Skip to contents

Docker

Source: vignettes/b03_docker.Rmd
b03_docker.Rmd

Using httpgd to display R plots in a Docker container (Linux container) may be easier than the traditional and common method; linking the X11 window system.

Basic usage

Build a docker image

See the vignette("a00_installation") for details on how to install httpgd on Linux.

You can create a Docker image with httpgd installed by create a Dockerfile like below.

FROM r-base:latest

# Install httpgd and dependent packages.
RUN apt-get update \
    && apt-get install -y --no-install-recommends \
    libfontconfig1-dev \
    && apt-get autoremove -y && apt-get clean -y && rm -rf /var/lib/apt/lists/* \
    && install2.r --error --skipinstalled --ncpu -1 \
    httpgd \
    && rm -rf /tmp/downloaded_packages

Run the docker build command from your shell to build a Docker image.

docker build . -f Dockerfile -t httpgd:test

Create a container

When creating a container with the docker run command, bind the port to be used by httpgd with the -p (--publish) option.

If you run R in a container with a command like the following, the 8888 port of the container will be bound to the 8888 port of the Docker host.

docker run --rm -it -p 8888:8888 httpgd:test R

Start httpgd server

Running the following command in the R console will initialize the graphics device and start the server.

httpgd::hgd(host = "0.0.0.0", port = 8888)

Then, copy the displayed link in your browser.

If you want to display the link again, execute the hgd_url() function as follows.
The hostname can be replaced with any value (e.g. localhost).

httpgd::hgd_url(host = "localhost")

Advanced usage

Set options in Rprofile

By setting options httpgd.host and httpgd.port in the Rprofile, you can omit setting the arguments when starting the httpgd server by hgd().

For example, if you create a Dockerfile with the following contents, you can build an image with these options already set in the Rprofile.

FROM r-base:latest

# Install httpgd and dependent packages.
RUN apt-get update \
    && apt-get install -y --no-install-recommends \
    libfontconfig1-dev \
    && apt-get autoremove -y && apt-get clean -y && rm -rf /var/lib/apt/lists/* \
    && install2.r --error --skipinstalled --ncpu -1 \
    httpgd \
    && rm -rf /tmp/downloaded_packages

# Set default values used in the httpgd::hgd() function.
RUN echo 'options(httpgd.host = "0.0.0.0", httpgd.port = 8888)' >> /etc/R/Rprofile.site

EXPOSE 8888