Dwarf Fortress within docker

Run Dwarf Fortress in a Docker container and play in the browser!

Versions

This repo contains two versions of Dwarf Fortress (v47.05) installations, each bundled with different settings and extras:

• game packed with dfhack, TWBT, Spacefox's tileset and embark profiles (main branch)
• base game with the "Kelora_16x16_diagonal-clouds" tileset and embark profiles (vanilla branch)

Resource usage

As per to its wiki page and when installed directly on your machine, you should expect the game to allocate between 300MB to 700MB RAM on medium regions and never more than 1GB.

However, when running a container from this image you can expect the resource usage on medium region to go up to ~1.40GB. That's because on top of the game itself there's also xvfb maintaining an in-memory representation of the Display together with x11vnc and noVNC making constant use of it and dfhack so that much is to be expected.

The stack of software making this posible

This image runs the following software:

• Xvfb - Virtual frame buffer X11 server. Creates a virtual Display.
• x11vnc - VNC server that interacts with X displays.
• noNVC - JavaScript VNC client library. Allows to connects to a VNC server through any browser.
• Dwarf Fortress - GUI application we intend to run.
• DFHack - Memory editing library for Dwarf Fortress.

All downloaded at runtime and built from debian:buster. In total the image size is around 635MB.

The image

The image can be customized with the runtime arguments:

• PLAY_INTRO if you want to play the intro movie. "YES"/"NO", defaults to "NO".
• SHOW_FPS if you want to see the game FPS. "YES"/"NO", defaults to "NO"

And environment variables:

• DISPLAY_DIMENSIONS dimensions for the virtual display created by Xvfb. Example being "1440x763".

If you decide to build the image yourself, be aware that it takes a long time to build.

The images are also available on DockerHub here.

Volumes

For the game save files to persist across container restarts it's necessary to mount a host directory to where the game saves these files inside the container. <host_directory>:/home/df/df_linux/data/save/

You can also mount the Dwarf Fortress and DFHack config files between host and container if you want to continue using your own configurations, with your own settings.

Ports

We want to access noVNC inside the container but from within our browser so we will have to map the port 8080 to any free port on the host machine.

Example of the docker commands

To build an image that won't skip the intro movie and shows the game FPS:

docker build \
    --build-arg PLAY_INTRO=YES \
    --build-arg SHOW_FPS=YES \
    . --tag=dwarffortress

Then, to run a container:

docker run \
    -e 'DISPLAY_DIMENSIONS'='1440x763' \
    -v '/home/user/games/dwarffortress/':'/home/df/df_linux/data/save/':'rw' \
    -p 9650:8080 \
    --security-opt=seccomp=unconfined \
    dwarffortress

The ugly bits

The connection between the browser and noVNC is unencrypted and it's not protected by any kind of authentication/authorization, therefore it's not meant to be used over the internet.

DFHack needs to be able to make a sys call which is, by default, blocked by Docker (personality). To overcome this restriction the container needs to run with and extra parameter --security-opt=seccomp=unconfined. While doing this fixes our problem it also presents a security risk. Read more here.

I am aware of two minor issues with this setup:

• embarking on brand new fortresses will sometimes crash the game, however it quickly reboots and the same thing won't happen twice on the same save file.
• playing with PLAY_INTRO=YES forces the game to launch in window mode. Press F11 to switch to fullscreen (on macos you need to bind a new key).

Logs

When inspecting the container logs you will find all the the processes output bundled together. Although this can make it more confusing against it's alternative - a log file per process inside the container - for the majority of times it's quicker to find the cause of a problem this way.

References

https://medium.com/@pigiuz/hw-accelerated-gui-apps-on-docker-7fd424fe813e https://github.com/BenLubar/df-docker/blob/3c08fafbadfd60788e12d6a9e0e11c05f4ed751b/README.md