syslogappender.java

apache的log4j源码

    } else if("LOCAL6".equalsIgnoreCase(facilityName)) {
      return LOG_LOCAL6;
    } else if("LOCAL7".equalsIgnoreCase(facilityName)) {
      return LOG_LOCAL7;
    } else {
      return -1;
    }
  }


  private void splitPacket(final String header, final String packet) {
      int byteCount = packet.getBytes().length;
      //
      //   if packet is less than RFC 3164 limit
      //      of 1024 bytes, then write it
      //      (must allow for up 5to 5 characters in the PRI section
      //          added by SyslogQuietWriter)
      if (byteCount <= 1019) {
          sqw.write(packet);
      } else {
          int split = header.length() + (packet.length() - header.length())/2;
          splitPacket(header, packet.substring(0, split) + "...");
          splitPacket(header, header + "..." + packet.substring(split));
      }      
  }

  public
  void append(LoggingEvent event) {

    if(!isAsSevereAsThreshold(event.getLevel()))
      return;

    // We must not attempt to append if sqw is null.
    if(sqw == null) {
      errorHandler.error("No syslog host is set for SyslogAppedender named \""+
			this.name+"\".");
      return;
    }

    if (!layoutHeaderChecked) {
        if (layout != null && layout.getHeader() != null) {
            sendLayoutMessage(layout.getHeader());
        }
        layoutHeaderChecked = true;
    }

    String hdr = getPacketHeader(event.timeStamp);
    String packet = layout.format(event);
    if(facilityPrinting || hdr.length() > 0) {
        StringBuffer buf = new StringBuffer(hdr);
        if(facilityPrinting) {
            buf.append(facilityStr);
        }
        buf.append(packet);
        packet = buf.toString();
    }

    sqw.setLevel(event.getLevel().getSyslogEquivalent());
    //
    //   if message has a remote likelihood of exceeding 1024 bytes
    //      when encoded, consider splitting message into multiple packets
    if (packet.length() > 256) {
        splitPacket(hdr, packet);
    } else {
        sqw.write(packet);
    }

    if (layout.ignoresThrowable()) {
      String[] s = event.getThrowableStrRep();
      if (s != null) {
        for(int i = 0; i < s.length; i++) {
            if (s[i].startsWith("\t")) {
               sqw.write(hdr+TAB+s[i].substring(1));
            } else {
               sqw.write(hdr+s[i]);
            }
        }
      }
    }
  }

  /**
     This method returns immediately as options are activated when they
     are set.
  */
  public
  void activateOptions() {
      if (header) {
        getLocalHostname();
      }
      if (layout != null && layout.getHeader() != null) {
          sendLayoutMessage(layout.getHeader());
      }
      layoutHeaderChecked = true;
  }

  /**
     The SyslogAppender requires a layout. Hence, this method returns
     <code>true</code>.

     @since 0.8.4 */
  public
  boolean requiresLayout() {
    return true;
  }

  /**
    The <b>SyslogHost</b> option is the name of the the syslog host
    where log output should go.  A non-default port can be specified by
    appending a colon and port number to a host name,
    an IPv4 address or an IPv6 address enclosed in square brackets.

    <b>WARNING</b> If the SyslogHost is not set, then this appender
    will fail.
   */
  public
  void setSyslogHost(final String syslogHost) {
    this.sqw = new SyslogQuietWriter(new SyslogWriter(syslogHost),
				     syslogFacility, errorHandler);
    //this.stp = new SyslogTracerPrintWriter(sqw);
    this.syslogHost = syslogHost;
  }

  /**
     Returns the value of the <b>SyslogHost</b> option.
   */
  public
  String getSyslogHost() {
    return syslogHost;
  }

  /**
     Set the syslog facility. This is the <b>Facility</b> option.

     <p>The <code>facilityName</code> parameter must be one of the
     strings KERN, USER, MAIL, DAEMON, AUTH, SYSLOG, LPR, NEWS, UUCP,
     CRON, AUTHPRIV, FTP, LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4,
     LOCAL5, LOCAL6, LOCAL7. Case is unimportant.

     @since 0.8.1 */
  public
  void setFacility(String facilityName) {
    if(facilityName == null)
      return;

    syslogFacility = getFacility(facilityName);
    if (syslogFacility == -1) {
      System.err.println("["+facilityName +
                  "] is an unknown syslog facility. Defaulting to [USER].");
      syslogFacility = LOG_USER;
    }

    this.initSyslogFacilityStr();

    // If there is already a sqw, make it use the new facility.
    if(sqw != null) {
      sqw.setSyslogFacility(this.syslogFacility);
    }
  }

  /**
     Returns the value of the <b>Facility</b> option.
   */
  public
  String getFacility() {
    return getFacilityString(syslogFacility);
  }

  /**
    If the <b>FacilityPrinting</b> option is set to true, the printed
    message will include the facility name of the application. It is
    <em>false</em> by default.
   */
  public
  void setFacilityPrinting(boolean on) {
    facilityPrinting = on;
  }

  /**
     Returns the value of the <b>FacilityPrinting</b> option.
   */
  public
  boolean getFacilityPrinting() {
    return facilityPrinting;
  }

  /**
   * If true, the appender will generate the HEADER part (that is, timestamp and host name)
   * of the syslog packet.  Default value is false for compatibility with existing behavior,
   * however should be true unless there is a specific justification.
   * @since 1.2.15
  */
  public final boolean getHeader() {
      return header;
  }

    /**
     * Returns whether the appender produces the HEADER part (that is, timestamp and host name)
     * of the syslog packet.
     * @since 1.2.15
    */
  public final void setHeader(final boolean val) {
      header = val;
  }

    /**
     * Get the host name used to identify this appender.
     * @return local host name
     * @since 1.2.15
     */
  private String getLocalHostname() {
      if (localHostname == null) {
          try {
            InetAddress addr = InetAddress.getLocalHost();
            localHostname = addr.getHostName();
          } catch (UnknownHostException uhe) {
            localHostname = "UNKNOWN_HOST";
          }
      }
      return localHostname;
  }

    /**
     * Gets HEADER portion of packet.
     * @param timeStamp number of milliseconds after the standard base time.
     * @return HEADER portion of packet, will be zero-length string if header is false.
     * @since 1.2.15
     */
  private String getPacketHeader(final long timeStamp) {
      if (header) {
        StringBuffer buf = new StringBuffer(dateFormat.format(new Date(timeStamp)));
        //  RFC 3164 says leading space, not leading zero on days 1-9
        if (buf.charAt(4) == '0') {
          buf.setCharAt(4, ' ');
        }
        buf.append(getLocalHostname());
        buf.append(' ');
        return buf.toString();
      }
      return "";
  }

    /**
     * Set header or footer of layout.
     * @param msg message body, may not be null.
     */
  private void sendLayoutMessage(final String msg) {
      if (sqw != null) {
          String packet = msg;
          String hdr = getPacketHeader(new Date().getTime());
          if(facilityPrinting || hdr.length() > 0) {
              StringBuffer buf = new StringBuffer(hdr);
              if(facilityPrinting) {
                  buf.append(facilityStr);
              }
              buf.append(msg);
              packet = buf.toString();
          }
          sqw.setLevel(6);
          sqw.write(packet);
      }
  }
}