Logr implements a logging framework that uses R's existing messaging
functionality, and builds upon it an API that is simple to use.
Because it shares the same underpinnings, logr can capture messages
and warnings generated by warning and message, making it easy to
adopt even in a mature codebase.
To install the latest development version, run:
devtools::install_github('cubranic/logr').
info_log('Hello there')
if (sample(6, 1) == 1)
warn_log('Not your lucky day')To start using this package, simply use one of the family of *_log
functions to output logging messages at the desired level of
importance (see below for list of all levels). With no other
configuration, these functions will behave as their closest equivalent
in base: info_log will act exactly like message (it can even be
turned off with suppressMessages), warn_log as warning and
error_log as stop. Messages with their level higher than INFO
(i.e., DEBUG and TRACE) will not be printed.
To exert a finer control, wrap the code where you want to enable
loggging inside a call to with_logging. Here you can specify logging
destinations (files, console, or even any writeable connections) and
level thresholds. This is useful to, for instance, output
at most informational messages to the console while recording
fine-level messages in a log file:
with_logging({
info_log('Hello there')
if (x <- sample(6, 1) == 1)
warn_log('Not your lucky day')
trace_log(paste('x:', x))
}, list('/var/tmp/myapp.log', 'DEBUG'), stderr())Similar to log4j and other logging frameworks, logr provides the following levels for message detail, from most to least important:
- ERROR: serious, un-recoverable errors that prevent the code from continuing with further execution
- WARN: reporting "suspicious" events, for instance, unexpected NAs, or that some automatic corrective action has failed (e.g., maximum number of retries reached)
- INFO: informing on major steps that software is performing, without drowning in too much detail
- DEBUG: detailed steps taken by operations
- TRACE: use for very detailed debugging, like printing local variable values