R6 abstract class to build other subclasses
which launch and manage workers.
See also
Other launcher:
crew_launcher()
Active bindings
workersData frame of worker information.
nameName of the 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().reset_globalsSee
crew_launcher().reset_packagesSee
crew_launcher().reset_optionsSee
crew_launcher().garbage_collectionSee
crew_launcher().launch_maxSee
crew_launcher().tlsSee
crew_launcher().processesSee
crew_launcher(). asynchronously.asyncA
crew_async()object to run low-level launcher tasks asynchronously.throttleA
crew_throttle()object to throttle scaling.
Methods
Method new()
Launcher constructor.
Usage
crew_class_launcher$new(
name = NULL,
seconds_interval = NULL,
seconds_timeout = NULL,
seconds_launch = NULL,
seconds_idle = NULL,
seconds_wall = NULL,
seconds_exit = NULL,
tasks_max = NULL,
tasks_timers = NULL,
reset_globals = NULL,
reset_packages = NULL,
reset_options = NULL,
garbage_collection = NULL,
launch_max = NULL,
tls = NULL,
processes = NULL
)Arguments
nameSee
crew_launcher().seconds_intervalSee
crew_launcher().seconds_timeoutSee
crew_launcher().seconds_launchSee
crew_launcher().seconds_idleSee
crew_launcher().seconds_wallSee
crew_launcher().seconds_exitSee
crew_launcher().tasks_maxSee
crew_launcher().tasks_timersSee
crew_launcher().reset_globalsSee
crew_launcher().reset_packagesSee
crew_launcher().reset_optionsSee
crew_launcher().garbage_collectionSee
crew_launcher().launch_maxSee
crew_launcher().tlsSee
crew_launcher().processesSee
crew_launcher().
Examples
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local(name = client$name)
launcher$start(workers = client$workers)
launcher$launch(index = 1L)
m <- mirai::mirai("result", .compute = client$name)
Sys.sleep(0.25)
m$data
client$terminate()
}Method settings()
List of arguments for mirai::daemon().
Returns
List of arguments for mirai::daemon().
Method call()
Create a call to crew_worker() to
help create custom launchers.
Arguments
socketSocket where the worker will receive tasks.
launcherCharacter of length 1, name of the launcher.
workerPositive integer of length 1, index of the worker. This worker index remains the same even when the current instance of the worker exits and a new instance launches.
instanceCharacter of length 1 to uniquely identify the instance of the worker.
Returns
Character of length 1 with a call to crew_worker().
Examples
launcher <- crew_launcher_local()
launcher$call(
socket = "ws://127.0.0.1:5000/3/cba033e58",
launcher = "launcher_a",
worker = 3L,
instance = "cba033e58"
)Method start()
Start the launcher.
Method summary()
Summarize the workers.
Returns
NULL if the launcher is not started. Otherwise, a tibble
with one row per crew worker and the following columns:
worker: integer index of the worker.launches: number of times the worker was launched. Each launch occurs at a different websocket because the token at the end of the URL is rotated before each new launch.online: logical vector, whether the current instance of each worker was actively connected to its NNG socket during the time of the last call totally().discovered: logical vector, whether the current instance of each worker had connected to its NNG socket at some point (and then possibly disconnected) during the time of the last call totally().assigned: cumulative number of tasks assigned, reported bymirai::daemons()and summed over all completed instances of the worker. Does not reflect the activity of the currently running instance of the worker.complete: cumulative number of tasks completed, reported bymirai::daemons()and summed over all completed instances of the worker. Does not reflect the activity of the currently running instance of the worker.socket: current websocket URL of the worker.
Method unlaunched()
Get indexes of unlaunched workers.
Method booting()
Get workers that may still be booting up.
Details
A worker is "booting" if its launch time is within the last
seconds_launch seconds. seconds_launch is a configurable grace
period when crew allows a worker to start up and connect to the
mirai dispatcher. The booting() function does not know about the
actual worker connection status, it just knows about launch times,
so it may return TRUE for workers that have already connected
and started doing tasks.
Method active()
Get active workers.
Method done()
Get done workers.
Method forward()
Forward an asynchronous launch/termination error condition of a worker.
Arguments
indexInteger of length 1, index of the worker to inspect.
conditionCharacter of length 1 indicating what to do with an error if found.
"error"to throw an error,"warning"to throw a warning,"message"to print a message, and"character"to return a character vector of specific task-level error messages. The return value isNULLif no error is found.
Method errors()
Collect and return the most recent error messages from asynchronous worker launching and termination.
Method scale()
Auto-scale workers out to meet the demand of tasks.
Arguments
demandNumber of unresolved tasks.
throttleTRUEto skip auto-scaling if it already happened within the lastseconds_intervalseconds.FALSEto auto-scale every timescale()is called. Throttling avoids overburdening themiraidispatcher and other resources.
Method launch_worker()
Abstract worker launch method.
Arguments
callCharacter of length 1 with a namespaced call to
crew_worker()which will run in the worker and accept tasks.nameCharacter of length 1 with an informative worker name.
launcherCharacter of length 1, name of the launcher.
workerPositive 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.
instanceCharacter of length 1 to uniquely identify the current instance of the worker a the index in the launcher.
Method terminate_worker()
Abstract worker termination method.
Examples
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local(name = client$name)
launcher$start(workers = client$workers)
launcher$launch(index = 1L)
m <- mirai::mirai("result", .compute = client$name)
Sys.sleep(0.25)
m$data
client$terminate()
}
## ------------------------------------------------
## Method `crew_class_launcher$new`
## ------------------------------------------------
if (identical(Sys.getenv("CREW_EXAMPLES"), "true")) {
client <- crew_client()
client$start()
launcher <- crew_launcher_local(name = client$name)
launcher$start(workers = client$workers)
launcher$launch(index = 1L)
m <- mirai::mirai("result", .compute = client$name)
Sys.sleep(0.25)
m$data
client$terminate()
}
## ------------------------------------------------
## Method `crew_class_launcher$call`
## ------------------------------------------------
launcher <- crew_launcher_local()
launcher$call(
socket = "ws://127.0.0.1:5000/3/cba033e58",
launcher = "launcher_a",
worker = 3L,
instance = "cba033e58"
)
#> [1] "crew::crew_worker(settings = list(url = \"ws://127.0.0.1:5000/3/cba033e58\", autoexit = 15L, cleanup = 1L, output = TRUE, maxtasks = Inf, idletime = Inf, walltime = Inf, timerstart = 0L, tls = NULL, rs = NULL), launcher = \"launcher_a\", worker = 3L, instance = \"cba033e58\")"