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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements. See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache license, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License. You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the license for the specific language governing permissions and
15   * limitations under the license.
16   */
17  package org.apache.logging.log4j.core.async;
18  
19  import java.util.Arrays;
20  import java.util.List;
21  
22  import org.apache.logging.log4j.Level;
23  import org.apache.logging.log4j.LogManager;
24  import org.apache.logging.log4j.core.Filter;
25  import org.apache.logging.log4j.core.LogEvent;
26  import org.apache.logging.log4j.core.config.AppenderRef;
27  import org.apache.logging.log4j.core.config.Configuration;
28  import org.apache.logging.log4j.core.config.LoggerConfig;
29  import org.apache.logging.log4j.core.config.Node;
30  import org.apache.logging.log4j.core.config.Property;
31  import org.apache.logging.log4j.core.config.plugins.Plugin;
32  import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
33  import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
34  import org.apache.logging.log4j.core.config.plugins.PluginElement;
35  import org.apache.logging.log4j.core.config.plugins.PluginFactory;
36  import org.apache.logging.log4j.core.jmx.RingBufferAdmin;
37  import org.apache.logging.log4j.core.util.Booleans;
38  import org.apache.logging.log4j.util.Strings;
39  
40  /**
41   * Asynchronous Logger object that is created via configuration and can be
42   * combined with synchronous loggers.
43   * <p>
44   * AsyncLoggerConfig is a logger designed for high throughput and low latency
45   * logging. It does not perform any I/O in the calling (application) thread, but
46   * instead hands off the work to another thread as soon as possible. The actual
47   * logging is performed in the background thread. It uses the LMAX Disruptor
48   * library for inter-thread communication. (<a
49   * href="http://lmax-exchange.github.com/disruptor/"
50   * >http://lmax-exchange.github.com/disruptor/</a>)
51   * <p>
52   * To use AsyncLoggerConfig, specify {@code <asyncLogger>} or
53   * {@code <asyncRoot>} in configuration.
54   * <p>
55   * Note that for performance reasons, this logger does not include source
56   * location by default. You need to specify {@code includeLocation="true"} in
57   * the configuration or any %class, %location or %line conversion patterns in
58   * your log4j.xml configuration will produce either a "?" character or no output
59   * at all.
60   * <p>
61   * For best performance, use AsyncLoggerConfig with the RandomAccessFileAppender or
62   * RollingRandomAccessFileAppender, with immediateFlush=false. These appenders have
63   * built-in support for the batching mechanism used by the Disruptor library,
64   * and they will flush to disk at the end of each batch. This means that even
65   * with immediateFlush=false, there will never be any items left in the buffer;
66   * all log events will all be written to disk in a very efficient manner.
67   */
68  @Plugin(name = "asyncLogger", category = Node.CATEGORY, printObject = true)
69  public class AsyncLoggerConfig extends LoggerConfig {
70  
71      private static final long serialVersionUID = 1L;
72  
73      private AsyncLoggerConfigHelper helper;
74  
75      /**
76       * Default constructor.
77       */
78      public AsyncLoggerConfig() {
79          super();
80      }
81  
82      /**
83       * Constructor that sets the name, level and additive values.
84       *
85       * @param name The Logger name.
86       * @param level The Level.
87       * @param additive true if the Logger is additive, false otherwise.
88       */
89      public AsyncLoggerConfig(final String name, final Level level,
90              final boolean additive) {
91          super(name, level, additive);
92      }
93  
94      protected AsyncLoggerConfig(final String name,
95              final List<AppenderRef> appenders, final Filter filter,
96              final Level level, final boolean additive,
97              final Property[] properties, final Configuration config,
98              final boolean includeLocation) {
99          super(name, appenders, filter, level, additive, properties, config,
100                 includeLocation);
101     }
102 
103     /**
104      * Passes on the event to a separate thread that will call
105      * {@link #asyncCallAppenders(LogEvent)}.
