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Get the igraph.

Source: R/tar_igraph.R
tar_igraph.Rd

Return an igraph object with the dependency graph of the pipeline.

Usage

tar_igraph(
  targets_only = FALSE,
  callr_function = callr::r,
  callr_arguments = targets::tar_callr_args_default(callr_function),
  envir = parent.frame(),
  script = targets::tar_config_get("script")
)

Arguments

targets_only

TRUE to restrict the output to just the actual targets in the pipeline, FALSE to include imported global functions and objects as well.

callr_function

A function from callr to start a fresh clean R process to do the work. Set to NULL to run in the current session instead of an external process (but restart your R session just before you do in order to clear debris out of the global environment). callr_function needs to be NULL for interactive debugging, e.g. tar_option_set(debug = "your_target"). However, callr_function should not be NULL for serious reproducible work.

callr_arguments

A list of arguments to callr_function.

envir

An environment, where to run the target R script (default: _targets.R) if callr_function is NULL. Ignored if callr_function is anything other than NULL. callr_function should only be NULL for debugging and testing purposes, not for serious runs of a pipeline, etc.

The envir argument of tar_make() and related functions always overrides the current value of tar_option_get("envir") in the current R session just before running the target script file, so whenever you need to set an alternative envir, you should always set it with tar_option_set() from within the target script file. In other words, if you call tar_option_set(envir = envir1) in an interactive session and then tar_make(envir = envir2, callr_function = NULL), then envir2 will be used.

script

Character of length 1, path to the target script file. Defaults to tar_config_get("script"), which in turn defaults to _targets.R. When you set this argument, the value of tar_config_get("script") is temporarily changed for the current function call. See tar_script(), tar_config_get(), and tar_config_set() for details about the target script file and how to set it persistently for a project.

Value

An igraph object with the dependency graph.

Details

If you have igraph >= 2.2.0 installed, then you can debug cycles in your pipeline by running igraph::find_cycle(tar_igraph()). This helps detect cycles in the dependency graph of the pipeline. A cycle happens when a target directly or indirectly depends on itself, which is not allowed. igraph::find_cycle() returns a character vector of the names of the targets and objects involved in the cycle (if a cycle exists).

See also

Other inspect: tar_deps(), tar_manifest(), tar_network(), tar_outdated(), tar_sitrep(), tar_validate()

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) { # for CRAN
  tar_dir({ # tar_dir() runs code from a temp dir for CRAN.
    tar_script(
      list(
        tar_target(x, 1),
        tar_target(y, 2)
      ),
      ask = FALSE
    )
    tar_igraph()
  })
}