Java tutorial
/** * * 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 com.alibaba.wasp.zookeeper; import com.alibaba.wasp.DeserializationException; import com.alibaba.wasp.ServerName; import org.apache.commons.lang.StringUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.EmptyWatcher; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.hbase.util.Threads; import org.apache.hadoop.hbase.zookeeper.ZKConfig; import org.apache.zookeeper.AsyncCallback; import org.apache.zookeeper.CreateMode; import org.apache.zookeeper.KeeperException; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooDefs.Ids; import org.apache.zookeeper.ZooKeeper; import org.apache.zookeeper.data.ACL; import org.apache.zookeeper.data.Stat; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.InetSocketAddress; import java.net.Socket; import java.util.ArrayList; import java.util.List; import java.util.Properties; /** * Internal Wasp utility class for ZooKeeper. * * <p> * Contains only static methods and constants. * * <p> * Methods all throw {@link org.apache.zookeeper.KeeperException} if there is an unexpected zookeeper * exception, so callers of these methods must handle appropriately. If ZK is * required for the operation, the server will need to be aborted. */ public class ZKUtil { private static final Log LOG = LogFactory.getLog(ZKUtil.class); // TODO: Replace this with ZooKeeper constant when ZOOKEEPER-277 is resolved. private static final char ZNODE_PATH_SEPARATOR = '/'; private static int zkDumpConnectionTimeOut; /** * Creates a new connection to ZooKeeper, pulling settings and ensemble config * from the specified configuration object using methods from {@link org.apache.hadoop.hbase.zookeeper.ZKConfig} * . * * Sets the connection status monitoring watcher to the specified watcher. * * @param conf * configuration to pull ensemble and other settings from * @param watcher * watcher to monitor connection changes * @return connection to zookeeper * @throws java.io.IOException * if unable to connect to zk or config problem */ public static RecoverableZooKeeper connect(Configuration conf, Watcher watcher) throws IOException { Properties properties = ZKConfig.makeZKProps(conf); String ensemble = ZKConfig.getZKQuorumServersString(properties); return connect(conf, ensemble, watcher); } public static RecoverableZooKeeper connect(Configuration conf, String ensemble, Watcher watcher) throws IOException { return connect(conf, ensemble, watcher, ""); } public static RecoverableZooKeeper connect(Configuration conf, String ensemble, Watcher watcher, final String descriptor) throws IOException { if (ensemble == null) { throw new IOException("Unable to determine ZooKeeper ensemble"); } int timeout = conf.getInt(HConstants.ZK_SESSION_TIMEOUT, HConstants.DEFAULT_ZK_SESSION_TIMEOUT); LOG.debug(descriptor + " opening connection to ZooKeeper with ensemble (" + ensemble + ")"); int retry = conf.getInt("zookeeper.recovery.retry", 3); int retryIntervalMillis = conf.getInt("zookeeper.recovery.retry.intervalmill", 1000); zkDumpConnectionTimeOut = conf.getInt("zookeeper.dump.connection.timeout", 1000); return new RecoverableZooKeeper(ensemble, timeout, watcher, retry, retryIntervalMillis); } // // Helper methods // /** * Join the prefix znode name with the suffix znode name to generate a proper * full znode name. * * Assumes prefix does not end with slash and suffix does not begin with it. * * @param prefix * beginning of znode name * @param suffix * ending of znode name * @return result of properly joining prefix with suffix */ public static String joinZNode(String prefix, String suffix) { return prefix + ZNODE_PATH_SEPARATOR + suffix; } /** * Returns the full path of the immediate parent of the specified node. * * @param node * path to get parent of * @return parent of path, null if passed the root node or an invalid node */ public static String getParent(String node) { int idx = node.lastIndexOf(ZNODE_PATH_SEPARATOR); return idx <= 0 ? null : node.substring(0, idx); } /** * Get the name of the current node from the specified fully-qualified path. * * @param path * fully-qualified path * @return name of the current node */ public static String getNodeName(String path) { return path.substring(path.lastIndexOf("/") + 1); } /** * Get the key to the ZK ensemble for this configuration without adding a name * at the end * * @param conf * Configuration to use to build the key * @return ensemble key without a name */ public static String getZooKeeperClusterKey(Configuration conf) { return getZooKeeperClusterKey(conf, null); } /** * Get the key to the ZK ensemble for this configuration and append a name at * the end * * @param conf * Configuration to use to build the key * @param name * Name that should be appended at the end if not empty or null * @return ensemble key with a name (if any) */ public static String getZooKeeperClusterKey(Configuration conf, String name) { String ensemble = conf.get(HConstants.ZOOKEEPER_QUORUM.replaceAll("[\\t\\n\\x0B\\f\\r]", "")); StringBuilder builder = new StringBuilder(ensemble); builder.append(":"); builder.append(conf.get(HConstants.ZOOKEEPER_CLIENT_PORT)); builder.append(":"); builder.append(conf.get(HConstants.ZOOKEEPER_ZNODE_PARENT)); if (name != null && !name.isEmpty()) { builder.append(","); builder.append(name); } return builder.toString(); } /** * Apply the settings in the given key to the given configuration, this is * used to communicate with distant clusters * * @param conf * configuration object to configure * @param key * string that contains the 3 required configuratins * @throws java.io.IOException */ public static void applyClusterKeyToConf(Configuration conf, String key) throws IOException { String[] parts = transformClusterKey(key); conf.set(HConstants.ZOOKEEPER_QUORUM, parts[0]); conf.set(HConstants.ZOOKEEPER_CLIENT_PORT, parts[1]); conf.set(HConstants.ZOOKEEPER_ZNODE_PARENT, parts[2]); } /** * Separate the given key into the three configurations it should contain: * hbase.zookeeper.quorum, hbase.zookeeper.client.port and * zookeeper.znode.parent * * @param key * @return the three configuration in the described order * @throws java.io.IOException */ public static String[] transformClusterKey(String key) throws IOException { String[] parts = key.split(":"); if (parts.length != 3) { throw new IOException("Cluster key invalid, the format should be:" + HConstants.ZOOKEEPER_QUORUM + ":hbase.zookeeper.client.port:" + HConstants.ZOOKEEPER_ZNODE_PARENT); } return parts; } // // Existence checks and watches // /** * Watch the specified znode for delete/create/change events. The watcher is * set whether or not the node exists. If the node already exists, the method * returns true. If the node does not exist, the method returns false. * * @param zkw * zk reference * @param znode * path of node to watch * @return true if znode exists, false if does not exist or error * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static boolean watchAndCheckExists(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { Stat s = zkw.getRecoverableZooKeeper().exists(znode, zkw); boolean exists = s != null ? true : false; if (exists) { LOG.debug(zkw.prefix("Set watcher on existing znode " + znode)); } else { LOG.debug(zkw.prefix(znode + " does not exist. Watcher is set.")); } return exists; } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to set watcher on znode " + znode), e); zkw.keeperException(e); return false; } catch (InterruptedException e) { LOG.warn(zkw.prefix("Unable to set watcher on znode " + znode), e); zkw.interruptedException(e); return false; } } /** * Check if the specified node exists. Sets no watches. * * @param zkw * zk reference * @param znode * path of node to watch * @return version of the node if it exists, -1 if does not exist * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static int checkExists(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { Stat s = zkw.getRecoverableZooKeeper().exists(znode, null); return s != null ? s.getVersion() : -1; } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to set watcher on znode (" + znode + ")"), e); zkw.keeperException(e); return -1; } catch (InterruptedException e) { LOG.warn(zkw.prefix("Unable to set watcher on znode (" + znode + ")"), e); zkw.interruptedException(e); return -1; } } // // Znode listings // /** * Lists the children znodes of the specified znode. Also sets a watch on the * specified znode which will capture a NodeDeleted event on the specified * znode as well as NodeChildrenChanged if any children of the specified znode * are created or deleted. * * Returns null if the specified node does not exist. Otherwise returns a list * of children of the specified node. If the node exists but it has no * children, an empty list will be returned. * * @param zkw * zk reference * @param