Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.classic.net;

import java.io.IOException;
import java.io.OutputStream;
import java.net.SocketException;
import java.net.UnknownHostException;

import ch.qos.logback.classic.PatternLayout;
import ch.qos.logback.classic.pattern.SyslogStartConverter;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.classic.spi.IThrowableProxy;
import ch.qos.logback.classic.spi.StackTraceElementProxy;
import ch.qos.logback.classic.util.LevelToSyslogSeverity;
import ch.qos.logback.core.CoreConstants;
import ch.qos.logback.core.Layout;
import ch.qos.logback.core.net.SyslogAppenderBase;
import ch.qos.logback.core.net.SyslogOutputStream;

This appender can be used to send messages to a remote syslog daemon. 
 For
more information about this appender, please refer to the online manual at
http://logback.qos.ch/manual/appenders.html#SyslogAppender
Author:
Ceki Gülcü/**
 * This appender can be used to send messages to a remote syslog daemon. <p> For
 * more information about this appender, please refer to the online manual at
 * http://logback.qos.ch/manual/appenders.html#SyslogAppender
 *
 * @author Ceki G&uuml;lc&uuml;
 */
public class SyslogAppender extends SyslogAppenderBase<ILoggingEvent> {

    static final public String DEFAULT_SUFFIX_PATTERN = "[%thread] %logger %msg";
    static final public String DEFAULT_STACKTRACE_PATTERN = "" + CoreConstants.TAB;

    PatternLayout stackTraceLayout = new PatternLayout();
    String stackTracePattern = DEFAULT_STACKTRACE_PATTERN;

    boolean throwableExcluded = false;

    public void start() {
        super.start();
        setupStackTraceLayout();
    }

    String getPrefixPattern() {
        return "%syslogStart{" + getFacility() + "}%nopex{}";
    }

    @Override
    public SyslogOutputStream createOutputStream() throws SocketException, UnknownHostException {
        return new SyslogOutputStream(getSyslogHost(), getPort());
    }

    
Convert a level to equivalent syslog severity. Only levels for printing
methods i.e DEBUG, WARN, INFO and ERROR are converted.
See Also:
getSeverityForEvent.getSeverityForEvent(Object)/**
     * Convert a level to equivalent syslog severity. Only levels for printing
     * methods i.e DEBUG, WARN, INFO and ERROR are converted.
     *
     * @see ch.qos.logback.core.net.SyslogAppenderBase#getSeverityForEvent(java.lang.Object)
     */
    @Override
    public int getSeverityForEvent(Object eventObject) {
        ILoggingEvent event = (ILoggingEvent) eventObject;
        return LevelToSyslogSeverity.convert(event);
    }

    @Override
    protected void postProcess(Object eventObject, OutputStream sw) {
        if (throwableExcluded)
            return;

        ILoggingEvent event = (ILoggingEvent) eventObject;
        IThrowableProxy tp = event.getThrowableProxy();

        if (tp == null)
            return;

        String stackTracePrefix = stackTraceLayout.doLayout(event);
        boolean isRootException = true;
        while (tp != null) {
            StackTraceElementProxy[] stepArray = tp.getStackTraceElementProxyArray();
            try {
                handleThrowableFirstLine(sw, tp, stackTracePrefix, isRootException);
                isRootException = false;
                for (StackTraceElementProxy step : stepArray) {
                    StringBuilder sb = new StringBuilder();
                    sb.append(stackTracePrefix).append(step);
                    sw.write(sb.toString().getBytes());
                    sw.flush();
                }
            } catch (IOException e) {
                break;
            }
            tp = tp.getCause();
        }
    }

    // LOGBACK-411 and LOGBACK-750
    private void handleThrowableFirstLine(OutputStream sw, IThrowableProxy tp, String stackTracePrefix, boolean isRootException) throws IOException {
        StringBuilder sb = new StringBuilder().append(stackTracePrefix);

        if (!isRootException) {
            sb.append(CoreConstants.CAUSED_BY);
        }
        sb.append(tp.getClassName()).append(": ").append(tp.getMessage());
        sw.write(sb.toString().getBytes());
        sw.flush();
    }

    boolean stackTraceHeaderLine(StringBuilder sb, boolean topException) {

        return false;
    }

    public Layout<ILoggingEvent> buildLayout() {
        PatternLayout layout = new PatternLayout();
        layout.getInstanceConverterMap().put("syslogStart", SyslogStartConverter.class.getName());
        if (suffixPattern == null) {
            suffixPattern = DEFAULT_SUFFIX_PATTERN;
        }
        layout.setPattern(getPrefixPattern() + suffixPattern);
        layout.setContext(getContext());
        layout.start();
        return layout;
    }

    private void setupStackTraceLayout() {
        stackTraceLayout.getInstanceConverterMap().put("syslogStart", SyslogStartConverter.class.getName());

        stackTraceLayout.setPattern(getPrefixPattern() + stackTracePattern);
        stackTraceLayout.setContext(getContext());
        stackTraceLayout.start();
    }

    public boolean isThrowableExcluded() {
        return throwableExcluded;
    }

    
Setting throwableExcluded to true causes no Throwable's stack trace data to be sent to
the syslog daemon. By default, stack trace data is sent to syslog daemon.
Params:
throwableExcluded – 
Since:
1.0.4/**
     * Setting throwableExcluded to true causes no Throwable's stack trace data to be sent to
     * the syslog daemon. By default, stack trace data is sent to syslog daemon.
     *
     * @param throwableExcluded
     * @since 1.0.4
     */
    public void setThrowableExcluded(boolean throwableExcluded) {
        this.throwableExcluded = throwableExcluded;
    }

    
See #setStackTracePattern(String).
Returns:
the stackTraceSuffixPattern
Since:
1.0.4/**
     * See {@link #setStackTracePattern(String).
     *
     * @return the stackTraceSuffixPattern
     * @since 1.0.4
     */
    public String getStackTracePattern() {
        return stackTracePattern;
    }

    
Stack trace lines are sent to the syslog server separately from the main message For stack trace lines, the stackTracePattern is used instead of SyslogAppenderBase<ILoggingEvent>.suffixPattern. The stackTracePattern option allows specification of a separately format for the
non-standardized part of stack trace lines.
Params:
stackTracePattern – 
Since:
1.0.4/**
     * Stack trace lines are sent to the syslog server separately from the main message
     * For stack trace lines, the stackTracePattern is used instead of {@link #suffixPattern}.
     * The <b>stackTracePattern</b> option allows specification of a separately format for the
     * non-standardized part of stack trace lines.
     *
     * @param stackTracePattern
     * @since 1.0.4
     */
    public void setStackTracePattern(String stackTracePattern) {
        this.stackTracePattern = stackTracePattern;
    }
}