print.LogEvent: Print or Format Logging Data

In lgr: A Fully Featured Logging Framework

Print or Format Logging Data

Description

Print or Format Logging Data

Usage

## S3 method for class 'LogEvent'
print(
  x,
  fmt = "%L [%t] %m  %f",
  timestamp_fmt = "%Y-%m-%d %H:%M:%S",
  colors = getOption("lgr.colors"),
  log_levels = getOption("lgr.log_levels"),
  pad_levels = "right",
  excluded_fields = NULL,
  ...
)

## S3 method for class 'LogEvent'
format(
  x,
  fmt = "%L [%t] %m  %f",
  timestamp_fmt = "%Y-%m-%d %H:%M:%S",
  colors = NULL,
  log_levels = getOption("lgr.log_levels"),
  pad_levels = "right",
  excluded_fields = NULL,
  ...
)

Arguments

x	a LogEvent
fmt	A character scalar that may contain any of the tokens listed bellow in the section Format Tokens.
timestamp_fmt	see format.POSIXct()
colors	A list of functions that will be used to color the log levels (likely from crayon::crayon).
log_levels	named integer vector of valid log levels
pad_levels	right, left or NULL. Whether or not to pad the log level names to the same width on the left or right side, or not at all.
excluded_fields	a character vector of fields to exclude from ⁠%j⁠ and ⁠%f⁠
...	ignored

Value

x for print() and a character scalar for format()

Format Tokens

⁠%t⁠

The timestamp of the message, formatted according to timestamp_fmt)

⁠%l⁠

the log level, lowercase character representation

⁠%L⁠

the log level, uppercase character representation

⁠%k⁠

the log level, first letter of lowercase character representation

⁠%K⁠

the log level, first letter of uppercase character representation

⁠%n⁠

the log level, integer representation

⁠%g⁠

the name of the logger

⁠%p⁠

the PID (process ID). Useful when logging code that uses multiple threads.

⁠%c⁠

the calling function

⁠%m⁠

the log message

⁠%r⁠

the raw log message (without string interpolation)

⁠%f⁠

all custom fields of x in a pseudo-JSON like format that is optimized for human readability and console output

⁠%j⁠

all custom fields of x in proper JSON. This requires that you have jsonlite installed and does not support colors as opposed to ⁠%f⁠

Examples

# standard fields can be printed using special tokens
x <- LogEvent$new(
  level = 300, msg = "a test event", caller = "testfun()", logger = lgr
)
print(x)
print(x, fmt = c("%t (%p) %c: %n - %m"))
print(x, colors = NULL)

# custom values
y <- LogEvent$new(
  level = 300, msg = "a gps track", logger = lgr,
  waypoints = 10, location = "Austria"
)

# default output with %f
print(y)

# proper JSON output with %j
if (requireNamespace("jsonlite")){
print(y, fmt = "%L [%t] %m  %j")
}

lgr documentation built on Aug. 8, 2025, 6:10 p.m.