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.io.IOException;
020import java.io.Writer;
021import java.nio.charset.Charset;
022import java.nio.charset.StandardCharsets;
023import java.util.HashMap;
024import java.util.Map;
025
026import org.apache.logging.log4j.core.Layout;
027import org.apache.logging.log4j.core.LogEvent;
028import org.apache.logging.log4j.core.config.Configuration;
029import org.apache.logging.log4j.core.config.DefaultConfiguration;
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.PluginBuilderAttribute;
033import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
034import org.apache.logging.log4j.core.config.plugins.PluginElement;
035import org.apache.logging.log4j.core.util.KeyValuePair;
036
037/**
038 * Appends a series of JSON events as strings serialized as bytes.
039 *
040 * <h3>Complete well-formed JSON vs. fragment JSON</h3>
041 * <p>
042 * If you configure {@code complete="true"}, the appender outputs a well-formed JSON document. By default, with
043 * {@code complete="false"}, you should include the output as an <em>external file</em> in a separate file to form a
044 * well-formed JSON document.
045 * </p>
046 * <p>
047 * If {@code complete="false"}, the appender does not write the JSON open array character "[" at the start
048 * of the document, "]" and the end, nor comma "," between records.
049 * </p>
050 * <h3>Encoding</h3>
051 * <p>
052 * Appenders using this layout should have their {@code charset} set to {@code UTF-8} or {@code UTF-16}, otherwise
053 * events containing non ASCII characters could result in corrupted log files.
054 * </p>
055 * <h3>Pretty vs. compact JSON</h3>
056 * <p>
057 * By default, the JSON layout is not compact (a.k.a. "pretty") with {@code compact="false"}, which means the
058 * appender uses end-of-line characters and indents lines to format the text. If {@code compact="true"}, then no
059 * end-of-line or indentation is used. Message content may contain, of course, escaped end-of-lines.
060 * </p>
061 * <h3>Additional Fields</h3>
062 * <p>
063 * This property allows addition of custom fields into generated JSON.
064 * {@code <JsonLayout><KeyValuePair key="foo" value="bar"/></JsonLayout>} inserts {@code "foo":"bar"} directly
065 * into JSON output. Supports Lookup expressions.
066 * </p>
067 */
068@Plugin(name = "JsonLayout", category = Node.CATEGORY, elementType = Layout.ELEMENT_TYPE, printObject = true)
069public final class JsonLayout extends AbstractJacksonLayout {
070
071    private static final String DEFAULT_FOOTER = "]";
072
073    private static final String DEFAULT_HEADER = "[";
074
075    static final String CONTENT_TYPE = "application/json";
076
077    public static class Builder<B extends Builder<B>> extends AbstractJacksonLayout.Builder<B>
078            implements org.apache.logging.log4j.core.util.Builder<JsonLayout> {
079
080        @PluginBuilderAttribute
081        private boolean propertiesAsList;
082
083        @PluginBuilderAttribute
084        private boolean objectMessageAsJsonObject;
085
086        @PluginElement("AdditionalField")
087        private KeyValuePair[] additionalFields;
088
089        public Builder() {
090            super();
091            setCharset(StandardCharsets.UTF_8);
092        }
093
094        @Override
095        public JsonLayout build() {
096            final boolean encodeThreadContextAsList = isProperties() && propertiesAsList;
097            final String headerPattern = toStringOrNull(getHeader());
098            final String footerPattern = toStringOrNull(getFooter());
099            return new JsonLayout(getConfiguration(), isLocationInfo(), isProperties(), encodeThreadContextAsList,
100                    isComplete(), isCompact(), getEventEol(), headerPattern, footerPattern, getCharset(),
101                    isIncludeStacktrace(), isStacktraceAsString(), isIncludeNullDelimiter(),
102                    getAdditionalFields(), getObjectMessageAsJsonObject());
103        }
104
105        public boolean isPropertiesAsList() {
106            return propertiesAsList;
107        }
108
109        public B setPropertiesAsList(final boolean propertiesAsList) {
110            this.propertiesAsList = propertiesAsList;
111            return asBuilder();
112        }
113
114        public boolean getObjectMessageAsJsonObject() {
115            return objectMessageAsJsonObject;
116        }
117
118        public B setObjectMessageAsJsonObject(final boolean objectMessageAsJsonObject) {
119            this.objectMessageAsJsonObject = objectMessageAsJsonObject;
120            return asBuilder();
121        }
122
123        @Override
124        public KeyValuePair[] getAdditionalFields() {
125            return additionalFields;
126        }
127
128        @Override
129        public B setAdditionalFields(KeyValuePair[] additionalFields) {
130            this.additionalFields = additionalFields;
131            return asBuilder();
132        }
133    }
134
135    /**
136     * @deprecated Use {@link #newBuilder()} instead
137     */
138    @Deprecated
139    protected JsonLayout(final Configuration config, final boolean locationInfo, final boolean properties,
140            final boolean encodeThreadContextAsList,
141            final boolean complete, final boolean compact, final boolean eventEol, final String headerPattern,
142            final String footerPattern, final Charset charset, final boolean includeStacktrace) {
143        super(config, new JacksonFactory.JSON(encodeThreadContextAsList, includeStacktrace, false, false).newWriter(
144                locationInfo, properties, compact),
145                charset, compact, complete, eventEol,
146                PatternLayout.newSerializerBuilder().setConfiguration(config).setPattern(headerPattern).setDefaultPattern(DEFAULT_HEADER).build(),
147                PatternLayout.newSerializerBuilder().setConfiguration(config).setPattern(footerPattern).setDefaultPattern(DEFAULT_FOOTER).build(),
148                false, null);
149    }
150
151    private JsonLayout(final Configuration config, final boolean locationInfo, final boolean properties,
152                       final boolean encodeThreadContextAsList,
153                       final boolean complete, final boolean compact, final boolean eventEol,
154                       final String headerPattern, final String footerPattern, final Charset charset,
155                       final boolean includeStacktrace, final boolean stacktraceAsString,
156                       final boolean includeNullDelimiter,
157                       final KeyValuePair[] additionalFields, final boolean objectMessageAsJsonObject) {
158        super(config, new JacksonFactory.JSON(encodeThreadContextAsList, includeStacktrace, stacktraceAsString, objectMessageAsJsonObject).newWriter(
159                locationInfo, properties, compact),
160                charset, compact, complete, eventEol,
161                PatternLayout.newSerializerBuilder().setConfiguration(config).setPattern(headerPattern).setDefaultPattern(DEFAULT_HEADER).build(),
162                PatternLayout.newSerializerBuilder().setConfiguration(config).setPattern(footerPattern).setDefaultPattern(DEFAULT_FOOTER).build(),
163                includeNullDelimiter,
164                additionalFields);
165    }
166
167    /**
168     * Returns appropriate JSON header.
