org.apache.logging.log4j.core.layout

Class JsonLayout

java.lang.Object

org.apache.logging.log4j.core.layout.AbstractLayout<String>

org.apache.logging.log4j.core.layout.AbstractStringLayout

org.apache.logging.log4j.core.layout.JsonLayout

All Implemented Interfaces:

LocationAware, Layout<String>, Encoder<LogEvent>, StringLayout

@Plugin(name="JsonLayout",
        category="Core",
        elementType="layout",
        printObject=true)
public final class JsonLayout
extends AbstractStringLayout

Note: The JsonLayout should be considered to be deprecated. Please use JsonTemplateLayout instead. Appends a series of JSON events as strings serialized as bytes.

Complete well-formed JSON vs. fragment JSON

If you configure complete="true", the appender outputs a well-formed JSON document. By default, with complete="false", you should include the output as an external file in a separate file to form a well-formed JSON document.

If complete="false", the appender does not write the JSON open array character "[" at the start of the document, "]" and the end, nor comma "," between records.

Encoding

Appenders using this layout should have their charset set to UTF-8 or UTF-16, otherwise events containing non ASCII characters could result in corrupted log files.

Pretty vs. compact JSON

By default, the JSON layout is not compact (a.k.a. "pretty") with compact="false", which means the appender uses end-of-line characters and indents lines to format the text. If compact="true", then no end-of-line or indentation is used. Message content may contain, of course, escaped end-of-lines.

Additional Fields

This property allows addition of custom fields into generated JSON. <JsonLayout><KeyValuePair key="foo" value="bar"/></JsonLayout> inserts "foo":"bar" directly into JSON output. Supports Lookup expressions.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractJacksonLayout.LogEventWithAdditionalFields
protected static class	AbstractJacksonLayout.ResolvableKeyValuePair
static class	JsonLayout.Builder<B extends JsonLayout.Builder<B>>

Nested classes/interfaces inherited from class org.apache.logging.log4j.core.layout.AbstractStringLayout

AbstractStringLayout.Serializer, AbstractStringLayout.Serializer2

Field Summary

Fields

Modifier and Type	Field and Description
protected AbstractJacksonLayout.ResolvableKeyValuePair[]	additionalFields
protected boolean	compact
protected static String	COMPACT_EOL
protected boolean	complete
protected static String	DEFAULT_EOL
protected String	eol
protected boolean	includeNullDelimiter
protected com.fasterxml.jackson.databind.ObjectWriter	objectWriter

Fields inherited from class org.apache.logging.log4j.core.layout.AbstractStringLayout

DEFAULT_STRING_BUILDER_SIZE, MAX_STRING_BUILDER_SIZE

Fields inherited from class org.apache.logging.log4j.core.layout.AbstractLayout

configuration, eventCount, footer, header, LOGGER

Fields inherited from interface org.apache.logging.log4j.core.Layout

ELEMENT_TYPE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JsonLayout(Configuration config, boolean locationInfo, boolean properties, boolean encodeThreadContextAsList, boolean complete, boolean compact, boolean eventEol, String endOfLine, String headerPattern, String footerPattern, Charset charset, boolean includeStacktrace) Deprecated. Use newBuilder() instead

Method Summary

Modifier and Type	Method and Description
static JsonLayout	createDefaultLayout() Creates a JSON Layout using the default settings.
static JsonLayout	createLayout(Configuration config, boolean locationInfo, boolean properties, boolean propertiesAsList, boolean complete, boolean compact, boolean eventEol, String headerPattern, String footerPattern, Charset charset, boolean includeStacktrace) Deprecated. Use newBuilder() instead
Map<String,String>	getContentFormat() Returns a description of the content format.
String	getContentType() Returns the content type output by this layout.
byte[]	getFooter() Returns appropriate JSON footer.
byte[]	getHeader() Returns appropriate JSON header.
static <B extends JsonLayout.Builder<B>> B	newBuilder()
String	toSerializable(LogEvent event) Formats a LogEvent.
void	toSerializable(LogEvent event, Writer writer)
protected static boolean	valueNeedsLookup(String value)
protected Object	wrapLogEvent(LogEvent event)

Methods inherited from class org.apache.logging.log4j.core.layout.AbstractStringLayout

getBytes, getCharset, getFooterSerializer, getHeaderSerializer, getStringBuilder, getStringBuilderEncoder, requiresLocation, serializeToBytes, serializeToString, toByteArray, trimToMaxSize

