Log to a file
A simple Appender that outputs to a file in the file system. If you plan
to log to text files, consider logging to JSON files and take a look at
AppenderJson, which is a shortcut for AppenderFile preconfigured with
LayoutJson.
lgr::Filterable -> lgr::Appender -> AppenderFile
filecharacter scalar. path to the log file
datacharacter scalar. Contents of file parsed to a
data.frame if used with a Layout that supports parsing of log
file data (notably LayoutJson).
datacharacter scalar. Like $data, but returns a data.table
instead (requires the data.table package).
new()
AppenderFile$new( file, threshold = NA_integer_, layout = LayoutFormat$new(), filters = NULL )
append()
AppenderFile$append(event)
set_file()
Set a log file
AppenderFile$set_file(file)
filecharacter scalar. Path to the log file. If file does not
exist it will be created.
show()
Display the contents of the log file.
AppenderFile$show(threshold = NA_integer_, n = 20L)
thresholdcharacter or integer scalar. The minimum log level
that should be displayed.
ninteger scalar. Show only the last n log entries that match
threshold.
lgr::Filterable -> lgr::Appender -> lgr::AppenderFile -> AppenderJson
new()
AppenderJson$new( file, threshold = NA_integer_, layout = LayoutJson$new(), filters = NULL )
lg <- get_logger("test")
default <- tempfile()
fancy <- tempfile()
json <- tempfile()
lg$add_appender(AppenderFile$new(default), "default")
lg$add_appender(
AppenderFile$new(fancy, layout = LayoutFormat$new("[%t] %c(): %L %m")), "fancy"
)
lg$add_appender(
AppenderFile$new(json, layout = LayoutJson$new()), "json"
)
lg$info("A test message")
readLines(default)
readLines(fancy)
readLines(json)
# cleanup
lg$config(NULL)
unlink(default)
unlink(fancy)
unlink(json)
tf <- tempfile()
lg <- get_logger("test")$
set_appenders(AppenderJson$new(tf))$
set_propagate(FALSE)
lg$info("A test message")
lg$info("A test message %s strings", "with format strings", and = "custom_fields")
lg$appenders[[1]]$show()
lg$appenders[[1]]$data
# cleanup
lg$config(NULL)
unlink(tf)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.