tar_process: Get main process info.

In targets: Dynamic Function-Oriented 'Make'-Like Declarative Pipelines

Get main process info.

Description

Get info on the most recent main R process to orchestrate the targets of the current project.

Usage

tar_process(names = NULL, store = targets::tar_config_get("store"))

Arguments

names	Optional, names of the data points to return. If supplied, tar_process() returns only the rows of the names you select. The object supplied to names should be NULL or a tidyselect expression like any_of() or starts_with().
store	Character of length 1, path to the targets data store. Defaults to tar_config_get("store"), which in turn defaults to ⁠_targets/⁠. When you set this argument, the value of tar_config_get("store") is temporarily changed for the current function call. See tar_config_get() and tar_config_set() for details about how to set the data store path persistently for a project.

Details

The main process is the R process invoked by tar_make() or similar. If callr_function is not NULL, this is an external process, and the pid in the return value will not agree with Sys.getpid() in your current interactive session. The process may or may not be alive. You may want to check the status with tar_pid() %in% ps::ps_pids() before running another call to tar_make() for the same project.

Value

A data frame with metadata on the most recent main R process to orchestrate the targets of the current project. The output includes the pid of the main process.

Storage access

Several functions like tar_make(), tar_read(), tar_load(), tar_meta(), and tar_progress() read or modify the local data store of the pipeline. The local data store is in flux while a pipeline is running, and depending on how distributed computing or cloud computing is set up, not all targets can even reach it. So please do not call these functions from inside a target as part of a running pipeline. The only exception is literate programming target factories in the tarchetypes package such as tar_render() and tar_quarto().

See Also

Other data: tar_crew(), tar_pid()

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) { # for CRAN
tar_dir({ # tar_dir() runs code from a temp dir for CRAN.
tar_script({
  library(targets)
  library(tarchetypes)
  list(
    tar_target(x, seq_len(2)),
    tar_target(y, 2 * x, pattern = map(x))
  )
}, ask = FALSE)
tar_make()
tar_process()
tar_process(pid)
})
}

targets documentation built on Oct. 3, 2024, 1:11 a.m.