113            discriminator = hostname + ":" + basedir;
114            try
115            {
116                return StringDigestUtil.sha1( discriminator );
117            }
118            catch ( Exception e )
119            {
120                LOGGER.warn( "Failed to calculate discriminator digest, using '{}'", DEFAULT_DISCRIMINATOR_DIGEST, e );
121                return DEFAULT_DISCRIMINATOR_DIGEST;
122            }
123        }
124        return discriminator;
125    }
126}