R/load.R

In datasketch/dsvalidate: Validate data for DS apps

#' Load requirements for validation
#'
#' Loads and checks the requirements.yaml file, raises necessary
#' errors and warnings if necessary, and prepares it for use by
#' validate_requirements.
#'
#' @param path Path for the requirements.yaml file; default is 'dsvalidate'
#' @param filename Filename of requirements file, default is 'requirements.yaml'
#'
#' @return List of requirements
#' @export
requirements_load <- function(path = "dsvalidate", filename = "requirements.yaml"){

  if(!dir.exists(path)) stop("dsvalidate folder not found")

  if(!grepl(".yaml", filename)) stop("Requirements file needs to be of type .yaml.")

  file_path <- file.path(path, filename)
  file_exists <- file.exists(file_path)

  if(!file_exists) stop("Requirements file not found.")

  requirements <- yaml::read_yaml(file_path)

  if(length(requirements) == 0) stop("Requirements file empty.")

  table_specs_exist <- "table" %in% names(requirements)
  if(!table_specs_exist) stop("Requirements file doesn't contain table specs.")

  table_names <- names(requirements$table)

  table_specs_non_empty <- length(table_names) > 0
  if(!table_specs_non_empty) stop("Requirements file doesn't contain table specs.")

  table_names %>% purrr::map(function(.x){
    if(any(!c("table_id", "specs", "fields") %in% names(requirements$table[[.x]]))) stop("All table requirements must include table_id, specs, and fields.")
  })

  # Stop if missing table requirements and make greater_than 0 default if no n_cols or n_rows specification
  requirements$table <- requirements$table %>% purrr::map(function(.x){
    if(any(!c("table_id", "specs", "fields") %in% names(.x))) stop("All table requirements must include table_id, specs, and fields.")
    if(!"n_cols" %in% names(.x$specs)) .x$specs$n_cols <- list(greater_than = 0)
    if(!"n_rows" %in% names(.x$specs)) .x$specs$n_rows <- list(greater_than = 0)

    .x$fields <- check_fields(.x$field)
    .x
  })

  requirements
}



check_fields <- function(fields){
  fields %>% purrr::map(function(.x){
    .x$n_cols <- check_req_n_cols(n_cols = .x$n_cols)
    .x$specs <- check_specs(specs = .x$specs)
    if(is.null(.x$id_required)) .x$id_required <- FALSE
    .x
  })
}


check_specs <- function(specs){
  if(is.null(specs)) stop("Column specs missing.")
  # If `equals` has been left out as short-cut it is added here
  for(specs_type in names(specs)){
    specification <- specs[[specs_type]]
    if(!is.list(specification)) specs[[specs_type]] <- list(equals = specification)
  }

  specs
}


check_req_n_cols <- function(n_cols){
  # If n_cols is null, must be greater than 0
  if(is.null(n_cols)) n_cols <- list(greater_than = 0)
  # If n_cols greater than 0 has been left out as short-cut it is added here
  if(!is.list(n_cols)) n_cols <- list(equals = n_cols)
  n_cols
}