Specify a non-blocking execution strategy for genproc()

Returns a configuration object to pass as the nonblocking argument of genproc(). When supplied, genproc() returns immediately with a genproc_result of status "running" while the actual work continues in a background future. Use status() to poll the state and await() to block until completion.

Usage

nonblocking_spec(strategy = "multisession", packages = NULL, globals = TRUE)

Arguments

strategy: Character, or NULL. One of "sequential", "multisession", "multicore", "cluster". Default "multisession". Unlike parallel_spec(), the default is not NULL: a function named "non-blocking" must not silently block because the current future::plan() is sequential. Pass strategy = NULL explicitly to defer to the caller's plan. "sequential" is accepted mainly for deterministic testing — it exercises the code path but does not actually free the console.
packages: Character vector, or NULL. Extra packages to attach on the background worker before running. genproc itself is attached automatically for every strategy other than "sequential".
globals: Logical or character. Forwarded to future::future()'s globals argument. Default TRUE enables automatic detection.

Value

A list of class "genproc_nonblocking_spec" with the validated, normalized fields.

Composition with parallel_spec()

nonblocking_spec() and parallel_spec() are orthogonal and can be combined. The non-blocking layer launches one outer future; inside it, the parallel layer dispatches cases via future.apply. With both strategies set to "multisession", future resolves the inner layer as "sequential" by default (see future::plan() nesting rules) unless the caller installs an explicit nested plan via future::plan(list(...)).

Examples

# Launch in the background, keep the console
if (FALSE) { # \dontrun{
  spec <- nonblocking_spec()
  job <- genproc(f = slow_fn, mask = mask, nonblocking = spec)
  status(job)           # "running"
  job <- await(job)     # blocks until done
  job$log
} # }

# Deterministic test: exercise the code path without real async
spec <- nonblocking_spec(strategy = "sequential")