Docker Image Won't Run? - docker

Question

I created an image of my Shiny app using Docker Toolbox for Windows 7. I used the instructions on this webpage, and when I got to the following command line in Docker terminal, my image won't run:
docker run -p 80:80 myimage
The error that I get is:
chown: invalid.user: shiny.shiny
I searched about this and I think this is due to conflict of users, when shiny is trying to access other files, it can't because some files are available to root. I don't have much experience with using terminal mode and all docker terminal commands.
how can the above issue be sustainably resolved through docker terminal? my next step would be to deploy the docker image on Digital Ocean server, so the Shiny app can be used over a website.
The Dockerfile code is below:
# Install R version 3.5
FROM r-base:3.5.0
# Install Ubuntu packages
RUN apt-get update && apt-get install -y \
sudo \
gdebi-core \
pandoc \
pandoc-citeproc \
libcurl4-gnutls-dev \
libcairo2-dev/unstable \
libxt-dev \
libssl-dev
# Download and install ShinyServer
RUN wget --no-verbose https://download3.rstudio.org/ubuntu-14.04/x86_64/shiny-server-1.5.7.907-amd64.deb && \
gdebi shiny-server-1.5.7.907-amd64.deb
# Install R packages that are required
RUN R -e "install.packages(c('Benchmarking', 'plotly', 'DT'), repos='http://cran.rstudio.com/')"
RUN R -e "install.packages('shiny', repos='https://cloud.r-project.org/')"
# Copy configuration files into the Docker image
COPY shiny-server.conf /etc/shiny-server/shiny-server.conf
COPY /app /srv/shiny-server/
# Make the ShinyApp available at port 80
EXPOSE 80
# Copy further configuration files into the Docker image
COPY shiny-server.sh /usr/bin/shiny-server.sh
CMD ["/usr/bin/shiny-server.sh"]

Answer 1

All you need to do is add a 'shiny' user of the group 'shiny'. There are many ways to do it, I decided to create a user with a home folder and also specified the uid and gid, feel free to customise that to your liking. Here's the Dockerfile you should use:
FROM r-base:3.5.0
# Install Ubuntu packages
RUN apt-get update && apt-get install -y \
sudo \
gdebi-core \
pandoc \
pandoc-citeproc \
libcurl4-gnutls-dev \
libcairo2-dev/unstable \
libxt-dev \
libssl-dev
# Add shiny user
RUN groupadd shiny \
&& useradd --gid shiny --shell /bin/bash --create-home shiny
# Download and install ShinyServer
RUN wget --no-verbose https://download3.rstudio.org/ubuntu-14.04/x86_64/shiny-server-1.5.7.907-amd64.deb && \
gdebi shiny-server-1.5.7.907-amd64.deb
# Install R packages that are required
RUN R -e "install.packages(c('Benchmarking', 'plotly', 'DT'), repos='http://cran.rstudio.com/')"
RUN R -e "install.packages('shiny', repos='https://cloud.r-project.org/')"
# Copy configuration files into the Docker image
COPY shiny-server.conf /etc/shiny-server/shiny-server.conf
COPY /app /srv/shiny-server/
# Make the ShinyApp available at port 80
EXPOSE 80
# Copy further configuration files into the Docker image
COPY shiny-server.sh /usr/bin/shiny-server.sh
CMD ["/usr/bin/shiny-server.sh"]