org.apache.hadoop.util.curator.ZKCuratorManager 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.curator;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import org.apache.curator.framework.AuthInfo;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.api.transaction.CuratorOp;
import org.apache.curator.retry.RetryNTimes;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CommonConfigurationKeys;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.util.ZKUtil;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.thirdparty.com.google.common.base.Preconditions;
/**
* Helper class that provides utility methods specific to ZK operations.
*/
@InterfaceAudience.Private
public final class ZKCuratorManager {
private static final Logger LOG =
LoggerFactory.getLogger(ZKCuratorManager.class);
/** Configuration for the ZooKeeper connection. */
private final Configuration conf;
/** Curator for ZooKeeper. */
private CuratorFramework curator;
public ZKCuratorManager(Configuration config) throws IOException {
this.conf = config;
}
/**
* Get the curator framework managing the ZooKeeper connection.
* @return Curator framework.
*/
public CuratorFramework getCurator() {
return curator;
}
/**
* Close the connection with ZooKeeper.
*/
public void close() {
if (curator != null) {
curator.close();
}
}
/**
* Utility method to fetch the ZK ACLs from the configuration.
* @throws java.io.IOException if the Zookeeper ACLs configuration file
* cannot be read
*/
public static List getZKAcls(Configuration conf) throws IOException {
// Parse authentication from configuration.
String zkAclConf = conf.get(CommonConfigurationKeys.ZK_ACL,
CommonConfigurationKeys.ZK_ACL_DEFAULT);
try {
zkAclConf = ZKUtil.resolveConfIndirection(zkAclConf);
return ZKUtil.parseACLs(zkAclConf);
} catch (IOException | ZKUtil.BadAclFormatException e) {
LOG.error("Couldn't read ACLs based on {}",
CommonConfigurationKeys.ZK_ACL);
throw e;
}
}
/**
* Utility method to fetch ZK auth info from the configuration.
* @throws java.io.IOException if the Zookeeper ACLs configuration file
* cannot be read
* @throws ZKUtil.BadAuthFormatException if the auth format is invalid
*/
public static List getZKAuths(Configuration conf)
throws IOException {
return SecurityUtil.getZKAuthInfos(conf, CommonConfigurationKeys.ZK_AUTH);
}
/**
* Start the connection to the ZooKeeper ensemble.
* @throws IOException If the connection cannot be started.
*/
public void start() throws IOException {
this.start(new ArrayList<>());
}
/**
* Start the connection to the ZooKeeper ensemble.
* @param authInfos List of authentication keys.
* @throws IOException If the connection cannot be started.
*/
public void start(List authInfos) throws IOException {
// Connect to the ZooKeeper ensemble
String zkHostPort = conf.get(CommonConfigurationKeys.ZK_ADDRESS);
if (zkHostPort == null) {
throw new IOException(
CommonConfigurationKeys.ZK_ADDRESS + " is not configured.");
}
int numRetries = conf.getInt(CommonConfigurationKeys.ZK_NUM_RETRIES,
CommonConfigurationKeys.ZK_NUM_RETRIES_DEFAULT);
int zkSessionTimeout = conf.getInt(CommonConfigurationKeys.ZK_TIMEOUT_MS,
CommonConfigurationKeys.ZK_TIMEOUT_MS_DEFAULT);
int zkRetryInterval = conf.getInt(
CommonConfigurationKeys.ZK_RETRY_INTERVAL_MS,
CommonConfigurationKeys.ZK_RETRY_INTERVAL_MS_DEFAULT);
RetryNTimes retryPolicy = new RetryNTimes(numRetries, zkRetryInterval);
// Set up ZK auths
List zkAuths = getZKAuths(conf);
if (authInfos == null) {
authInfos = new ArrayList<>();
}
for (ZKUtil.ZKAuthInfo zkAuth : zkAuths) {
authInfos.add(new AuthInfo(zkAuth.getScheme(), zkAuth.getAuth()));
}
CuratorFramework client = CuratorFrameworkFactory.builder()
.connectString(zkHostPort)
.sessionTimeoutMs(zkSessionTimeout)
.retryPolicy(retryPolicy)
.authorization(authInfos)
.build();
client.start();
this.curator = client;
}
/**
* Get ACLs for a ZNode.
