git.lttng.org Git - lttng-ust.git/blob

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2015-2022 EfficiOS Inc.
   5  * Copyright (C) 2015 Alexandre Montplaisir <alexmonthy@efficios.com>
   6  * Copyright (C) 2014 Christian Babeux <christian.babeux@efficios.com>
   7  */
   8
   9 package org.lttng.ust.agent.log4j2;
  10
  11 import java.io.IOException;
  12 import java.util.Collection;
  13 import java.util.Map;
  14 import java.util.Map.Entry;
  15 import java.util.concurrent.TimeUnit;
  16 import java.util.concurrent.atomic.AtomicLong;
  17
  18 import org.apache.logging.log4j.core.Appender;
  19 import org.apache.logging.log4j.core.Core;
  20 import org.apache.logging.log4j.core.Filter;
  21 import org.apache.logging.log4j.core.LogEvent;
  22 import org.apache.logging.log4j.core.appender.AbstractAppender;
  23 import org.apache.logging.log4j.core.config.Property;
  24 import org.apache.logging.log4j.core.config.plugins.Plugin;
  25 import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
  26 import org.apache.logging.log4j.core.config.plugins.PluginElement;
  27 import org.apache.logging.log4j.core.config.plugins.PluginFactory;
  28 import org.apache.logging.log4j.message.Message;
  29 import org.lttng.ust.agent.ILttngHandler;
  30 import org.lttng.ust.agent.context.ContextInfoSerializer;
  31
  32 /**
  33  * LTTng-UST Log4j 2.x log handler.
  34  *
  35  * Applications can attach this appender to their
  36  * {@link org.apache.log4j.Logger} to have it generate UST events from logging
  37  * events received through the logger.
  38  *
  39  * It sends its events to UST via the JNI library "liblttng-ust-log4j-jni.so".
  40  * Make sure this library is available before using this appender.
  41  *
  42  */
  43 @Plugin(name = LttngLogAppender.PLUGIN_NAME, category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = false)
  44 public final class LttngLogAppender extends AbstractAppender implements ILttngHandler {
  45
  46         /**
  47          * The name of the appender in the configuration.
  48          */
  49         public static final String PLUGIN_NAME = "Lttng";
  50
  51         private static final String SHARED_OBJECT_NAME = "lttng-ust-log4j-jni";
  52
  53         /**
  54          * Number of events logged (really sent through JNI) by this handler
  55          */
  56         private final AtomicLong eventCount = new AtomicLong(0);
  57
  58         private final LttngLog4j2Agent agent;
  59
  60         /**
  61          * Constructor
  62          *
  63          * @param name             The name of the Appender.
  64          * @param filter           The Filter or null.
  65          * @param ignoreExceptions If {@code "true"} (default) exceptions encountered
  66          *                         when appending events are logged; otherwise they are
  67          *                         propagated to the caller.
  68          *
  69          * @throws IOException       This handler requires the lttng-ust-log4j-jni.so
  70          *                           native library, through which it will send the
  71          *                           trace events. This exception is thrown if this
  72          *                           library cannot be found.
  73          * @throws SecurityException We will forward any SecurityExcepion that may be
  74          *                           thrown when trying to load the JNI library.
  75          */
  76         protected LttngLogAppender(String name, Filter filter, boolean ignoreExceptions)
  77                         throws IOException, SecurityException {
  78
  79                 super(name, filter, null, ignoreExceptions, Property.EMPTY_ARRAY);
  80
  81                 /* Initialize LTTng UST tracer. */
  82                 try {
  83                         System.loadLibrary(SHARED_OBJECT_NAME); // $NON-NLS-1$
  84                 } catch (UnsatisfiedLinkError e) {
  85                         throw new IOException(e);
  86                 }
  87
  88                 /* Register to the relevant agent. */
  89                 agent = LttngLog4j2Agent.getInstance();
  90                 agent.registerHandler(this);
  91         }
  92
  93         /**
  94          * Create an LttngLogAppender.
  95          *
  96          * @param name             The name of the Appender, null returns null.
