[R] Application logging in R

[B Rowe]

Hello,

I'm curious to know how people log their applications in R. It seems
like it's a combination of cat statements or writing out the session to
a file, given the discussions I've had with people. This is fine for
interactive work but is a little lacking for automated systems. To
address this, I've written a logging facility modeled on the log4j Java
library. The basic concept is that you can route logging statements to
customizable loggers, each with their own 'threshold' (e.g. debug, info,
warn) and output. The output can be anything from stdout, a file, a URL,
to a message bus, depending on the implementation.

Here are some quick examples:

  library(futile)
  # Use the ROOT logger
  logger.info("Hello, world")
  logger.debug("Won't print since level is currently INFO")
  setLogger('ROOT', level='DEBUG')
  logger.debug("This will %s print", 'now')

  # Create new loggers
  addLogger('a.logger', 'WARN', logger.stdout)
  addLogger('b.logger', 'INFO', logger.file, file='temp.log')
  object <- 1
  logger.debug("This is a %s", class(object), logger='a.logger')
  logger.warn("This is a %s", class(object), logger='b.logger')

This type of control also provides an alternative to stdout redirection
in distributed environments, which can facilitate debugging.

Version 1.1.1 of the package is available on CRAN. Any thoughts on how
to improve this or requests for other loggers are appreciated.

Regards,
Brian