src/lib/lttng-ust-java-agent/java/lttng-ust-agent-log4j2/org/lttng/ust/agent/log4j2/LttngLogAppender.java

   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.ILttngAgent.Domain;
  30 import org.lttng.ust.agent.ILttngHandler;
  31 import org.lttng.ust.agent.context.ContextInfoSerializer;
  32
  33 /**
  34  * LTTng-UST Log4j 2.x log handler.
  35  *
  36  * Applications can attach this appender to their
  37  * {@link org.apache.log4j.Logger} to have it generate UST events from logging
  38  * events received through the logger.
  39  *
  40  * It sends its events to UST via the JNI library "liblttng-ust-log4j-jni.so".
  41  * Make sure this library is available before using this appender.
  42  *
  43  */
  44 @Plugin(name = LttngLogAppender.PLUGIN_NAME, category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = false)
  45 public final class LttngLogAppender extends AbstractAppender implements ILttngHandler {
  46
  47         /**
  48          * The name of the appender in the configuration.
  49          */
  50         public static final String PLUGIN_NAME = "Lttng";
  51
  52         private static final String SHARED_OBJECT_NAME = "lttng-ust-log4j-jni";
  53
  54         /**
  55          * Number of events logged (really sent through JNI) by this handler
  56          */
  57         private final AtomicLong eventCount = new AtomicLong(0);
  58
  59         private final LttngLog4j2Agent agent;
  60
  61         /**
  62          * Constructor
  63          *
  64          * @param name             The name of the Appender.
  65          * @param domain           The LTTng-UST agent domain 'LOG4J' / 'LOG4J2'.
  66          * @param filter           The Filter or null.
  67          * @param ignoreExceptions If {@code "true"} exceptions encountered when
  68          *                         appending events are logged; otherwise they are
  69          *                         propagated to the caller.
  70          *
  71          * @throws IOException              This handler requires the
  72          *                                  lttng-ust-log4j-jni.so native library,
  73          *                                  through which it will send the trace events.
  74          *                                  This exception is thrown if this library
  75          *                                  cannot be found.
  76          * @throws IllegalArgumentException If the provided domain is unsupported.
  77          * @throws SecurityException        We will forward any SecurityExcepion that
  78          *                                  may be thrown when trying to load the JNI
  79          *                                  library.
  80          */
  81         protected LttngLogAppender(String name, LttngLog4j2Agent.Domain domain, Filter filter, boolean ignoreExceptions)
  82                         throws IOException, IllegalArgumentException, SecurityException {
  83
  84                 super(name, filter, null, ignoreExceptions, Property.EMPTY_ARRAY);
  85
  86                 /* Initialize LTTng UST tracer. */
  87                 try {
  88                         System.loadLibrary(SHARED_OBJECT_NAME); // $NON-NLS-1$
  89                 } catch (UnsatisfiedLinkError e) {
  90                         throw new IOException(e);
  91                 }
  92
  93                 /* Register to the relevant agent. */
  94                 if (domain == LttngLog4j2Agent.Domain.LOG4J) {
  95                         agent = LttngLog4j2Agent.getInstance();
  96                 } else {
  97                         throw new IllegalArgumentException("Unsupported domain '" + domain + "'");
  98                 }
  99
 100                 agent.registerHandler(this);
 101         }
 102
 103         /**
 104          * Create an LttngLogAppender.
 105          *
 106          * @param name             The name of the Appender, null returns null.
 107          * @param domain           The LTTng-UST agent domain 'LOG4J' / 'LOG4J2'.
 108          * @param ignoreExceptions If {@code "true"} (default) exceptions encountered
 109          *                         when appending events are logged; otherwise they are
 110          *                         propagated to the caller.
 111          * @param filter           The Filter or null.
 112          *
 113          * @return A new LttngLogAppender, null if the name was null or the domain is
 114          *         null or invalid.