znode * path of node to list and watch children of * @return list of children of the specified node, an empty list if the node * exists but has no children, and null if the node does not exist * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static List<String> listChildrenAndWatchForNewChildren(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { List<String> children = zkw.getRecoverableZooKeeper().getChildren(znode, zkw); return children; } catch (KeeperException.NoNodeException ke) { LOG.debug(zkw.prefix("Unable to list children of znode " + znode + " " + "because node does not exist (not an error)")); return null; } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to list children of znode " + znode + " "), e); zkw.keeperException(e); return null; } catch (InterruptedException e) { LOG.warn(zkw.prefix("Unable to list children of znode " + znode + " "), e); zkw.interruptedException(e); return null; } } /** * List all the children of the specified znode, setting a watch for children * changes and also setting a watch on every individual child in order to get * the NodeCreated and NodeDeleted events. * * @param zkw * zookeeper reference * @param znode * node to get children of and watch * @return list of znode names, null if the node doesn't exist * @throws org.apache.zookeeper.KeeperException */ public static List<String> listChildrenAndWatchThem(ZooKeeperWatcher zkw, String znode) throws KeeperException { List<String> children = listChildrenAndWatchForNewChildren(zkw, znode); if (children == null) { return null; } for (String child : children) { watchAndCheckExists(zkw, joinZNode(znode, child)); } return children; } /** * Lists the children of the specified znode without setting any watches. * * Used to list the currently online fservers and their addresses. * * Sets no watches at all, this method is best effort. * * Returns an empty list if the node has no children. Returns null if the * parent node itself does not exist. * * @param zkw * zookeeper reference * @param znode * node to get children of as addresses * @return list of data of children of specified znode, empty if no children, * null if parent does not exist * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static List<String> listChildrenNoWatch(ZooKeeperWatcher zkw, String znode) throws KeeperException { List<String> children = null; try { // List the children without watching children = zkw.getRecoverableZooKeeper().getChildren(znode, null); } catch (KeeperException.NoNodeException nne) { return null; } catch (InterruptedException ie) { zkw.interruptedException(ie); } return children; } /** * Checks if the specified znode has any children. Sets no watches. * * Returns true if the node exists and has children. Returns false if the node * does not exist or if the node does not have any children. * * Used during master initialization to determine if the master is a * failed-over-to master or the first master during initial cluster startup. * If the directory for fserver ephemeral nodes is empty then this is a * cluster startup, if not then it is not cluster startup. * * @param zkw * zk reference * @param znode * path of node to check for children of * @return true if node has children, false if not or node does not exist * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static boolean nodeHasChildren(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { return !zkw.getRecoverableZooKeeper().getChildren(znode, null).isEmpty(); } catch (KeeperException.NoNodeException ke) { LOG.debug(zkw.prefix("Unable to list children of znode " + znode + " " + "because node does not exist (not an error)")); return false; } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to list children of znode " + znode), e); zkw.keeperException(e); return false; } catch (InterruptedException e) { LOG.warn(zkw.prefix("Unable to list children of znode " + znode), e); zkw.interruptedException(e); return false; } } /** * Get the number of children of the specified node. * * If the node does not exist or has no children, returns 0. * * Sets no watches at all. * * @param zkw * zk reference * @param znode * path of node to count children of * @return number of children of specified node, 0 if none or parent does not * exist * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static int getNumberOfChildren(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { Stat stat = zkw.getRecoverableZooKeeper().exists(znode, null); return stat == null ? 0 : stat.getNumChildren(); } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to get children of node " + znode)); zkw.keeperException(e); } catch (InterruptedException e) { zkw.interruptedException(e); } return 0; } // // Data retrieval // /** * Get znode data. Does not set a watcher. * * @return ZNode data, null if the node does not exist or if there is an * error. */ public static byte[] getData(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { byte[] data = zkw.getRecoverableZooKeeper().getData(znode, null, null); logRetrievedMsg(zkw, znode, data, false); return data; } catch (KeeperException.NoNodeException e) { LOG.debug(zkw.prefix( "Unable to get data of znode " + znode + " " + "because node does not exist (not an error)")); return null; } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to get data of znode " + znode), e); zkw.keeperException(e); return null; } catch (InterruptedException e) { LOG.warn(zkw.prefix("Unable to get data of znode " + znode), e); zkw.interruptedException(e); return null; } } /** * Get the data at the specified znode and set a watch. * * Returns the data and sets a watch if the node exists. Returns null and no * watch is set if the node does not exist or there is an exception. * * @param zkw * zk reference * @param znode * path of node * @return data of the specified znode, or null * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static byte[] getDataAndWatch(ZooKeeperWatcher zkw, String znode) throws KeeperException { return getDataInternal(zkw, znode, null, true); } /** * Get the data at the specified znode and set a watch. * * Returns the data and sets a watch if the node exists. Returns null and no * watch is set if the node does not exist or there is an exception. * * @param zkw * zk reference * @param znode * path of node * @param stat * object to populate the version of the znode * @return data of the specified znode, or null * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static byte[] getDataAndWatch(ZooKeeperWatcher zkw, String znode, Stat stat) throws KeeperException { return getDataInternal(zkw, znode, stat, true); } private static byte[] getDataInternal(ZooKeeperWatcher zkw, String znode, Stat stat, boolean watcherSet) throws KeeperException { try { byte[] data = zkw.getRecoverableZooKeeper().getData(znode, zkw, stat); logRetrievedMsg(zkw, znode, data, watcherSet); return data; } catch (KeeperException.NoNodeException e) { // This log can get pretty annoying when we cycle on 100ms waits. // Enable trace if you really want to see it. LOG.trace(zkw.prefix( "Unable to get data of znode " + znode + " " + "because node does not exist (not an error)")); return null; } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to get data of znode " + znode), e); zkw.keeperException(e); return null; } catch (InterruptedException e) { LOG.warn(zkw.prefix("Unable to get data of znode " + znode), e); zkw.interruptedException(e); return null; } } /** * Get the data at the specified znode without setting a watch. * * Returns the data if the node exists. Returns null if the node does not * exist. * * Sets the stats of the node in the passed Stat object. Pass a null stat if * not interested. * * @param zkw * zk reference * @param znode * path of node * @param stat * node status to get if node exists * @return data of the specified znode, or null if node does not exist * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static byte[] getDataNoWatch(ZooKeeperWatcher zkw, String znode, Stat stat) throws KeeperException { try { byte[] data = zkw.getRecoverableZooKeeper().getData(znode, null, stat); logRetrievedMsg(zkw, znode, data, false); return data; } catch (KeeperException.NoNodeException e) { LOG.debug(zkw.prefix("Unable to get data of znode " + znode + " " + "because node does not exist (not necessarily an error)")); return null; } catch (KeeperException e) { LOG.warn(zkw.prefix("Unable to get data of znode " + znode), e); zkw.keeperException(e); return null; } catch (InterruptedException e) { LOG.warn(zkw.prefix("Unable to get data of znode " + znode), e); zkw.interruptedException(e); return null; } } // // Data setting // /** * Sets the data of the existing znode to be the specified data. Ensures that * the current data has the specified expected version. * * <p> * If the node does not exist, a {@link