R/write_distribution.R

In rDataPipeline: Functions to Interact with the 'FAIR Data Pipeline'

#' Write distribution component to TOML file
#'
#' @param distribution a \code{string} specifying the name of the distribution
#' @param parameters a \code{list} specifying the distribution parameters
#' @param handle an object of class \code{fdp, R6} containing metadata required
#' by the Data Pipeline API
#' @param data_product a \code{string} specifying the name of the data product
#' @param component a \code{string} specifying a location within the toml file
#' @param description a \code{string} describing the data product component
#'
#' @return Returns a handle index associated with the just written component,
#' which can be used to raise an issue if necessary
#'
#' @family write functions
#' @export
#'
write_distribution <- function(distribution,
                               parameters,
                               handle,
                               data_product,
                               component,
                               description) {

  # If data product is already recorded in handle return index
  index <- check_handle(handle, data_product, "outputs", component)
  if (!is.null(index)) return(invisible(index))

  # If data product is missing from config file throw an error
  check_config(handle, data_product, "write")

  # Get metadata ------------------------------------------------------------

  write_metadata <- resolve_write(handle = handle,
                                  data_product = data_product,
                                  file_type = "toml")
  write_data_product <- write_metadata$data_product
  write_version <- write_metadata$version
  write_namespace <- write_metadata$namespace
  write_public <- write_metadata$public
  data_product_decription <- write_metadata$description
  path <- write_metadata$path

  # Checks ------------------------------------------------------------------

  if (!is.list(parameters))
    usethis::ui_stop("parameters should be a list")

  # If path doesn't exist, generate directory structure
  directory <- dirname(path)
  if (!file.exists(directory)) dir.create(directory, recursive = TRUE)

  # Write toml file ---------------------------------------------------------

  start <- paste0("[", component, "]\n",
                  "type = \"distribution\"\n",
                  "distribution = \"", distribution, "\"\n")

  end <- vapply(seq_along(parameters), function(x)
    paste0(names(parameters[x]), " = ", parameters[x]),
    FUN.VALUE = character(1)) %>%
    paste0(collapse = "\n")

  contents <- paste0(start, end, "\n")

  if (file.exists(path)) {

    # Check that component doesn't already exist
    existing <- configr::read.config(file = path)
    if (component %in% names(existing))
      usethis::ui_stop("{component} is already listed in toml file")

    cat(paste0("\n", contents), file = path, append = TRUE)

  } else {
    cat(contents, file = path, append = FALSE)
  }

  cli::cli_alert_success(
    "Writing {.value {write_data_product}} to file")

  # Write to handle ---------------------------------------------------------

  handle$output(data_product = data_product,
                use_data_product = write_data_product,
                use_component = component,
                use_version = write_version,
                use_namespace = write_namespace,
                path = path,
                data_product_description = data_product_decription,
                component_description = description,
                public = write_public)

  invisible(handle$output_index(data_product = data_product,
                                component = component,
                                version = write_version,
                                namespace = write_namespace))
}