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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.conf.Configuration;
28  import org.apache.hadoop.hbase.classification.InterfaceAudience;
29  import org.apache.hadoop.hbase.classification.InterfaceStability;
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     * @deprecated Please use create() instead.
46     */
47    @Deprecated
48    public HBaseConfiguration() {
49      //TODO:replace with private constructor, HBaseConfiguration should not extend Configuration
50      super();
51      addHbaseResources(this);
52      LOG.warn("instantiating HBaseConfiguration() is deprecated. Please use"
53          + " HBaseConfiguration#create() to construct a plain Configuration");
54    }
55  
56    /**
57     * Instantiating HBaseConfiguration() is deprecated. Please use
58     * HBaseConfiguration#create(conf) to construct a plain Configuration
59     * @deprecated Please user create(conf) instead.
60     */
61    @Deprecated
62    public HBaseConfiguration(final Configuration c) {
63      //TODO:replace with private constructor
64      this();
65      merge(this, c);
66    }
67  
68    private static void checkDefaultsVersion(Configuration conf) {
69      if (conf.getBoolean("hbase.defaults.for.version.skip", Boolean.FALSE)) return;
70      String defaultsVersion = conf.get("hbase.defaults.for.version");
71      String thisVersion = VersionInfo.getVersion();
72      if (!thisVersion.equals(defaultsVersion)) {
73        throw new RuntimeException(
74          "hbase-default.xml file seems to be for and old version of HBase (" +
75          defaultsVersion + "), this version is " + thisVersion);
76      }
77    }
78  
79    public static Configuration addHbaseResources(Configuration conf) {
80      conf.addResource("hbase-default.xml");
81      conf.addResource("hbase-site.xml");
82  
83      checkDefaultsVersion(conf);
84      HeapMemorySizeUtil.checkForClusterFreeMemoryLimit(conf);
85      return conf;
86    }
87  
88    /**
89     * Creates a Configuration with HBase resources
90     * @return a Configuration with HBase resources
91     */
92    public static Configuration create() {
93      Configuration conf = new Configuration();
94      return addHbaseResources(conf);
95    }
96  
97    /**
98     * @param that Configuration to clone.
99     * @return a Configuration created with the hbase-*.xml files plus
100    * the given configuration.
101    */
102   public static Configuration create(final Configuration that) {
103     Configuration conf = create();
104     merge(conf, that);
105     return conf;
106   }
107 
108   /**
109    * Merge two configurations.
110    * @param destConf the configuration that will be overwritten with items
111    *                 from the srcConf
112    * @param srcConf the source configuration
113    **/
114   public static void merge(Configuration destConf, Configuration srcConf) {
115     for (Entry<String, String> e : srcConf) {
116       destConf.set(e.getKey(), e.getValue());
117     }
118   }
119 
120   /**
121    * @return whether to show HBase Configuration in servlet
122    */
123   public static boolean isShowConfInServlet() {
124     boolean isShowConf = false;
125     try {
126       if (Class.forName("org.apache.hadoop.conf.ConfServlet") != null) {
127         isShowConf = true;
128       }
129     } catch (LinkageError e) {
130        // should we handle it more aggressively in addition to log the error?
131        LOG.warn("Error thrown: ", e);
132     } catch (ClassNotFoundException ce) {
133       LOG.debug("ClassNotFound: ConfServlet");
134       // ignore
135     }
136     return isShowConf;
137   }
138 
139   /**
140    * Get the value of the <code>name</code> property as an <code>int</code>, possibly
141    * referring to the deprecated name of the configuration property.
142    * If no such property exists, the provided default value is returned,
143    * or if the specified value is not a valid <code>int</code>,
144    * then an error is thrown.
145    *
146    * @param name property name.
147    * @param deprecatedName a deprecatedName for the property to use
148    * if non-deprecated name is not used
149    * @param defaultValue default value.
150    * @throws NumberFormatException when the value is invalid
151    * @return property value as an <code>int</code>,
152    *         or <code>defaultValue</code>.
153    */
154   // TODO: developer note: This duplicates the functionality of deprecated
155   // property support in Configuration in Hadoop 2. But since Hadoop-1 does not
156   // contain these changes, we will do our own as usual. Replace these when H2 is default.
157   public static int getInt(Configuration conf, String name,
158       String deprecatedName, int defaultValue) {
159     if (conf.get(deprecatedName) != null) {
160       LOG.warn(String.format("Config option \"%s\" is deprecated. Instead, use \"%s\""
161         , deprecatedName, name));
162       return conf.getInt(deprecatedName, defaultValue);
163     } else {
164       return conf.getInt(name, defaultValue);
165     }
166   }
167 
168   /**
169    * Get the password from the Configuration instance using the
170    * getPassword method if it exists. If not, then fall back to the
171    * general get method for configuration elements.
172    *
173    * @param conf    configuration instance for accessing the passwords
174    * @param alias   the name of the password element
175    * @param defPass the default password
176    * @return String password or default password
177    * @throws IOException
178    */
179   public static String getPassword(Configuration conf, String alias,
180       String defPass) throws IOException {
181     String passwd = null;
182     try {
183       Method m = Configuration.class.getMethod("getPassword", String.class);
184       char[] p = (char[]) m.invoke(conf, alias);
185       if (p != null) {
186         LOG.debug(String.format("Config option \"%s\" was found through" +
187             " the Configuration getPassword method.", alias));
188         passwd = new String(p);
189       } else {
190         LOG.debug(String.format(
191             "Config option \"%s\" was not found. Using provided default value",
192             alias));
193         passwd = defPass;
194       }
195     } catch (NoSuchMethodException e) {
196       // this is a version of Hadoop where the credential
197       //provider API doesn't exist yet
198       LOG.debug(String.format(
199           "Credential.getPassword method is not available." +
200               " Falling back to configuration."));
201       passwd = conf.get(alias, defPass);
202     } catch (SecurityException e) {
203       throw new IOException(e.getMessage(), e);
204     } catch (IllegalAccessException e) {
205       throw new IOException(e.getMessage(), e);
206     } catch (IllegalArgumentException e) {
207       throw new IOException(e.getMessage(), e);
208     } catch (InvocationTargetException e) {
209       throw new IOException(e.getMessage(), e);
210     }
211     return passwd;
212   }
213 
214   /**
215    * For debugging.  Dump configurations to system output as xml format.
216    * Master and RS configurations can also be dumped using
217    * http services. e.g. "curl http://master:16010/dump"
218    */
219   public static void main(String[] args) throws Exception {
220     HBaseConfiguration.create().writeXml(System.out);
221   }
222 }