org.apache.zookeeper.KeeperException.NoNodeException} will be thrown. * * <p> * If their is a version mismatch, method returns null. * * <p> * No watches are set but setting data will trigger other watchers of this * node. * * <p> * If there is another problem, a KeeperException will be thrown. * * @param zkw * zk reference * @param znode * path of node * @param data * data to set for node * @param expectedVersion * version expected when setting data * @return true if data set, false if version mismatch * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static boolean setData(ZooKeeperWatcher zkw, String znode, byte[] data, int expectedVersion) throws KeeperException, KeeperException.NoNodeException { try { return zkw.getRecoverableZooKeeper().setData(znode, data, expectedVersion) != null; } catch (InterruptedException e) { zkw.interruptedException(e); return false; } } /** * Set data into node creating node if it doesn't yet exist. Does not set * watch. * * @param zkw * zk reference * @param znode * path of node * @param data * data to set for node * @throws org.apache.zookeeper.KeeperException */ public static void createSetData(final ZooKeeperWatcher zkw, final String znode, final byte[] data) throws KeeperException { if (checkExists(zkw, znode) == -1) { ZKUtil.createWithParents(zkw, znode); } ZKUtil.setData(zkw, znode, data); } /** * Sets the data of the existing znode to be the specified data. The node must * exist but no checks are done on the existing data or version. * * <p> * If the node does not exist, a {@link org.apache.zookeeper.KeeperException.NoNodeException} will be thrown. * * <p> * No watches are set but setting data will trigger other watchers of this * node. * * <p> * If there is another problem, a KeeperException will be thrown. * * @param zkw * zk reference * @param znode * path of node * @param data * data to set for node * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static void setData(ZooKeeperWatcher zkw, String znode, byte[] data) throws KeeperException, KeeperException.NoNodeException { setData(zkw, znode, data, -1); } public static boolean isSecureZooKeeper(Configuration conf) { // TODO: We need a better check for security enabled ZooKeeper. Currently // the secure ZooKeeper client is set up using a supplied JaaS // configuration file. But if the system property for the JaaS // configuration file is set, this may not be an exclusive indication // that HBase should set ACLs on znodes. As an alternative, we could do // this more like Hadoop and build a JaaS configuration programmatically // based on a site conf setting. The scope of such a change will be // addressed in HBASE-4791. return (System.getProperty("java.security.auth.login.config") != null); } private static ArrayList<ACL> createACL(ZooKeeperWatcher zkw, String node) { if (isSecureZooKeeper(zkw.getConfiguration())) { // Certain znodes are accessed directly by the client, // so they must be readable by non-authenticated clients if ((node.equals(zkw.baseZNode) == true) || (node.equals(zkw.getMasterAddressZNode()) == true) || (node.equals(zkw.clusterIdZNode) == true) || (node.equals(zkw.fsZNode) == true) || (node.equals(zkw.backupMasterAddressesZNode) == true) || (node.startsWith(zkw.tableZNode) == true)) { return ZooKeeperWatcher.CREATOR_ALL_AND_WORLD_READABLE; } return Ids.CREATOR_ALL_ACL; } else { return Ids.OPEN_ACL_UNSAFE; } } public static void waitForZKConnectionIfAuthenticating(ZooKeeperWatcher zkw) throws InterruptedException { if (isSecureZooKeeper(zkw.getConfiguration())) { LOG.debug("Waiting for ZooKeeperWatcher to authenticate"); zkw.saslLatch.await(); LOG.debug("Done waiting."); } } // // Node creation // /** * * Set the specified znode to be an ephemeral node carrying the specified * data. * * If the node is created successfully, a watcher is also set on the node. * * If the node is not created successfully because it already exists, this * method will also set a watcher on the node. * * If there is another problem, a KeeperException will be thrown. * * @param zkw * zk reference * @param znode * path of node * @param data * data of node * @return true if node created, false if not, watch set in both cases * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static boolean createEphemeralNodeAndWatch(ZooKeeperWatcher zkw, String znode, byte[] data) throws KeeperException { try { waitForZKConnectionIfAuthenticating(zkw); zkw.getRecoverableZooKeeper().create(znode, data, createACL(zkw, znode), CreateMode.EPHEMERAL); } catch (KeeperException.NodeExistsException nee) { if (!watchAndCheckExists(zkw, znode)) { // It did exist but now it doesn't, try again return createEphemeralNodeAndWatch(zkw, znode, data); } return false; } catch (InterruptedException e) { LOG.info("Interrupted", e); Thread.currentThread().interrupt(); } return true; } /** * Creates the specified znode to be a persistent node carrying the specified * data. * * Returns true if the node was successfully created, false if the node * already existed. * * If the node is created successfully, a watcher is also set on the node. * * If the node is not created successfully because it already exists, this * method will also set a watcher on the node but return false. * * If there is another problem, a KeeperException will be thrown. * * @param zkw * zk reference * @param znode * path of node * @param data * data of node * @return true if node created, false if not, watch set in both cases * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static boolean createNodeIfNotExistsAndWatch(ZooKeeperWatcher zkw, String znode, byte[] data) throws KeeperException { try { waitForZKConnectionIfAuthenticating(zkw); zkw.getRecoverableZooKeeper().create(znode, data, createACL(zkw, znode), CreateMode.PERSISTENT); } catch (KeeperException.NodeExistsException nee) { try { zkw.getRecoverableZooKeeper().exists(znode, zkw); } catch (InterruptedException e) { zkw.interruptedException(e); return false; } return false; } catch (InterruptedException e) { zkw.interruptedException(e); return false; } return true; } /** * Creates the specified node with the specified data and watches it. * * <p> * Throws an exception if the node already exists. * * <p> * The node created is persistent and open access. * * <p> * Returns the version number of the created node if successful. * * @param zkw * zk reference * @param znode * path of node to create * @param data * data of node to create * @return version of node created * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception * @throws org.apache.zookeeper.KeeperException.NodeExistsException * if node already exists */ public static int createAndWatch(ZooKeeperWatcher zkw, String znode, byte[] data) throws KeeperException, KeeperException.NodeExistsException { try { waitForZKConnectionIfAuthenticating(zkw); zkw.getRecoverableZooKeeper().create(znode, data, createACL(zkw, znode), CreateMode.PERSISTENT); return zkw.getRecoverableZooKeeper().exists(znode, zkw).getVersion(); } catch (InterruptedException e) { zkw.interruptedException(e); return -1; } } /** * Async creates the specified node with the specified data. * * <p> * Throws an exception if the node already exists. * * <p> * The node created is persistent and open access. * * @param zkw * zk reference * @param znode * path of node to create * @param data * data of node to create * @param cb * @param ctx * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception * @throws org.apache.zookeeper.KeeperException.NodeExistsException * if node already exists */ public static void asyncCreate(ZooKeeperWatcher zkw, String znode, byte[] data, final AsyncCallback.StringCallback cb, final Object ctx) { try { waitForZKConnectionIfAuthenticating(zkw); zkw.getRecoverableZooKeeper().getZooKeeper().create(znode, data, createACL(zkw, znode), CreateMode.PERSISTENT, cb, ctx); } catch (InterruptedException e) { zkw.interruptedException(e); } } /** * Creates the specified node, if the node does not exist. Does not set a * watch and fails silently if the node already exists. * * The node created is persistent and open access. * * @param zkw * zk reference * @param znode * path of node * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static void createAndFailSilent(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { RecoverableZooKeeper zk = zkw.getRecoverableZooKeeper(); waitForZKConnectionIfAuthenticating(zkw); if (zk.exists(znode, false) == null) { zk.create(znode, new byte[0], createACL(zkw, znode), CreateMode.PERSISTENT); } } catch (KeeperException.NodeExistsException nee) { } catch (KeeperException.NoAuthException nee) { try { if (null == zkw.getRecoverableZooKeeper().exists(znode, false)) { // If we failed to create the file and it does not already exist. throw (nee); } } catch (InterruptedException