How to run textual apps in docker?

[mgaitan]

I'm developing my first Textual app . I'm borrowing some code from the "demo" app adapting it to my needs. It's going quite well (and I'm enjoying the experience), but my app must run inside a docker container, as part of a complex service orchestrated by docker-compose and I've encountered some problems. Here I'm going to show them with the Textual demo app (python -m textual)

The first one, which I managed to get around, is that in order to make the app look really nice, I had to set COLORTERM: truecolor as an environment variable to the container, since it originally looked like this:

However, once I got over that one I still had these:

1. There is no support for mouse events. Is it possible to enable it?
2. I see blinking "cursor" artifacts. For example if I close and open the "Sidebar", I see the cursor here.

Thanks in advance

[davep]

I have almost zero experience with Docker so can't directly help with this, but it might be useful if you could run textual diagnose in the environment and post the output here. Might give some clues.

[mgaitan]

Hi davep. Here it is:

Textual Diagnostics

Versions

Name	Value
Textual	0.15.1
Rich	13.3.2

Python

Name	Value
Version	3.8.12
Implementation	CPython
Compiler	GCC 10.2.1 20210110
Executable	/usr/local/bin/python

Operating System

Name	Value
System	Linux
Release	5.19.0-35-generic
Version	#36~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Fri Feb 17 15:17:25 UTC 2

Terminal

Name	Value
Terminal Application	Unknown
TERM	xterm
COLORTERM	truecolor
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=119, height=33
legacy_windows	False
min_width	1
max_width	119
is_terminal	True
encoding	utf-8
max_height	33
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

[TomJGooding]

Could you try running the command: export TERM=xterm-256color?

I'm wondering if you need to set the TERM environment variable in the container (though also zero experience with Docker here I'm afraid!)

[mgaitan]

I've just tried that (I've noted was a diff in textual diagnose between the container and my host), but there are no changes 😞 . The blinking and the lack of mouse are there.

[mgaitan]

I have been debugging this problem with a minimal scenario here
https://github.com/mgaitan/textual-docker-example and strangely I could not reproduce it.

With all the base images I used (python3.10, python3.10-alpine, and "fastapi 3.8" -the one I use in my app, based on python3.8-) and in all cases the textual behaves fine, with no flickering and correct mouse events.

Maybe it is a resource problem when more services are started with compose?

[TomJGooding]

This would suggest that some other service is interfering with Textual somehow, but I'm not sure the problem is resource usage.

Presumably there's a way of logging events and resource usage with Docker? Hopefully someone with more experience with Docker can help, but will probably need more info about exactly what other services you are running.

[cknoll]

@mgaitan I would suggest that you continue to try to create a minimal "working" example, where "working" means: "can reproduce the issue". I suggest doing this by incrementally transforming your fastapi 3.8- example (without the issue) into your actual project via copy-and-paste. Somewhere on that way the issue must occur. If you have pinpointed the cause, you might find a workaround or at least ask more precise questions.

As the two mentioned issues (no mouse events/blinking cursor) might have different causes, it might be recommendable to analyze the separately.

[popey]

Hello! Sorry to necro an old discussion, but I may have the answer!

tl;dr You have to pass -it at a minimum, because without them, Docker doesn't allocate a proper terminal interface. Add -e TERM=xterm-256color to get appropriate colour support.

I made a Docker container of a textual app I wrote, and figured out how to fix this:

My app (sbommage) is used to load an SBOM (Software Bill of Materials) and display it in a tree-like format using Textualize.

For example, if I do not specify -it, the command below shows the screenshot beneath:

docker run -v $(pwd)/example_sboms:/sboms sbommage /sboms/syft_1.31.0_docker.io_alpine_latest_spdx.json

Note in the screenshot, it's only taking up a portion of the screen:

Adding -it gives us the ability to interact, and it occupies the entire terminal.

docker run -it -v $(pwd)/example_sboms:/sboms sbommage /sboms/syft_1.31.0_docker.io_alpine_latest_spdx.json

However, if we also add -e TERM=xterm-256color, we get the right colours.

docker run -it -e TERM=xterm-256color -v $(pwd)/example_sboms:/sboms sbommage /sboms/syft_1.31.0_docker.io_alpine_latest_spdx.json

[willmcgugan]

Nice. You might also want to set COLORTERM=truecolor