Create an abstract launcher.

This function is useful for inheriting argument documentation in functions that create custom third-party launchers. See @inheritParams crew::crew_launcher in the source code file of crew_launcher_local().

Usage

crew_launcher(
  name = NULL,
  seconds_interval = 0.5,
  seconds_timeout = 60,
  seconds_launch = 30,
  seconds_idle = 300,
  seconds_wall = Inf,
  seconds_exit = NULL,
  tasks_max = Inf,
  tasks_timers = 0L,
  reset_globals = TRUE,
  reset_packages = FALSE,
  reset_options = FALSE,
  garbage_collection = FALSE,
  crashes_error = 5L,
  launch_max = NULL,
  tls = crew::crew_tls(),
  processes = NULL,
  r_arguments = c("--no-save", "--no-restore"),
  options_metrics = crew::crew_options_metrics()
)

Arguments

name: Name of the launcher.
seconds_interval: Number of seconds between polling intervals waiting for certain internal synchronous operations to complete, such as checking mirai::status().
seconds_timeout: Number of seconds until timing out while waiting for certain synchronous operations to complete, such as checking mirai::status().
seconds_launch: Seconds of startup time to allow. A worker is unconditionally assumed to be alive from the moment of its launch until seconds_launch seconds later. After seconds_launch seconds, the worker is only considered alive if it is actively connected to its assign websocket.
seconds_idle: Maximum number of seconds that a worker can idle since the completion of the last task. If exceeded, the worker exits. But the timer does not launch until tasks_timers tasks have completed. See the idletime argument of mirai::daemon(). crew does not excel with perfectly transient workers because it does not micromanage the assignment of tasks to workers, so please allow enough idle time for a new worker to be delegated a new task.
seconds_wall: Soft wall time in seconds. The timer does not launch until tasks_timers tasks have completed. See the walltime argument of mirai::daemon().
seconds_exit: Deprecated on 2023-09-21 in version 0.5.0.9002. No longer necessary.
tasks_max: Maximum number of tasks that a worker will do before exiting. See the maxtasks argument of mirai::daemon(). crew does not excel with perfectly transient workers because it does not micromanage the assignment of tasks to workers, it is recommended to set tasks_max to a value greater than 1.
tasks_timers: Number of tasks to do before activating the timers for seconds_idle and seconds_wall. See the timerstart argument of mirai::daemon().
reset_globals: TRUE to reset global environment variables between tasks, FALSE to leave them alone.
reset_packages: TRUE to unload any packages loaded during a task (runs between each task), FALSE to leave packages alone.
reset_options: TRUE to reset global options to their original state between each task, FALSE otherwise. It is recommended to only set reset_options = TRUE if reset_packages is also TRUE because packages sometimes rely on options they set at loading time.
garbage_collection: TRUE to run garbage collection between tasks, FALSE to skip.
crashes_error: Positive integer scalar. If a worker exits crashes_error times in a row without completing all its assigned tasks, then the launcher throws an informative error. The reason for crashes_error is to avoid an infinite loop where a task crashes a worker (through a segfault, maxing out memory, etc) but the worker always relaunches. To monitor the resources of crew workers, please see https://wlandau.github.io/crew/articles/logging.html.
launch_max: Deprecated on 2024-11-04 (version 0.10.1.9000). Use crashes_error instead.
tls: A TLS configuration object from crew_tls().
processes: NULL or positive integer of length 1, number of local processes to launch to allow worker launches to happen asynchronously. If NULL, then no local processes are launched. If 1 or greater, then the launcher starts the processes on start() and ends them on terminate(). Plugins that may use these processes should run asynchronous calls using launcher$async$eval() and expect a mirai task object as the return value.
r_arguments: Optional character vector of command line arguments to pass to Rscript (non-Windows) or Rscript.exe (Windows) when starting a worker. Example: r_arguments = c("--vanilla", "--max-connections=32").
options_metrics: Either NULL to opt out of resource metric logging for workers, or an object from crew_options_metrics() to enable and configure resource metric logging for workers. For resource logging to run, the autometric R package version 0.1.0 or higher must be installed.

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()
}

Usage

Arguments

See also

Examples