A lightweight, modern and flexibly logging utility for R -- heavily inspired by the futile.logger
R package and logging
Python module.
logger
is not on CRAN yet, please install from GitHub:
remotes::install_github('daroczig/logger')
Setting the log level threshold to something low and logging various messages in ad-hoc and programmatic ways:
library(logger)
log_threshold(DEBUG)
log_info('Script starting up...')
#> INFO [2018-20-11 22:49:36] Script starting up...
pkgs <- available.packages()
log_info('There are {nrow(pkgs)} R packages hosted on CRAN!')
#> INFO [2018-20-11 22:49:37] There are 13433 R packages hosted on CRAN!
for (letter in letters) {
lpkgs <- sum(grepl(letter, pkgs[, 'Package'], ignore.case = TRUE))
log_level(if (lpkgs < 5000) TRACE else DEBUG,
'{lpkgs} R packages including the {shQuote(letter)} letter')
}
#> DEBUG [2018-20-11 22:49:38] 6300 R packages including the 'a' letter
#> DEBUG [2018-20-11 22:49:38] 6772 R packages including the 'e' letter
#> DEBUG [2018-20-11 22:49:38] 5412 R packages including the 'i' letter
#> DEBUG [2018-20-11 22:49:38] 7014 R packages including the 'r' letter
#> DEBUG [2018-20-11 22:49:38] 6402 R packages including the 's' letter
#> DEBUG [2018-20-11 22:49:38] 5864 R packages including the 't' letter
log_warn('There might be many, like {1:2} or more warnings!!!')
#> WARN [2018-20-11 22:49:39] There might be many, like 1 or more warnings!!!
#> WARN [2018-20-11 22:49:39] There might be many, like 2 or more warnings!!!
Setting a custom log layout to render the log records with colors:
library(logger)
log_layout(layout_glue_colors)
log_threshold(TRACE)
log_info('Starting the script...')
log_debug('This is the second log line')
log_trace('Note that the 2nd line is being placed right after the 1st one.')
log_success('Doing pretty well so far!')
log_warn('But beware, as some errors might come :/')
log_error('This is a problem')
log_debug('Note that getting an error is usually bad')
log_error('This is another problem')
log_fatal('The last problem')
Or simply run the related demo:
demo(colors, package = 'logger', echo = FALSE)
But you could set up any custom colors and layout, eg using custom colors only for the log levels, make it grayscale, include the calling function or R package namespace with specific colors etc. For more details, see the related vignettes.
Although there are multiple pretty good options already hosted on CRAN when it comes to logging in R, such as
futile.logger
: probably the most popularlog4j
variant (and I'm a big fan)logging
: just like Python'slogging
packageloggit
: capturemessage
,warning
andstop
function messages in a JSON filelog4r
:log4j
-based, object-oriented loggerrsyslog
: logging tosyslog
on 'POSIX'-compatible operating systemslumberjack
: provides a special operator to log changes in data
Also many more work-in-progress R packages hosted on eg GitHub, such as
- https://github.com/smbache/loggr
- https://github.com/nfultz/tron
- https://github.com/metrumresearchgroup/logrrr
- https://github.com/lorenzwalthert/drogger
- https://github.com/s-fleck/yog
But some/most of these packages are
- not actively maintained any more, and/or maintainers are not being open for new features / patches
- not being modular enough for extensions
- prone to scoping issues
- using strange syntax elements, eg dots in function names or object-oriented approaches not being very familiar to most R users
- requires a lot of typing and code repetitions
So based on all the above subjective opinions, I decided to write the n+1
th extensible log4j
logger that fits my liking -- and hopefully yours as well -- with the focus being on:
- keep it close to
log4j
- respect the most recent function / variable naming conventions and general R coding style
- by default, rely on
glue
when it comes to formatting / rendering log messages, but keep it flexible if others prefersprintf
(eg for performance reasons) or other functions - support vectorization (eg passing a vector to be logged on multiple lines)
- make it easy to extend with new features (eg custom layouts, message formats and output)
- prepare for writing to various services, streams etc
- provide support for namespaces, preferably automatically finding and creating a custom namespace for all R packages writing log messages, each with optionally configurable log level threshold, message and output formats
- allow stacking loggers to implement logger hierarchy -- even within a namespace, so that the very same
log
call can write all theTRACE
log messages to the console, while only pushingERROR
s to DataDog and egINFO
messages to CloudWatch - optionally colorize log message based on the log level
- make logging fun
Welcome to the Bazaar, and if you have happened to already use any of the above mentioned R packages for logging, you might find useful the Migration Guide.
Check out the main documentation site at https://daroczig.github.io/logger or the vignettes on the below topics: