TaskJob R6 Class — TaskJob • cs9

Run a cs9 task in a background R process with live output streaming back to the current R console via later::later() polling. Equivalent in spirit to run_task_sequentially_as_rstudio_job_using_load_all() but does not depend on RStudio's job API (which Positron does not implement).

Methods:

$start() spawns the background process and starts to poll its output.
$wait(t) blocks this session until the task finishes. It drains the event loop while it waits.
$is_alive() returns TRUE while the background process runs.
$status() prints a brief status summary.
$tail(n) prints the last n lines of the log file (a snapshot, not live).
$kill() terminates the background process.

Public fields

task_name: Character string. Name of the task being run.
ss_prefix: Character string. R expression used to access the surveillance system in the child process.
script_path: Character string. Path to the temporary R script that is sourced in the background process.
log_path: Character string. Path to the log file where background process output is written.
started_at: POSIXct. Time at which $start() was called.
finished_at: POSIXct. Time at which the background process exited.

Methods

`TaskJob$new()`

Create a new TaskJob.

Usage

TaskJob$new(
  task_name,
  ss_prefix = "global$ss",
  log_dir = tempdir(check = TRUE)
)

Arguments

task_name: Character string. Name of the task to run, as registered in the surveillance system (e.g. ss$tasks[["my_task"]]).
ss_prefix: Character string. R expression that evaluates to the surveillance system object in the child process. Defaults to "global$ss".
log_dir: Character string. Directory where the temporary script and log file are written. Defaults to tempdir().

Returns

A new TaskJob object. Call $start() to launch the background process.

`TaskJob$start()`

Spawn the background process and start to poll its output.

Usage

TaskJob$start()

Returns

Invisibly returns the TaskJob object.

`TaskJob$is_alive()`

Check whether the background process is still running.

Usage

TaskJob$is_alive()

Returns

Logical. TRUE while the background process is alive.

`TaskJob$status()`

Print a brief status summary (task name, start time, alive status, log path).

Usage

TaskJob$status()

Returns

Invisibly returns the TaskJob object.

`TaskJob$wait()`

Block the current session until the background task finishes or the timeout expires. This method drains the later event loop while it waits.

Usage

TaskJob$wait(timeout_s = 600)

Arguments

timeout_s: Numeric. Maximum number of seconds to wait. Defaults to 600 (10 minutes).

Returns

Invisibly returns the TaskJob object.

`TaskJob$kill()`

Terminate the background process.

Usage

TaskJob$kill()

Returns

Invisibly returns the TaskJob object.

`TaskJob$tail()`

Print the last n lines of the task log file (snapshot, not live).

Usage

TaskJob$tail(n = 20)

Arguments

n: Integer. Number of trailing lines to show. Defaults to 20.

Returns

Invisibly returns the TaskJob object.

`TaskJob$clone()`

The objects of this class are cloneable with this method.

Usage

TaskJob$clone(deep = FALSE)

Arguments

deep: Whether to make a deep clone.

Examples

if (FALSE) { # \dontrun{
job <- TaskJob$new("my_task")
job$start()
job$status()
job$wait(timeout_s = 120)
job$tail(n = 30)
} # }