feat: Set DISPLAY env, so X11 apps show on the host

[larseggert]

No description provided.

[NGPixel]

Note that host.docker.internal is only defined on Docker for Desktop on Mac and Windows. On Linux this entry doesn't exist and need to be added manually when creating the container using --add-host=host.docker.internal:host-gateway.

Would this create issues for Linux users that don't have this hostname defined in their containers?

[larseggert]

I doubt it, but maybe we can add that setting to the container settings?

[jennifer-richards]

Tried this on Linux - even adding the host.dockerinternal:host-gateway, I can't open X connections. Am I leaving something out?

Added "host.docker.internal:host-gateway" via docker-compose and get

dev ➜ /workspace $ ping host.docker.internal 
PING host.docker.internal (172.17.0.1) 56(84) bytes of data.
64 bytes from host.docker.internal (172.17.0.1): icmp_seq=1 ttl=64 time=0.102 ms

dev ➜ /workspace $ xterm
xterm: Xt error: Can't open display: host.docker.internal:0

(I opened X on the host with xhost + but it's been a while since I've done much X11 work so I may have missed some setup?)

[jennifer-richards]

Poked around, I think my problem is that Ubuntu does not accept TCP connections for X11. I haven't found the magic to change this. TCP connections from the container work for nc, though.

[larseggert]

You probably need to set xhost + or something similar

[jennifer-richards]

You probably need to set xhost + or something similar

It's more than that - the Ubuntu config has its xserver started with TCP listeners disabled entirely. I chased things for a while but did not find what piece was setting that command line before giving up.

The changes here were not harmful, they just don't make X connections work. I think that's enough to accept this PR. There'll just be further work needed to make X work with a system like mine.

I think it'd be fine to add the host.docker.internal address.