SshdSessionFactoryBuilder.java
/*
* Copyright (C) 2020 Thomas Wolf <thomas.wolf@paranor.ch> and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.transport.sshd;
import java.io.File;
import java.nio.file.Path;
import java.security.KeyPair;
import java.util.Collections;
import java.util.List;
import java.util.function.BiFunction;
import java.util.function.Function;
import org.eclipse.jgit.annotations.NonNull;
import org.eclipse.jgit.transport.CredentialsProvider;
import org.eclipse.jgit.transport.SshConfigStore;
import org.eclipse.jgit.util.StringUtils;
/**
* A builder API to configure {@link SshdSessionFactory SshdSessionFactories}.
*
* @since 5.8
*/
public final class SshdSessionFactoryBuilder {
private final State state = new State();
/**
* Sets the {@link ProxyDataFactory} to use for {@link SshdSessionFactory
* SshdSessionFactories} created by {@link #build(KeyCache)}.
*
* @param proxyDataFactory
* to use
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setProxyDataFactory(
ProxyDataFactory proxyDataFactory) {
this.state.proxyDataFactory = proxyDataFactory;
return this;
}
/**
* Sets the home directory to use for {@link SshdSessionFactory
* SshdSessionFactories} created by {@link #build(KeyCache)}.
*
* @param homeDirectory
* to use; may be {@code null}, in which case the home directory
* as defined by {@link org.eclipse.jgit.util.FS#userHome()
* FS.userHome()} is assumed
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setHomeDirectory(File homeDirectory) {
this.state.homeDirectory = homeDirectory;
return this;
}
/**
* Sets the SSH directory to use for {@link SshdSessionFactory
* SshdSessionFactories} created by {@link #build(KeyCache)}.
*
* @param sshDirectory
* to use; may be {@code null}, in which case ".ssh" under the
* {@link #setHomeDirectory(File) home directory} is assumed
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setSshDirectory(File sshDirectory) {
this.state.sshDirectory = sshDirectory;
return this;
}
/**
* Sets the default preferred authentication mechanisms to use for
* {@link SshdSessionFactory SshdSessionFactories} created by
* {@link #build(KeyCache)}.
*
* @param authentications
* comma-separated list of authentication mechanism names; if
* {@code null} or empty, the default as specified by
* {@link SshdSessionFactory#getDefaultPreferredAuthentications()}
* will be used
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setPreferredAuthentications(
String authentications) {
this.state.preferredAuthentications = authentications;
return this;
}
/**
* Sets a function that returns the SSH config file, given the SSH
* directory. The function may return {@code null}, in which case no SSH
* config file will be used. If a non-null file is returned, it will be used
* when it exists. If no supplier has been set, or the supplier has been set
* explicitly to {@code null}, by default a file named
* {@link org.eclipse.jgit.transport.SshConstants#CONFIG
* SshConstants.CONFIG} in the {@link #setSshDirectory(File) SSH directory}
* is used.
*
* @param supplier
* returning a {@link File} for the SSH config file to use, or
* returning {@code null} if no config file is to be used
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setConfigFile(
Function<File, File> supplier) {
this.state.configFileFinder = supplier;
return this;
}
/**
* A factory interface for creating a @link SshConfigStore}.
*/
@FunctionalInterface
public interface ConfigStoreFactory {
/**
* Creates a {@link SshConfigStore}. May return {@code null} if none is
* to be used.
*
* @param homeDir
* to use for ~-replacements
* @param configFile
* to use, may be {@code null} if none
* @param localUserName
* name of the current user in the local OS
* @return the {@link SshConfigStore}, or {@code null} if none is to be
* used
*/
SshConfigStore create(@NonNull File homeDir, File configFile,
String localUserName);
}
/**
* Sets a factory for the {@link SshConfigStore} to use. If not set or
* explicitly set to {@code null}, the default as specified by
* {@link SshdSessionFactory#createSshConfigStore(File, File, String)} is
* used.
*
* @param factory
* to set
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setConfigStoreFactory(
ConfigStoreFactory factory) {
this.state.configFactory = factory;
return this;
}
/**
* Sets a function that returns the default known hosts files, given the SSH
* directory. If not set or explicitly set to {@code null}, the defaults as
* specified by {@link SshdSessionFactory#getDefaultKnownHostsFiles(File)}
* are used.
*
* @param supplier
* to get the default known hosts files
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setDefaultKnownHostsFiles(
Function<File, List<Path>> supplier) {
this.state.knownHostsFileFinder = supplier;
return this;
}
/**
* Sets a function that returns the default private key files, given the SSH
* directory. If not set or explicitly set to {@code null}, the defaults as
* specified by {@link SshdSessionFactory#getDefaultIdentities(File)} are
* used.
*
* @param supplier
* to get the default private key files
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setDefaultIdentities(
Function<File, List<Path>> supplier) {
this.state.defaultKeyFileFinder = supplier;
return this;
}
/**
* Sets a function that returns the default private keys, given the SSH
* directory. If not set or explicitly set to {@code null}, the defaults as
* specified by {@link SshdSessionFactory#getDefaultKeys(File)} are used.
*
* @param provider
* to get the default private key files
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setDefaultKeysProvider(
Function<File, Iterable<KeyPair>> provider) {
this.state.defaultKeysProvider = provider;
return this;
}
/**
* Sets a factory function to create a {@link KeyPasswordProvider}. If not
* set or explicitly set to {@code null}, or if the factory returns
* {@code null}, the default as specified by
* {@link SshdSessionFactory#createKeyPasswordProvider(CredentialsProvider)}
* is used.
