cancel_if {drake}

Cancel a target mid-build under some condition

Description

Cancel a target mid-build if some logical condition is met. Upon cancellation, drake halts the current target and moves to the next one. The target's previous value and metadata, if they exist, remain in the cache.

Usage

cancel_if(condition, allow_missing = TRUE)

Arguments

condition

Logical, whether to cancel the target.

allow_missing

Logical. If FALSE, drake will not cancel the target if it is missing from the cache (or if you removed the key with clean()).

Value

Nothing.

See Also

cancel

Examples

## Not run: 
isolate_example("cancel_if()", {
f <- function(x) {
  cancel_if(x > 1)
  Sys.sleep(2) # Does not run if x > 1.
}
g <- function(x) f(x)
plan <- drake_plan(y = g(2))
make(plan)
# Does not exist.
# readd(y)
})

## End(Not run)