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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.hbase;
19  
20  import java.io.IOException;
21  import java.lang.reflect.InvocationTargetException;
22  import java.lang.reflect.Method;
23  import java.util.Map.Entry;
24  
25  import org.apache.commons.logging.Log;
26  import org.apache.commons.logging.LogFactory;
27  import org.apache.hadoop.classification.InterfaceAudience;
28  import org.apache.hadoop.classification.InterfaceStability;
29  import org.apache.hadoop.conf.Configuration;
30  import org.apache.hadoop.hbase.io.util.HeapMemorySizeUtil;
31  import org.apache.hadoop.hbase.util.VersionInfo;
32  
33  /**
34   * Adds HBase configuration files to a Configuration
35   */
36  @InterfaceAudience.Public
37  @InterfaceStability.Stable
38  public class HBaseConfiguration extends Configuration {
39  
40    private static final Log LOG = LogFactory.getLog(HBaseConfiguration.class);
41  
42    /**
43     * Instantinating HBaseConfiguration() is deprecated. Please use
44     * HBaseConfiguration#create() to construct a plain Configuration
45     */
46    @Deprecated
47    public HBaseConfiguration() {
48      //TODO:replace with private constructor, HBaseConfiguration should not extend Configuration
49      super();
50      addHbaseResources(this);
51      LOG.warn("instantiating HBaseConfiguration() is deprecated. Please use"
52          + " HBaseConfiguration#create() to construct a plain Configuration");
53    }
54  
55    /**
56     * Instantiating HBaseConfiguration() is deprecated. Please use
57     * HBaseConfiguration#create(conf) to construct a plain Configuration
58     */
59    @Deprecated
60    public HBaseConfiguration(final Configuration c) {
61      //TODO:replace with private constructor
62      this();
63      merge(this, c);
64    }
65  
66    private static void checkDefaultsVersion(Configuration conf) {
67      if (conf.getBoolean("hbase.defaults.for.version.skip", Boolean.FALSE)) return;
68      String defaultsVersion = conf.get("hbase.defaults.for.version");
69      String thisVersion = VersionInfo.getVersion();
70      if (!thisVersion.equals(defaultsVersion)) {
71        throw new RuntimeException(
72          "hbase-default.xml file seems to be for and old version of HBase (" +
73          defaultsVersion + "), this version is " + thisVersion);
74      }
75    }
76  
77    public static Configuration addHbaseResources(Configuration conf) {
78      conf.addResource("hbase-default.xml");
79      conf.addResource("hbase-site.xml");
80  
81      checkDefaultsVersion(conf);
82      HeapMemorySizeUtil.checkForClusterFreeMemoryLimit(conf);
83      return conf;
84    }
85  
86    /**
87     * Creates a Configuration with HBase resources
88     * @return a Configuration with HBase resources
89     */
90    public static Configuration create() {
91      Configuration conf = new Configuration();
92      return addHbaseResources(conf);
93    }
94  
95    /**
96     * @param that Configuration to clone.
97     * @return a Configuration created with the hbase-*.xml files plus
98     * the given configuration.
99     */
100   public static Configuration create(final Configuration that) {
101     Configuration conf = create();
102     merge(conf, that);
103     return conf;
104   }
105 
106   /**
107    * Merge two configurations.
108    * @param destConf the configuration that will be overwritten with items
109    *                 from the srcConf
110    * @param srcConf the source configuration
111    **/
112   public static void merge(Configuration destConf, Configuration srcConf) {
113     for (Entry<String, String> e : srcConf) {
114       destConf.set(e.getKey(), e.getValue());
115     }
116   }
117 
118   /**
119    * @return whether to show HBase Configuration in servlet
120    */
121   public static boolean isShowConfInServlet() {
122     boolean isShowConf = false;
123     try {
124       if (Class.forName("org.apache.hadoop.conf.ConfServlet") != null) {
125         isShowConf = true;
126       }
127     } catch (LinkageError e) {
128        // should we handle it more aggressively in addition to log the error?
129        LOG.warn("Error thrown: ", e);
130     } catch (ClassNotFoundException ce) {
131       LOG.debug("ClassNotFound: ConfServlet");
132       // ignore
133     }
134     return isShowConf;
135   }
136 
137   /**
138    * Get the value of the <code>name</code> property as an <code>int</code>, possibly
139    * referring to the deprecated name of the configuration property.
140    * If no such property exists, the provided default value is returned,
141    * or if the specified value is not a valid <code>int</code>,
142    * then an error is thrown.
143    *
144    * @param name property name.
145    * @param deprecatedName a deprecatedName for the property to use
146    * if non-deprecated name is not used
147    * @param defaultValue default value.
148    * @throws NumberFormatException when the value is invalid
149    * @return property value as an <code>int</code>,
150    *         or <code>defaultValue</code>.
151    */
152   // TODO: developer note: This duplicates the functionality of deprecated
153   // property support in Configuration in Hadoop 2. But since Hadoop-1 does not
154   // contain these changes, we will do our own as usual. Replace these when H2 is default.
155   public static int getInt(Configuration conf, String name,
156       String deprecatedName, int defaultValue) {
157     if (conf.get(deprecatedName) != null) {
158       LOG.warn(String.format("Config option \"%s\" is deprecated. Instead, use \"%s\""
159         , deprecatedName, name));
160       return conf.getInt(deprecatedName, defaultValue);
161     } else {
162       return conf.getInt(name, defaultValue);
163     }
164   }
165 
166   /**
167    * Get the password from the Configuration instance using the
168    * getPassword method if it exists. If not, then fall back to the
169    * general get method for configuration elements.
170    * @param conf configuration instance for accessing the passwords
171    * @param alias the name of the password element
172    * @param defPass the default password
173    * @return String password or default password
174    * @throws IOException
175    */
176   public static String getPassword(Configuration conf, String alias,
177       String defPass) throws IOException {
178     String passwd = null;
179     try {
180       Method m = Configuration.class.getMethod("getPassword", String.class);
181       char[] p = (char[]) m.invoke(conf, alias);
182       if (p != null) {
183         LOG.debug(String.format("Config option \"%s\" was found through" +
184         		" the Configuration getPassword method.", alias));
185         passwd = new String(p);
186       }
187       else {
188         LOG.debug(String.format(
189             "Config option \"%s\" was not found. Using provided default value",
190             alias));
191         passwd = defPass;
192       }
193     } catch (NoSuchMethodException e) {
194       // this is a version of Hadoop where the credential
195       //provider API doesn't exist yet
196       LOG.debug(String.format(
197           "Credential.getPassword method is not available." +
198           " Falling back to configuration."));
199       passwd = conf.get(alias, defPass);
200     } catch (SecurityException e) {
201       throw new IOException(e.getMessage(), e);
202     } catch (IllegalAccessException e) {
203       throw new IOException(e.getMessage(), e);
204     } catch (IllegalArgumentException e) {
205       throw new IOException(e.getMessage(), e);
206     } catch (InvocationTargetException e) {
207       throw new IOException(e.getMessage(), e);
208     }
209     return passwd;
210   }
211 
212   /** For debugging.  Dump configurations to system output as xml format.
213    * Master and RS configurations can also be dumped using
214    * http services. e.g. "curl http://master:16010/dump"
215    */
216   public static void main(String[] args) throws Exception {
217     HBaseConfiguration.create().writeXml(System.out);
218   }
219 }