169     *
170     * @return a byte array containing the header, opening the JSON array.
171     */
172    @Override
173    public byte[] getHeader() {
174        if (!this.complete) {
175            return null;
176        }
177        final StringBuilder buf = new StringBuilder();
178        final String str = serializeToString(getHeaderSerializer());
179        if (str != null) {
180            buf.append(str);
181        }
182        buf.append(this.eol);
183        return getBytes(buf.toString());
184    }
185
186    /**
187     * Returns appropriate JSON footer.
188     *
189     * @return a byte array containing the footer, closing the JSON array.
190     */
191    @Override
192    public byte[] getFooter() {
193        if (!this.complete) {
194            return null;
195        }
196        final StringBuilder buf = new StringBuilder();
197        buf.append(this.eol);
198        final String str = serializeToString(getFooterSerializer());
199        if (str != null) {
200            buf.append(str);
201        }
202        buf.append(this.eol);
203        return getBytes(buf.toString());
204    }
205
206    @Override
207    public Map<String, String> getContentFormat() {
208        final Map<String, String> result = new HashMap<>();
209        result.put("version", "2.0");
210        return result;
211    }
212
213    /**
214     * @return The content type.
215     */
216    @Override
217    public String getContentType() {
218        return CONTENT_TYPE + "; charset=" + this.getCharset();
219    }
220
221    /**
222     * Creates a JSON Layout.
223     * @param config
224     *           The plugin configuration.
225     * @param locationInfo
226     *            If "true", includes the location information in the generated JSON.
227     * @param properties
228     *            If "true", includes the thread context map in the generated JSON.
229     * @param propertiesAsList
230     *            If true, the thread context map is included as a list of map entry objects, where each entry has
231     *            a "key" attribute (whose value is the key) and a "value" attribute (whose value is the value).
232     *            Defaults to false, in which case the thread context map is included as a simple map of key-value
233     *            pairs.
234     * @param complete
235     *            If "true", includes the JSON header and footer, and comma between records.
236     * @param compact
237     *            If "true", does not use end-of-lines and indentation, defaults to "false".
238     * @param eventEol
239     *            If "true", forces an EOL after each log event (even if compact is "true"), defaults to "false". This
240     *            allows one even per line, even in compact mode.
241     * @param headerPattern
242     *            The header pattern, defaults to {@code "["} if null.
243     * @param footerPattern
244     *            The header pattern, defaults to {@code "]"} if null.
245     * @param charset
246     *            The character set to use, if {@code null}, uses "UTF-8".
247     * @param includeStacktrace
248     *            If "true", includes the stacktrace of any Throwable in the generated JSON, defaults to "true".
249     * @return A JSON Layout.
250     *
251     * @deprecated Use {@link #newBuilder()} instead
252     */
253    @Deprecated
254    public static JsonLayout createLayout(
255            final Configuration config,
256            final boolean locationInfo,
257            final boolean properties,
258            final boolean propertiesAsList,
259            final boolean complete,
260            final boolean compact,
261            final boolean eventEol,
262            final String headerPattern,
263            final String footerPattern,
264            final Charset charset,
265            final boolean includeStacktrace) {
266        final boolean encodeThreadContextAsList = properties && propertiesAsList;
267        return new JsonLayout(config, locationInfo, properties, encodeThreadContextAsList, complete, compact, eventEol,
268                headerPattern, footerPattern, charset, includeStacktrace, false, false, null, false);
269    }
270
271    @PluginBuilderFactory
272    public static <B extends Builder<B>> B newBuilder() {
273        return new Builder<B>().asBuilder();
274    }
275
276    /**
277     * Creates a JSON Layout using the default settings. Useful for testing.
278     *
279     * @return A JSON Layout.
280     */
281    public static JsonLayout createDefaultLayout() {
282        return new JsonLayout(new DefaultConfiguration(), false, false, false, false, false, false,
283                DEFAULT_HEADER, DEFAULT_FOOTER, StandardCharsets.UTF_8, true, false, false, null, false);
284    }
285
286    @Override
287    public void toSerializable(final LogEvent event, final Writer writer) throws IOException {
288        if (complete && eventCount > 0) {
289            writer.append(", ");
290        }
291        super.toSerializable(event, writer);
292    }
293}