crew_class_launcher: Launcher abstract class
In crew: A Distributed Worker Launcher Framework
crew_class_launcher R Documentation
Launcher abstract class
Description
R6 abstract class to build other subclasses
which launch and manage workers.
Active bindings
nameSee crew_launcher().
workersSee crew_launcher().
seconds_intervalSee crew_launcher().
seconds_timeoutSee crew_launcher().
seconds_launchSee crew_launcher().
seconds_idleSee crew_launcher().
seconds_wallSee crew_launcher().
tasks_maxSee crew_launcher().
tasks_timersSee crew_launcher().
tlsSee crew_launcher().
r_argumentsSee crew_launcher().
options_metricsSee crew_launcher().
urlWebsocket URL for worker connections.
profilemirai compute profile of the launcher.
launchesData frame tracking worker launches with one row
per launch. Each launch may create more than one worker.
Old superfluous rows are periodically discarded for efficiency.
The handle column is used internally for testing and
worker launching logic only.
Handles are not guaranteed to
persist for the full duration of a pipeline:
crew prunes old rows as workers connect and disconnect,
so handles may become unavailable in long-running
or high-throughput workflows.
throttleA crew_throttle() object to throttle scaling.
failedNumber of failed worker launches
(launches that exceed seconds_launch seconds to dial in).
Methods
Public methods
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Method new()
Launcher constructor.
Usage
crew_class_launcher$new(
name = NULL,
workers = NULL,
seconds_interval = NULL,
seconds_timeout = NULL,
seconds_launch = NULL,
seconds_idle = NULL,
seconds_wall = NULL,
seconds_exit = NULL,
tasks_max = NULL,
tasks_timers = NULL,
reset_globals = NULL,
reset_packages = NULL,
reset_options = NULL,
garbage_collection = NULL,
crashes_error = NULL,
launch_max = NULL,
tls = NULL,
processes = NULL,
r_arguments = NULL,
options_metrics = NULL
)
Arguments
nameSee crew_launcher().
workersSee crew_launcher().
seconds_intervalSee crew_launcher().
seconds_timeoutSee crew_launcher().
seconds_launchSee crew_launcher().
seconds_idleSee crew_launcher().
seconds_wallSee crew_launcher().
seconds_exitSee crew_launcher().
tasks_maxSee crew_launcher().
tasks_timersSee crew_launcher().
reset_globalsDeprecated. See crew_launcher().
reset_packagesDeprecated. See crew_launcher().
reset_optionsDeprecated. See crew_launcher().
garbage_collectionDeprecated. See crew_launcher().
crashes_errorSee crew_launcher().
launch_maxDeprecated.
tlsSee crew_launcher().
processesDeprecated on 2025-08-27 (crew version 1.2.1.9009).
r_argumentsSee crew_launcher().
options_metricsSee crew_launcher().
Returns
An R6 object with the launcher.
Examples
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local()
launcher$start(url = client$url, profile = client$profile)
launcher$launch()
task <- mirai::mirai("result", .compute = client$profile)
mirai::call_mirai(task)
task$data
client$terminate()
}
Method validate()
Validate the launcher.
Usage
crew_class_launcher$validate()
Returns
NULL (invisibly).
Method poll()
Poll the throttle.
Usage
crew_class_launcher$poll()
Returns
TRUE to run whatever work comes next, FALSE to skip
until the appropriate time.
Method settings()
List of arguments for mirai::daemon().
Usage
crew_class_launcher$settings()
Returns
List of arguments for mirai::daemon().
Method call()
Create a call to crew_worker() to
help create custom launchers.
Usage
crew_class_launcher$call(worker = NULL)
Arguments
workerDeprecated on 2025-08-28 (crew version 1.2.1.9009).
Returns
Character string with a call to crew_worker().
Examples
launcher <- crew_launcher_local()
launcher$start(url = "tcp://127.0.0.1:57000", profile = "profile")
launcher$call()
launcher$terminate()
Method start()
Start the launcher.
Usage
crew_class_launcher$start(url = NULL, profile = NULL, sockets = NULL)
Arguments
urlCharacter string, websocket URL for worker connections.
profileCharacter string, mirai compute profile.
socketsDeprecated on 2025-01-28 (crew version 1.0.0).
Returns
NULL (invisibly).
Method terminate()
Terminate the whole launcher, including all workers.
Usage
crew_class_launcher$terminate()
Returns
NULL (invisibly).
Method launch()
Launch a worker.
Usage
crew_class_launcher$launch(n = 1L)
Arguments
nPositive integer, number of workers to launch.
Returns
Handle of the launched worker (stored internally for
auto-scaling logic and testing but not
guaranteed to persist; see the launches field).
Method launch_worker()
Abstract worker launch method.
Usage
crew_class_launcher$launch_worker(call)
Arguments
callCharacter of length 1 with a namespaced call to
crew_worker() which will run in the worker and accept tasks.
Details
Launcher plugins will overwrite this method.
Returns
A handle to mock the worker launch.