ie) { zkw.interruptedException(ie); } } catch (InterruptedException ie) { zkw.interruptedException(ie); } } /** * Creates the specified node and all parent nodes required for it to exist. * * No watches are set and no errors are thrown if the node already exists. * * The nodes created are persistent and open access. * * @param zkw * zk reference * @param znode * path of node * @throws org.apache.zookeeper.KeeperException * if unexpected zookeeper exception */ public static void createWithParents(ZooKeeperWatcher zkw, String znode) throws KeeperException { try { if (znode == null) { return; } waitForZKConnectionIfAuthenticating(zkw); zkw.getRecoverableZooKeeper().create(znode, new byte[0], createACL(zkw, znode), CreateMode.PERSISTENT); } catch (KeeperException.NodeExistsException nee) { return; } catch (KeeperException.NoNodeException nne) { createWithParents(zkw, getParent(znode)); createWithParents(zkw, znode); } catch (InterruptedException ie) { zkw.interruptedException(ie); } } // // Deletes // /** * Delete the specified node. Sets no watches. Throws all exceptions. */ public static void deleteNode(ZooKeeperWatcher zkw, String node) throws KeeperException { deleteNode(zkw, node, -1); } /** * Delete the specified node with the specified version. Sets no watches. * Throws all exceptions. */ public static boolean deleteNode(ZooKeeperWatcher zkw, String node, int version) throws KeeperException { try { zkw.getRecoverableZooKeeper().delete(node, version); return true; } catch (KeeperException.BadVersionException bve) { return false; } catch (InterruptedException ie) { zkw.interruptedException(ie); return false; } } /** * Deletes the specified node. Fails silent if the node does not exist. * * @param zkw * @param node * @throws org.apache.zookeeper.KeeperException */ public static void deleteNodeFailSilent(ZooKeeperWatcher zkw, String node) throws KeeperException { try { zkw.getRecoverableZooKeeper().delete(node, -1); } catch (KeeperException.NoNodeException nne) { } catch (InterruptedException ie) { zkw.interruptedException(ie); } } /** * Delete the specified node and all of it's children. * <p> * If the node does not exist, just returns. * <p> * Sets no watches. Throws all exceptions besides dealing with deletion of * children. */ public static void deleteNodeRecursively(ZooKeeperWatcher zkw, String node) throws KeeperException { try { List<String> children = ZKUtil.listChildrenNoWatch(zkw, node); // the node is already deleted, so we just finish if (children == null) return; if (!children.isEmpty()) { for (String child : children) { deleteNodeRecursively(zkw, joinZNode(node, child)); } } zkw.getRecoverableZooKeeper().delete(node, -1); } catch (InterruptedException ie) { zkw.interruptedException(ie); } } /** * Delete all the children of the specified node but not the node itself. * * Sets no watches. Throws all exceptions besides dealing with deletion of * children. */ public static void deleteChildrenRecursively(ZooKeeperWatcher zkw, String node) throws KeeperException { List<String> children = ZKUtil.listChildrenNoWatch(zkw, node); if (children == null || children.isEmpty()) return; for (String child : children) { deleteNodeRecursively(zkw, joinZNode(node, child)); } } // // ZooKeeper cluster information // /** @return String dump of everything in ZooKeeper. */ public static String dump(ZooKeeperWatcher zkw) { StringBuilder sb = new StringBuilder(); try { sb.append("Wasp is rooted at ").append(zkw.baseZNode); sb.append("\nActive master address: "); try { sb.append(MasterAddressTracker.getMasterAddress(zkw)); } catch (IOException e) { sb.append("<<FAILED LOOKUP: " + e.getMessage() + ">>"); } sb.append("\nBackup master addresses:"); for (String child : listChildrenNoWatch(zkw, zkw.backupMasterAddressesZNode)) { sb.append("\n ").append(child); } sb.append("\nFServers:"); for (String child : listChildrenNoWatch(zkw, zkw.fsZNode)) { sb.append("\n ").append(child); } sb.append("\nQuorum Server Statistics:"); String[] servers = zkw.getQuorum().split(","); for (String server : servers) { sb.append("\n ").append(server); try { String[] stat = getServerStats(server, ZKUtil.zkDumpConnectionTimeOut); if (stat == null) { sb.append("[Error] invalid quorum server: " + server); break; } for (String s : stat) { sb.append("\n ").append(s); } } catch (Exception e) { sb.append("\n ERROR: ").append(e.getMessage()); } } } catch (KeeperException ke) { sb.append("\nFATAL ZooKeeper Exception!