com.google.cloud.logging

Class LoggingHandler

java.lang.Object

java.util.logging.Handler

com.google.cloud.logging.LoggingHandler

public class LoggingHandler
extends Handler

A logging handler that 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.getLabels(). 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.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).
• com.google.cloud.logging.LoggingHandler.enhancers specifies a comma separated list of LoggingEnhancer classes. This handler will call each enhancer list whenever it builds a LogEntry instance (defaults to empty list).
• com.google.cloud.logging.LoggingHandler.resourceType the type name to use when creating the default MonitoredResource (defaults to auto-detected resource type, else "global").
• com.google.cloud.logging.Synchronicity the synchronicity of the write method to use to write logs to the Stackdriver Logging service (defaults to Synchronicity.ASYNC).

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, com.google.cloud.MonitoredResource monitoredResource) Creates a handler that publishes messages to Stackdriver Logging.
LoggingHandler(String log, LoggingOptions options, com.google.cloud.MonitoredResource monitoredResource, List<LoggingEnhancer> enhancers) Creates a handler that publishes messages to Stackdriver Logging.

Method Summary

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()
Level	getFlushLevel() Get the flush log level.
Synchronicity	getSynchronicity() Get the flush log level.
void	publish(LogRecord record)
void	setFlushLevel(Level flushLevel) Sets minimum logging level to log immediately and flush any pending writes.
void	setSynchronicity(Synchronicity synchronicity) Sets synchronicity of logging writes.

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,
                      com.google.cloud.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. If it is null then a default resource is created based on the project ID and deployment environment.

LoggingHandler

public LoggingHandler(String log,
                      LoggingOptions options,
                      com.google.cloud.MonitoredResource monitoredResource,
                      List<LoggingEnhancer> enhancers)

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. If it is null then a default resource is created based on the project ID and deployment environment.

enhancers - List of LoggingEnhancer instances used to enhance anyLogEntry instances built by this handler.

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

getFlushLevel

public Level getFlushLevel()

Get the flush log level.

setFlushLevel

public void setFlushLevel(Level flushLevel)

Sets minimum logging level to log immediately and flush any pending writes.

Parameters:

flushLevel - minimum log level to trigger flush

setSynchronicity

public void setSynchronicity(Synchronicity synchronicity)

Sets synchronicity of logging writes. By default, writes are asynchronous.

Parameters:

synchronicity - Synchronicity

getSynchronicity

public Synchronicity getSynchronicity()

Get the flush log level.

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.