org.apache.hadoop.util.ZKUtil Maven / Gradle / Ivy
/**
* 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.util;
import java.io.File;
import java.io.IOException;
import java.util.List;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.HadoopIllegalArgumentException;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Id;
import org.apache.hadoop.thirdparty.com.google.common.base.Charsets;
import org.apache.hadoop.thirdparty.com.google.common.base.Splitter;
import org.apache.hadoop.thirdparty.com.google.common.collect.Lists;
import org.apache.hadoop.thirdparty.com.google.common.io.Files;
/**
* Utilities for working with ZooKeeper.
*/
@InterfaceAudience.Private
public class ZKUtil {
/**
* Parse ACL permission string, partially borrowed from
* ZooKeeperMain private method
*/
private static int getPermFromString(String permString) {
int perm = 0;
for (int i = 0; i < permString.length(); i++) {
char c = permString.charAt(i);
switch (c) {
case 'r':
perm |= ZooDefs.Perms.READ;
break;
case 'w':
perm |= ZooDefs.Perms.WRITE;
break;
case 'c':
perm |= ZooDefs.Perms.CREATE;
break;
case 'd':
perm |= ZooDefs.Perms.DELETE;
break;
case 'a':
perm |= ZooDefs.Perms.ADMIN;
break;
default:
throw new BadAclFormatException(
"Invalid permission '" + c + "' in permission string '" +
permString + "'");
}
}
return perm;
}
/**
* Helper method to remove a subset of permissions (remove) from a
* given set (perms).
* @param perms The permissions flag to remove from. Should be an OR of a
* some combination of {@link ZooDefs.Perms}
* @param remove The permissions to be removed. Should be an OR of a
* some combination of {@link ZooDefs.Perms}
* @return A permissions flag that is an OR of {@link ZooDefs.Perms}
* present in perms and not present in remove
*/
public static int removeSpecificPerms(int perms, int remove) {
return perms ^ remove;
}
/**
* Parse comma separated list of ACL entries to secure generated nodes, e.g.
* sasl:hdfs/[email protected]:cdrwa,sasl:hdfs/[email protected]:cdrwa
*
* @return ACL list
* @throws BadAclFormatException if an ACL is invalid
*/
public static List parseACLs(String aclString) throws
BadAclFormatException {
List acl = Lists.newArrayList();
if (aclString == null) {
return acl;
}
List aclComps = Lists.newArrayList(
Splitter.on(',').omitEmptyStrings().trimResults()
.split(aclString));
for (String a : aclComps) {
// from ZooKeeperMain private method
int firstColon = a.indexOf(':');
int lastColon = a.lastIndexOf(':');
if (firstColon == -1 || lastColon == -1 || firstColon == lastColon) {
throw new BadAclFormatException(
"ACL '" + a + "' not of expected form scheme:id:perm");
}
ACL newAcl = new ACL();
newAcl.setId(new Id(a.substring(0, firstColon), a.substring(
firstColon + 1, lastColon)));
newAcl.setPerms(getPermFromString(a.substring(lastColon + 1)));
acl.add(newAcl);
}
return acl;
}
/**
* Parse a comma-separated list of authentication mechanisms. Each
* such mechanism should be of the form 'scheme:auth' -- the same
* syntax used for the 'addAuth' command in the ZK CLI.
*
* @param authString the comma-separated auth mechanisms
* @return a list of parsed authentications
* @throws BadAuthFormatException if the auth format is invalid
*/
public static List parseAuth(String authString) throws
BadAuthFormatException{
List ret = Lists.newArrayList();
if (authString == null) {
return ret;
}
List authComps = Lists.newArrayList(
Splitter.on(',').omitEmptyStrings().trimResults()
.split(authString));
for (String comp : authComps) {
String parts[] = comp.split(":", 2);
if (parts.length != 2) {
throw new BadAuthFormatException(
"Auth '" + comp + "' not of expected form scheme:auth");
}
ret.add(new ZKAuthInfo(parts[0],
parts[1].getBytes(Charsets.UTF_8)));
}
return ret;
}
/**
* Because ZK ACLs and authentication information may be secret,
* allow the configuration values to be indirected through a file
* by specifying the configuration as "@/path/to/file". If this
* syntax is used, this function will return the contents of the file
* as a String.
*
* @param valInConf the value from the Configuration
* @return either the same value, or the contents of the referenced
* file if the configured value starts with "@"
* @throws IOException if the file cannot be read
*/
public static String resolveConfIndirection(String valInConf)
throws IOException {
if (valInConf == null) return null;
if (!valInConf.startsWith("@")) {
return valInConf;
}
String path = valInConf.substring(1).trim();
return Files.asCharSource(new File(path), Charsets.UTF_8).read().trim();
}
/**
* An authentication token passed to ZooKeeper.addAuthInfo
*/
@InterfaceAudience.Private
public static class ZKAuthInfo {
private final String scheme;
private final byte[] auth;
public ZKAuthInfo(String scheme, byte[] auth) {
super();
this.scheme = scheme;
this.auth = auth;
}
public String getScheme() {
return scheme;
}
public byte[] getAuth() {
return auth;
}
}
@InterfaceAudience.Private
public static class BadAclFormatException extends
HadoopIllegalArgumentException {
private static final long serialVersionUID = 1L;
public BadAclFormatException(String message) {
super(message);
}
}
@InterfaceAudience.Private
public static class BadAuthFormatException extends
HadoopIllegalArgumentException {
private static final long serialVersionUID = 1L;
public BadAuthFormatException(String message) {
super(message);
}
}
}