 115          */
 116         @PluginFactory
 117         public static LttngLogAppender createAppender(@PluginAttribute("name") String name,
 118                         @PluginAttribute("domain") String domain, @PluginAttribute("ignoreExceptions") Boolean ignoreExceptions,
 119                         @PluginElement("Filters") Filter filter) {
 120
 121                 if (name == null) {
 122                         LOGGER.error("No name provided for LttngLogAppender");
 123                         return null;
 124                 }
 125
 126                 if (domain == null) {
 127                         LOGGER.error("No domain provided for LttngLogAppender");
 128                         return null;
 129                 }
 130
 131                 if (ignoreExceptions == null) {
 132                         ignoreExceptions = true;
 133                 }
 134
 135                 /* Parse the domain string */
 136                 LttngLog4j2Agent.Domain parsedDomain;
 137                 try {
 138                         parsedDomain = LttngLog4j2Agent.Domain.valueOf(domain.toUpperCase());
 139                 } catch (IllegalArgumentException e) {
 140                         LOGGER.error("Invalid domain '{}' for LttngLogAppender", domain);
 141                         return null;
 142                 }
 143
 144                 /* Create the appender and handle the possible failures. */
 145                 LttngLogAppender newAppender;
 146                 try {
 147                         newAppender = new LttngLogAppender(name, parsedDomain, filter, ignoreExceptions);
 148                 } catch (IllegalArgumentException e) {
 149                         LOGGER.error("Invalid domain '{}' for LttngLogAppender", parsedDomain);
 150                         newAppender = null;
 151                 } catch (SecurityException e) {
 152                         LOGGER.error("Security error trying to load '{}' JNI library for LttngLogAppender", SHARED_OBJECT_NAME);
 153                         newAppender = null;
 154                 } catch (IOException e) {
 155                         LOGGER.error("Failed to load '{}' JNI library for LttngLogAppender", SHARED_OBJECT_NAME);
 156                         newAppender = null;
 157                 }
 158
 159                 return newAppender;
 160         }
 161
 162         @Override
 163         public synchronized void close() {
 164                 agent.unregisterHandler(this);
 165         }
 166
 167         @Override
 168         public void stop() {
 169                 close();
 170                 super.stop();
 171
 172                 getStatusLogger().debug("Appender Lttng stopped");
 173         }
 174
 175         @Override
 176         public boolean stop(final long timeout, final TimeUnit timeUnit) {
 177                 close();
 178                 boolean status = super.stop(timeout, timeUnit);
 179
 180                 getStatusLogger().debug("Appender Lttng stopped with status " + status);
 181
 182                 return status;
 183         }
 184
 185         /**
 186          * Get the number of events logged by this handler so far. This means the number
 187          * of events actually sent through JNI to UST.
 188          *
 189          * @return The number of events logged so far
 190          */
 191         @Override
 192         public long getEventCount() {
 193                 return eventCount.get();
 194         }
 195
 196         @Override
 197         public void append(LogEvent event) {
 198                 /*
 199                  * Check if the current message should be logged, according to the UST session
 200                  * settings.
 201                  */
 202                 String loggername = event.getLoggerName();
 203                 if (loggername == null || !agent.isEventEnabled(loggername)) {
 204                         return;
 205                 }
 206
 207                 /*
 208                  * Default value if the Message is null.
 209                  */
 210                 String message = "";
 211
 212                 Message eventMessage = event.getMessage();
 213                 if (eventMessage != null) {
 214                         message = eventMessage.getFormattedMessage();
 215                 }
 216
 217                 /*
 218                  * Default values if the StackTraceElement is null.
 219                  */
 220                 String classname = "";
 221                 String methodname = "";
 222                 String filename = "";
 223                 int line = -1;
 224
 225                 StackTraceElement ste = event.getSource();
 226                 if (ste != null) {
 227                         classname = ste.getClassName();
 228                         methodname = ste.getMethodName();
 229                         filename = ste.getFileName();
 230                         line = ste.getLineNumber();
 231                 }
 232
 233                 /* Retrieve all the requested context information we can find. */
 234                 Collection<Entry<String, Map<String, Integer>>> enabledContexts = agent.getEnabledAppContexts();
 235                 ContextInfoSerializer.SerializedContexts contextInfo = ContextInfoSerializer
 236                                 .queryAndSerializeRequestedContexts(enabledContexts);
 237
 238                 eventCount.incrementAndGet();
 239
 240                 LttngLog4j2Api.tracepointWithContext(message, loggername, classname, methodname, filename, line,
 241                                 event.getTimeMillis(), event.getLevel().intLevel(), event.getThreadName(),
 242                                 contextInfo.getEntriesArray(), contextInfo.getStringsArray());
 243         }
 244 }