RStudio pixi integration

rsession-wrapper.sh

#!/bin/bash
# rsession-wrapper — RStudio Server rsession wrapper with per-project pixi support
#
# When a user opens (or switches to) a project that contains a pixi.toml,
# this wrapper activates the pixi environment before launching rsession.
# This gives each project its own R installation and library paths.
#
# HOW IT WORKS
# ------------
# RStudio Server does not pass project information to rsession at launch.
# Instead, it records the most-recently-used project in:
#
#   ~/.local/share/rstudio/monitored/lists/project_mru
#
# This file is updated *before* a new rsession is spawned (including on
# project switch, which kills the old session and starts a fresh one).
# The wrapper reads line 1 of that file to identify the active project.
#
# If the project directory contains pixi.toml, the pixi environment is
# activated and:
#   - R_HOME is set to pixi's R, so rsession uses the correct R runtime.
#   - LD_LIBRARY_PATH is updated to include pixi's libraries (libR, libstdc++,
#     libicu, etc.), preventing ABI mismatches with system libraries.
#
# If there is no MRU entry, no pixi.toml, or pixi is not installed, the
# wrapper falls back silently to the system R.
#
# INSTALL
# -------
# 1. sudo cp rsession-wrapper.sh /usr/local/bin/rsession-wrapper
# 2. sudo chmod +x /usr/local/bin/rsession-wrapper
# 3. Add to /etc/rstudio/rserver.conf:
#      rsession-path=/usr/local/bin/rsession-wrapper
# 4. sudo systemctl restart rstudio-server
#
# REQUIREMENTS
# ------------
#   - pixi in PATH (typically ~/.pixi/bin/pixi)
#   - Each project must have a pixi.toml with R as a dependency
#   - RStudio Server open-source edition
#
# TROUBLESHOOTING
# ---------------
# Enable tracing by uncommenting the two lines below, then check:
#   sudo journalctl -f -t rstudio-wrapper
#
# exec > >(logger -t rstudio-wrapper) 2>&1
# set -x

set -euo pipefail

# ── Configuration ─────────────────────────────────────────────────────────────
RSESSION_BIN=/usr/lib/rstudio-server/bin/rsession
MRU_LIST="${HOME}/.local/share/rstudio/monitored/lists/project_mru"

# ── Validate rsession exists ─────────────────────────────────────────────────
[[ -x "$RSESSION_BIN" ]] || {
  echo "ERROR: rsession not found at ${RSESSION_BIN}" >&2
  exit 1
}

# ── Detect active project from MRU ───────────────────────────────────────────
PROJECT_DIR=""
if [[ -f "$MRU_LIST" ]]; then
  RPROJ_FILE=$(head -1 "$MRU_LIST" 2>/dev/null || true)
  if [[ -n "$RPROJ_FILE" && -f "$RPROJ_FILE" ]]; then
    PROJECT_DIR="$(dirname "$RPROJ_FILE")"
  fi
fi

# ── Activate pixi environment ────────────────────────────────────────────────
if [[ -n "$PROJECT_DIR" && -f "$PROJECT_DIR/pixi.toml" ]]; then
  if command -v pixi &>/dev/null; then
    # Activate the pixi environment (sets PATH, CONDA_PREFIX, etc.)
    pixi_hook="$(pixi shell-hook --manifest-path "$PROJECT_DIR/pixi.toml" --shell bash 2>/dev/null)" \
      && eval "$pixi_hook" \
      || logger -t rstudio-wrapper "WARNING: pixi shell-hook failed for ${PROJECT_DIR}"

    # Point R_HOME to pixi's R and update LD_LIBRARY_PATH so the dynamic
    # linker resolves all shared libraries from the pixi environment.
    PIXI_R_HOME=$(R RHOME 2>/dev/null || true)
    if [[ -n "$PIXI_R_HOME" ]]; then
      export R_HOME="$PIXI_R_HOME"
      PIXI_PREFIX="${CONDA_PREFIX:-${PROJECT_DIR}/.pixi/envs/default}"
      export LD_LIBRARY_PATH="${PIXI_PREFIX}/lib:${PIXI_R_HOME}/lib${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}"
    else
      logger -t rstudio-wrapper "WARNING: R RHOME failed — falling back to system R for ${PROJECT_DIR}"
    fi
  fi
fi

# ── Launch rsession ──────────────────────────────────────────────────────────
exec "${RSESSION_BIN}" "$@"

Might need a set -a before eval?