.devcontainer/README.md

In rpodcast/shinylearning: Illustrate the evolution of a Shiny application from prototype to finished product

R Projects Development Setup

This repo contains the various configurations, container settings, and other setup files that I will use in my new development setup for R projects on linux. Typically I would install R directly in my system along with the various IDEs and other tools that integrate with R. Now that I have systems with larger amounts of memory and faster CPUs, I am now experimenting with a development environment based on container technology, in particular Docker contaners. I have the following goals for my new development setup:

• Ability to use RStudio, Visual Studio Code, or other IDEs that can reference Docker containers or be fully contained inside one.
• Share a central R package cache between containers using the {renv} package management system.
• Leave no traces of the R installation or system dependencies on the host system. While that sounds a little brazen, I plan on using a custom Linux PC built for media production and I want to keep that system fairly clean and lean!

🎥 Check out this previous Shiny Developer Series livestream to see my detailed walkthrough!

Pre-requisites

• Install Docker for your particular OS. For my development setup, it is Ubuntu 20.04. Instructions can be found at docs.docker.com/get-docker
  • If you are using a Linux-based operating system: Ensure that your user ID is added to the docker group.
• Install Visual Studio Code. Downloads and more information can be found at code.visualstudio.com
  • Install the Remote Development Extension Pack
  • Install the Docker Extension Pack (while not necessarily required, I find it very useful for managing my containers inside the IDE)
  • If you use SSH keys with your online code repository account (for example GitHub or GitLab) you need to share your key with containers built. The process is documented at on the VSCode docs here. For my setup, I have to run this once before launching VSCode: ssh-add ~/.ssh/{name_of_key}. I have a custom key but I would imagine most users will have a default key name of id_rsa.

Visual Studio Code Setup

The .devcontainer directory in this repository contains the custom configuration files and build instructions for creating the development container. The Dockerfile and devcontainer.json were adapted from the VSCode dev containers GitHub repository here. Highlights of the customizations I made:

• Use the base Docker image of rocker/r-ver:4.0.2 from the Rocker Project
• Install the Fish shell instead of ZSH
• Install additional OS libraries to make installation of R package binaries relatively painless
• Install the radian alternative R console
• Install renv
• Install certain dotnet core runtime packages (this may not be necessary in future)
• Configure environment variables for custom location of renv cache directory mounted into the container
• Set the default user as my user account and not root

With everything set up, I was able to mostly follow the official VS Code documenation page on developing inside a container to get the development container launched. I am still learning the ropes so to speak with day-to-day usage of VS-Code with R coding. Here are some additional observations that I will update as I continue my journey:

• There have been some random occurrances where I cannot view a Shiny app in a tab within VS Code when launching the app (the tab appears completely blank). However, when I click the notification in the lower-corner to open the link in an external browser, the app loads just fine. The only way I have found to at least manually fix the problem in the active session is to perform the workaround documented in vscode-R/380 . Basically, run options(vsc.browser=FALSE) once in the R session, then run the application (which will open the app in an external window). Close the app, then run options(vsc.browser="Active") in the R session, and then run the app again. The app should open in the VS-Code tab like usual.
• The default linting is based on the {lintr} package and might need some tweaking. Consult the project configuration of the lintr repository for more infomation.

RStudio Setup

In recent years, the open-source version of RStudio Server has been succesfully integrated into Docker containers in multiple projects including the excellent Rocker Project led by Carl Boettiger, Dirk Eddelbuettel, and Noam Ross. Recently, they created version-stable R containers based on R version 4.0.0 or later at the rocker-org/rocker-versioned2 GitHub repository based on the recent Ubuntu 20.04 LTS release, as well as integrated the new RStudio Package Manager (RSPM) which hosts compiled binaries of R packages for installation on Linux. I decided to create a custom container for RStudio server following principles in their new infrastructure with a custom Dockerfile inspired by their Dockerfile_rstudio_4.0.2, and wrapping the execution within Docker Compose. Highlights of the customizations I implemented:

• Install additional OS libraries to make installation of R package binaries relatively painless
• Install the radian alternative R console
• Configure environment variables for custom location of renv cache directory mounted into the container
• Install renv
• Store certain environment variables inside a custom text file called rstudio.env

Configuring a central package cache

I have set up a local directory on my system that is mounted as a volume in each container to hold the R package cache. As long as your logged-in user has read and write priveleges to this directory on your host system, there should be no issues with each container reading and writing to the cache dir. In the containers, the directory is located at /renv/cache while on my host system it is located at /opt/local/renv/cache, but this could be any directory on your host system. In the Docker configuration files for each container, I set up the following environment variables:

RENV_PATHS_CACHE_HOST=/opt/local/renv/cache
RENV_PATHS_CACHE_CONTAINER=/renv/cache
RENV_PATHS_CACHE=/renv/cache

Using Renv with VS-Code

One (intentional) effect of using renv is that out of the box the project's package library will not link to packages in the default library that are not included in the base installation of R. The interactions between an R session and VS-Code are largely driven by the {launguageserver} package available on CRAN. My solution to ensure any project with renv enabled can use all of the same integrations with VS-Code is to create a custom .Rprofile that contains certain triggers to bootstrap the installation of languageserver and perform necessary environment configurations if the session detects that the TERM_PROGRAM environment variable is set to vscode. The file .devcontainer/library-scripts/.Rprofile-vscode is automatically copied to the container's renv cache directory, and can be manually copied to overwrite the current project's .Rprofile file. Much of this solution was adapted from ideas discussed in issue vscode-R/259. The contents are below:

# setup if using with vscode and R plugin
if (Sys.getenv("TERM_PROGRAM") == "vscode") {
    source(file.path(Sys.getenv(if (.Platform$OS.type == "windows") "USERPROFILE" else "HOME"), ".vscode-R", "init.R"))
}
source("renv/activate.R")

if (Sys.getenv("TERM_PROGRAM") == "vscode") {
    # obtain list of packages in renv library currently
    project <- renv:::renv_project_resolve(NULL)
    lib_packages <- names(unclass(renv:::renv_diagnostics_packages_library(project))$Packages)

    # detect whether key packages are already installed
    # was: !require("languageserver")
    if (!"languageserver" %in% lib_packages) {
        message("installing languageserver package")
        renv::install("languageserver")
    }

    if (!"httpgd" %in% lib_packages) {
        message("installing httpgd package")
        renv::install("nx10/httpgd")
    }

    if (!"vscDebugger %in% lib_packages) {
        message("installation vscDebugger package")
        renv::install("ManuelHentschel/vscDebugger@v0.4.3")
    }

    # use the new httpgd plotting device
    options(vsc.plot = FALSE)
    options(device = function(...) {
      httpgd::httpgd()
      .vsc.browser(httpgd::httpgdURL(), viewer = "Beside")
    })
}

Next Steps

I would still consider this journey a work in progress, so here are some additonal tasks I hope to complete. Contributions and feedback are more than welcome!

• [ ] Figure out a way to seamlessly add this development setup inside a specific project.
• [ ] Automatically override the default .Rprofile file created by renv so that I do not need to manually copy over the customized version.

rpodcast/shinylearning documentation built on April 4, 2022, 10:44 p.m.