Python Tkinter in Docker .TclError: couldn't connect to display

Question

I am new to python and am trying to build a small app. It needs to be a GUI app and I was wanting to containerise it with docker. I am getting the following error and can not find a solution

No protocol specified
No protocol specified
Traceback (most recent call last):
  File "tkinker.py", line 7, in <module>
    tinker = Tk()
  File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 1818, in __init__
    self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: couldn't connect to display ":0.0"

It starts locally but wont start in docker. My OS is Xubuntu.

I have created a sample app (below), see run-test.sh https://github.com/jeremysells/test/tree/master/docker-tkinter

Deuterium

Again, adding -e DISPLAY=$DISPLAY is not enough. – Pruter

It might be OS specific but I would not think so. Does anyone know if I have to configure anything locally to get this to work? – Deuterium

Sorry, I thought you were on Mac – Pruter

Answer 1

As described here, you would need an X11 graphic layer.
But since you are already on an '(X)Ubuntu, setting the DISPLAY should be enough:

export DISPLAY=127.0.0.1:0.0

docker run -it -e DISPLAY=$DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix yourImage

Check also XAuthority.

Pruter

See also github.com/docker/docker/issues/8710#issuecomment-71113263 to expose local xquartz socket on a TCP port. – Pruter

Answer 2

Type xhost + in your terminal. Then

docker run --rm \
    --network=host --privileged \
    -v /dev:/dev \
    -e DISPLAY=$DISPLAY \
    -v /tmp/.X11-unix:/tmp/.X11-unix \
    -v $HOME/.Xauthority:/root/.Xauthority \
    -it yourimage

worked for me. xhost + disables access control. After which a client can connect from any host.

Tears

"Connect" here implies being able to run things like screen captures and keystroke loggers: you really don't want to allow this ability "from any host". – Teddman

So, what is the better alternative, @DavidMaze ? – Mikemikel

Answer 3

You'll have to set DISPLAY in the container. You can add it as an argument to the docker run command like this:

docker run -ti -e DISPLAY=$DISPLAY blah-image blah-command

DISPLAY should be set in the Xubuntu shell you are running the command from.

Gibson

Saidly same issue # docker run -ti -e DISPLAY=$DISPLAY tkinter-test:latest Traceback (most recent call last): File "tkinker.py", line 7, in <module> tinker = Tk() File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 1818, in init self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use) _tkinter.TclError: couldn't connect to display ":0.0" – Deuterium

Is display set in the shell where you start the command? Are you able to run GUIs from outside of docker? – Gibson

Yes the display is enabled. When I run #echo $DISPLAY it returns ":0.0". I wonder if it has something to do with xauth (#16297253 and wiki.ros.org/docker/Tutorials/GUI). I don't have any free time at the moment, so will have to get back to testing this when I do – Deuterium

Use the IP address of your Linux/UNIX system (not the Docker container). For example, -e DISPLAY=10.0.0.1:0.0 (replace 10.0.0.1 with the IP address of your Linux/UNIX system). – Ramification

Answer 4

Derived from the other answer here and inspired by its such comment, my quest ends up with 2 workable solutions. Pick either one you prefer.

• xhost local:root && docker -e DISPLAY=$DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix your_image
• xhost local:root && docker -e DISPLAY=$DISPLAY --net=host your_image

Mikemikel

Answer 5

If you just want it to run on you current screen, it looks like docker has some nice DNS stuff built in for that:

docker run -ti -e DISPLAY=host.docker.internal:0 appname

and for vscode in launch.json add this to the end of your configuration.

"env": {
    "DISPLAY": "host.docker.internal:0"
}

Then, of course, if you are running windows, you need something like xming to receive the X11 packets.

Scorn