* @param path Path of the ZNode.
* @return The list of ACLs.
* @throws Exception
*/
public List getACL(final String path) throws Exception {
return curator.getACL().forPath(path);
}
/**
* Get the data in a ZNode.
* @param path Path of the ZNode.
* @return The data in the ZNode.
* @throws Exception If it cannot contact Zookeeper.
*/
public byte[] getData(final String path) throws Exception {
return curator.getData().forPath(path);
}
/**
* Get the data in a ZNode.
* @param path Path of the ZNode.
* @param stat
* @return The data in the ZNode.
* @throws Exception If it cannot contact Zookeeper.
*/
public byte[] getData(final String path, Stat stat) throws Exception {
return curator.getData().storingStatIn(stat).forPath(path);
}
/**
* Get the data in a ZNode.
* @param path Path of the ZNode.
* @return The data in the ZNode.
* @throws Exception If it cannot contact Zookeeper.
*/
public String getStringData(final String path) throws Exception {
byte[] bytes = getData(path);
if (bytes != null) {
return new String(bytes, Charset.forName("UTF-8"));
}
return null;
}
/**
* Get the data in a ZNode.
* @param path Path of the ZNode.
* @param stat Output statistics of the ZNode.
* @return The data in the ZNode.
* @throws Exception If it cannot contact Zookeeper.
*/
public String getStringData(final String path, Stat stat) throws Exception {
byte[] bytes = getData(path, stat);
if (bytes != null) {
return new String(bytes, Charset.forName("UTF-8"));
}
return null;
}
/**
* Set data into a ZNode.
* @param path Path of the ZNode.
* @param data Data to set.
* @param version Version of the data to store.
* @throws Exception If it cannot contact Zookeeper.
*/
public void setData(String path, byte[] data, int version) throws Exception {
curator.setData().withVersion(version).forPath(path, data);
}
/**
* Set data into a ZNode.
* @param path Path of the ZNode.
* @param data Data to set as String.
* @param version Version of the data to store.
* @throws Exception If it cannot contact Zookeeper.
*/
public void setData(String path, String data, int version) throws Exception {
byte[] bytes = data.getBytes(Charset.forName("UTF-8"));
setData(path, bytes, version);
}
/**
* Get children of a ZNode.
* @param path Path of the ZNode.
* @return The list of children.
* @throws Exception If it cannot contact Zookeeper.
*/
public List getChildren(final String path) throws Exception {
return curator.getChildren().forPath(path);
}
/**
* Check if a ZNode exists.
* @param path Path of the ZNode.
* @return If the ZNode exists.
* @throws Exception If it cannot contact Zookeeper.
*/
public boolean exists(final String path) throws Exception {
return curator.checkExists().forPath(path) != null;
}
/**
* Create a ZNode.
* @param path Path of the ZNode.
* @return If the ZNode was created.
* @throws Exception If it cannot contact Zookeeper.
*/
public boolean create(final String path) throws Exception {
return create(path, null);
}
/**
* Create a ZNode.
* @param path Path of the ZNode.
* @param zkAcl ACL for the node.
* @return If the ZNode was created.
* @throws Exception If it cannot contact Zookeeper.
*/
public boolean create(final String path, List zkAcl) throws Exception {
boolean created = false;
if (!exists(path)) {
curator.create()
.withMode(CreateMode.PERSISTENT)
.withACL(zkAcl)
.forPath(path, null);
created = true;
}
return created;
}
/**
* Utility function to ensure that the configured base znode exists.
* This recursively creates the znode as well as all of its parents.
