Alpine for RPI Zero with Python3 / Numpy / Scipy / OpenCV 4... (WORK IN PROGRESS!!!)

Dockerfile

FROM arm32v6/alpine

RUN apk add --update --no-cache \
      build-base \
      unzip \
      wget \
      cmake \
      # A C language family front-end for LLVM (development files)
      clang-dev \
      linux-headers

ENV OPENCV_VERSION=4.1.0 
#ENV OPENCV_VERSION=3.3.0

RUN cd /opt && \
  wget https://github.com/opencv/opencv/archive/${OPENCV_VERSION}.zip && \
  unzip ${OPENCV_VERSION}.zip && \
  rm -rf ${OPENCV_VERSION}.zip

# opencv_contrib
RUN cd /opt && \
  wget https://github.com/opencv/opencv_contrib/archive/${OPENCV_VERSION}.zip && \
  unzip ${OPENCV_VERSION}.zip && \
  rm -rf ${OPENCV_VERSION}.zip

  
RUN apk add --update --no-cache \
#   --virtual .build-deps \
      #Intel® TBB, a widely used C++ template library for task parallelism'
      #libtbb  \
      #libtbb-dev   \
      # Wrapper for libjpeg-turbo
      libjpeg  \
      # accelerated baseline JPEG compression and decompression library
      libjpeg-turbo-dev \
      # Portable Network Graphics library
      libpng-dev \
      # A software-based implementation of the codec specified in the emerging JPEG-2000 Part-1 standard (development files)
      jasper-dev \
      # Provides support for the Tag Image File Format or TIFF (development files)
      tiff-dev \
      # Libraries for working with WebP images (development files)
      libwebp-dev \
      # 
      v4l-utils-dev \
      tiff-dev \
      ffmpeg-dev \
      ffmpeg-libs \
      v4l-utils-libs \
      xvidcore-dev \
      x264-dev \
      python3 \
      python3-dev \
# Using pip actually compiles from source!
# RUN pip3 install --no-cache-dir numpy scipy
      py3-numpy \
      py3-scipy \
      eigen-dev \
      openblas-dev \
      gfortran \
    #   gstreamer-dev \ # tried gstreamer and gstreamer-dev, but cmake can't find it...
      protobuf-dev \ 
      # keeps giving me seg fault...
      protobuf \
      ccache

ENV CC /usr/bin/clang
ENV CXX /usr/bin/clang++

RUN mkdir -p /opt/opencv-${OPENCV_VERSION}/build && \
  cd /opt/opencv-${OPENCV_VERSION}/build && \
  cmake \
  -D OPENCV_EXTRA_MODULES_PATH=/opt/opencv_contrib-${OPENCV_VERSION}/modules \
  -D CMAKE_BUILD_TYPE=RELEASE \
  -D CMAKE_INSTALL_PREFIX=/usr/local \
  -D WITH_FFMPEG=ON \
  -D WITH_IPP=NO \
  -D WITH_OPENEXR=NO \
  -D WITH_OPENGLES=ON \
  # RPI ZERO doesn't has full OPENGL, but OPENGLES.
  -D ENABLE_NEON=NO \
  -D ENABLE_VFPV3=NO \  
  # RPI ZERO doesn't has NEON or VFPV3
  -D OPENCV_ENABLE_NONFREE=ON \
  -D WITH_QT=OFF \
  -D WITH_GTK=OFF \
  -D WITH_CUDA=OFF \
  -D BUILD_opencv_java=OFF \
  -D WITH_TBB=NO \
  -D BUILD_EXAMPLES=NO \
  -D BUILD_ANDROID_EXAMPLES=NO \
  -D INSTALL_PYTHON_EXAMPLES=NO \
  -D BUILD_DOCS=NO \
  -D BUILD_opencv_python2=NO \
  -D BUILD_opencv_python3=ON \
  # Protobuf was generating seg faults
  -D BUILD_PROTOBUF=OFF \
  -D PROTOBUF_UPDATE_FILES=ON \
  -D WITH_GSTREAMER=OFF \
  -D BUILD_JAVA=NO \
  # ADE was always failing to compile...
  -D BUILD_opencv_gapi=OFF \
  -D WITH_ADE=OFF \
# All the things below will be automatically found...
#   -D PYTHON3_EXECUTABLE=/usr/local/bin/python \
#   -D PYTHON3_INCLUDE_DIR=/usr/local/include/python3.6m/ \
#   -D PYTHON3_LIBRARY=/usr/local/lib/libpython3.so \
#   -D PYTHON_LIBRARY=/usr/local/lib/libpython3.so \
#   -D PYTHON3_PACKAGES_PATH=/usr/local/lib/python3.6/site-packages/ \
#   -D PYTHON3_NUMPY_INCLUDE_DIRS=/usr/local/lib/python3.6/site-packages/numpy/core/include/ \
  .. && \
  # make VERBOSE=1 && \
  make && \
  make install && \
  ldconfig \
  rm -rf /opt/opencv-${OPENCV_VERSION}