Get or set log record appender function

Get or set log record appender function

log_appender(appender = NULL, namespace = "global", index = 1)

Arguments

appender

function delivering a log record to the destination, eg appender_console(), appender_file() or appender_tee(), default NULL

namespace

logger namespace

index

index of the logger within the namespace

See also

Other log configutation functions: log_formatter(), log_layout(), log_threshold()

Examples

## change appender to "tee" that writes to the console and a file as well
t <- tempfile()
log_appender(appender_tee(t))
log_info(42)
#> INFO [2025-09-17 13:55:11] 42
log_info(43)
#> INFO [2025-09-17 13:55:11] 43
log_info(44)
#> INFO [2025-09-17 13:55:11] 44
readLines(t)
#> [1] "INFO [2025-09-17 13:55:11] 42" "INFO [2025-09-17 13:55:11] 43"
#> [3] "INFO [2025-09-17 13:55:11] 44"

## poor man's tee by stacking loggers in the namespace
t <- tempfile()
log_appender(appender_stdout)
log_appender(appender_file(t), index = 2)
log_info(42)
#> INFO [2025-09-17 13:55:11] 42
readLines(t)
#> [1] "INFO [2025-09-17 13:55:11] 42"