org.apache.flume.clients.log4jappender
Class LoadBalancingLog4jAppender

java.lang.Object
  org.apache.log4j.AppenderSkeleton
      org.apache.flume.clients.log4jappender.Log4jAppender
          org.apache.flume.clients.log4jappender.LoadBalancingLog4jAppender

All Implemented Interfaces:

org.apache.log4j.Appender, org.apache.log4j.spi.OptionHandler

public class LoadBalancingLog4jAppender
extends Log4jAppender

Appends Log4j Events to an external Flume client which is decribed by the Log4j configuration file. The appender takes the following required parameters:

Hosts : A space separated list of host:port of the first hop at which Flume (through an AvroSource) is listening for events.

Selector : Selection mechanism. Must be either ROUND_ROBIN, RANDOM or custom FQDN to class that inherits from LoadBalancingSelector. If empty defaults to ROUND_ROBIN

The appender also takes the following optional parameters:

MaxBackoff : A long value representing the maximum amount of time in milliseconds the Load balancing client will backoff from a node that has failed to consume an event

A sample log4j properties file which appends to a source would look like:

 

 log4j.appender.out2 = org.apache.flume.clients.log4jappender.LoadBalancingLog4jAppender
 log4j.appender.out2.Hosts = fooflumesource.com:25430 barflumesource.com:25430
 log4j.appender.out2.Selector = RANDOM
 log4j.logger.org.apache.flume.clients.log4jappender = DEBUG,out2
 

 

 log4j.appender.out2 = org.apache.flume.clients.log4jappender.LoadBalancingLog4jAppender
 log4j.appender.out2.Hosts = fooflumesource.com:25430 barflumesource.com:25430
 log4j.appender.out2.Selector = ROUND_ROBIN
 log4j.appender.out2.MaxBackoff = 60000
 log4j.logger.org.apache.flume.clients.log4jappender = DEBUG,out2
 

Note: Change the last line to the package of the class(es), that will do the appending.For example if classes from the package com.bar.foo are appending, the last line would be:

 
log4j.logger.com.bar.foo = DEBUG,out2
 

Field Summary

Fields inherited from class org.apache.log4j.AppenderSkeleton

closed, errorHandler, headFilter, layout, name, tailFilter, threshold

Constructor Summary

LoadBalancingLog4jAppender()

Method Summary

void	activateOptions() Activate the options set using setHosts(), setSelector and setMaxBackoff
void	append(org.apache.log4j.spi.LoggingEvent event) Append the LoggingEvent, to send to the first Flume hop.
void	setHosts(String hostNames)
void	setMaxBackoff(String maxBackoff)
void	setSelector(String selector)

Methods inherited from class org.apache.flume.clients.log4jappender.Log4jAppender

close, getTimeout, getUnsafeMode, populateAvroHeaders, requiresLayout, setAvroReflectionEnabled, setAvroSchemaUrl, setHostname, setPort, setTimeout, setUnsafeMode

Methods inherited from class org.apache.log4j.AppenderSkeleton

addFilter, clearFilters, doAppend, finalize, getErrorHandler, getFilter, getFirstFilter, getLayout, getName, getThreshold, isAsSevereAsThreshold, setErrorHandler, setLayout, setName, setThreshold

Methods inherited from class java.lang.Object

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

Constructor Detail

LoadBalancingLog4jAppender

public LoadBalancingLog4jAppender()

Method Detail

setHosts

public void setHosts(String hostNames)

setSelector

public void setSelector(String selector)

setMaxBackoff

public void setMaxBackoff(String maxBackoff)

append

public void append(org.apache.log4j.spi.LoggingEvent event)

Description copied from class: Log4jAppender

Append the LoggingEvent, to send to the first Flume hop.

Overrides:

append in class Log4jAppender

Parameters:

event - The LoggingEvent to be appended to the flume.

activateOptions

public void activateOptions()
                     throws FlumeException

Activate the options set using setHosts(), setSelector and setMaxBackoff

Specified by:

activateOptions in interface org.apache.log4j.spi.OptionHandler

Overrides:

activateOptions in class Log4jAppender

Throws:

FlumeException - if the LoadBalancingRpcClient cannot be instantiated.