Get the timestamp associated with a target's last successful run.

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

Arguments

name

Symbol, 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.

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 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.

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.

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 formats like "aws_rds" and "url", then targets chooses instead to simply record the time the target last successfully ran.

See also

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) {
tar_dir({ # tar_dir() runs code from a temporary directory.
tar_script({
  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()
})
}