106      */
107     @Override
108     protected void callAppenders(final LogEvent event) {
109         // populate lazily initialized fields
110         event.getSource();
111         event.getThreadName();
112 
113         // pass on the event to a separate thread
114         if (!helper.callAppendersFromAnotherThread(event)) {
115             super.callAppenders(event);
116         }
117     }
118 
119     /** Called by AsyncLoggerConfigHelper.RingBufferLog4jEventHandler. */
120     void asyncCallAppenders(final LogEvent event) {
121         super.callAppenders(event);
122     }
123 
124     private String displayName() {
125         return LogManager.ROOT_LOGGER_NAME.equals(getName()) ? "root" : getName();
126     }
127 
128     @Override
129     public void start() {
130         LOGGER.trace("AsyncLoggerConfig[{}] starting...", displayName());
131         this.setStarting();
132         if (helper == null) {
133             helper = new AsyncLoggerConfigHelper(this);
134         } else {
135             AsyncLoggerConfigHelper.claim(); // LOG4J2-336
136         }
137         super.start();
138     }
139 
140     @Override
141     public void stop() {
142         LOGGER.trace("AsyncLoggerConfig[{}] stopping...", displayName());
143         this.setStopping();
144         AsyncLoggerConfigHelper.release();
145         super.stop();
146     }
147 
148     /**
149      * Creates and returns a new {@code RingBufferAdmin} that instruments the
150      * ringbuffer of this {@code AsyncLoggerConfig}.
151      *
152      * @param contextName name of the {@code LoggerContext}
153      */
154     public RingBufferAdmin createRingBufferAdmin(final String contextName) {
155         return helper.createRingBufferAdmin(contextName, getName());
156     }
157 
158     /**
159      * Factory method to create a LoggerConfig.
160      *
161      * @param additivity True if additive, false otherwise.
162      * @param levelName The Level to be associated with the Logger.
163      * @param loggerName The name of the Logger.
164      * @param includeLocation "true" if location should be passed downstream
165      * @param refs An array of Appender names.
166      * @param properties Properties to pass to the Logger.
167      * @param config The Configuration.
168      * @param filter A Filter.
169      * @return A new LoggerConfig.
170      */
171     @PluginFactory
172     public static LoggerConfig createLogger(
173             @PluginAttribute("additivity") final String additivity,
174             @PluginAttribute("level") final String levelName,
175             @PluginAttribute("name") final String loggerName,
176             @PluginAttribute("includeLocation") final String includeLocation,
177             @PluginElement("AppenderRef") final AppenderRef[] refs,
178             @PluginElement("Properties") final Property[] properties,
179             @PluginConfiguration final Configuration config,
180             @PluginElement("Filter") final Filter filter) {
181         if (loggerName == null) {
182             LOGGER.error("Loggers cannot be configured without a name");
183             return null;
184         }
185 
186         final List<AppenderRef> appenderRefs = Arrays.asList(refs);
187         Level level;
188         try {
189             level = Level.toLevel(levelName, Level.ERROR);
190         } catch (final Exception ex) {
191             LOGGER.error(
192                     "Invalid Log level specified: {}. Defaulting to Error",
193                     levelName);
194             level = Level.ERROR;
195         }
196         final String name = loggerName.equals("root") ? Strings.EMPTY : loggerName;
197         final boolean additive = Booleans.parseBoolean(additivity, true);
198 
199         return new AsyncLoggerConfig(name, appenderRefs, filter, level,
200                 additive, properties, config, includeLocation(includeLocation));
201     }
202 
203     // Note: for asynchronous loggers, includeLocation default is FALSE
204     protected static boolean includeLocation(final String includeLocationConfigValue) {
205         return Boolean.parseBoolean(includeLocationConfigValue);
206     }
207 
208     /**
209      * An asynchronous root Logger.
210      */
211     @Plugin(name = "asyncRoot", category = "Core", printObject = true)
212     public static class RootLogger extends LoggerConfig {
213 
214         private static final long serialVersionUID = 1L;
215 
216         @PluginFactory
217         public static LoggerConfig createLogger(
218                 @PluginAttribute("additivity") final String additivity,
219                 @PluginAttribute("level") final String levelName,
220                 @PluginAttribute("includeLocation") final String includeLocation,
221                 @PluginElement("AppenderRef") final AppenderRef[] refs,
222                 @PluginElement("Properties") final Property[] properties,
223                 @PluginConfiguration final Configuration config,
224                 @PluginElement("Filter") final Filter filter) {
225             final List<AppenderRef> appenderRefs = Arrays.asList(refs);
226             Level level;
227             try {
228                 level = Level.toLevel(levelName, Level.ERROR);
229             } catch (final Exception ex) {
230                 LOGGER.error(
231                         "Invalid Log level specified: {}. Defaulting to Error",
232                         levelName);
233                 level = Level.ERROR;
234             }
235             final boolean additive = Booleans.parseBoolean(additivity, true);
236 
237             return new AsyncLoggerConfig(LogManager.ROOT_LOGGER_NAME,
238                     appenderRefs, filter, level, additive, properties, config,
239                     includeLocation(includeLocation));
240         }
241     }
242 }