Feature request: add max_tries to insistently()

[mmuurr]

Would be useful to have a {purrr} adverb that is similar to {httr2}'s req_retry().

I think(?) adding a max_tries = Inf (or NULL default) param to insistently() wouldn't scope-creep too much, and let insistently() signal the (final) error once the retry count is exhausted.

An motivating use case is wrapping a function that delegates to some system call (e.g. via {processx}) that itself might be making network calls with some potential failure rate. (My particular instance of this is with wrapping some AWS CLI calls, which can fail due to intermitent network issues.)

[hadley]

Should probably mimic https://httr2.r-lib.org/reference/req_retry.html and provide both max_tries and max_seconds.

Would be useful to have this also as something you can use on a block of code, not just a function.

[hadley]

There is already a max_tries argument, but it's hard to see because it's an argument to rate_backoff():

library(purrr)

f <- local({
  i <- 0
  f <- function() {
    i <- i + 1
    if (i < 5) stop("Error")
    i * 10
  }
}) 
insistently(f)(1)
#> Error in `rate_sleep()`:
#> ! Request failed after 3 attempts.

#> Backtrace:
#>     ▆
#>  1. └─insistently(f)(1)
#>  2.   └─purrr::rate_sleep(rate, quiet = quiet)
#>  3.     └─purrr:::stop_rate_excess(rate)
#>  4.       └─cli::cli_abort(...)
#>  5.         └─rlang::abort(...)

^{Created on 2023-02-07 with reprex v2.0.2}

I think we're now somewhat moving away from these adverbs (in hindsight their names seem too clever), but I'll probably implement with_retries() shortly.