com.google.cloud.logging

Class LoggingHandler

java.lang.Object

java.util.logging.Handler

com.google.cloud.logging.LoggingHandler

Direct Known Subclasses:

AsyncLoggingHandler

public class LoggingHandler
extends Handler

A logging handler that synchronously outputs logs generated with Logger to Stackdriver Logging.

Java logging levels (see Level) are mapped to the following Google Stackdriver Logging severities:

Java Level	Stackdriver Logging Severity
SEVERE	ERROR
WARNING	WARNING
INFO	INFO
CONFIG	INFO
FINE	DEBUG
FINER	DEBUG
FINEST	DEBUG

Original Java logging levels are added as labels (with levelName and levelValue keys, respectively) to the corresponding Stackdriver Logging LogEntry. You can read entry labels using LogEntry.labels(). To use logging levels that correspond to Stackdriver Logging severities you can use LoggingLevel.

Configuration: By default each LoggingHandler is initialized using the following LogManager configuration properties (that you can set in the logging.properties file). If properties are not defined (or have invalid values) then the specified default values are used.

• com.google.cloud.logging.LoggingHandler.log the log name (defaults to java.log).
• com.google.cloud.logging.LoggingHandler.level specifies the default level for the handler (defaults to Level.INFO).
• com.google.cloud.logging.LoggingHandler.filter specifies the name of a Filter class to use (defaults to no filter).
• com.google.cloud.logging.LoggingHandler.formatter specifies the name of a Formatter class to use (defaults to SimpleFormatter).
• com.google.cloud.logging.LoggingHandler.flushSize specifies the maximum size of the log buffer. Once reached, logs are transmitted to the Stackdriver Logging service (defaults to 1).
• com.google.cloud.logging.LoggingHandler.flushLevel specifies the flush log level. When a log with this level is published, logs are transmitted to the Stackdriver Logging service (defaults to LoggingLevel.ERROR).

To add a LoggingHandler to an existing Logger and be sure to avoid infinite recursion when logging, use the addHandler(Logger, LoggingHandler) method. Alternatively you can add the handler via logging.properties. For example using the following line:

 com.example.mypackage.handlers=com.google.cloud.logging.LoggingHandler
 

Constructor Summary

Constructors

Constructor and Description
LoggingHandler() Creates an handler that publishes messages to Stackdriver Logging.
LoggingHandler(String log) Creates a handler that publishes messages to Stackdriver Logging.
LoggingHandler(String log, LoggingOptions options) Creates a handler that publishes messages to Stackdriver Logging.
LoggingHandler(String log, LoggingOptions options, MonitoredResource monitoredResource) Creates a handler that publishes messages to Stackdriver Logging.

Method Summary

Methods

Modifier and Type	Method and Description
static void	addHandler(Logger logger, LoggingHandler handler) Adds the provided LoggingHandler to logger.
void	close() Closes the handler and the associated Logging object.
void	flush()
void	publish(LogRecord record)
Level	setFlushLevel(Level flushLevel) Sets the flush log level.
long	setFlushSize(long flushSize) Sets the maximum size of the log buffer.

Methods inherited from class java.util.logging.Handler

getEncoding, getErrorManager, getFilter, getFormatter, getLevel, isLoggable, reportError, setEncoding, setErrorManager, setFilter, setFormatter, setLevel

Methods inherited from class java.lang.Object

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

Constructor Detail

LoggingHandler

public LoggingHandler()

Creates an handler that publishes messages to Stackdriver Logging.

LoggingHandler

public LoggingHandler(String log)

Creates a handler that publishes messages to Stackdriver Logging.

Parameters:

log - the name of the log to which log entries are written

LoggingHandler

public LoggingHandler(String log,
              LoggingOptions options)

Creates a handler that publishes messages to Stackdriver Logging.

Parameters:

log - the name of the log to which log entries are written

options - options for the Stackdriver Logging service

LoggingHandler

public LoggingHandler(String log,
              LoggingOptions options,
              MonitoredResource monitoredResource)

Creates a handler that publishes messages to Stackdriver Logging.

Parameters:

log - the name of the log to which log entries are written

options - options for the Stackdriver Logging service

monitoredResource - the monitored resource to which log entries refer

Method Detail

publish

public void publish(LogRecord record)

Specified by:

publish in class Handler

flush

public void flush()

Specified by:

flush in class Handler

close

public void close()
           throws SecurityException

Closes the handler and the associated Logging object.

Specified by:

close in class Handler

Throws:

SecurityException

setFlushLevel

public Level setFlushLevel(Level flushLevel)

Sets the flush log level. When a log with this level is published, the log buffer is transmitted to the Stackdriver Logging service, regardless of its size. If not set, LoggingLevel.ERROR is used.

setFlushSize

public long setFlushSize(long flushSize)

Sets the maximum size of the log buffer. Once the maximum size of the buffer is reached, logs are transmitted to the Stackdriver Logging service. If not set, a log is sent to the service as soon as published.

addHandler

public static void addHandler(Logger logger,
              LoggingHandler handler)

Adds the provided LoggingHandler to logger. Use this method to register Cloud Logging handlers instead of Logger.addHandler(Handler) to avoid infinite recursion when logging.