Logging Sensor

Owned by Stefan Siegl
Aug 20, 2015

Logging Frameworks to be addressed

  • Log4J
  • java.util.logging
  • Apache Commons Logging
  • Logback (basically always used through SLF4J)

Facades

Mostly logging is not used directly but often used through a facade like SLF4J. In fact most tutorials on logback state that it has be used with SLF4J

Instrumentation

We need a method/methods that provide the following:

  • read the log level
  • read the log message
  • operate on as little methods as possible

 

FrameworkInstrumentation point 
log4Jlog4j offers a nice central point where loggings of all levels are handled. This method is org.apache.log4j.Category.forcedLog 
java.util.logging  
Apache Commons Logging  
LogbackActuall instrumenting logback classic directly is not too nice. The class handling the logging is https://github.com/qos-ch/logback/blob/master/logback-classic/src/main/java/ch/qos/logback/classic/Logger.java which provides different internal logging methods for each level. There is no central place where the logging is handled independently of the loglevel. We would have to instrument a bunch of methods. 
SLF4J

http://grepcode.com/file/repo1.maven.org/maven2/org.slf4j/slf4j-api/1.7.12/org/slf4j/Logger.java#Logger is an interface uses the http://grepcode.com/file/repo1.maven.org/maven2/org.slf4j/slf4j-api/1.7.12/org/slf4j/LoggerFactory.java#LoggerFactory.getILoggerFactory%28%29 to find a LoggingFactory to create a Logger.

So in fact we just need to have a look at the concrete adaptors for the technologies: