com.xpcagey.logback

Class CloudWatchClassicAppender

java.lang.Object

ch.qos.logback.core.spi.ContextAwareBase

ch.qos.logback.core.UnsynchronizedAppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>

com.xpcagey.logback.CloudWatchClassicAppender

All Implemented Interfaces:

ch.qos.logback.core.Appender<ch.qos.logback.classic.spi.ILoggingEvent>, ch.qos.logback.core.spi.ContextAware, ch.qos.logback.core.spi.FilterAttachable<ch.qos.logback.classic.spi.ILoggingEvent>, ch.qos.logback.core.spi.LifeCycle

public class CloudWatchClassicAppender
extends ch.qos.logback.core.UnsynchronizedAppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>

CloudWatchClassicAppender implements the logback Appender interface with a connection to Amazon CloudWatch for Logback classic implementations. This class is a lightweight wrapper around a CloudWatchWorker that pushes appended ILoggingEvents into a BlockingQueue for asynchronous processing. If you will be using this appender in a cluster, it is *strongly recommended* that you use the setStreamNameSupplier interface to give each process a unique log stream name inside of your log group. This code attempts to correct for stream write collisions, but the Amazon CloudWatch system expects that each log producer has a distinct stream and this appender will need to retry every send that is written after another process has touched a stream.

See Also:

ILoggingEvent, Encoder

Field Summary

Fields inherited from class ch.qos.logback.core.UnsynchronizedAppenderBase

name, started

Fields inherited from class ch.qos.logback.core.spi.ContextAwareBase

context

Constructor Summary

Constructors

Constructor and Description
CloudWatchClassicAppender()

Method Summary

Modifier and Type	Method and Description
protected void	append(ch.qos.logback.classic.spi.ILoggingEvent event) Calling this function will ship the event to AWSLogs
void	setAWSLogsSupplier(Supplier<com.amazonaws.services.logs.AWSLogs> supplier) Allows injection of an AWSLogs that is built using custom credentials.
void	setEncoder(ch.qos.logback.core.encoder.Encoder<ch.qos.logback.classic.spi.ILoggingEvent> encoder) Sets the encoder to be used by this logging system; any encoder that is legal for an OutputStreamAppender may also be used here.
void	setGroupName(String groupName) Sets a static group name; if this group is not present an exception will be thrown during start().
void	setStreamName(String streamName) Sets a static stream name; if this group is not present in the AWS account it will be manually created.
void	setStreamNameSupplier(Supplier<String> source) Allows injection of a custom stream name creator that can use fields like IP address or EC2 instance id to provide a unique stream name for each member of a cluster.
void	start() Called by Logback during startup or reset; attempts to connect to AWSLogs and either create or use a log stream.
void	stop() Called by Logback during reset or shutdown; safely tears down the connection to AWSLogs

Methods inherited from class ch.qos.logback.core.UnsynchronizedAppenderBase

addFilter, clearAllFilters, doAppend, getCopyOfAttachedFiltersList, getFilterChainDecision, getName, isStarted, setName, toString

Methods inherited from class ch.qos.logback.core.spi.ContextAwareBase

addError, addError, addInfo, addInfo, addStatus, addWarn, addWarn, getContext, getDeclaredOrigin, getStatusManager, setContext

Methods inherited from class java.lang.Object

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

Methods inherited from interface ch.qos.logback.core.spi.ContextAware

addError, addError, addInfo, addInfo, addStatus, addWarn, addWarn, getContext, setContext

Constructor Detail

CloudWatchClassicAppender

public CloudWatchClassicAppender()

Method Detail

setEncoder

public void setEncoder(ch.qos.logback.core.encoder.Encoder<ch.qos.logback.classic.spi.ILoggingEvent> encoder)

Sets the encoder to be used by this logging system; any encoder that is legal for an OutputStreamAppender may also be used here. The header and footer for the appender will be sent at startup and shutdown of this appender if they are not empty.

Parameters:

encoder - the encoder to use for logging

setGroupName

public void setGroupName(String groupName)

Sets a static group name; if this group is not present an exception will be thrown during start().

Parameters:

groupName - group name passed through the AWSLogs API

setStreamName

public void setStreamName(String streamName)

Sets a static stream name; if this group is not present in the AWS account it will be manually created. Should only be used when no stream name source has been set.

Parameters:

streamName - stream name passed through the AWSLogs API

setStreamNameSupplier

public void setStreamNameSupplier(Supplier<String> source)

Allows injection of a custom stream name creator that can use fields like IP address or EC2 instance id to provide a unique stream name for each member of a cluster. If the generated name is not present in the AWS account it will be manually created. Should only be used when no stream name has been explicitly set.

Parameters:

source - generator for the stream name to use for this instance

setAWSLogsSupplier

public void setAWSLogsSupplier(Supplier<com.amazonaws.services.logs.AWSLogs> supplier)

Allows injection of an AWSLogs that is built using custom credentials.

Parameters:

supplier - the overloaded supplier that will be used to construct the worker at startup

See Also:

AWSLogs

start

public void start()

Called by Logback during startup or reset; attempts to connect to AWSLogs and either create or use a log stream.

Specified by:

start in interface ch.qos.logback.core.spi.LifeCycle

Overrides:

start in class ch.qos.logback.core.UnsynchronizedAppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>

Throws:

IllegalArgumentException - if the group name or stream name is rejected by Amazon CloudWatch or the encoder has not been set

com.amazonaws.services.logs.model.ResourceNotFoundException - if the log group has not been created in Amazon CloudWatch

stop

public void stop()

Called by Logback during reset or shutdown; safely tears down the connection to AWSLogs

Specified by:

stop in interface ch.qos.logback.core.spi.LifeCycle

Overrides:

stop in class ch.qos.logback.core.UnsynchronizedAppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>

append

protected void append(ch.qos.logback.classic.spi.ILoggingEvent event)

Calling this function will ship the event to AWSLogs

Specified by:

append in class ch.qos.logback.core.UnsynchronizedAppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>