org.apache.kafka.common.config.provider.DirectoryConfigProvider Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.common.config.provider;
import org.apache.kafka.common.config.ConfigData;
import org.apache.kafka.common.config.ConfigException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Map;
import java.util.Set;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import static java.util.Collections.emptyMap;
/**
* An implementation of {@link ConfigProvider} based on a directory of files.
* Property keys correspond to the names of the regular (i.e. non-directory)
* files in a directory given by the path parameter.
* Property values are taken from the file contents corresponding to each key.
*/
public class DirectoryConfigProvider implements ConfigProvider {
private static final Logger log = LoggerFactory.getLogger(DirectoryConfigProvider.class);
@Override
public void configure(Map configs) { }
@Override
public void close() throws IOException { }
/**
* Retrieves the data contained in regular files in the directory given by {@code path}.
* Non-regular files (such as directories) in the given directory are silently ignored.
* @param path the directory where data files reside.
* @return the configuration data.
*/
@Override
public ConfigData get(String path) {
return get(path, Files::isRegularFile);
}
/**
* Retrieves the data contained in the regular files named by {@code keys} in the directory given by {@code path}.
* Non-regular files (such as directories) in the given directory are silently ignored.
* @param path the directory where data files reside.
* @param keys the keys whose values will be retrieved.
* @return the configuration data.
*/
@Override
public ConfigData get(String path, Set keys) {
return get(path, pathname ->
Files.isRegularFile(pathname)
&& keys.contains(pathname.getFileName().toString()));
}
private static ConfigData get(String path, Predicate fileFilter) {
Map map = emptyMap();
if (path != null && !path.isEmpty()) {
Path dir = new File(path).toPath();
if (!Files.isDirectory(dir)) {
log.warn("The path {} is not a directory", path);
} else {
try {
map = Files.list(dir)
.filter(fileFilter)
.collect(Collectors.toMap(
p -> p.getFileName().toString(),
p -> read(p)));
} catch (IOException e) {
throw new ConfigException("Could not list directory " + dir, e);
}
}
}
return new ConfigData(map);
}
private static String read(Path path) {
try {
return new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
} catch (IOException e) {
throw new ConfigException("Could not read file " + path + " for property " + path.getFileName(), e);
}
}
}