loggit {loggit}

Log entries to file

Description

This function executes immediately before the function definitions for the base handler functions (message, warning, and stop, and logs their timestamped output (a bit more verbosely) to a log file. The log file is an ndjson file, which is a portable, JSON-based format that is easily parsed by many line-processing systems.

Usage

loggit(log_lvl, log_msg, ..., echo = TRUE, custom_log_lvl = FALSE, sanitizer)

Arguments

log_lvl

Level of log output. In actual practice, one of "DEBUG", "INFO", "WARN", and "ERROR" are common, but any string may be supplied if custom_log_lvl is TRUE. Will be coerced to class character.

log_msg

Main log message. Will be coerced to class character.

...

A named list or named vector (each element of length one) of other custom fields you wish to log. You do not need to explicitly provide these fields as a formal list or vector, as shown in the example; R handles the coercion.

echo

Should the log file entry be printed to the console as well? Defaults to TRUE, and will print out the ndjson line to be logged. This argument is passed as FALSE when called from loggit's handlers, since they still call base R's handlers at the end of execution, all of which print to the console as well.

custom_log_lvl

Allow log levels other than "DEBUG", "INFO", "WARN", and "ERROR"? Defaults to FALSE, to prevent possible typos by the developer, and to limit the variation in structured log contents. Overall, setting this to 'TRUE“ is not recommended, but is an option for consistency with other frameworks the user may work with.

sanitizer

Sanitizer function to run over elements in log data. The default sanitizer, if not specified, is default_ndjson_sanitizer(). See the sanitizers documentation for information on how to write your own (un)sanitizer functions.

Examples

  loggit("INFO", "This is a message", but_maybe = "you want more fields?",
  sure = "why not?", like = 2, or = 10, what = "ever")