\n"); sb.append("\n" + ke.getMessage()); } return sb.toString(); } /** * Gets the statistics from the given server. * * @param server * The server to get the statistics from. * @param timeout * The socket timeout to use. * @return The array of response strings. * @throws java.io.IOException * When the socket communication fails. */ public static String[] getServerStats(String server, int timeout) throws IOException { String[] sp = server.split(":"); if (sp == null || sp.length == 0) { return null; } String host = sp[0]; int port = sp.length > 1 ? Integer.parseInt(sp[1]) : HConstants.DEFAULT_ZOOKEPER_CLIENT_PORT; Socket socket = new Socket(); InetSocketAddress sockAddr = new InetSocketAddress(host, port); socket.connect(sockAddr, timeout); socket.setSoTimeout(timeout); PrintWriter out = new PrintWriter(socket.getOutputStream(), true); BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); out.println("stat"); out.flush(); ArrayList<String> res = new ArrayList<String>(); while (true) { String line = in.readLine(); if (line != null) { res.add(line); } else { break; } } socket.close(); return res.toArray(new String[res.size()]); } private static void logRetrievedMsg(final ZooKeeperWatcher zkw, final String znode, final byte[] data, final boolean watcherSet) { if (!LOG.isDebugEnabled()) return; LOG.debug(zkw.prefix("Retrieved " + ((data == null) ? 0 : data.length) + " byte(s) of data from znode " + znode + (watcherSet ? " and set watcher; " : "; data=") + (data == null ? "null" : data.length == 0 ? "empty" : (znode.startsWith(zkw.assignmentZNode) ? ZKAssign.toString(data) : // We should not be doing this // reaching into another class znode.startsWith(zkw.backupMasterAddressesZNode) ? getServerNameOrEmptyString(data) : StringUtils.abbreviate(Bytes.toStringBinary(data), 32))))); } private static String getServerNameOrEmptyString(final byte[] data) { try { return ServerName.parseFrom(data).toString(); } catch (DeserializationException e) { return ""; } } /** * Waits for HBase installation's base (parent) znode to become available. * * @throws java.io.IOException * on ZK errors */ public static void waitForBaseZNode(Configuration conf) throws IOException { LOG.info("Waiting until the base znode is available"); String parentZNode = conf.get(HConstants.ZOOKEEPER_ZNODE_PARENT, HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT); ZooKeeper zk = new ZooKeeper(ZKConfig.getZKQuorumServersString(conf), conf.getInt(HConstants.ZK_SESSION_TIMEOUT, HConstants.DEFAULT_ZK_SESSION_TIMEOUT), EmptyWatcher.instance); final int maxTimeMs = 10000; final int maxNumAttempts = maxTimeMs / HConstants.SOCKET_RETRY_WAIT_MS; KeeperException keeperEx = null; try { try { for (int attempt = 0; attempt < maxNumAttempts; ++attempt) { try { if (zk.exists(parentZNode, false) != null) { LOG.info("Parent znode exists: " + parentZNode); keeperEx = null; break; } } catch (KeeperException e) { keeperEx = e; } Threads.sleepWithoutInterrupt(HConstants.SOCKET_RETRY_WAIT_MS); } } finally { zk.close(); } } catch (InterruptedException ex) { Thread.currentThread().interrupt(); } if (keeperEx != null) { throw new IOException(keeperEx); } } public static byte[] blockUntilAvailable(final ZooKeeperWatcher zkw, final String znode, final long timeout) throws InterruptedException { if (timeout < 0) throw new IllegalArgumentException(); if (zkw == null) throw new IllegalArgumentException(); if (znode == null) throw new IllegalArgumentException(); byte[] data = null; boolean finished = false; final long endTime = System.currentTimeMillis() + timeout; while (!finished) { try { data = ZKUtil.getData(zkw, znode); } catch (KeeperException e) { LOG.warn("Unexpected exception handling blockUntilAvailable", e); } if (data == null && (System.currentTimeMillis() + HConstants.SOCKET_RETRY_WAIT_MS < endTime)) { Thread.sleep(HConstants.SOCKET_RETRY_WAIT_MS); } else { finished = true; } } return data; } /** * Convert a {@link com.alibaba.wasp.DeserializationException} to a more palatable * {@link org.apache.zookeeper.KeeperException}. Used when can't let a * {@link com.alibaba.wasp.DeserializationException} out w/o changing public API. * * @param e * Exception to convert * @return Converted exception */ public static KeeperException convert(final DeserializationException e) { KeeperException ke = new KeeperException.DataInconsistencyException(); ke.initCause(e); return ke; } }