migrate to faster image resizing

Dockerfile

-FROM ubuntu:focal AS nodejs_base
+FROM ubuntu:focal AS essential_base 
 
 LABEL maintainer="andreas.knote@uni-wuerzburg.de"
 
@@ -9,15 +9,9 @@ RUN apt-get update && apt-get upgrade && \
     apt-get install -y \
     curl ssh git-lfs build-essential locales
 
-RUN apt-get update && \
-    curl -sL https://deb.nodesource.com/setup_13.x | bash - && \
-    apt-get install -y nodejs && \
-    echo 'Node: ' && \
-    node -v && \
-    echo 'NPM: ' && \
-    npm -v
 
-FROM nodejs_base AS ruby_jekyll
+# Install Ruby and Jekyll
+FROM essential_base AS ruby_jekyll
 
 RUN apt-get update && \
     apt-get install -y \
@@ -39,18 +33,37 @@ RUN locale-gen en_US.UTF-8 && \
 ENV LANG en_US.UTF-8 
 ENV LC_ALL en_US.UTF-8
 
-FROM ruby_jekyll AS image_resize
 
-RUN apt-get update && apt-get install -y \
-    imagemagick
+## Install NodeJS
+FROM ruby_jekyll AS nodejs 
+
+RUN apt-get update && \
+    curl -sL https://deb.nodesource.com/setup_13.x | bash - && \
+    apt-get install -y nodejs && \
+    echo 'Node: ' && \
+    node -v && \
+    echo 'NPM: ' && \
+    npm -v
+
 
-FROM image_resize AS hci_theme 
+## Install the batch-resize script
+FROM nodejs AS image_resize
 
-## Build Theme from source
+RUN apt-get update && apt-get install -y \
+    python3-pil imgp rsync inotify-tools && \
+    git clone https://gitlab2.informatik.uni-wuerzburg.de/hci-development/batch-resize.git /batch-resize && \
+    ln -s /batch-resize/batch-resize /usr/bin/batch-resize
+
+## Build HCI-Theme from source
 ## Installs the built gem system-wide
+
 COPY . /
 RUN bundle install && \
     bundle exec rake gem && \
     gem install hci-theme.gem && \
     rm -rf node_modules && \
     rm package-lock.json 
+
+# Make development scripts available
+RUN  ln -s /scripts/* /usr/bin/ && hash
+

scripts/development

 #!/usr/bin/env bash
-# Build
+
+# Resize Images
+watch-and-resize ./assets/images/ ./public/assets/images/ &
+
+# Serve HCI Site
 bundle
 bundle update
-bundle exec war&
-jekyll serve --host=0.0.0.0 --port=4200 --trace --incremental&
+jekyll serve --host=0.0.0.0 --port=4200 --trace --incremental &
+
 PIDS[0]=$!
 trap "kill ${PIDS[*]}" SIGINT
-wait
\ No newline at end of file
+wait

scripts/watch-and-resize

+#!/usr/bin/env bash
+
+source_dir=${1}
+target_dir=${2}
+
+batch-resize ${source_dir} ${target_dir}
+
+echo "[watch-and-resize] $source_dir -> $target_dir"
+while inotifywait -q -e modify -r ${source_dir}; do
+  batch-resize ${source_dir} ${target_dir}
+done
+