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Stop workers

Source: R/rrq_workers.R
rrq_worker_stop.Rd

Stop workers, causing them to exit. Workers can be stopped in a few different ways (see Details), but after executing this function, assume that any worker targeted will no longer be available to work on tasks.

Usage

rrq_worker_stop(
  worker_ids = NULL,
  type = "message",
  timeout = 0,
  time_poll = 0.1,
  progress = NULL,
  controller = NULL
)

Arguments

worker_ids

Optional vector of worker ids. If NULL then all active workers will be stopped.

type

The strategy used to stop the workers. Can be message, kill or kill_local (see Details).

timeout

Optional timeout; if greater than zero then we poll for a response from the worker for this many seconds until they acknowledge the message and stop (only has an effect if type is message). If a timeout of greater than zero is given, then for a message-based stop we wait up to this many seconds for the worker to exit. That means that we might wait up to 2 * timeout seconds for this function to return.

time_poll

If type is message and timeout is greater than zero, this is the polling interval used between redis calls. Increasing this reduces network load but decreases the ability to interrupt the process.

progress

Optional logical indicating if a progress bar should be displayed. If NULL we fall back on the value of the global option rrq.progress, and if that is unset display a progress bar if in an interactive session.

controller

The controller to use. If not given (or NULL) we'll use the controller registered with rrq_default_controller_set().

Value

The names of the stopped workers, invisibly.

Details

The type parameter indicates the strategy used to stop workers, and interacts with other parameters. The strategies used by the different values are:

  • message, in which case a STOP message will be sent to the worker, which they will receive after finishing any currently running task (if RUNNING; IDLE workers will stop immediately).

  • kill, in which case a kill signal will be sent via the heartbeat (if the worker is using one). This will kill the worker even if is currently working on a task, eventually leaving that task with a status of DIED.

  • kill_local, in which case a kill signal is sent using operating system signals, which requires that the worker is on the same machine as the controller.

Examples

if (FALSE) { # rrq:::enable_examples(require_queue = "rrq:example")
obj <- rrq_controller("rrq:example")
w <- rrq_worker_spawn(controller = obj)
rrq_worker_list(controller = obj)
rrq_worker_stop(w$id, timeout = 10, controller = obj)
rrq_worker_list(controller = obj)
}