Generates a logging message using glue and crayon, with some bells/whistles.

Source: R/logging.R

Like other logging approaches, each message created with this function is assigned a level (priority). If the current logging level, which is returned from a call to flog_level (ostensibly determenied by the value of the "facile.log.level(.*?)" option) is less than or equal to level of this message, then the message will be generated and sent to file. You can include a namespace for the message to provide a namespace-specific level/priority hierarchy.

flog(
  ...,
  level = "info",
  ns = NULL,
  session = NULL,
  file = stderr(),
  sep = "",
  fill = FALSE,
  labels = NULL,
  append = FALSE,
  newline = !is.null(file)
)

Arguments

...

the string elements to pass into glue::glue()
level

the "firing level" of this message. Defaults to "info"
ns

(namespace) if included, then the message checks the namespace-specific logging priority
session, file, sep, fill, labels, append

sent to base::cat()
newline

If TRUE, appends a \\n to the message. By default, this is TRUE when file is not NULL.

Value

invisibly returns the text generated in the logging message.

Details

Conveninece wrapper functions are provided for each logging level, ie. call fwarn("message") instead of flog("message", level = "warn"). Also, each facile* package provides its own flog()function which sets the namespacens` parameter to default to a package-specific namespace so you can control logging at the different package level.

Logging Levels

Logging levels are

.flog_levels <- c("all"  = 0, "trace" = 1, "debug" = 2, "info" = 3,
                  "warn" = 4, "error" = 5, "fatal" = 6)

crayon

Glue lets you put cayon functions in {} to stylize output. For instance, you can make "bold and red" the color red and also bold, like so:

flog("This is {red}{bold}bold and red{reset}, right?")

Nice! It might be more convenient if we could make it a bit more terse, as shown below, but that might happen at another time.

flog("This is rb`bold and red`, right?")

Colors:

  • b: blue

  • c: cyan

  • g: green

  • k: black

  • m: magenta

  • r: red

  • y: yellow

Styles:

  • i: italic

  • s: strong (bold)

  • S: striketthrough

  • u: underline