Docker: How to use Volumes for desktop applications - docker

Question

Let's take an example. Here, I'm trying to read an image and write it in a temp folder, using opencv. I want to put this desktop application on Docker and save the output using Docker volume. From volumes, I want to save the output to my local machine.
For the problem statement, I assigned a volume to the container, so that I can save the output. When I'm running the code, it's getting executed, but I'm not understanding how to save to local machine.
This is the DockerFile for the opencv example:
FROM python:3.7
RUN apt-get update \
&& apt-get install -y \
build-essential \
cmake \
git \
wget \
unzip \
yasm \
pkg-config \
libswscale-dev \
libtbb2 \
libtbb-dev \
libjpeg-dev \
libpng-dev \
libtiff-dev \
libavformat-dev \
libpq-dev \
&& rm -rf /var/lib/apt/lists/*
RUN pip install numpy
ENV OPENCV_VERSION="4.1.0"
RUN wget https://github.com/opencv/opencv/archive/${OPENCV_VERSION}.zip \
&& unzip ${OPENCV_VERSION}.zip \
&& mkdir /opencv-${OPENCV_VERSION}/cmake_binary \
&& cd /opencv-${OPENCV_VERSION}/cmake_binary \
&& cmake -DBUILD_TIFF=ON \
-DBUILD_opencv_java=OFF \
-DWITH_CUDA=OFF \
-DWITH_OPENGL=ON \
-DWITH_OPENCL=ON \
-DWITH_IPP=ON \
-DWITH_TBB=ON \
-DWITH_EIGEN=ON \
-DWITH_V4L=ON \
-DBUILD_TESTS=OFF \
-DBUILD_PERF_TESTS=OFF \
-DCMAKE_BUILD_TYPE=RELEASE \
-DCMAKE_INSTALL_PREFIX=$(python3.7 -c "import sys; print(sys.prefix)") \
-DPYTHON_EXECUTABLE=$(which python3.7) \
-DPYTHON_INCLUDE_DIR=$(python3.7 -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())") \
-DPYTHON_PACKAGES_PATH=$(python3.7 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())") \
.. \
&& make install \
&& rm /${OPENCV_VERSION}.zip \
&& rm -r /opencv-${OPENCV_VERSION}
RUN ln -s \
/usr/local/python/cv2/python-3.7/cv2.cpython-37m-x86_64-linux-gnu.so \
/usr/local/lib/python3.7/site-packages/cv2.so
WORKDIR /opencv_example
COPY . .
I need some help to understand how Docker volumes are used for desktop applications and the code to save the volume's output in local path.

Answer 1

How are you starting the container? Paste your command.
If you're using Windows, you need to enable shared drives in Docker settings, and then start your container like written below. If you're on MacOS or Linux, then you only need to execute the command. (Given you probably have other flags there as well)
docker run -v <path-on-host>:<path-inside-container> <image-name>
For more reference check out this link.