Log4j 2.x appender for AWS CloudWatch logs

Sends logs to specified logGroupName.
Creates log streams with optional logStreamNamePrefix and year/month. Every month a new log stream will be created.

log4j2.xml example

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">

  <Properties>
    <Property name="PID">????</Property>
    <Property name="LOG_EXCEPTION_CONVERSION_WORD">%xwEx</Property>
    <Property name="LOG_LEVEL_PATTERN">%5p</Property>
    <Property name="CONSOLE_LOG_PATTERN">%clr{%d{yyyy-MM-dd HH:mm:ss.SSS}}{faint} %clr{${LOG_LEVEL_PATTERN}}%clr{${sys:PID}}{magenta} %clr{---}{faint} %clr{[%15.15t]}{faint} %clr{%-40.40c{1.}}{cyan} %clr{:}{faint}%m%n${sys:LOG_EXCEPTION_CONVERSION_WORD}</Property>
    <Property name="CLOUDWATCH_LOG_PATTERN">${LOG_LEVEL_PATTERN} ${sys:PID} --- [%t]%-40.40c{1.} : %m%n${sys:LOG_EXCEPTION_CONVERSION_WORD}</Property>
  </Properties>

  <Appenders>

    <Console name="Console" target="SYSTEM_OUT" follow="true">
      <PatternLayout pattern="${sys:CONSOLE_LOG_PATTERN}"/>
    </Console>

    <CloudWatchAppender name="CloudWatch" logGroupName="test-logging" logStreamNamePrefix="logging">
      <PatternLayout>
        <Pattern>${sys:CLOUDWATCH_LOG_PATTERN}</Pattern>
      </PatternLayout>
    </CloudWatchAppender>

  </Appenders>

  <Loggers>
    <Root level="info">
      <AppenderRef ref="Console"/>
      <AppenderRef ref="CloudWatch"/>
    </Root>
  </Loggers>

</Configuration>

AWS credentials

AWS credentials are read using DefaultAWSCredentialsProviderChain:

• Environment Variables: AWS_ACCESS_KEY, AWS_SECRET_KEY and AWS_REGION
• Java System Properties: aws.accessKeyId and aws.secretKey
• Credential profiles file at the default location (~/.aws/credentials) shared by all AWS SDKs and the AWS CLI
• Credentials delivered through the Amazon EC2 container service if AWS_CONTAINER_CREDENTIALS_RELATIVE_URI environment variable is set and security manager has permission to access the variable
• Instance profile credentials delivered through the Amazon EC2 metadata service

Build

./gradlew clean build