A lightweight, modern and flexibly logging utility for R – heavily
inspired by the futile.logger R package and logging Python module.
install.packages("logger")The most recent, development version of logger can also be installed
from GitHub:
# install.packages("pak")
pak::pak("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 [2024-08-15 11:59:27] Script starting up...
pkgs <- available.packages()
log_info("There are {nrow(pkgs)} R packages hosted on CRAN!")
#> INFO [2024-08-15 11:59:28] There are 21131 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 [2024-08-15 11:59:28] 10193 R packages including the 'a' letter
#> DEBUG [2024-08-15 11:59:28] 7016 R packages including the 'c' letter
#> DEBUG [2024-08-15 11:59:28] 5751 R packages including the 'd' letter
#> DEBUG [2024-08-15 11:59:28] 10907 R packages including the 'e' letter
#> DEBUG [2024-08-15 11:59:28] 8825 R packages including the 'i' letter
#> DEBUG [2024-08-15 11:59:28] 7059 R packages including the 'l' letter
#> DEBUG [2024-08-15 11:59:28] 7045 R packages including the 'm' letter
#> DEBUG [2024-08-15 11:59:28] 6665 R packages including the 'n' letter
#> DEBUG [2024-08-15 11:59:28] 7863 R packages including the 'o' letter
#> DEBUG [2024-08-15 11:59:28] 6581 R packages including the 'p' letter
#> DEBUG [2024-08-15 11:59:28] 11229 R packages including the 'r' letter
#> DEBUG [2024-08-15 11:59:28] 10296 R packages including the 's' letter
#> DEBUG [2024-08-15 11:59:28] 9531 R packages including the 't' letter
log_warn("There might be many, like {1:2} or more warnings!!!")
#> WARN [2024-08-15 11:59:28] There might be many, like 1 or more warnings!!!
#> WARN [2024-08-15 11:59:28] There might be many, like 2 or more warnings!!!You can even use a custom log layout to render the log records with
colors, as you can see in layout_glue_colors():
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 vignette("write_custom_extensions").
There are many other logging packages available on CRAN:
futile.logger: probably the most popularlog4jvariant (and I’m a big fan)logging: just like Python’sloggingpackagelgr: built on top of R6.loggit: capturemessage,warningandstopfunction messages in a JSON filelog4r:log4j-based, object-oriented loggerrsyslog: logging tosyslogon ‘POSIX’-compatible operating systemslumberjack: provides a special operator to log changes in data
Why use logger? I decided to write the n+1th extensible log4j logger
that fits my liking — and hopefully yours as well — with the aim to:
- Keep it close to
log4j. - Respect the modern 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()(e.g. 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 (e.g. 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
logcall can write all theTRACElog messages to the console, while only pushingERRORs to DataDog and egINFOmessages to CloudWatch. - Optionally colorize log message based on the log level.
- Make logging fun!
Welcome to the
Bazaar! If
you already use any of the above packages for logging, you might find
vignette("migration") useful.
Check out the main documentation site at https://daroczig.github.io/logger or the vignettes on the below topics:
If you prefer visual content, you can watch the video recording of the “Getting things logged” talk at RStudio::conf(2020):
