feat: add Hugging Face Spaces Docker deployment

Two-stage Dockerfile caches R package installation in a base layer
so only app code changes trigger fast rebuilds (~1-2 min vs 15-20 min
on shinyapps.io). GitHub Actions workflow auto-deploys on push to main.

Existing shinyapps.io deployment remains untouched as fallback.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: pjt222

.Rbuildignore

@@ -19,3 +19,6 @@
 ^Rplots\.pdf$
 ^LICENSE\.md$
 inst/shiny-app/\.rscignore$
+^Dockerfile$
+^\.dockerignore$
+^hf-spaces$

.dockerignore

@@ -0,0 +1,21 @@
+.git
+.github
+.Rproj.user
+.claude
+renv/library
+renv/local
+renv/staging
+renv/sandbox
+renv/python
+tests/
+docs/
+quarto/
+output/
+man/
+vignettes/
+temp/
+hf-spaces/
+*.Rproj
+CLAUDE.md
+GEMINI.md
+CONTINUE_HERE.md

.github/workflows/deploy-hf-spaces.yml

@@ -0,0 +1,45 @@
+name: Deploy to Hugging Face Spaces
+
+on:
+  push:
+    branches: [main]
+    paths-ignore:
+      - 'quarto/**'
+      - 'docs/**'
+      - 'tests/**'
+      - '*.md'
+      - '!hf-spaces/README.md'
+  workflow_dispatch:
+
+concurrency:
+  group: hf-spaces-deploy
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  deploy-hf:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          lfs: true
+
+      - name: Prepare HF Spaces deployment
+        run: |
+          # Replace README with HF Spaces version (YAML frontmatter for Docker SDK)
+          cp hf-spaces/README.md README.md
+
+      - name: Push to Hugging Face Spaces
+        env:
+          HF_TOKEN: ${{ secrets.HF_TOKEN }}
+        run: |
+          git config user.name "GitHub Actions"
+          git config user.email "actions@github.com"
+          git add -A
+          git commit -m "Deploy to HF Spaces" --allow-empty
+          git push --force https://pjt222:${HF_TOKEN}@huggingface.co/spaces/pjt222/jigsawR main

Dockerfile

@@ -0,0 +1,75 @@
+# ===========================================================================
+# Stage 1: Dependencies (cached layer -- only rebuilds when DESCRIPTION changes)
+# ===========================================================================
+FROM rocker/r-ver:4.4.2 AS deps
+
+# Headless rgl (no X11 display in Docker)
+ENV RGL_USE_NULL=TRUE
+
+# System libraries needed by R packages
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    build-essential \
+    libcurl4-openssl-dev \
+    libssl-dev \
+    libxml2-dev \
+    libmagick++-dev \
+    librsvg2-dev \
+    libpng-dev \
+    libgl1-mesa-dev \
+    libglu1-mesa-dev \
+    libfreetype6-dev \
+    libharfbuzz-dev \
+    libfribidi-dev \
+    libfontconfig1-dev \
+    libtiff5-dev \
+    libjpeg-dev \
+    libwebp-dev \
+    zlib1g-dev \
+    git \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy only dependency-defining file for cache optimization
+COPY DESCRIPTION /tmp/pkg/DESCRIPTION
+
+# Install all R packages (PPM binaries where available)
+RUN Rscript -e " \
+  install.packages('remotes', repos='https://cloud.r-project.org'); \
+  # Imports \
+  install.packages(c('Rcpp', 'ggplot2', 'ggfx', 'viridis', 'config', 'cli', 'rlang'), \
+    repos='https://cloud.r-project.org'); \
+  # Shiny runtime dependencies \
+  install.packages(c('shiny', 'bslib', 'bsicons', 'shinyjs', 'colourpicker', 'waiter', \
+    'rsvg', 'magick', 'zip', 'scales', 'ambient', 'png', 'base64enc', \
+    'deldir', 'snic', 'ggforce', 'data.table'), \
+    repos='https://cloud.r-project.org'); \
+  # GitHub-only packages \
+  remotes::install_github('stla/RCDT'); \
+"
+
+# ===========================================================================
+# Stage 2: Application (fast rebuild on code changes)
+# ===========================================================================
+FROM deps AS app
+
+# Create app user (HF Spaces runs as uid 1000)
+RUN useradd -m -u 1000 appuser
+
+# Copy package source and install (compiles Rcpp C++)
+COPY . /tmp/jigsawR-src
+RUN cd /tmp/jigsawR-src && \
+    R CMD INSTALL --no-test-load . && \
+    rm -rf /tmp/jigsawR-src
+
+# Set up the Shiny app directory
+RUN mkdir -p /app/output
+COPY inst/shiny-app/ /app/
+COPY inst/config.yml /app/config.yml
+
+RUN chown -R appuser:appuser /app
+
+USER appuser
+WORKDIR /app
+
+EXPOSE 7860
+
+CMD ["Rscript", "-e", "shiny::runApp('/app', host='0.0.0.0', port=7860, launch.browser=FALSE)"]

hf-spaces/README.md

@@ -0,0 +1,11 @@
+---
+title: jigsawR
+emoji: "\U0001F9E9"
+colorFrom: blue
+colorTo: green
+sdk: docker
+app_port: 7860
+pinned: false
+license: gpl-3.0
+short_description: Interactive jigsaw puzzle generator
+---