* @param path Path of the znode to create.
* @throws Exception If it cannot create the file.
*/
public void createRootDirRecursively(String path) throws Exception {
createRootDirRecursively(path, null);
}
/**
* Utility function to ensure that the configured base znode exists.
* This recursively creates the znode as well as all of its parents.
* @param path Path of the znode to create.
* @param zkAcl ACLs for ZooKeeper.
* @throws Exception If it cannot create the file.
*/
public void createRootDirRecursively(String path, List zkAcl)
throws Exception {
String[] pathParts = path.split("/");
Preconditions.checkArgument(
pathParts.length >= 1 && pathParts[0].isEmpty(),
"Invalid path: %s", path);
StringBuilder sb = new StringBuilder();
for (int i = 1; i < pathParts.length; i++) {
sb.append("/").append(pathParts[i]);
create(sb.toString(), zkAcl);
}
}
/**
* Delete a ZNode.
* @param path Path of the ZNode.
* @return If the znode was deleted.
* @throws Exception If it cannot contact ZooKeeper.
*/
public boolean delete(final String path) throws Exception {
if (exists(path)) {
curator.delete().deletingChildrenIfNeeded().forPath(path);
return true;
}
return false;
}
/**
* Get the path for a ZNode.
* @param root Root of the ZNode.
* @param nodeName Name of the ZNode.
* @return Path for the ZNode.
*/
public static String getNodePath(String root, String nodeName) {
return root + "/" + nodeName;
}
public void safeCreate(String path, byte[] data, List acl,
CreateMode mode, List fencingACL, String fencingNodePath)
throws Exception {
if (!exists(path)) {
SafeTransaction transaction = createTransaction(fencingACL,
fencingNodePath);
transaction.create(path, data, acl, mode);
transaction.commit();
}
}
/**
* Deletes the path. Checks for existence of path as well.
* @param path Path to be deleted.
* @throws Exception if any problem occurs while performing deletion.
*/
public void safeDelete(final String path, List fencingACL,
String fencingNodePath) throws Exception {
if (exists(path)) {
SafeTransaction transaction = createTransaction(fencingACL,
fencingNodePath);
transaction.delete(path);
transaction.commit();
}
}
public void safeSetData(String path, byte[] data, int version,
List fencingACL, String fencingNodePath)
throws Exception {
SafeTransaction transaction = createTransaction(fencingACL,
fencingNodePath);
transaction.setData(path, data, version);
transaction.commit();
}
public SafeTransaction createTransaction(List fencingACL,
String fencingNodePath) throws Exception {
return new SafeTransaction(fencingACL, fencingNodePath);
}
/**
* Use curator transactions to ensure zk-operations are performed in an all
* or nothing fashion. This is equivalent to using ZooKeeper#multi.
*/
public class SafeTransaction {
private String fencingNodePath;
private List curatorOperations = new LinkedList<>();
SafeTransaction(List fencingACL, String fencingNodePath)
throws Exception {
this.fencingNodePath = fencingNodePath;
curatorOperations.add(curator.transactionOp().create()
.withMode(CreateMode.PERSISTENT)
.withACL(fencingACL)
.forPath(fencingNodePath, new byte[0]));
}
public void commit() throws Exception {
curatorOperations.add(curator.transactionOp().delete()
.forPath(fencingNodePath));
curator.transaction().forOperations(curatorOperations);
curatorOperations.clear();
}
public void create(String path, byte[] data, List acl, CreateMode mode)
throws Exception {
curatorOperations.add(curator.transactionOp().create()
.withMode(mode)
.withACL(acl)
.forPath(path, data));
}
public void delete(String path) throws Exception {
curatorOperations.add(curator.transactionOp().delete()
.forPath(path));
}
public void setData(String path, byte[] data, int version)
throws Exception {
curatorOperations.add(curator.transactionOp().setData()
.withVersion(version)
.forPath(path, data));
}
}
}