Run Qt GUI application inside docker.

dariusz.o

@devjb I know this possibility, but it won't work for me. I need to run my X server inside docker, I can't provide X11 socket as volume from host, cuz final host won't have GPU and X at all.
What I didn't say earlier is that I don't need any preview, this app have to do something with OpenGL in offscreen mode. I just need images that was created by this app. Byt thanks for your reply !

Pablo J. Rogina

@dariusz-o said in Run Qt GUI application inside docker.:

final host won't have GPU

Just curious how you expect to have an X server running inside the Docker container if the host won't provide a graphical device...

No devices to configure. Configuration failed.

dariusz.o

@Pablo-J-Rogina I think that it's possible to tell X server that there is fake monitor connected and for OpenGL usage I can use CPU through MESA drivers. I'm not 100% sure if it possible and if I understand it well. But just for now it seems legit for me.

Pablo J. Rogina

@dariusz-o said in Run Qt GUI application inside docker.:

this app have to do something with OpenGL in offscreen mode.

Not sure why X server ended up being considered, when you goal is offscreen OpenGL.
Anyway, I guess you may want to consider QOffscreenSurface

dariusz.o

@Pablo-J-Rogina This app I want to run won't work without X, X are needed to create OpenGL context. In this case I have to adjust environment to app, not app to environment.

Pablo J. Rogina

@dariusz-o said in Run Qt GUI application inside docker.:

X are needed to create OpenGL context

Not much expertise with graphic backends (X, OpenGL) but I do run Qt apps on RPi devices using fullscreen EGL without X server at all...

So again, IMO it looks like your X server requirement seems at odds with the OpenGL requirement at some extent

mrjj

hi
What version of Qt do you use ?
After upgrading from 5.9 to 5.15 in Linux Mint
i had to do
sudo apt-get install --reinstall libxcb-xinerama0
to fix the error
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
when i tried to run Creator but not sure its the same as I didnt get
"qt.qpa.xcb: could not connect to display"

dariusz.o

@mrjj I'm using Qt 5.12.2
I managed how to connect fake display with Xvfb :1 -screen 0 1024x768x16 .
This display works cuz I launched glxgears and I made screenshot with ImageMagick (gears were visable on it).

After I connected this virtual display I don't get "qt.qpa.xcb: could not connect to display" anymore. So I'm one step closer.

Now I'getting info like this

Got keys from plugin meta data ("xcb")
loaded library "/home/user/app/platforms/libqxcb.so"
loaded library "Xcursor"
QFactoryLoader::QFactoryLoader() checking directory path "/home/user/app/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "/home/user/app/platforminputcontexts" ...
QFactoryLoader::QFactoryLoader() checking directory path "/home/user/app/styles"

I got all those catalogs at /opt/Qt/5.12.2/gcc_64/plugins/ and I added this path to LD_LIBRARY_PATH I'm not sure why it suggests me that those catalogs are missed.

dariusz.o

@Pablo-J-Rogina But do your apps on RPi use OpenGL context, shaders, etc. ?

Pablo J. Rogina

@dariusz-o said in Run Qt GUI application inside docker.:

But do your apps on RPi use OpenGL context, shaders, etc. ?

I really don't know...

dariusz.o

@Pablo-J-Rogina @mrjj

Ok, setting virtual display with Xvfb :1 -screen 0 1024x768x16 & and setting variables:

ENV QT_DEBUG_PLUGINS=1
ENV QT_QPA_PLATFORM=xcb
ENV QT_QPA_PLATFORM_PLUGIN_PATH=/opt/Qt/${QT_VERSION}/gcc_64/plugins
ENV QT_PLUGIN_PATH=/opt/Qt/${QT_VERSION}/gcc_64/plugins
ENV DISPLAY=:1

solved everything!
It finally works ! :)

Thanks for yours interest!