anchor.diff:          # required for PDF meta analysis
           poppler-utils \
           zlibc \
  +        # required for mermaid
  +        nodejs \
  +        yarn \
       # clean up
       && apt-get clean && \
       rm -rf /var/lib/apt/lists/* /etc/apt/apt.conf.d/01proxy
  
positive.code: ADD requirements.txt ./
  RUN pip3 --no-cache-dir install --find-links file://${PWD}/cache -r requirements.txt
  
  VOLUME /pandoc
  WORKDIR /pandoc
  ADD pandoc.sh /usr/local/bin
  
negative.code:         echo "Acquire::http::Proxy \"${APT_CACHER}\";" | tee /etc/apt/apt.conf.d/01proxy ; \
      fi; \
      apt-get -qq update && \
      apt-get -qy install --no-install-recommends --allow-unauthenticated \
          # for deployment
          openssh-client \
          rsync \
  