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Elasticsearch subproject :server
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.discovery;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.message.ParameterizedMessage;
import org.elasticsearch.common.transport.TransportAddress;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* An implementation of {@link SeedHostsProvider} that reads hosts/ports
* from {@link #UNICAST_HOSTS_FILE}.
*
* Each host/port that is part of the discovery process must be listed on
* a separate line. If the port is left off an entry, we default to the
* first port in the {@code transport.port} range.
* An example unicast hosts file could read:
*
* 67.81.244.10
* 67.81.244.11:9305
* 67.81.244.15:9400
*/
public class FileBasedSeedHostsProvider implements SeedHostsProvider {
private static final Logger logger = LogManager.getLogger(FileBasedSeedHostsProvider.class);
public static final String UNICAST_HOSTS_FILE = "unicast_hosts.txt";
private final Path unicastHostsFilePath;
public FileBasedSeedHostsProvider(Path configFile) {
this.unicastHostsFilePath = configFile.resolve(UNICAST_HOSTS_FILE);
}
private List getHostsList() {
if (Files.exists(unicastHostsFilePath)) {
try (Stream lines = Files.lines(unicastHostsFilePath)) {
return lines.filter(line -> line.startsWith("#") == false) // lines starting with `#` are comments
.collect(Collectors.toList());
} catch (IOException e) {
logger.warn(() -> new ParameterizedMessage("failed to read file [{}]", unicastHostsFilePath), e);
return Collections.emptyList();
}
}
logger.warn("expected, but did not find, a dynamic hosts list at [{}]", unicastHostsFilePath);
return Collections.emptyList();
}
@Override
public List getSeedAddresses(HostsResolver hostsResolver) {
final List transportAddresses = hostsResolver.resolveHosts(getHostsList());
logger.debug("seed addresses: {}", transportAddresses);
return transportAddresses;
}
}