How can I replace a failed target with a missing value?

Question

I am fitting a bunch of models using a drake plan. Some of them are failing due to problems in the initialization. I am running `make(plan, keep_going = T) in order to finish the plan in anyway, but what I would really like is to be able to skip the failed targets and treat them as missing values in the rest of the plan.

Is there anyway to replace failed targets with, let's say a constant NA symbol?

score 1 · Accepted Answer · answered Nov 14 '19 at 14:59

Edit

Here is a better example than the one I originally provided. All you need is to wrap your models in a custom function that turns failures into NAs.

library(drake)

fail_na <- function(code) {
  tryCatch(code, error = error_na)
}

error_na <- function(e) {
  NA
}

plan <- drake_plan(
  failure = fail_na(stop()),
  success = fail_na("success")
)

make(plan, keep_going = TRUE)
#> In drake, consider r_make() instead of make(). r_make() runs make() in a fresh R session for enhanced robustness and reproducibility.
#> target success
#> target failure

readd(failure)
#> [1] NA

readd(success)
#> [1] "success"

^{Created on 2019-11-14 by the reprex package (v0.3.0)}

Original answer

It is possible, but it requires some custom code. Below, we need to check that x is NULL or missing.

library(drake)

`%||%` <- function(x, y) {
  if (is.null(x)) {
    y
  } else {
    x
  }
}

na_fallback <- function(x) {
  out <- tryCatch(
    x %||% NA,
    error = function(e) {
      NA
    }
  )
  out
}

plan <- drake_plan(
  x = stop(),
  y = na_fallback(x)
)

make(plan, keep_going = TRUE)
#> In drake, consider r_make() instead of make(). r_make() runs make() in a fresh R session for enhanced robustness and reproducibility.
#> target x
#> fail x
#> target y

readd(y)
#> [1] NA

^{Created on 2019-11-14 by the reprex package (v0.3.0)}

How can I replace a failed target with a missing value?

1 Answers1

Edit

Original answer