001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.layout;
018
019import java.net.InetAddress;
020import java.net.UnknownHostException;
021import java.nio.charset.Charset;
022import java.text.SimpleDateFormat;
023import java.util.Date;
024import java.util.HashMap;
025import java.util.Locale;
026import java.util.Map;
027import java.util.regex.Matcher;
028import java.util.regex.Pattern;
029
030import org.apache.logging.log4j.core.LogEvent;
031import org.apache.logging.log4j.core.config.plugins.Plugin;
032import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
033import org.apache.logging.log4j.core.config.plugins.PluginFactory;
034import org.apache.logging.log4j.core.helpers.Charsets;
035import org.apache.logging.log4j.core.net.Facility;
036import org.apache.logging.log4j.core.net.Priority;
037
038
039/**
040 * Formats a log event as a BSD Log record.
041 */
042@Plugin(name = "SyslogLayout", category = "Core", elementType = "layout", printObject = true)
043public class SyslogLayout extends AbstractStringLayout {
044    /**
045     * Match newlines in a platform-independent manner.
046     */
047    public static final Pattern NEWLINE_PATTERN = Pattern.compile("\\r?\\n");
048
049    private final Facility facility;
050    private final boolean includeNewLine;
051    private final String escapeNewLine;
052
053    /**
054     * Date format used if header = true.
055     */
056    private final SimpleDateFormat dateFormat = new SimpleDateFormat("MMM dd HH:mm:ss ", Locale.ENGLISH);
057    /**
058     * Host name used to identify messages from this appender.
059     */
060    private final String localHostname = getLocalHostname();
061
062
063
064    protected SyslogLayout(final Facility facility, final boolean includeNL, final String escapeNL, final Charset charset) {
065        super(charset);
066        this.facility = facility;
067        this.includeNewLine = includeNL;
068        this.escapeNewLine = escapeNL == null ? null : Matcher.quoteReplacement(escapeNL);
069    }
070
071    /**
072     * Formats a {@link org.apache.logging.log4j.core.LogEvent} in conformance with the BSD Log record format.
073     *
074     * @param event The LogEvent
075     * @return the event formatted as a String.
076     */
077    @Override
078    public String toSerializable(final LogEvent event) {
079        final StringBuilder buf = new StringBuilder();
080
081        buf.append("<");
082        buf.append(Priority.getPriority(facility, event.getLevel()));
083        buf.append(">");
084        addDate(event.getMillis(), buf);
085        buf.append(" ");
086        buf.append(localHostname);
087        buf.append(" ");
088
089        String message = event.getMessage().getFormattedMessage();
090        if (null != escapeNewLine) {
091            message = NEWLINE_PATTERN.matcher(message).replaceAll(escapeNewLine);
092        }
093        buf.append(message);
094
095        if (includeNewLine) {
096            buf.append("\n");
097        }
098        return buf.toString();
099    }
100
101    /**
102     * This method gets the network name of the machine we are running on.
103     * Returns "UNKNOWN_LOCALHOST" in the unlikely case where the host name
104     * cannot be found.
105     *
106     * @return String the name of the local host
107     */
108    private String getLocalHostname() {
109        try {
110            final InetAddress addr = InetAddress.getLocalHost();
111            return addr.getHostName();
112        } catch (final UnknownHostException uhe) {
113            LOGGER.error("Could not determine local host name", uhe);
114            return "UNKNOWN_LOCALHOST";
115        }
116    }
117
118    private synchronized void addDate(final long timestamp, final StringBuilder buf) {
119        final int index = buf.length() + 4;
120        buf.append(dateFormat.format(new Date(timestamp)));
121        //  RFC 3164 says leading space, not leading zero on days 1-9
122        if (buf.charAt(index) == '0') {
123            buf.setCharAt(index, ' ');
124        }
125    }
126
127    /**
128     * SyslogLayout's content format is specified by:<p/>
129     * Key: "structured" Value: "false"<p/>
130     * Key: "dateFormat" Value: "MMM dd HH:mm:ss "<p/>
131     * Key: "format" Value: "<LEVEL>TIMESTAMP PROP(HOSTNAME) MESSAGE"<p/>
132     * Key: "formatType" Value: "logfilepatternreceiver" (format uses the keywords supported by LogFilePatternReceiver)
133     * @return Map of content format keys supporting SyslogLayout
134     */
135    @Override
136    public Map<String, String> getContentFormat()
137    {
138        final Map<String, String> result = new HashMap<String, String>();
139        result.put("structured", "false");
140        result.put("formatType", "logfilepatternreceiver");
141        result.put("dateFormat", dateFormat.toPattern());
142        result.put("format", "<LEVEL>TIMESTAMP PROP(HOSTNAME) MESSAGE");
143        return result;
144    }
145
146    /**
147     * Create a SyslogLayout.
148     * @param facility The Facility is used to try to classify the message.
149     * @param includeNL If true a newline will be appended to the result.
150     * @param escapeNL Pattern to use for replacing newlines.
151     * @param charsetName The character set.
152     * @return A SyslogLayout.
153     */
154    @PluginFactory
155    public static SyslogLayout createLayout(
156            @PluginAttribute("facility") final String facility,
157            @PluginAttribute("newLine") final String includeNL,
158            @PluginAttribute("newLineEscape") final String escapeNL,
159            @PluginAttribute("charset") final String charsetName) {
160        final Charset charset = Charsets.getSupportedCharset(charsetName);
161        final boolean includeNewLine = Boolean.parseBoolean(includeNL);
162        final Facility f = Facility.toFacility(facility, Facility.LOCAL0);
163        return new SyslogLayout(f, includeNewLine, escapeNL, charset);
164    }
165}