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Send logs to their final destination with Appenders

Source: R/appenders.R
appenders.Rd

In log4j etymology, Appenders are destinations where logs are written. Appenders have no control over formatting; this is controlled by the Layout.

The most basic appenders write logs to the console or to a file; these are described below.

For implementing your own appenders, see Details.

Usage

console_appender(layout = default_log_layout())

file_appender(file, append = TRUE, layout = default_log_layout())

Arguments

layout

A layout function taking a level parameter and additional arguments corresponding to the message. See layouts().

file

The file to write messages to.

append

When TRUE, the file is not truncated when opening for the first time.

Details

Appenders are implemented as functions with the interface function(level, ...). These functions are expected to write their arguments to a destination and return invisible(NULL).

See also

tcp_appender(), http_appender(), syslog_appender()

Examples

# The behaviour of an appender can be seen by using them directly; the
# following snippet will write the message to the console.
appender <- console_appender()
appender("INFO", "Input has length ", 0, ".")
#> INFO  [2024-10-18 17:06:47] Input has length 0.