R/distro.R

In distro: Linux Distribution Properties

#' Get info on the system's Linux distribution
#'
#' @return On Linux distributions, it returns a list of four elements:
#' * `id`, e.g. "ubuntu", "debian"
#' * `version`, e.g. "18.04", "7.7.1908"
#' * `codename`, e.g. "bionic", "bullseye"
#' * `short_version`, which for Ubuntu is the `yy.mm` version ("18.04") but for
#'   all other distributions is the major version number only ("7")
#'
#' Not all fields are guaranteed to be defined on all systems. On non-Linux
#' systems, the function returns `NULL`.
#' @export
#' @examples
#' distro()
distro <- function() {
  out <- lsb_release()
  if (is.null(out)) {
    out <- os_release()
    if (is.null(out)) {
      out <- system_release()
    }
  }
  if (is.null(out)) {
    return(NULL)
  }

  out$id <- tolower(out$id)
  if (grepl("bullseye", out$codename)) {
    # debian unstable doesn't include a number but we can map from pretty name
    out$short_version <- "11"
  } else if (out$id == "ubuntu") {
    # Keep major.minor version
    out$short_version <- sub('^"?([0-9]+\\.[0-9]+).*"?.*$', "\\1", out$version)
  } else {
    # Only major version number
    out$short_version <- sub('^"?([0-9]+).*"?.*$', "\\1", out$version)
  }
  out
}

lsb_release <- function() {
  if (have_lsb_release()) {
    list(
      id = call_lsb("-is"),
      version = call_lsb("-rs"),
      codename = call_lsb("-cs")
    )
  } else {
    NULL
  }
}

have_lsb_release <- function() nzchar(Sys.which("lsb_release"))
call_lsb <- function(args) system(paste("lsb_release", args), intern = TRUE)

os_release <- function() {
  rel_data <- read_os_release()
  if (!is.null(rel_data)) {
    vals <- as.list(sub('^.*="?(.*?)"?$', "\\1", rel_data))
    names(vals) <- sub("^(.*)=.*$", "\\1", rel_data)

    out <- list(
      id = vals[["ID"]],
      version = vals[["VERSION_ID"]]
    )
    if ("VERSION_CODENAME" %in% names(vals)) {
      out$codename <- vals[["VERSION_CODENAME"]]
    } else {
      # This probably isn't right, maybe could extract codename from pretty name?
      out$codename = vals[["PRETTY_NAME"]]
    }
    out
  } else {
    NULL
  }
}

read_os_release <- function() {
  if (file.exists("/etc/os-release")) {
    readLines("/etc/os-release")
  }
}

system_release <- function() {
  rel_data <- read_system_release()
  if (!is.null(rel_data)) {
    # Something like "CentOS Linux release 7.7.1908 (Core)"
    list(
      id = sub("^([a-zA-Z]+) .* ([0-9.]+).*$", "\\1", rel_data),
      version = sub("^([a-zA-Z]+) .* ([0-9.]+).*$", "\\2", rel_data),
      codename = NA
    )
  } else {
    NULL
  }
}

read_system_release <- function() {
  if (file.exists("/etc/system-release")) {
    readLines("/etc/system-release")[1]
  }
}