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Common functionality for HBase
/**
* 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.hbase;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Map;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.util.VersionInfo;
import org.apache.hadoop.hbase.zookeeper.ZKConfig;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Adds HBase configuration files to a Configuration
*/
@InterfaceAudience.Public
public class HBaseConfiguration extends Configuration {
private static final Logger LOG = LoggerFactory.getLogger(HBaseConfiguration.class);
/**
* Instantiating HBaseConfiguration() is deprecated. Please use
* HBaseConfiguration#create() to construct a plain Configuration
* @deprecated Please use create() instead.
*/
@Deprecated
public HBaseConfiguration() {
//TODO:replace with private constructor, HBaseConfiguration should not extend Configuration
super();
addHbaseResources(this);
LOG.warn("instantiating HBaseConfiguration() is deprecated. Please use"
+ " HBaseConfiguration#create() to construct a plain Configuration");
}
/**
* Instantiating HBaseConfiguration() is deprecated. Please use
* HBaseConfiguration#create(conf) to construct a plain Configuration
* @deprecated Please user create(conf) instead.
*/
@Deprecated
public HBaseConfiguration(final Configuration c) {
//TODO:replace with private constructor
this();
merge(this, c);
}
private static void checkDefaultsVersion(Configuration conf) {
if (conf.getBoolean("hbase.defaults.for.version.skip", Boolean.FALSE)) return;
String defaultsVersion = conf.get("hbase.defaults.for.version");
String thisVersion = VersionInfo.getVersion();
if (!thisVersion.equals(defaultsVersion)) {
throw new RuntimeException(
"hbase-default.xml file seems to be for an older version of HBase (" +
defaultsVersion + "), this version is " + thisVersion);
}
}
public static Configuration addHbaseResources(Configuration conf) {
conf.addResource("hbase-default.xml");
conf.addResource("hbase-site.xml");
checkDefaultsVersion(conf);
return conf;
}
/**
* Creates a Configuration with HBase resources
* @return a Configuration with HBase resources
*/
public static Configuration create() {
Configuration conf = new Configuration();
// In case HBaseConfiguration is loaded from a different classloader than
// Configuration, conf needs to be set with appropriate class loader to resolve
// HBase resources.
conf.setClassLoader(HBaseConfiguration.class.getClassLoader());
return addHbaseResources(conf);
}
/**
* @param that Configuration to clone.
* @return a Configuration created with the hbase-*.xml files plus
* the given configuration.
*/
public static Configuration create(final Configuration that) {
Configuration conf = create();
merge(conf, that);
return conf;
}
/**
* Merge two configurations.
* @param destConf the configuration that will be overwritten with items
* from the srcConf
* @param srcConf the source configuration
**/
public static void merge(Configuration destConf, Configuration srcConf) {
for (Map.Entry e : srcConf) {
destConf.set(e.getKey(), e.getValue());
}
}
/**
* Returns a subset of the configuration properties, matching the given key prefix.
* The prefix is stripped from the return keys, ie. when calling with a prefix of "myprefix",
* the entry "myprefix.key1 = value1" would be returned as "key1 = value1". If an entry's
* key matches the prefix exactly ("myprefix = value2"), it will not be
* included in the results, since it would show up as an entry with an empty key.
*/
public static Configuration subset(Configuration srcConf, String prefix) {
Configuration newConf = new Configuration(false);
for (Map.Entry entry : srcConf) {
if (entry.getKey().startsWith(prefix)) {
String newKey = entry.getKey().substring(prefix.length());
// avoid entries that would produce an empty key
if (!newKey.isEmpty()) {
newConf.set(newKey, entry.getValue());
}
}
}
return newConf;
}
/**
* Sets all the entries in the provided {@code Map} as properties in the
* given {@code Configuration}. Each property will have the specified prefix prepended,
* so that the configuration entries are keyed by {@code prefix + entry.getKey()}.
*/
public static void setWithPrefix(Configuration conf, String prefix,
Iterable> properties) {
for (Map.Entry entry : properties) {
conf.set(prefix + entry.getKey(), entry.getValue());
}
}
/**
* @return whether to show HBase Configuration in servlet
*/
public static boolean isShowConfInServlet() {
boolean isShowConf = false;
try {
if (Class.forName("org.apache.hadoop.conf.ConfServlet") != null) {
isShowConf = true;
}
} catch (LinkageError e) {
// should we handle it more aggressively in addition to log the error?
LOG.warn("Error thrown: ", e);
} catch (ClassNotFoundException ce) {
LOG.debug("ClassNotFound: ConfServlet");
// ignore
}
return isShowConf;
}
/**
* Get the value of the name property as an int, possibly referring to
* the deprecated name of the configuration property. If no such property exists, the provided
* default value is returned, or if the specified value is not a valid int, then an
* error is thrown.
* @param name property name.
