Reset an finished future to a lazy future

A future that has successfully completed, has been interrupted, or failed due to an error, can be relaunched by first resetting it.

reset(x, ...)

Arguments

x

A Future.

...

All arguments used by the S3 methods.

Value

reset() returns a lazy, vanilla Future that can be relaunched.

Examples

## Like mean(), but fails 90% of the time
shaky_mean <- function(x) {
  if (as.double(Sys.time()) %% 1 < 0.90) stop("boom")
  mean(x)
}

x <- rnorm(100)

## Calculate the mean of 'x' with a risk of failing randomly
f <- future({ shaky_mean(x) })

## Relaunch until success
repeat({
  v <- tryCatch(value(f), error = identity)
  if (!inherits(v, "error")) break
  message("Resetting failed future, and retry in 0.1 seconds")
  f <- reset(f)
  Sys.sleep(0.1)
})
#> Resetting failed future, and retry in 0.1 seconds
#> Resetting failed future, and retry in 0.1 seconds
#> Resetting failed future, and retry in 0.1 seconds
#> Resetting failed future, and retry in 0.1 seconds
#> Resetting failed future, and retry in 0.1 seconds
#> Resetting failed future, and retry in 0.1 seconds
#> Resetting failed future, and retry in 0.1 seconds
#> Resetting failed future, and retry in 0.1 seconds
cat("mean:", v, "\n")
#> mean: -0.0300474