anchor.diff:  ARG terragrunt_version_arg=0.25.4
   ARG ami_manager_arg=0.8.0
   ARG node_version_arg=12.x
  +ARG pip_install_version=21.1.3
   
   ENV PACKER_VERSION=${packer_version_arg}
   ENV ANSIBLE_VERSION=${ansible_version_arg}
  
positive.code: 
  # install ansible
  # RUN pip3.6 install --upgrade pip==21.1.3
  RUN python3 -m pip install --upgrade pip==21.1.3
  RUN pip3 install ansible==${ANSIBLE_VERSION}
  
  # install terraform and create an symlink on /usr/local
  
negative.code: ENV TERRAGRUNT_VERSION=${terragrunt_version_arg}
  ENV AMI_MANAGER_VERSION=${ami_manager_arg}
  ENV NODE_VERSION=${node_version_arg}
  ENV PYTHON_PIP_VERSION=${pip_install_version}
  
  # set up nodejs repo
  RUN curl -sL https://rpm.nodesource.com/setup_${NODE_VERSION} | bash -
  