* @param deprecatedName a deprecatedName for the property to use if non-deprecated name is not
* used
* @param defaultValue default value.
* @throws NumberFormatException when the value is invalid
* @return property value as an int, or defaultValue.
* @deprecated it will be removed in 3.0.0. Use
* {@link Configuration#addDeprecation(String, String)} instead.
*/
@Deprecated
public static int getInt(Configuration conf, String name,
String deprecatedName, int defaultValue) {
if (conf.get(deprecatedName) != null) {
LOG.warn(String.format("Config option \"%s\" is deprecated. Instead, use \"%s\""
, deprecatedName, name));
return conf.getInt(deprecatedName, defaultValue);
} else {
return conf.getInt(name, defaultValue);
}
}
/**
* Get the password from the Configuration instance using the
* getPassword method if it exists. If not, then fall back to the
* general get method for configuration elements.
*
* @param conf configuration instance for accessing the passwords
* @param alias the name of the password element
* @param defPass the default password
* @return String password or default password
* @throws IOException
*/
public static String getPassword(Configuration conf, String alias,
String defPass) throws IOException {
String passwd = null;
try {
Method m = Configuration.class.getMethod("getPassword", String.class);
char[] p = (char[]) m.invoke(conf, alias);
if (p != null) {
LOG.debug(String.format("Config option \"%s\" was found through" +
" the Configuration getPassword method.", alias));
passwd = new String(p);
} else {
LOG.debug(String.format(
"Config option \"%s\" was not found. Using provided default value",
alias));
passwd = defPass;
}
} catch (NoSuchMethodException e) {
// this is a version of Hadoop where the credential
//provider API doesn't exist yet
LOG.debug(String.format(
"Credential.getPassword method is not available." +
" Falling back to configuration."));
passwd = conf.get(alias, defPass);
} catch (SecurityException e) {
throw new IOException(e.getMessage(), e);
} catch (IllegalAccessException e) {
throw new IOException(e.getMessage(), e);
} catch (IllegalArgumentException e) {
throw new IOException(e.getMessage(), e);
} catch (InvocationTargetException e) {
throw new IOException(e.getMessage(), e);
}
return passwd;
}
/**
* Generates a {@link Configuration} instance by applying the ZooKeeper cluster key
* to the base Configuration. Note that additional configuration properties may be needed
* for a remote cluster, so it is preferable to use
* {@link #createClusterConf(Configuration, String, String)}.
*
* @param baseConf the base configuration to use, containing prefixed override properties
* @param clusterKey the ZooKeeper quorum cluster key to apply, or {@code null} if none
*
* @return the merged configuration with override properties and cluster key applied
*
* @see #createClusterConf(Configuration, String, String)
*/
public static Configuration createClusterConf(Configuration baseConf, String clusterKey)
throws IOException {
return createClusterConf(baseConf, clusterKey, null);
}
/**
* Generates a {@link Configuration} instance by applying property overrides prefixed by
* a cluster profile key to the base Configuration. Override properties are extracted by
* the {@link #subset(Configuration, String)} method, then the merged on top of the base
* Configuration and returned.
*
* @param baseConf the base configuration to use, containing prefixed override properties
* @param clusterKey the ZooKeeper quorum cluster key to apply, or {@code null} if none
* @param overridePrefix the property key prefix to match for override properties,
* or {@code null} if none
* @return the merged configuration with override properties and cluster key applied
*/
public static Configuration createClusterConf(Configuration baseConf, String clusterKey,
String overridePrefix) throws IOException {
Configuration clusterConf = HBaseConfiguration.create(baseConf);
if (clusterKey != null && !clusterKey.isEmpty()) {
applyClusterKeyToConf(clusterConf, clusterKey);
}
if (overridePrefix != null && !overridePrefix.isEmpty()) {
Configuration clusterSubset = HBaseConfiguration.subset(clusterConf, overridePrefix);
HBaseConfiguration.merge(clusterConf, clusterSubset);
}
return clusterConf;
}
/**
* 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 IOException
*/
private static void applyClusterKeyToConf(Configuration conf, String key)
throws IOException{
ZKConfig.ZKClusterKey zkClusterKey = ZKConfig.transformClusterKey(key);
conf.set(HConstants.ZOOKEEPER_QUORUM, zkClusterKey.getQuorumString());
conf.setInt(HConstants.ZOOKEEPER_CLIENT_PORT, zkClusterKey.getClientPort());
conf.set(HConstants.ZOOKEEPER_ZNODE_PARENT, zkClusterKey.getZnodeParent());
}
/**
* For debugging. Dump configurations to system output as xml format.
* Master and RS configurations can also be dumped using
* http services. e.g. "curl http://master:16010/dump"
*/
public static void main(String[] args) throws Exception {
HBaseConfiguration.create().writeXml(System.out);
}
}