Methods inherited from class org.apache.logging.log4j.core.layout.AbstractLayout

encode, getConfiguration, markEvent

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.logging.log4j.core.layout.Encoder

encode

Field Detail

DEFAULT_EOL

protected static final String DEFAULT_EOL

See Also:

Constant Field Values

COMPACT_EOL

protected static final String COMPACT_EOL

See Also:

Constant Field Values

eol

protected final String eol

objectWriter

protected final com.fasterxml.jackson.databind.ObjectWriter objectWriter

compact

protected final boolean compact

complete

protected final boolean complete

includeNullDelimiter

protected final boolean includeNullDelimiter

additionalFields

protected final AbstractJacksonLayout.ResolvableKeyValuePair[] additionalFields

Constructor Detail

JsonLayout

@Deprecated
protected JsonLayout(Configuration config,
                                 boolean locationInfo,
                                 boolean properties,
                                 boolean encodeThreadContextAsList,
                                 boolean complete,
                                 boolean compact,
                                 boolean eventEol,
                                 String endOfLine,
                                 String headerPattern,
                                 String footerPattern,
                                 Charset charset,
                                 boolean includeStacktrace)

Deprecated. Use newBuilder() instead

Method Detail

getHeader

public byte[] getHeader()

Returns appropriate JSON header.

Specified by:

getHeader in interface Layout<String>

Overrides:

getHeader in class AbstractStringLayout

Returns:

a byte array containing the header, opening the JSON array.

getFooter

public byte[] getFooter()

Returns appropriate JSON footer.

Specified by:

getFooter in interface Layout<String>

Overrides:

getFooter in class AbstractStringLayout

Returns:

a byte array containing the footer, closing the JSON array.

getContentFormat

public Map<String,String> getContentFormat()

Description copied from interface: Layout

Returns a description of the content format.

Specified by:

getContentFormat in interface Layout<String>

Overrides:

getContentFormat in class AbstractLayout<String>

Returns:

a Map of key/value pairs describing the Layout-specific content format, or an empty Map if no content format descriptors are specified.

getContentType

public String getContentType()

Description copied from interface: Layout

Returns the content type output by this layout. The base class returns "text/plain".

Specified by:

getContentType in interface Layout<String>

Overrides:

getContentType in class AbstractStringLayout

Returns:

The content type.

createLayout

@Deprecated
public static JsonLayout createLayout(Configuration config,
                                                  boolean locationInfo,
                                                  boolean properties,
                                                  boolean propertiesAsList,
                                                  boolean complete,
                                                  boolean compact,
                                                  boolean eventEol,
                                                  String headerPattern,
                                                  String footerPattern,
                                                  Charset charset,
                                                  boolean includeStacktrace)

Deprecated. Use newBuilder() instead

Creates a JSON Layout.

Parameters:

config - The plugin configuration.

locationInfo - If "true", includes the location information in the generated JSON.

properties - If "true", includes the thread context map in the generated JSON.

propertiesAsList - If true, the thread context map is included as a list of map entry objects, where each entry has a "key" attribute (whose value is the key) and a "value" attribute (whose value is the value). Defaults to false, in which case the thread context map is included as a simple map of key-value pairs.

complete - If "true", includes the JSON header and footer, and comma between records.

compact - If "true", does not use end-of-lines and indentation, defaults to "false".

eventEol - If "true", forces an EOL after each log event (even if compact is "true"), defaults to "false". This allows one even per line, even in compact mode.

headerPattern - The header pattern, defaults to "[" if null.

footerPattern - The header pattern, defaults to "]" if null.

charset - The character set to use, if null, uses "UTF-8".

includeStacktrace - If "true", includes the stacktrace of any Throwable in the generated JSON, defaults to "true".

Returns:

A JSON Layout.

newBuilder

@PluginBuilderFactory
public static <B extends JsonLayout.Builder<B>> B newBuilder()

createDefaultLayout

public static JsonLayout createDefaultLayout()

Creates a JSON Layout using the default settings. Useful for testing.

Returns:

A JSON Layout.

toSerializable

public void toSerializable(LogEvent event,
                           Writer writer)
                    throws IOException

Throws:

IOException

valueNeedsLookup

protected static boolean valueNeedsLookup(String value)

toSerializable

public String toSerializable(LogEvent event)

Formats a LogEvent.

Parameters:

event - The LogEvent.

Returns:

The XML representation of the LogEvent.

wrapLogEvent

protected Object wrapLogEvent(LogEvent event)