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Ensure Julia and required Julia packages are ready

Source: R/julia_ready.R
julia_ready.Rd

Performs the steps needed to make Julia and a set of Julia packages callable from R via JuliaConnectoR:

Usage

julia_ready(
  packages,
  github = character(),
  state_env = new.env(parent = emptyenv()),
  install = TRUE,
  project = NULL,
  match_manifest = TRUE,
  verbose = TRUE
)

Arguments

packages

Character vector of Julia package names to ensure are loaded (e.g. c("EpiBranch", "Distributions")).

github

Named character vector of GitHub URLs for packages not in the General registry. Names must match entries in packages. Values may be a full URL, an "owner/repo" shorthand, or "owner/repo:subdir".

state_env

An environment used to track initialisation state. The caller (typically a wrapping R package) supplies its own environment. Several consuming packages then keep separate state.

install

If FALSE, a missing package is an error.

project

Optional path to a Julia project directory containing a Project.toml (and ideally a Manifest.toml). When supplied, the project is activated and instantiated in a subprocess. Setting JULIA_PROJECT before JuliaConnectoR starts makes the server use the project. Use this when your package ships a pinned Julia environment under inst/julia/. Pkg.instantiate() fetches everything in the project's manifest; packages then only names the packages to load with using.

match_manifest

If TRUE and project is supplied, read the Julia version its Manifest.toml was resolved with and use that version, installing it with juliaup where available. Instantiating a manifest under a different Julia can fail, because it pins standard-library versions that exist only on the version that resolved it. Ignored when the user has chosen a binary through JULIACONNECTOR_JULIABIN or JULIA_BINDIR. A JuliaConnectoR server that is already running, for instance one another package started, keeps its Julia: the project is then instantiated under the matched version but loaded in the running one.

verbose

If TRUE, print progress messages.

Value

Invisibly TRUE.

Details

  1. Locates the Julia binary (see julia_bin()).

  2. Without project, checks in a Julia subprocess that each required package loads. If a package is missing and install = TRUE, installs it (from a GitHub URL if listed in github, otherwise from the General registry). With project, instantiates that project instead. Both run in a subprocess, apart from the JuliaConnectoR server.

  3. Starts (or attaches to) the JuliaConnectoR server.

  4. Loads each package with juliaEval("using <pkg>"). Dotted constructor names such as EpiBranch.NegBin then resolve.

Idempotent: if state_env$ready is already TRUE, returns immediately.

Examples

if (FALSE) { # \dontrun{
.my_pkg_env <- new.env(parent = emptyenv())
julia_ready(
  packages = c("EpiBranch", "Distributions", "Random"),
  github   = c(EpiBranch = "epiforecasts/EpiBranch.jl"),
  state_env = .my_pkg_env
)
} # }