Module org.elasticsearch.server

Package org.elasticsearch.common.logging

Class ChunkedLoggingStream

java.lang.Object

java.io.OutputStream

org.elasticsearch.common.logging.ChunkedLoggingStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class ChunkedLoggingStream
extends OutputStream

An OutputStream which Gzip-compresses the written data, Base64-encodes it, and writes it in fixed-size chunks to a logger. This is useful for debugging information that may be too large for a single log message and/or which may include data which cannot be recorded faithfully in plain-text (e.g. binary data or data with significant whitespace).

Method Summary

Modifier and Type	Method	Description
void	close()
static OutputStream	create(org.apache.logging.log4j.Logger logger, org.apache.logging.log4j.Level level, String prefix, ReferenceDocs referenceDocs)	Create an OutputStream which Gzip-compresses the written data, Base64-encodes it, and writes it in fixed-size (2kiB) chunks to the given logger.
void	write(byte[] b, int off, int len)
void	write(int b)

Methods inherited from class java.io.OutputStream

flush, nullOutputStream, write

Methods inherited from class java.lang.Object

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

Method Details

create

public static OutputStream create(org.apache.logging.log4j.Logger logger,
 org.apache.logging.log4j.Level level,
 String prefix,
 ReferenceDocs referenceDocs)
                           throws IOException

Create an OutputStream which Gzip-compresses the written data, Base64-encodes it, and writes it in fixed-size (2kiB) chunks to the given logger. If the data fits into a single chunk then the output looks like this:

 $PREFIX (gzip compressed and base64-encoded; for details see ...): H4sIAAAAA...
 

If there are multiple chunks then they are written like this:

 $PREFIX [part 1]: H4sIAAAAA...
 $PREFIX [part 2]: r38c4MBHO...
 $PREFIX [part 3]: ECyRFONaL...
 $PREFIX [part 4]: kTgm+Qswm...
 $PREFIX (gzip compressed, base64-encoded, and split into 4 parts on preceding log lines; for details see ...)
 

Parameters:

logger - The logger to receive the chunks of data.

level - The log level to use for the logging.

prefix - A prefix for each chunk, which should be reasonably unique to allow for reconstruction of the original message even if multiple such streams are used concurrently.

referenceDocs - A link to the relevant reference docs to help users interpret the output. Relevant reference docs are required because the output is rather human-unfriendly and we need somewhere to describe how to decode it.

Throws:

IOException

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] b,
 int off,
 int len)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class OutputStream

Throws:

IOException