Use host's X11 socket to use GUI

[limerainne]

After some research, there are some methods to enable X11 display inside the container.

Local display

• simple guide
  somatorio.org:Running GUI apps with Docker
• detailed guide with many methods
  ROS Wiki:Docker GUI

Simple (insecure) method did not work in my (remote) environment (SSH + X11 forwarding). If yours are similar to my ones, then please try below.

Remote display with SSH forwarding (my situation)

StackOverflow by Ruben

• assuming docker host's virtual NIC has IP as 172.17.0.1. If not, change the DISPLAY variable regarding your situation.

• Let SSH daemon allow remote X11 connection (TODO insecure)
  /etc/ssh/sshd_config: X11UseLocalhost no

• Make another Xauthority file

touch /tmp/.docker.xauth
XAUTH=/tmp/.docker.xauth
xauth nlist $DISPLAY | sed -e 's/^..../ffff/' | sudo xauth -f $XAUTH nmerge -
sudo chmod 777 $XAUTH

• (I skipped configuring firewall (ufw)...)

• Run the docker container with dedicated Xauthority file, modified DISPLAY variable

sudo docker run --rm -it \
        -e LM_LICENSE_FILE="<port>@<host>" \
        -e DISPLAY=$(echo $DISPLAY | sed 's/^[^:]*\(.*\)/172.17.0.1\1/') \
        -v $XAUTH:$XAUTH -e XAUTHORITY=$XAUTH \
        synopsys_dc:N-2017.09 dc_shell -gui

hmm... is there an unified and somewhat official way?

[limerainne]

(Above commit referencing this issue was made by a mistake...)