R/H2O.initializer.R

In frbl/OnlineSuperLearner: Online SuperLearner package

setOldClass("h2o")

#' H2O.Available
#'
#' Function to check whether the h2o cluster is already running
#' @import h2o
#' @return boolean TRUE if the cluster is running and FALSE if not.
#' @export
H2O.Available <- function() {
  ## TODO: It is bad practice to use this try-catch construction, but I could not find a method that
  ## would just return true false instead of throwing an error.
  result <- tryCatch({
    status <- h2o.clusterIsUp()
    if (status == FALSE) {
      return(FALSE)
    }
    return(TRUE) 
  }, warning = function(e) {
    warning(e)
    return(FALSE) 
  }, error = function(e) {
    return(FALSE) 
  })
  return(result)
}

#' H2O.Initializer
#'
#' This function is used to initialize the H2O cluster. Idealy I'd like to use
#' a singletonpattern for this, but this also seems to work.
#'
#' @import h2o
#' @param host the host on which H2O is or should be running
#' @param port the port for that host
#' @param runlocal boolean whether or not we should start an H2O cluster
#' @param verbose the verbosity to run with
#' @return boolean whther the cluster was initialized (TRUE) or was already running (FALSE)
#' @export
H2O.Initializer <- function(host = "localhost", port = 54321, runlocal = TRUE, verbose = FALSE) {
  h2o.no_progress()
  if(H2O.Available()) {
    verbose && cat(verbose, 'Cluster is up, not initializing.')
    return(FALSE)
  }
  verbose && enter(verbose, 'Initializing cluster...')
  h2o.init(
    ip = host,
    port = port,
    startH2O = runlocal
  )

  if(!h2o.clusterIsUp()) throw('Connecting to cluster failed, at host ', host)
  verbose && exit(verbose)
  return(TRUE)
}

##H2O.Initializer <-
##R6Class(
##"H2O.Initializer",
##private =
##list(
##localH2O = NULL
##),
##active =
##list(
##getValidity = function() {
##errors <- character()
##if(!h2o.clusterIsUp()) {
##msg <- 'The provided cluster is down. Please use a cluster that is up, or run a local one.'
##errors <- c(errors, msg)
##}
##if (length(errors) == 0) TRUE else errors
##}
##),
##public =
##list(
##initialize = function(host = "localhost", port = 54321, runlocal = TRUE) {
##if(!h2o.clusterIsUp()) {
##private$localH2O = h2o.init(ip = host, port = port, startH2O = runlocal)
##}
##}
##)
#)