/*
* 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.hadoop.registry.client.binding;
import com.google.common.base.Preconditions;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.PathNotFoundException;
import org.apache.hadoop.registry.client.exceptions.InvalidPathnameException;
import org.apache.hadoop.registry.client.impl.zk.RegistryInternalConstants;
import org.apache.zookeeper.common.PathUtils;
import java.net.IDN;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;
/**
* Basic operations on paths: manipulating them and creating and validating
* path elements.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class RegistryPathUtils {
/**
* Compiled down pattern to validate single entries in the path
*/
private static final Pattern PATH_ENTRY_VALIDATION_PATTERN =
Pattern.compile(RegistryInternalConstants.VALID_PATH_ENTRY_PATTERN);
/**
* Validate ZK path with the path itself included in
* the exception text
* @param path path to validate
* @return the path parameter
* @throws InvalidPathnameException if the pathname is invalid.
*/
public static String validateZKPath(String path) throws
InvalidPathnameException {
try {
PathUtils.validatePath(path);
} catch (IllegalArgumentException e) {
throw new InvalidPathnameException(path,
"Invalid Path \"" + path + "\" : " + e, e);
}
return path;
}
/**
* Validate ZK path as valid for a DNS hostname.
* @param path path to validate
* @return the path parameter
* @throws InvalidPathnameException if the pathname is invalid.
*/
public static String validateElementsAsDNS(String path) throws
InvalidPathnameException {
List<String> splitpath = split(path);
for (String fragment : splitpath) {
if (!PATH_ENTRY_VALIDATION_PATTERN.matcher(fragment).matches()) {
throw new InvalidPathnameException(path,
"Invalid Path element \"" + fragment + "\"");
}
}
return path;
}
/**
* Create a full path from the registry root and the supplied subdir
* @param path path of operation
* @return an absolute path
* @throws InvalidPathnameException if the path is invalid
*/
public static String createFullPath(String base, String path) throws
InvalidPathnameException {
Preconditions.checkArgument(path != null, "null path");
Preconditions.checkArgument(base != null, "null path");
return validateZKPath(join(base, path));
}
/**
* Join two paths, guaranteeing that there will not be exactly
* one separator between the two, and exactly one at the front
* of the path. There will be no trailing "/" except for the special
* case that this is the root path
* @param base base path
* @param path second path to add
* @return a combined path.
*/
public static String join(String base, String path) {
Preconditions.checkArgument(path != null, "null path");
Preconditions.checkArgument(base != null, "null path");
StringBuilder fullpath = new StringBuilder();
if (!base.startsWith("/")) {
fullpath.append('/');
}
fullpath.append(base);
// guarantee a trailing /
if (!fullpath.toString().endsWith("/")) {
fullpath.append("/");
}
// strip off any at the beginning
if (path.startsWith("/")) {
// path starts with /, so append all other characters -if present
if (path.length() > 1) {
fullpath.append(path.substring(1));
}
} else {
fullpath.append(path);
}
//here there may be a trailing "/"
String finalpath = fullpath.toString();
if (finalpath.endsWith("/") && !"/".equals(finalpath)) {
finalpath = finalpath.substring(0, finalpath.length() - 1);
}
return finalpath;
}
/**
* split a path into elements, stripping empty elements
* @param path the path
* @return the split path
*/
public static List<String> split(String path) {
//
String[] pathelements = path.split("/");
List<String> dirs = new ArrayList<String>(pathelements.length);
for (String pathelement : pathelements) {
if (!pathelement.isEmpty()) {
dirs.add(pathelement);
}
}
return dirs;
}
/**
* Get the last entry in a path; for an empty path
* returns "". The split logic is that of
* {@link #split(String)}
* @param path path of operation
* @return the last path entry or "" if none.
*/
public static String lastPathEntry(String path) {
List<String> splits = split(path);
if (splits.isEmpty()) {
// empty path. Return ""
return "";
} else {
return splits.get(splits.size() - 1);
}
}
/**
* Get the parent of a path
* @param path path to look at
* @return the parent path
* @throws PathNotFoundException if the path was at root.
*/
public static String parentOf(String path) throws PathNotFoundException {
List<String> elements = split(path);
int size = elements.size();
if (size == 0) {
throw new PathNotFoundException("No parent of " + path);
}
if (size == 1) {
return "/";
}
elements.remove(size - 1);
StringBuilder parent = new StringBuilder(path.length());
for (String element : elements) {
parent.append("/");
parent.append(element);
}
return parent.toString();
}
/**
* Perform any formatting for the registry needed to convert
* non-simple-DNS elements
* @param element element to encode
* @return an encoded string
*/
public static String encodeForRegistry(String element) {
return IDN.toASCII(element);
}
/**
* Perform whatever transforms are needed to get a YARN ID into
* a DNS-compatible name
* @param yarnId ID as string of YARN application, instance or container
* @return a string suitable for use in registry paths.
*/
public static String encodeYarnID(String yarnId) {
return yarnId.replace("_", "-");
}
}