Sun, 27 Sep 2026

#060: Using bubblewrap for R sandboxing

Welcome to post 60 in the R4 series.

bubblewrap is a great tool and very suitable for using with an agent harness. It is a very compelling—and lightweight—alternative to using a full-blown docker container as it offers low-level unprivileged sandboxing on Linux hosts.

In a nutshell, bubblewrap can ‘turn everything off’ (see unshare-all below) and allow access only to selected services and directories (as shown below). This makes it a very useful tool be used on a main workstation as it can provide a lower-risk deployment quite easily while taking advantage of the already installed software stack. I continue to get a lot of value out of docker, especially as r2u makes installing R package dependencies so trivial. Its slogan ‘easy, fast, reliable: pick all three’ clearly holds for r2u. But sometimes bubblewrap is compelling, for example to launch opencode (documented for example at the debian-inference site).

When using R we need add more directories to the example to provide /etc/alternatives which is governing inter alia the LAPACK / BLAS resolution on Debian / Ubuntu systems; this is now on debian-inference site but wasn’t when I first tried it a few days ago ;-) as well as /etc/R for config files and possibly ~/.R/Makevars for compiler settings. With that my current wrapper is

#!/bin/bash
#
# cf https://inference.debian.net/doc
#    and 'curl' command to set bearer code
bwrap \
  --ro-bind /usr /usr \
  --symlink usr/bin /bin \
  --symlink usr/lib /lib \
  --symlink usr/lib64 /lib64 \
  --ro-bind /etc/ssl /etc/ssl \
  --ro-bind /etc/resolv.conf /etc/resolv.conf \
  --ro-bind $HOME/.gitconfig $HOME/.gitconfig \
  --bind $HOME/.config/opencode $HOME/.config/opencode \
  --bind $HOME/.cache/opencode $HOME/.cache/opencode \
  --bind $HOME/.opencode $HOME/.opencode \
  --bind $HOME/.local/share/opencode $HOME/.local/share/opencode \
  --bind $HOME/.local/state/opencode $HOME/.local/state/opencode \
  --ro-bind $HOME/.R/Makevars $HOME/.R/Makevars \
  --ro-bind /etc/R/ /etc/R \
  --ro-bind /etc/alternatives/ /etc/alternatives \
  --proc /proc \
  --dev /dev \
  --tmpfs /tmp \
  --bind $(pwd) $(pwd) \
  --chdir $(pwd) \
  --unshare-all \
  --share-net \
  --die-with-parent \
  /usr/local/bin/opencode "$@"

Launched that way we can have agents use R to check packages sources, builds, and triage for bugs. this works equally well with local models served via ollama (and with that a quick shoutout to packages.lingfish.net for providing an apt service for ollama) as it does with the various cloud-based offerings. So harness away with R!

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. If you like this or other open-source work I do, you can now sponsor me at GitHub.

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