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.nio.charset.Charset;
020import java.text.SimpleDateFormat;
021import java.util.Date;
022import java.util.HashMap;
023import java.util.Locale;
024import java.util.Map;
025import java.util.regex.Matcher;
026import java.util.regex.Pattern;
027
028import org.apache.logging.log4j.core.Layout;
029import org.apache.logging.log4j.core.LogEvent;
030import org.apache.logging.log4j.core.config.Node;
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.net.Facility;
035import org.apache.logging.log4j.core.net.Priority;
036import org.apache.logging.log4j.core.util.NetUtils;
037import org.apache.logging.log4j.util.Chars;
038
039
040/**
041 * Formats a log event as a BSD Log record.
042 */
043@Plugin(name = "SyslogLayout", category = Node.CATEGORY, elementType = Layout.ELEMENT_TYPE, printObject = true)
044public final class SyslogLayout extends AbstractStringLayout {
045
046    /**
047     * Match newlines in a platform-independent manner.
048     */
049    public static final Pattern NEWLINE_PATTERN = Pattern.compile("\\r?\\n");
050
051    private final Facility facility;
052    private final boolean includeNewLine;
053    private final String escapeNewLine;
054
055    /**
056     * Date format used if header = true.
057     */
058    private final SimpleDateFormat dateFormat = new SimpleDateFormat("MMM dd HH:mm:ss", Locale.ENGLISH);
059    /**
060     * Host name used to identify messages from this appender.
061     */
062    private final String localHostname = NetUtils.getLocalHostname();
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 = getStringBuilder();
080
081        buf.append('<');
082        buf.append(Priority.getPriority(facility, event.getLevel()));
083        buf.append('>');
084        addDate(event.getTimeMillis(), buf);
085        buf.append(Chars.SPACE);
086        buf.append(localHostname);
087        buf.append(Chars.SPACE);
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    private synchronized void addDate(final long timestamp, final StringBuilder buf) {
102        final int index = buf.length() + 4;
103        buf.append(dateFormat.format(new Date(timestamp)));
104        //  RFC 3164 says leading space, not leading zero on days 1-9
105        if (buf.charAt(index) == '0') {
106            buf.setCharAt(index, Chars.SPACE);
107        }
108    }
109
110    /**
111     * Gets this SyslogLayout's content format. Specified by:
112     * <ul>
113     * <li>Key: "structured" Value: "false"</li>
114     * <li>Key: "dateFormat" Value: "MMM dd HH:mm:ss"</li>
115     * <li>Key: "format" Value: "&lt;LEVEL&gt;TIMESTAMP PROP(HOSTNAME) MESSAGE"</li>
116     * <li>Key: "formatType" Value: "logfilepatternreceiver" (format uses the keywords supported by
117     * LogFilePatternReceiver)</li>
118     * </ul>
119     * 
120     * @return Map of content format keys supporting SyslogLayout
121     */
122    @Override
123    public Map<String, String> getContentFormat() {
124        final Map<String, String> result = new HashMap<>();
125        result.put("structured", "false");
126        result.put("formatType", "logfilepatternreceiver");
127        result.put("dateFormat", dateFormat.toPattern());
128        result.put("format", "<LEVEL>TIMESTAMP PROP(HOSTNAME) MESSAGE");
129        return result;
130    }
131
132    /**
133     * Create a SyslogLayout.
134     * @param facility The Facility is used to try to classify the message.
135     * @param includeNewLine If true a newline will be appended to the result.
136     * @param escapeNL Pattern to use for replacing newlines.
137     * @param charset The character set.
138     * @return A SyslogLayout.
139     */
140    @PluginFactory
141    public static SyslogLayout createLayout(
142            @PluginAttribute(value = "facility", defaultString = "LOCAL0") final Facility facility,
143            @PluginAttribute(value = "newLine", defaultBoolean = false) final boolean includeNewLine,
144            @PluginAttribute("newLineEscape") final String escapeNL,
145            @PluginAttribute(value = "charset", defaultString = "UTF-8") final Charset charset) {
146        return new SyslogLayout(facility, includeNewLine, escapeNL, charset);
147    }
148}