Handles are used internally for testing and
worker launching logic only. They are not guaranteed
to persist in long-running or high-throughput pipelines
(see the launches field).
Method launch_workers()
Launch multiple workers.
Usage
crew_class_launcher$launch_workers(call, n)
Arguments
callCharacter of length 1 with a namespaced call to
crew_worker() which will run in each worker and accept tasks.
nPositive integer, number of workers to launch.
Details
Launcher plugins may overwrite this method
to launch multiple workers from a single system call.
Returns
A handle to mock the worker launch.
Handles are used internally for testing and
worker launching logic only. They are not guaranteed
to persist in long-running or high-throughput pipelines
(see the launches field).
Method scale()
Auto-scale workers out to meet the demand of tasks.
Usage
crew_class_launcher$scale(status, throttle = NULL)
Arguments
statusA mirai status list with worker and task information.
throttleDeprecated, only used in the controller
as of 2025-01-16 (crew version 0.10.2.9003).
Returns
Invisibly returns TRUE if there was any relevant
auto-scaling activity (new worker launches or worker
connection/disconnection events) (FALSE otherwise).
Method terminate_workers()
Deprecated on 2025-08-26
(crew version 1.2.1.9004).
Usage
crew_class_launcher$terminate_workers()
Returns
NULL (invisibly).
Method crashes()
Deprecated on 2025-01-28 (crew version 1.0.0).
Usage
crew_class_launcher$crashes(index = NULL)
Arguments
indexUnused argument.
Returns
The integer 1, for compatibility.
Method set_name()
Deprecated on 2025-01-28 (crew version 1.0.0).
Usage
crew_class_launcher$set_name(name)
Arguments
nameName to set for the launcher.
Returns
NULL (invisibly).
Method clone()
The objects of this class are cloneable with this method.
Usage
crew_class_launcher$clone(deep = FALSE)
Arguments
deepWhether to make a deep clone.
See Also
Other launcher:
crew_launcher()
Examples
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local()
launcher$start(url = client$url, profile = client$profile)
launcher$launch()
task <- mirai::mirai("result", .compute = client$profile)
mirai::call_mirai(task)
task$data
client$terminate()
}
## ------------------------------------------------
## Method `crew_class_launcher$new`
## ------------------------------------------------
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local()
launcher$start(url = client$url, profile = client$profile)
launcher$launch()
task <- mirai::mirai("result", .compute = client$profile)
mirai::call_mirai(task)
task$data
client$terminate()
}
## ------------------------------------------------
## Method `crew_class_launcher$call`
## ------------------------------------------------
launcher <- crew_launcher_local()
launcher$start(url = "tcp://127.0.0.1:57000", profile = "profile")
launcher$call()
launcher$terminate()
crew documentation built on Sept. 4, 2026, 9:07 a.m.
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| crew_class_launcher | R Documentation |
Launcher abstract class
Description
R6 abstract class to build other subclasses
which launch and manage workers.
Active bindings
nameSee
crew_launcher().workersSee
crew_launcher().seconds_intervalSee
crew_launcher().seconds_timeoutSee
crew_launcher().seconds_launchSee
crew_launcher().seconds_idleSee
crew_launcher().seconds_wallSee
crew_launcher().tasks_maxSee
crew_launcher().tasks_timersSee
crew_launcher().tlsSee
crew_launcher().r_argumentsSee
crew_launcher().options_metricsSee
crew_launcher().urlWebsocket URL for worker connections.
profilemiraicompute profile of the launcher.launchesData frame tracking worker launches with one row per launch. Each launch may create more than one worker. Old superfluous rows are periodically discarded for efficiency. The
handlecolumn is used internally for testing and worker launching logic only. Handles are not guaranteed to persist for the full duration of a pipeline:crewprunes old rows as workers connect and disconnect, so handles may become unavailable in long-running or high-throughput workflows.throttleA
crew_throttle()object to throttle scaling.failedNumber of failed worker launches (launches that exceed
seconds_launchseconds to dial in).
Methods
Public methods
Method new()
Launcher constructor.
Usage
crew_class_launcher$new( name = NULL, workers = 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, crashes_error = NULL, launch_max = NULL, tls = NULL, processes = NULL, r_arguments = NULL, options_metrics = NULL )
Arguments
nameSee
crew_launcher().workersSee
crew_launcher().seconds_intervalSee
crew_launcher().seconds_timeoutSee
crew_launcher().seconds_launchSee
crew_launcher().seconds_idleSee
crew_launcher().seconds_wallSee
crew_launcher().seconds_exitSee
crew_launcher().tasks_maxSee
crew_launcher().tasks_timersSee
crew_launcher().reset_globalsDeprecated. See
crew_launcher().reset_packagesDeprecated. See
crew_launcher().reset_optionsDeprecated. See
crew_launcher().garbage_collectionDeprecated. See
crew_launcher().crashes_errorSee
crew_launcher().launch_maxDeprecated.
tlsSee
crew_launcher().processesDeprecated on 2025-08-27 (
crewversion 1.2.1.9009).r_argumentsSee
crew_launcher().options_metricsSee
crew_launcher().
