Enable logging in WSO2 Identity Server with Log4j2
We need logging to debug our codes. Sometimes these log statements will save your day :).
Log4j is a logging library used in Java. By using Log4j we can enable logging at runtime without modifying the application binary. Logging behaviour such as logging level, enabling logging for a specific component can be controlled by editing a configuration file. Moreover, the Log4j is designed to contain the log statements in the code without causing a heavy performance cost.
On August 5, 2015, Log4j 1.x reached the end of life. For more information please refer to the blog.
Now the new version is Log4j 2. Apache Log4j 2 is an upgrade to Log4j 1.x. We will see what are the improvements of Log4j 2 over Log4j 1.x
Why Log4j 2?
There are several new features introduced in Log4j 2 compared to Log4j 1.x
1. API Separation
The API for Log4j is separate from the implementation. The Log4j API is a logging facade that may be used with the Log4j implementation, but may also be used with other logging implementations.
2. Improved Performance
Log4j 2 contains next-generation Asynchronous Loggers. Log4j 2 significantly outperforms Log4j 1.x, Logback and java.util.logging, especially in multi-threaded applications.
3. Support for multiple APIs
Log4j 2 provides support for the Log4j 1.2, SLF4J, Commons Logging and java.util.logging (JUL) APIs.
Please refer to the documentation to find more interesting features of Log4j 2.
Enable logging in WSO2 Identity Server with Log4j2
WSO2 Identity Server (WSO2 IS-5.9.0) uses Log4j2 for logging requirements. Before IS-5.9.0 we used Log4j 1.x.
You can find the log4j2.properties file under <IS-HOME>/repository/conf directory.
How to add a new Appender?
This is a sample format of an appender
appender.<Appender_name_you _define>.type = <Appender_type>
appender.<Appender_name_you _define>.name = <Real _appender_name>
appender.<Appender_name_you _define>.layout.type = <Layout_type>
After introducing the appender add the appender to the appenders list
appenders = Appender_x, <Appender_name_you _define>
Below are two examples of a Console Appender and a RollingFile Appender
- Console Appender
appender.CARBON_CONSOLE.type = Console
appender.CARBON_CONSOLE.name = CARBON_CONSOLE
appender.CARBON_CONSOLE.layout.type = PatternLayout
appender.CARBON_CONSOLE.layout.pattern = [%d] %5p {%c} — %m%ex%n
appender.CARBON_CONSOLE.filter.threshold.type = ThresholdFilter
appender.CARBON_CONSOLE.filter.threshold.level = DEBUG
2. RollingFile Appender
appender.CARBON_LOGFILE.type = RollingFile
appender.CARBON_LOGFILE.name = CARBON_LOGFILE
appender.CARBON_LOGFILE.fileName = ${sys:carbon.home}/repository/logs/wso2carbon.log
appender.CARBON_LOGFILE.filePattern = ${sys:carbon.home}/repository/logs/wso2carbon-%d{MM-dd-yyyy}.log
appender.CARBON_LOGFILE.layout.type = PatternLayout
appender.CARBON_LOGFILE.layout.pattern = TID: [%tenantId] [%appName] [%d] %5p {%c} — %m%ex%n
appender.CARBON_LOGFILE.policies.type = Policies
appender.CARBON_LOGFILE.policies.time.type = TimeBasedTriggeringPolicy
appender.CARBON_LOGFILE.policies.time.interval = 1
appender.CARBON_LOGFILE.policies.time.modulate = true
appender.CARBON_LOGFILE.policies.size.type = SizeBasedTriggeringPolicy
appender.CARBON_LOGFILE.policies.size.size=10MB
appender.CARBON_LOGFILE.strategy.type = DefaultRolloverStrategy
appender.CARBON_LOGFILE.strategy.max = 20
appender.CARBON_LOGFILE.filter.threshold.type = ThresholdFilter
appender.CARBON_LOGFILE.filter.threshold.level = DEBUG
How to add a new Logger
This is a sample format of a logger.
logger.<Logger_name_you _define>.name = <Real _logger_name>
logger.<Logger_name_you _define>.level =<Log_level>
logger.<Logger_name_you _define>.appenderRef.<Appender_name_you _define>.ref = <Real _appender_name>
logger.<Logger_name_you _define>.additivity = false
After introducing the logger add the logger to the loggers list.
loggers = Logger_x, <Logger_name_you _define>
Below is an example of a Logger.
logger.org-apache-axis2-wsdl-codegen-writer-PrettyPrinter.name = org.apache.axis2.wsdl.codegen.writer.PrettyPrinter
logger.org-apache-axis2-wsdl-codegen-writer-PrettyPrinter.level = ERROR
logger.org-apache-axis2-wsdl-codegen-writer-PrettyPrinter.appenderRef.CARBON_LOGFILE.ref = CARBON_LOGFILE
logger.org-apache-axis2-wsdl-codegen-writer-PrettyPrinter.appenderRef.CARBON_MEMORY.ref = CARBON_MEMORY
I hope that everyone got some idea about why we moved to Log4j2 and how to configure loggers and appenders using Log4j2.properties file. Thank you for reading.
