package de.bwaldvogel.log4j;
import com.sun.jna.Native;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.util.Booleans;
import org.apache.logging.log4j.util.ReadOnlyStringMap;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
@Plugin(name = "SystemdJournal", category = "Core", elementType = "appender", printObject = true)
public class SystemdJournalAppender extends AbstractAppender {
private final SystemdJournalLibrary journalLibrary;
private final boolean logStacktrace;
private final boolean logSource;
private final boolean logThreadName;
private final boolean logLoggerName;
private final boolean logAppenderName;
private final boolean logThreadContext;
private final String threadContextPrefix;
private final String syslogIdentifier;
private final String syslogFacility;
SystemdJournalAppender(String name, Filter filter, Layout<?> layout, boolean ignoreExceptions,
SystemdJournalLibrary journalLibrary, boolean logSource, boolean logStacktrace, boolean logThreadName,
boolean logLoggerName, boolean logAppenderName, boolean logThreadContext, String threadContextPrefix, String syslogIdentifier, String syslogFacility) {
super(name, filter, layout, ignoreExceptions);
this.journalLibrary = journalLibrary;
this.logSource = logSource;
this.logStacktrace = logStacktrace;
this.logThreadName = logThreadName;
this.logLoggerName = logLoggerName;
this.logAppenderName = logAppenderName;
this.logThreadContext = logThreadContext;
if (threadContextPrefix == null) {
this.threadContextPrefix = "THREAD_CONTEXT_";
} else {
this.threadContextPrefix = normalizeKey(threadContextPrefix);
}
this.syslogIdentifier = syslogIdentifier;
this.syslogFacility = syslogFacility;
}
@PluginFactory
public static SystemdJournalAppender createAppender(@PluginAttribute("name") final String name,
@PluginAttribute("ignoreExceptions") final String ignoreExceptionsString,
@PluginAttribute("logSource") final String logSourceString,
@PluginAttribute("logStacktrace") final String logStacktraceString,
@PluginAttribute("logLoggerName") final String logLoggerNameString,
@PluginAttribute("logAppenderName") final String logAppenderNameString,
@PluginAttribute("logThreadName") final String logThreadNameString,
@PluginAttribute("logThreadContext") final String logThreadContextString,
@PluginAttribute("threadContextPrefix") final String threadContextPrefix,
@PluginAttribute("syslogIdentifier") final String syslogIdentifier,
@PluginAttribute("syslogFacility") final String syslogFacility,
@PluginElement("Layout") final Layout<?> layout,
@PluginElement("Filter") final Filter filter,
@PluginConfiguration final Configuration config) {
final boolean ignoreExceptions = Booleans.parseBoolean(ignoreExceptionsString, true);
final boolean logSource = Booleans.parseBoolean(logSourceString, false);
final boolean logStacktrace = Booleans.parseBoolean(logStacktraceString, true);
final boolean logThreadName = Booleans.parseBoolean(logThreadNameString, true);
final boolean logLoggerName = Booleans.parseBoolean(logLoggerNameString, true);
final boolean logAppenderName = Booleans.parseBoolean(logAppenderNameString, true);
final boolean logThreadContext = Booleans.parseBoolean(logThreadContextString, true);
if (name == null) {
LOGGER.error("No name provided for SystemdJournalAppender");
return null;
}
final SystemdJournalLibrary journalLibrary;
try {
journalLibrary = Native.loadLibrary("systemd", SystemdJournalLibrary.class);
} catch (UnsatisfiedLinkError e) {
throw new RuntimeException("Failed to load systemd library." +
" Please note that JNA requires an executable temporary folder." +
" It can be explicitly defined with -Djna.tmpdir", e);
}
return new SystemdJournalAppender(name, filter, layout, ignoreExceptions, journalLibrary, logSource, logStacktrace,
logThreadName, logLoggerName, logAppenderName, logThreadContext, threadContextPrefix, syslogIdentifier, syslogFacility);
}
private int log4jLevelToJournalPriority(Level level) {
//
// syslog.h
//
// #define LOG_EMERG 0 - system is unusable
// #define LOG_ALERT 1 - action must be taken immediately
// #define LOG_CRIT 2 - critical conditions
// #define LOG_ERR 3 - error conditions
// #define LOG_WARNING 4 - warning conditions
// #define LOG_NOTICE 5 - normal but significant condition
// #define LOG_INFO 6 - informational
// #define LOG_DEBUG 7 - debug-level messages
//
switch (level.getStandardLevel()) {
case FATAL:
return 2; // LOG_CRIT
case ERROR:
return 3; // LOG_ERR
case WARN:
return 4; // LOG_WARNING
case INFO:
return 6; // LOG_INFO
case DEBUG:
case TRACE:
return 7; // LOG_DEBUG
default:
throw new IllegalArgumentException("Cannot map log level: " + level);
}
}
@Override
public void append(LogEvent event) {
List<Object> args = new ArrayList<>();
args.add(buildFormattedMessage(event));
args.add("PRIORITY=%d");
args.add(Integer.valueOf(log4jLevelToJournalPriority(event.getLevel())));
if (logThreadName) {
args.add("THREAD_NAME=%s");
args.add(event.getThreadName());
}
if (logLoggerName) {
args.add("LOG4J_LOGGER=%s");
args.add(event.getLoggerName());
}
if (logAppenderName) {
args.add("LOG4J_APPENDER=%s");
args.add(getName());
}
if (logStacktrace && event.getThrown() != null) {
StringWriter stacktrace = new StringWriter();
event.getThrown().printStackTrace(new PrintWriter(stacktrace));
args.add("STACKTRACE=%s");
args.add(stacktrace.toString());
}
if (logSource && event.getSource() != null) {
String fileName = event.getSource().getFileName();
args.add("CODE_FILE=%s");
args.add(fileName);
String methodName = event.getSource().getMethodName();
args.add("CODE_FUNC=%s");
args.add(methodName);
int lineNumber = event.getSource().getLineNumber();
args.add("CODE_LINE=%d");
args.add(Integer.valueOf(lineNumber));
}
if (logThreadContext) {
ReadOnlyStringMap context = event.getContextData();
if (context != null) {
for (Entry<String, String> entry : context.toMap().entrySet()) {
String key = entry.getKey();
args.add(threadContextPrefix + normalizeKey(key) + "=%s");
args.add(entry.getValue());
}
}
}
if (syslogIdentifier != null && !syslogIdentifier.isEmpty()) {
args.add("SYSLOG_IDENTIFIER=%s");
args.add(syslogIdentifier);
}
if (syslogFacility != null && !syslogFacility.isEmpty()) {
args.add("SYSLOG_FACILITY=%d");
args.add(Integer.valueOf(syslogFacility));
}
args.add(null); // null terminated
journalLibrary.sd_journal_send("MESSAGE=%s", args.toArray());
}
private String buildFormattedMessage(LogEvent event) {
if (getLayout() != null) {
byte[] message = getLayout().toByteArray(event);
return new String(message, StandardCharsets.UTF_8);
}
return event.getMessage().getFormattedMessage();
}
private static String normalizeKey(String key) {
return key.toUpperCase().replaceAll("[^_A-Z0-9]", "_");
}
}
