tar_age {tarchetypes} | R Documentation |
Create a target that runs when the last run gets old
Description
tar_age()
creates a target that reruns
itself when it gets old enough.
In other words, the target reruns periodically at regular
intervals of time.
Usage
tar_age(
name,
command,
age,
pattern = NULL,
tidy_eval = targets::tar_option_get("tidy_eval"),
packages = targets::tar_option_get("packages"),
library = targets::tar_option_get("library"),
format = targets::tar_option_get("format"),
repository = targets::tar_option_get("repository"),
iteration = targets::tar_option_get("iteration"),
error = targets::tar_option_get("error"),
memory = targets::tar_option_get("memory"),
garbage_collection = targets::tar_option_get("garbage_collection"),
deployment = targets::tar_option_get("deployment"),
priority = targets::tar_option_get("priority"),
resources = targets::tar_option_get("resources"),
storage = targets::tar_option_get("storage"),
retrieval = targets::tar_option_get("retrieval"),
cue = targets::tar_option_get("cue"),
description = targets::tar_option_get("description")
)
Arguments
name |
Name of the target.
|
command |
R code to run the target and return a value. |
age |
A |
pattern |
Code to define a dynamic branching branching for a target.
In To demonstrate dynamic branching patterns, suppose we have
a pipeline with numeric vector targets |
tidy_eval |
Logical, whether to enable tidy evaluation
when interpreting |
packages |
Character vector of packages to load right before
the target runs or the output data is reloaded for
downstream targets. Use |
library |
Character vector of library paths to try
when loading |
format |
Logical, whether to rerun the target if the user-specified
storage format changed. The storage format is user-specified through
|
repository |
Logical, whether to rerun the target if the user-specified
storage repository changed. The storage repository is user-specified
through |
iteration |
Logical, whether to rerun the target if the user-specified
iteration method changed. The iteration method is user-specified through
|
error |
Character of length 1, what to do if the target stops and throws an error. Options:
|
memory |
Character of length 1, memory strategy. Possible values:
For cloud-based file targets
(e.g. |
garbage_collection |
Logical: |
deployment |
Character of length 1. If |
priority |
Deprecated on 2025-04-08 ( |
resources |
Object returned by |
storage |
Character string to control when the output of the target
is saved to storage. Only relevant when using
|
retrieval |
Character string to control when the current target
loads its dependencies into memory before running.
(Here, a "dependency" is another target upstream that the current one
depends on.) Only relevant when using
|
cue |
A |
description |
Character of length 1, a custom free-form human-readable
text description of the target. Descriptions appear as target labels
in functions like |
Details
tar_age()
uses the cue from tar_cue_age()
, which
uses the time stamps from targets::tar_meta()$time
.
See the help file of targets::tar_timestamp()
for an explanation of how this time stamp is calculated.
Value
A target object. See the "Target objects" section for background.
Dynamic branches at regular time intervals
Time stamps are not recorded for whole dynamic targets,
so tar_age()
is not a good fit for dynamic branching.
To invalidate dynamic branches at regular intervals,
it is recommended to use targets::tar_older()
in combination
with targets::tar_invalidate()
right before calling tar_make()
.
For example,
tar_invalidate(any_of(tar_older(Sys.time - as.difftime(1, units = "weeks"))))
# nolint
invalidates all targets more than a week old. Then, the next tar_make()
will rerun those targets.
Target objects
Most tarchetypes
functions are target factories,
which means they return target objects
or lists of target objects.
Target objects represent skippable steps of the analysis pipeline
as described at https://books.ropensci.org/targets/.
Please read the walkthrough at
https://books.ropensci.org/targets/walkthrough.html
to understand the role of target objects in analysis pipelines.
For developers, https://wlandau.github.io/targetopia/contributing.html#target-factories explains target factories (functions like this one which generate targets) and the design specification at https://books.ropensci.org/targets-design/ details the structure and composition of target objects.
See Also
Other cues:
tar_cue_age()
,
tar_cue_force()
,
tar_cue_skip()
Examples
if (identical(Sys.getenv("TAR_LONG_EXAMPLES"), "true")) {
targets::tar_dir({ # tar_dir() runs code from a temporary directory.
targets::tar_script({
library(tarchetypes)
list(
tarchetypes::tar_age(
data,
data.frame(x = seq_len(26)),
age = as.difftime(0.5, units = "secs")
)
)
})
targets::tar_make()
Sys.sleep(0.6)
targets::tar_make()
})
}