tar_timestamp: Get the timestamp(s) of a target.

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

Get the timestamp(s) of a target.

Description

Get the timestamp associated with a target's last successful run. tar_timestamp() expects the name argument to be an unevaluated symbol, whereas tar_timestamp_raw() expects name to be a character string.

Usage

tar_timestamp(
  name = NULL,
  format = NULL,
  tz = NULL,
  parse = NULL,
  store = targets::tar_config_get("store")
)

tar_timestamp_raw(
  name = NULL,
  format = NULL,
  tz = NULL,
  parse = NULL,
  store = targets::tar_config_get("store")
)

Arguments

name	Name of the target. If NULL (default) then tar_timestamp() will attempt to return the timestamp of the target currently running. Must be called inside a target's command or a supporting function in order to work. tar_timestamp() expects the name argument to be an unevaluated symbol, whereas tar_timestamp_raw() expects name to be a character string.
format	Deprecated in targets version 0.6.0 (2021-07-21).
tz	Deprecated in targets version 0.6.0 (2021-07-21).
parse	Deprecated in targets version 0.6.0 (2021-07-21).
store	Character string, directory path to the data store of the pipeline.

Details

tar_timestamp() checks the metadata in ⁠_targets/meta/meta⁠, not the actual returned data of the target. The timestamp depends on the storage format of the target. If storage is local, e.g. formats like "rds" and "file", then the time stamp is the latest modification time of the target data files at the time the target last successfully ran. For non-local storage as with repository = "aws" and format = "url", targets chooses instead to simply record the time the target last successfully ran.

Value

If the target is not recorded in the metadata or cannot be parsed correctly, then tar_timestamp() returns a POSIXct object at ⁠1970-01-01 UTC⁠.

See Also

Other time: tar_newer(), tar_older()

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, 1))
}, ask = FALSE)
tar_make()
# Get the timestamp.
tar_timestamp(x)
# We can use the timestamp to cancel the target
# if it already ran within the last hour.
# Be sure to set `cue = tar_cue(mode = "always")`
# if you want the target to always check the timestamp.
tar_script({
  list(
  tar_target(
    x,
    tar_cancel((Sys.time() - tar_timestamp()) < 3600),
    cue = tar_cue(mode = "always")
  )
)}, ask = FALSE)
tar_make()
})
}

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