sysInstallAndDownload: download.files or install.packages in a separate process

Description

This uses sys package so that messaging can be controlled. This also provides the option to parallelize by spawning multiple background process to allow parallel e.g., downloads. Noting that if libcurl is installed (and detected using capabilities("libcurl")), then no explicit parallelism will be allowed, instead method = "libcurl" will be passed enabling parallel downloads.

Usage

sysInstallAndDownload(
  args,
  splitOn = "pkgs",
  doLine = "outfiles <- do.call(download.packages, args)",
  returnOutfile = FALSE,
  doLineVectorized = TRUE,
  tmpdir,
  libPaths,
  verbose
)

Value

Mostly for side effects, namely installed packages or downloaded packages or files. However, in the case of returnOutfile = TRUE, then a list of filenames will be returned with any outputs from the doLine.

Arguments

args: A list with all arguments for a do.call to either download.file, install.packagesor a custom other function e.g.,downloadAndBuildToLocalFile`.
splitOn: A character vector of the names in args to parallelize over. Defaults to pkgs. All other named elements in args will be assumed to be length 1 and used for every parallel process.
doLine: A character string with the "outfiles <- do.call(..., args)" line.
returnOutfile: A logical. If TRUE, then the names of the outfiles will be returned.
doLineVectorized: A logical. If TRUE, and parallism is being used, this indicates that the doLine is a function that allows for multiple elements in args[[splitOn[[1]]]. If FALSE, the function will make multiple sequential calls within each parallel process to the doLine call.
tmpdir: A single path where all downloads will be put
libPaths: The library path (or libraries) where all packages should be installed, and looked for to load (i.e., call library). This can be used to create isolated, stand alone package installations, if used with standAlone = TRUE. Currently, the path supplied here will be prepended to .libPaths() (temporarily during this call) to Require if standAlone = FALSE or will set (temporarily) .libPaths() to c(libPaths, tail(libPaths(), 1) to keep base packages.
verbose: Numeric or logical indicating how verbose should the function be. If -1 or -2, then as little verbosity as possible. If 0 or FALSE, then minimal outputs; if 1 or TRUE, more outputs; 2 even more. NOTE: in Require function, when verbose >= 2, also returns details as if returnDetails = TRUE (for backwards compatibility).