  97          * @param ignoreExceptions If {@code "true"} (default) exceptions encountered
  98          *                         when appending events are logged; otherwise they are
  99          *                         propagated to the caller.
 100          * @param filter           The Filter or null.
 101          *
 102          * @return A new LttngLogAppender, null if the name was null.
 103          *
 104          * @throws IOException       This handler requires the lttng-ust-log4j-jni.so
 105          *                           native library, through which it will send the
 106          *                           trace events. This exception is thrown if this
 107          *                           library cannot be found.
 108          * @throws SecurityException We will forward any SecurityExcepion that may be
 109          *                           thrown when trying to load the JNI library.
 110          */
 111         @PluginFactory
 112         public static LttngLogAppender createAppender(@PluginAttribute("name") String name,
 113                         @PluginAttribute("ignoreExceptions") Boolean ignoreExceptions, @PluginElement("Filters") Filter filter)
 114                         throws IOException, SecurityException {
 115
 116                 if (name == null) {
 117                         LOGGER.error("No name provided for LttngLogAppender");
 118                         return null;
 119                 }
 120
 121                 if (ignoreExceptions == null) {
 122                         ignoreExceptions = true;
 123                 }
 124
 125                 return new LttngLogAppender(name, filter, ignoreExceptions);
 126         }
 127
 128         @Override
 129         public synchronized void close() {
 130                 agent.unregisterHandler(this);
 131         }
 132
 133         @Override
 134         public void stop() {
 135                 close();
 136                 super.stop();
 137
 138                 getStatusLogger().debug("Appender Lttng stopped");
 139         }
 140
 141         @Override
 142         public boolean stop(final long timeout, final TimeUnit timeUnit) {
 143                 close();
 144                 boolean status = super.stop(timeout, timeUnit);
 145
 146                 getStatusLogger().debug("Appender Lttng stopped with status " + status);
 147
 148                 return status;
 149         }
 150
 151         /**
 152          * Get the number of events logged by this handler so far. This means the number
 153          * of events actually sent through JNI to UST.
 154          *
 155          * @return The number of events logged so far
 156          */
 157         @Override
 158         public long getEventCount() {
 159                 return eventCount.get();
 160         }
 161
 162         @Override
 163         public void append(LogEvent event) {
 164                 /*
 165                  * Check if the current message should be logged, according to the UST session
 166                  * settings.
 167                  */
 168                 String loggername = event.getLoggerName();
 169                 if (loggername == null || !agent.isEventEnabled(loggername)) {
 170                         return;
 171                 }
 172
 173                 /*
 174                  * Default value if the Message is null.
 175                  */
 176                 String message = "";
 177
 178                 Message eventMessage = event.getMessage();
 179                 if (eventMessage != null) {
 180                         message = eventMessage.getFormattedMessage();
 181                 }
 182
 183                 /*
 184                  * Default values if the StackTraceElement is null.
 185                  */
 186                 String classname = "";
 187                 String methodname = "";
 188                 String filename = "";
 189                 int line = -1;
 190
 191                 StackTraceElement ste = event.getSource();
 192                 if (ste != null) {
 193                         classname = ste.getClassName();
 194                         methodname = ste.getMethodName();
 195                         filename = ste.getFileName();
 196                         line = ste.getLineNumber();
 197                 }
 198
 199                 /* Retrieve all the requested context information we can find. */
 200                 Collection<Entry<String, Map<String, Integer>>> enabledContexts = agent.getEnabledAppContexts();
 201                 ContextInfoSerializer.SerializedContexts contextInfo = ContextInfoSerializer
 202                                 .queryAndSerializeRequestedContexts(enabledContexts);
 203
 204                 eventCount.incrementAndGet();
 205
 206                 LttngLog4j2Api.tracepointWithContext(message, loggername, classname, methodname, filename, line,
 207                                 event.getTimeMillis(), event.getLevel().intLevel(), event.getThreadName(),
 208                                 contextInfo.getEntriesArray(), contextInfo.getStringsArray());
 209         }
 210 }