log (version 1.1.1)

Logger: Logger

Description

Create a logger.

Public fields

printer

A callback function to write the message to the console, must accept a single argument, defaults to cat.

predicate

A predicate function that determines whether to actually run the log, useful if you want to switch the logger on and off for debugging.

If the function returns TRUE the logger runs as normal, if FALSE the logger does not actually print, write or dump the messages.

Methods

Public methods

• Logger$new()

• Logger$date()

• Logger$time()

• Logger$unix()

• Logger$hook()

• Logger$dir()

• Logger$flag()

• Logger$log()

• Logger$dump()

• Logger$clone()

Method new()

Usage

Logger$new(prefix = NULL, write = FALSE, file = "log.log", sep = "\t")

Arguments

prefix

String to prefix all log messages.

write

Whether to write the log to the file.

file

Name of the file to dump the logs to, only used if write is TRUE.

sep

Separator between prefix and other flags and messages.

Details

Initialise

Examples

info <- Logger$new("INFO")
info$log("hello")

Method date()

Usage

Logger$date(format = "%d-%m-%Y")

Arguments

format

Formatter for the item, passed to format().

Details

Include the date in the log

Examples

info <- Logger$new("INFO")$date()
info$log("today")

Method time()

Usage

Logger$time(format = "%H:%M:%S")

Arguments

format

Formatter for the item, passed to format().

Details

Include the time in the log

Examples

info <- Logger$new("INFO")$time()
info$log("now")

Method unix()

Usage

Logger$unix()

Details

Include the time in the log

Examples

info <- Logger$new("INFO")$unix()
info$log("timestamp")

Method hook()

Usage

Logger$hook(fn)

Arguments

fn

A function that accepts one argument (string) and returns a modified version of that string.

Details

Preprocess the prefix with a custom function

Examples

err <- Logger$new("INFO")$hook(crayon::red)
err$log("hello")

Method dir()

Usage

Logger$dir()

Details

Include the directory in the log

Examples

info <- Logger$new("INFO")$dir()
info$log("directory")

Method flag()

Usage

Logger$flag(what)

Arguments

what

Function to run for every message logged or string to include in log message.

Details

Pass a custom flag

Examples

fl <- function(){
 paste0(sample(letters, 4), collapse = "")
}

info <- Logger$new("INFO")$flag(fl) info$log("random")

Method log()

Usage

Logger$log(..., sep = " ", collapse = " ")

Arguments

...

Elements to compose message.

sep, collapse

Separators passed to paste().

Details

Log messages

Examples

info <- Logger$new("INFO")
info$log("Logger")

Method dump()

Usage

Logger$dump(file = "dump.log")

Arguments

file

Name of the file to dump the logs to.

Details

Dump the log to a file

Examples

info <- Logger$new("INFO")
info$log("hello")
\dontrun{info$dump()}

Method clone()

The objects of this class are cloneable with this method.

Usage

Logger$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

# NOT RUN {
info <- Logger$new("INFO")$
 date()$
 time()$
 hook(crayon::blue)

info$log("Hello")
Sys.sleep(.7)
info$log("World")


## ------------------------------------------------
## Method `Logger$new`
## ------------------------------------------------

info <- Logger$new("INFO")
info$log("hello")

## ------------------------------------------------
## Method `Logger$date`
## ------------------------------------------------

info <- Logger$new("INFO")$date()
info$log("today")

## ------------------------------------------------
## Method `Logger$time`
## ------------------------------------------------

info <- Logger$new("INFO")$time()
info$log("now")

## ------------------------------------------------
## Method `Logger$unix`
## ------------------------------------------------

info <- Logger$new("INFO")$unix()
info$log("timestamp")

## ------------------------------------------------
## Method `Logger$hook`
## ------------------------------------------------

err <- Logger$new("INFO")$hook(crayon::red)
err$log("hello")

## ------------------------------------------------
## Method `Logger$dir`
## ------------------------------------------------

info <- Logger$new("INFO")$dir()
info$log("directory")

## ------------------------------------------------
## Method `Logger$flag`
## ------------------------------------------------

fl <- function(){
 paste0(sample(letters, 4), collapse = "")
}

info <- Logger$new("INFO")$flag(fl)
info$log("random")

## ------------------------------------------------
## Method `Logger$log`
## ------------------------------------------------

info <- Logger$new("INFO")
info$log("Logger")

## ------------------------------------------------
## Method `Logger$dump`
## ------------------------------------------------

info <- Logger$new("INFO")
info$log("hello")
# }
# NOT RUN {
info$dump()
# }