*
* @param factory
* to create a {@link KeyPasswordProvider}
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setKeyPasswordProvider(
Function<CredentialsProvider, KeyPasswordProvider> factory) {
this.state.passphraseProviderFactory = factory;
return this;
}
/**
* Sets a function that creates a new {@link ServerKeyDatabase}, given the
* SSH and home directory. If not set or explicitly set to {@code null}, or
* if the {@code factory} returns {@code null}, the default as specified by
* {@link SshdSessionFactory#createServerKeyDatabase(File, File)} is used.
*
* @param factory
* to create a {@link ServerKeyDatabase}
* @return this {@link SshdSessionFactoryBuilder}
*/
public SshdSessionFactoryBuilder setServerKeyDatabase(
BiFunction<File, File, ServerKeyDatabase> factory) {
this.state.serverKeyDatabaseCreator = factory;
return this;
}
/**
* Builds a {@link SshdSessionFactory} as configured, using the given
* {@link KeyCache} for caching keys.
* <p>
* Different {@link SshdSessionFactory SshdSessionFactories} should
* <em>not</em> share the same {@link KeyCache} since the cache is
* invalidated when the factory itself or when the last {@link SshdSession}
* created from the factory is closed.
* </p>
*
* @param cache
* to use for caching ssh keys; may be {@code null} if no caching
* is desired.
* @return the {@link SshdSessionFactory}
*/
public SshdSessionFactory build(KeyCache cache) {
// Use a copy to avoid that subsequent calls to setters affect an
// already created SshdSessionFactory.
return state.copy().build(cache);
}
private static class State {
ProxyDataFactory proxyDataFactory;
File homeDirectory;
File sshDirectory;
String preferredAuthentications;
Function<File, File> configFileFinder;
ConfigStoreFactory configFactory;
Function<CredentialsProvider, KeyPasswordProvider> passphraseProviderFactory;
Function<File, List<Path>> knownHostsFileFinder;
Function<File, List<Path>> defaultKeyFileFinder;
Function<File, Iterable<KeyPair>> defaultKeysProvider;
BiFunction<File, File, ServerKeyDatabase> serverKeyDatabaseCreator;
State copy() {
State c = new State();
c.proxyDataFactory = proxyDataFactory;
c.homeDirectory = homeDirectory;
c.sshDirectory = sshDirectory;
c.preferredAuthentications = preferredAuthentications;
c.configFileFinder = configFileFinder;
c.configFactory = configFactory;
c.passphraseProviderFactory = passphraseProviderFactory;
c.knownHostsFileFinder = knownHostsFileFinder;
c.defaultKeyFileFinder = defaultKeyFileFinder;
c.defaultKeysProvider = defaultKeysProvider;
c.serverKeyDatabaseCreator = serverKeyDatabaseCreator;
return c;
}
SshdSessionFactory build(KeyCache cache) {
SshdSessionFactory factory = new SessionFactory(cache,
proxyDataFactory);
factory.setHomeDirectory(homeDirectory);
factory.setSshDirectory(sshDirectory);
return factory;
}
private class SessionFactory extends SshdSessionFactory {
public SessionFactory(KeyCache cache,
ProxyDataFactory proxyDataFactory) {
super(cache, proxyDataFactory);
}
@Override
protected File getSshConfig(File sshDir) {
if (configFileFinder != null) {
return configFileFinder.apply(sshDir);
}
return super.getSshConfig(sshDir);
}
@Override
protected List<Path> getDefaultKnownHostsFiles(File sshDir) {
if (knownHostsFileFinder != null) {
List<Path> result = knownHostsFileFinder.apply(sshDir);
return result == null ? Collections.emptyList() : result;
}
return super.getDefaultKnownHostsFiles(sshDir);
}
@Override
protected List<Path> getDefaultIdentities(File sshDir) {
if (defaultKeyFileFinder != null) {
List<Path> result = defaultKeyFileFinder.apply(sshDir);
return result == null ? Collections.emptyList() : result;
}
return super.getDefaultIdentities(sshDir);
}
@Override
protected String getDefaultPreferredAuthentications() {
if (!StringUtils.isEmptyOrNull(preferredAuthentications)) {
return preferredAuthentications;
}
return super.getDefaultPreferredAuthentications();
}
@Override
protected Iterable<KeyPair> getDefaultKeys(File sshDir) {
if (defaultKeysProvider != null) {
Iterable<KeyPair> result = defaultKeysProvider
.apply(sshDir);
return result == null ? Collections.emptyList() : result;
}
return super.getDefaultKeys(sshDir);
}
@Override
protected KeyPasswordProvider createKeyPasswordProvider(
CredentialsProvider provider) {
if (passphraseProviderFactory != null) {
KeyPasswordProvider result = passphraseProviderFactory
.apply(provider);
if (result != null) {
return result;
}
}
return super.createKeyPasswordProvider(provider);
}
@Override
protected ServerKeyDatabase createServerKeyDatabase(File homeDir,
File sshDir) {
if (serverKeyDatabaseCreator != null) {
ServerKeyDatabase result = serverKeyDatabaseCreator
.apply(homeDir, sshDir);
if (result != null) {
return result;
}
}
return super.createServerKeyDatabase(homeDir, sshDir);
}
@Override
protected SshConfigStore createSshConfigStore(File homeDir,
File configFile, String localUserName) {
if (configFactory != null) {
return configFactory.create(homeDir, configFile,
localUserName);
}
return super.createSshConfigStore(homeDir, configFile,
localUserName);
}
}
}
}