Persistent configuration files

[gaborcsardi]

Via https://github.com/hadley/rappdirs? So that a config file survives the re-install of a package or project.

I am not sure if this is in the scope of config, just an idea. I am also not sure how it would work together with the current mechanism of looking for the config file in the parent directories.

[jimhester]

FWIW I think this is a good suggestion. Another idea would be to have the fallback in the home directory, possibly prefixed with .. I think we could support all of them by looking for values in the following order

1. Current working directory
2. Parent directories
3. Application directories
4. Home directory

Something like

fallback <- function(..., appname, file = "config.yml", use_parent = TRUE) {
  res <- tryCatch(config::get(..., file = file, use_parent = use_parent), error = function(e) NULL)

  if (!is.null(res)) {
    return(res)
  }
  for (file_path in c(
      file.path(rappdirs::user_config_dir(appname), file),
      file.path(Sys.getenv("HOME"), paste0(".", file)))) {
    res <- tryCatch(config::get(..., file = file_path, use_parent = FALSE), error = function(e) NULL)
    if (!is.null(res)) {
      return(res)
    }
  }
  NULL
}

[gaborcsardi]

The user's application directories are already in the home directory, so I would personally omit 4.

❯ rappdirs::user_log_dir(os = "unix")
[1] "/Users/gaborcsardi/.cache/log"
❯ rappdirs::user_data_dir(os = "unix")
[1] "/Users/gaborcsardi/.local/share"
❯ rappdirs::user_config_dir(os = "unix")
[1] "/Users/gaborcsardi/.config"
❯ rappdirs::user_cache_dir(os = "unix")
[1] "/Users/gaborcsardi/.cache"

[gaborcsardi]

Btw. 4. is probably also included in 2...