R/write_runtime.R

In karthik/holepunch: Configure Your R Project for 'binderhub'

#' Write runtime.txt
#'
#' This function writes the language (in this case R) and a date from which
#' packages will be downloaded from \href{https://mran.microsoft.com/}{MRAN}. The file is written to a hidden folder
#' called `.binder/`.
#'
#' @param path Path to project
#' @template r_date
#' @param version Version of R to lock down.
#' @importFrom lubridate ymd today
#'
#' @export
#'
write_runtime <-
  function(path = ".",
          version = NULL,
             r_date = lubridate::ymd(lubridate::today())) {
    path <- sanitize_path(path) # To kill trailing slashes
    if (fs::file_exists(glue::glue("{path}/.binder/Dockerfile"))) {
      warning(
        glue::glue(
          "A Dockerfile exists in {path}/.binder/. This means that all other 
          settings (runtime.txt and install.R) will be ignored. Consider 
          deleting the Dockerfile if you wish to take the runtime approach"
        )
      )
    }
    if(is.null(version)) {
      txt <- glue::glue("r-{r_date}")  
    } else {
      txt <- glue::glue("r-{version}-{r_date}")
    }
    
    fs::dir_create(glue::glue("{path}/.binder"))
    fileConn <- file(glue::glue("{path}/.binder/runtime.txt"))
    writeLines(txt, fileConn)
    close(fileConn)
  }