Local process launcher class

R6 class to launch and manage local process workers.

Details

See crew_launcher_local().

See also

Other plugin_local: crew_controller_local(), crew_launcher_local()

Super class

crew::crew_class_launcher -> crew_class_launcher_local

Active bindings

local_log_directory

See crew_launcher_local().

local_log_join

See crew_launcher_local().

Methods

Public methods

• crew_class_launcher_local$new()

• crew_class_launcher_local$validate()

• crew_class_launcher_local$launch_worker()

• crew_class_launcher_local$terminate_worker()

Inherited methods

• crew::crew_class_launcher$active()
• crew::crew_class_launcher$booting()
• crew::crew_class_launcher$call()
• crew::crew_class_launcher$done()
• crew::crew_class_launcher$errors()
• crew::crew_class_launcher$forward()
• crew::crew_class_launcher$launch()
• crew::crew_class_launcher$rotate()
• crew::crew_class_launcher$scale()
• crew::crew_class_launcher$set_name()
• crew::crew_class_launcher$settings()
• crew::crew_class_launcher$start()
• crew::crew_class_launcher$summary()
• crew::crew_class_launcher$tally()
• crew::crew_class_launcher$terminate()
• crew::crew_class_launcher$terminate_workers()
• crew::crew_class_launcher$unlaunched()
• crew::crew_class_launcher$wait()

---

Method new()

Local launcher constructor.

Usage

crew_class_launcher_local$new(
  name = NULL,
  seconds_interval = NULL,
  seconds_timeout = NULL,
  seconds_launch = NULL,
  seconds_idle = NULL,
  seconds_wall = NULL,
  seconds_exit = NULL,
  tasks_max = NULL,
  tasks_timers = NULL,
  reset_globals = NULL,
  reset_packages = NULL,
  reset_options = NULL,
  garbage_collection = NULL,
  launch_max = NULL,
  tls = NULL,
  processes = NULL,
  local_log_directory = NULL,
  local_log_join = NULL
)

Arguments

name

See crew_launcher().

seconds_interval

See crew_launcher().

seconds_timeout

See crew_launcher().

seconds_launch

See crew_launcher().

seconds_idle

See crew_launcher().

seconds_wall

See crew_launcher().

seconds_exit

See crew_launcher().

tasks_max

See crew_launcher().

tasks_timers

See crew_launcher().

reset_globals

See crew_launcher().

reset_packages

See crew_launcher().

reset_options

See crew_launcher().

garbage_collection

See crew_launcher().

launch_max

See crew_launcher().

tls

See crew_launcher().

processes

See crew_launcher().

local_log_directory

See crew_launcher_local().

local_log_join

See crew_launcher_local().

Returns

An R6 object with the local launcher.

Examples

if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local(name = client$name)
launcher$start(sockets = client$summary()$socket)
launcher$launch(index = 1L)
task <- mirai::mirai("result", .compute = client$name)
mirai::call_mirai_(task)
task$data
client$terminate()
}

---

Method validate()

Validate the local launcher.

Usage

crew_class_launcher_local$validate()

Returns

NULL (invisibly).

---

Method launch_worker()

Launch a local process worker which will dial into a socket.

Usage

crew_class_launcher_local$launch_worker(call, name, launcher, worker, instance)

Arguments

call

Character of length 1 with a namespaced call to crew_worker() which will run in the worker and accept tasks.

name

Character of length 1 with a long informative worker name which contains the launcher, worker, and instance arguments described below.

launcher

Character of length 1, name of the launcher.

worker

Positive integer of length 1, index of the worker. This worker index remains the same even when the current instance of the worker exits and a new instance launches. It is always between 1 and the maximum number of concurrent workers.

instance

Character of length 1 to uniquely identify the current instance of the worker a the index in the launcher.

Details

The call argument is R code that will run to initiate the worker. Together, the launcher, worker, and instance arguments are useful for constructing informative job names.

Returns

A handle object to allow the termination of the worker later on.

---

Method terminate_worker()

Terminate a local process worker.

Usage

crew_class_launcher_local$terminate_worker(handle)

Arguments

handle

A process handle object previously returned by launch_worker().

Returns

A list with the process ID of the worker.

Examples

if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local(name = client$name)
launcher$start(sockets = client$summary()$socket)
launcher$launch(index = 1L)
task <- mirai::mirai("result", .compute = client$name)
mirai::call_mirai_(task)
task$data
client$terminate()
}

## ------------------------------------------------
## Method `crew_class_launcher_local$new`
## ------------------------------------------------

if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local(name = client$name)
launcher$start(sockets = client$summary()$socket)
launcher$launch(index = 1L)
task <- mirai::mirai("result", .compute = client$name)
mirai::call_mirai_(task)
task$data
client$terminate()
}