Returns
An R6 object with the launcher.
Examples
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local()
launcher$start(url = client$url, profile = client$profile)
launcher$launch()
task <- mirai::mirai("result", .compute = client$profile)
mirai::call_mirai(task)
task$data
client$terminate()
}
Method validate()
Validate the launcher.
Usage
crew_class_launcher$validate()
Returns
NULL (invisibly).
Method poll()
Poll the throttle.
Usage
crew_class_launcher$poll()
Returns
TRUE to run whatever work comes next, FALSE to skip
until the appropriate time.
Method settings()
List of arguments for mirai::daemon().
Usage
crew_class_launcher$settings()
Returns
List of arguments for mirai::daemon().
Method call()
Create a call to crew_worker() to
help create custom launchers.
Usage
crew_class_launcher$call(worker = NULL)
Arguments
workerDeprecated on 2025-08-28 (
crewversion 1.2.1.9009).
Returns
Character string with a call to crew_worker().
Examples
launcher <- crew_launcher_local() launcher$start(url = "tcp://127.0.0.1:57000", profile = "profile") launcher$call() launcher$terminate()
Method start()
Start the launcher.
Usage
crew_class_launcher$start(url = NULL, profile = NULL, sockets = NULL)
Arguments
urlCharacter string, websocket URL for worker connections.
profileCharacter string,
miraicompute profile.socketsDeprecated on 2025-01-28 (
crewversion 1.0.0).
Returns
NULL (invisibly).
Method terminate()
Terminate the whole launcher, including all workers.
Usage
crew_class_launcher$terminate()
Returns
NULL (invisibly).
Method launch()
Launch a worker.
Usage
crew_class_launcher$launch(n = 1L)
Arguments
nPositive integer, number of workers to launch.
Returns
Handle of the launched worker (stored internally for
auto-scaling logic and testing but not
guaranteed to persist; see the launches field).
Method launch_worker()
Abstract worker launch method.
Usage
crew_class_launcher$launch_worker(call)
Arguments
callCharacter of length 1 with a namespaced call to
crew_worker()which will run in the worker and accept tasks.
Details
Launcher plugins will overwrite this method.
Returns
A handle to mock the worker launch.
Handles are used internally for testing and
worker launching logic only. They are not guaranteed
to persist in long-running or high-throughput pipelines
(see the launches field).
Method launch_workers()
Launch multiple workers.
Usage
crew_class_launcher$launch_workers(call, n)
Arguments
callCharacter of length 1 with a namespaced call to
crew_worker()which will run in each worker and accept tasks.nPositive integer, number of workers to launch.
Details
Launcher plugins may overwrite this method to launch multiple workers from a single system call.
Returns
A handle to mock the worker launch.
Handles are used internally for testing and
worker launching logic only. They are not guaranteed
to persist in long-running or high-throughput pipelines
(see the launches field).
Method scale()
Auto-scale workers out to meet the demand of tasks.
Usage
crew_class_launcher$scale(status, throttle = NULL)
Arguments
statusA
miraistatus list with worker and task information.throttleDeprecated, only used in the controller as of 2025-01-16 (
crewversion 0.10.2.9003).
Returns
Invisibly returns TRUE if there was any relevant
auto-scaling activity (new worker launches or worker
connection/disconnection events) (FALSE otherwise).
Method terminate_workers()
Deprecated on 2025-08-26
(crew version 1.2.1.9004).
Usage
crew_class_launcher$terminate_workers()
Returns
NULL (invisibly).
Method crashes()
Deprecated on 2025-01-28 (crew version 1.0.0).
Usage
crew_class_launcher$crashes(index = NULL)
Arguments
indexUnused argument.
Returns
The integer 1, for compatibility.
Method set_name()
Deprecated on 2025-01-28 (crew version 1.0.0).
Usage
crew_class_launcher$set_name(name)
Arguments
nameName to set for the launcher.
Returns
NULL (invisibly).
Method clone()
The objects of this class are cloneable with this method.
Usage
crew_class_launcher$clone(deep = FALSE)
Arguments
deepWhether to make a deep clone.
See Also
Other launcher:
crew_launcher()
Examples
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local()
launcher$start(url = client$url, profile = client$profile)
launcher$launch()
task <- mirai::mirai("result", .compute = client$profile)
mirai::call_mirai(task)
task$data
client$terminate()
}
## ------------------------------------------------
## Method `crew_class_launcher$new`
## ------------------------------------------------
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local()
launcher$start(url = client$url, profile = client$profile)
launcher$launch()
task <- mirai::mirai("result", .compute = client$profile)
mirai::call_mirai(task)
task$data
client$terminate()
}
## ------------------------------------------------
## Method `crew_class_launcher$call`
## ------------------------------------------------
launcher <- crew_launcher_local()
launcher$start(url = "tcp://127.0.0.1:57000", profile = "profile")
launcher$call()
launcher$terminate()
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