/*
* 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.sshd.client.config.hosts;
import java.io.File;
import java.io.IOException;
import java.nio.file.LinkOption;
import java.nio.file.Path;
import java.util.Collection;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.io.IoUtils;
import org.apache.sshd.common.util.io.ModifiableFileWatcher;
/**
* Watches for changes in a configuration file and automatically reloads any changes
*
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public class ConfigFileHostEntryResolver extends ModifiableFileWatcher implements HostConfigEntryResolver {
private final AtomicReference<HostConfigEntryResolver> delegateHolder = // assumes initially empty
new AtomicReference<>(HostConfigEntryResolver.EMPTY);
public ConfigFileHostEntryResolver(File file) {
this(Objects.requireNonNull(file, "No file to watch").toPath());
}
public ConfigFileHostEntryResolver(Path file) {
this(file, IoUtils.EMPTY_LINK_OPTIONS);
}
public ConfigFileHostEntryResolver(Path file, LinkOption... options) {
super(file, options);
}
@Override
public HostConfigEntry resolveEffectiveHost(String host, int port, String username) throws IOException {
try {
HostConfigEntryResolver delegate = Objects.requireNonNull(resolveEffectiveResolver(host, port, username), "No delegate");
HostConfigEntry entry = delegate.resolveEffectiveHost(host, port, username);
if (log.isDebugEnabled()) {
log.debug("resolveEffectiveHost({}@{}:{}) => {}", username, host, port, entry);
}
return entry;
} catch (Throwable e) {
if (log.isDebugEnabled()) {
log.debug("resolveEffectiveHost({}@{}:{}) failed ({}) to resolve: {}",
username, host, port, e.getClass().getSimpleName(), e.getMessage());
}
if (log.isTraceEnabled()) {
log.trace("resolveEffectiveHost(" + username + "@" + host + ":" + port + ") resolution failure details", e);
}
if (e instanceof IOException) {
throw (IOException) e;
} else {
throw new IOException(e);
}
}
}
protected HostConfigEntryResolver resolveEffectiveResolver(String host, int port, String username) throws IOException {
if (checkReloadRequired()) {
delegateHolder.set(HostConfigEntryResolver.EMPTY); // start fresh
Path path = getPath();
if (exists()) {
Collection<HostConfigEntry> entries = reloadHostConfigEntries(path, host, port, username);
if (GenericUtils.size(entries) > 0) {
delegateHolder.set(HostConfigEntry.toHostConfigEntryResolver(entries));
}
} else {
log.info("resolveEffectiveResolver({}@{}:{}) no configuration file at {}", username, host, port, path);
}
}
return delegateHolder.get();
}
protected List<HostConfigEntry> reloadHostConfigEntries(Path path, String host, int port, String username) throws IOException {
List<HostConfigEntry> entries = HostConfigEntry.readHostConfigEntries(path);
log.info("resolveEffectiveResolver({}@{}:{}) loaded {} entries from {}", username, host, port, GenericUtils.size(entries), path);
updateReloadAttributes();
return entries;
}
}