cannot import httpx when running weather.py app from Textual dev command line.

[greendavegreen]

working with the weather.py example in the workers section of the documentation, I ran into trouble running from Textual dev tooling. when I run either regular or dev mode using textual, I get a httpx module not found error.

the same trouble affects my application which I have been happily developing once I added httpx as an import. I would like to debug and see events while making network calls.

textual diagnose

Traceback (most recent call last):
  File "/Users/gdave/VSProjects/tui/1337/weather.py", line 1, in <module>
    import httpx
ModuleNotFoundError: No module named 'httpx'

Textual Diagnostics

Versions

Name	Value
Textual	0.45.1
Rich	13.7.0

Python

Name	Value
Version	3.11.6
Implementation	CPython
Compiler	Clang 15.0.0 (clang-1500.0.40.1)
Executable	/usr/local/opt/[email protected]/bin/python3.11

Operating System

Name	Value
System	Darwin
Release	23.2.0
Version	Darwin Kernel Version 23.2.0: Wed Nov 15 21:54:10 PST 2023; root:xnu-10002.61.3~2/RELEASE_X86_64

Terminal

Name	Value
Terminal Application	iTerm.app (3.4.22)
TERM	xterm-256color
COLORTERM	truecolor
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=143, height=58
legacy_windows	False
min_width	1
max_width	143
is_terminal	True
encoding	utf-8
max_height	58
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

[TomJGooding]

httpx is an external library which you will need to install with pip install httpx.

[rodrigogiraoserrao]

Well, httpx is a dev dependency of Textual, but not a regular dependency, so it doesn't get automatically installed with Textual.

As to why python weather4.py runs but textual run --dev weather4.py doesn't, maybe you're using a Python that's different from the Python with which textual-dev was installed?

That would mean you could have httpx installed with your python weather4.py Python but not with textual.

One thing that might be a good idea is run textual diagnose (you already did), look for the Python section, and see if the version/executable matches that of python (you can run which python to figure out what's the executable associated with the command python).

[greendavegreen]

This was very helpful for tracking down more precisely what is happening. I had a mental model that the only Python executable involved was the one in my active VirtualEnv. textual diagnose highlighted that it was using my system python. yup, I had textual in both places and system python was first in the search path. I uninstalled from system and my VirtualEnv, then activated the VirtualEnv and installed both textual and httpx. This configuration also didn't work.

[greendavegreen]

I then moved to installing both in the system python and that did work. My next question is how does Textual determine the active python at the time it is installed?

[rodrigogiraoserrao]

When installing packages with pip, I always do python -m pip install X, which makes it blatantly clear that the package X is being installed on the Python version that the command python runs.
So, Textual needs to be installed with the correct Python / in the correct environment if you want to use Textual with a specific Python version / inside a specific virtual environment.

Does this make sense?
(It probably does because you seemed to have resolved your issue already.)

[greendavegreen]

yes, definitely makes sense. thank you much. the python -m pip install X is a very good torch to carry when travelling in the swamp. python dependency management isn't quite windows DLL hell from the 90s, but it has its moments.

[willmcgugan]

This usually indicates you have the textual command in a different environment. If you are using a virtual environments, be sure to install both textual and textual-dev.

[greendavegreen]

I created a virtualenv with a particular python runtime via python3.10 -m venv venv, source venv/bin/activate, pip install textual , and pip install textual-dev. the problem still exists where it is fails resolving httpx.

the only working path I have found is deactivating the venv and doing an install of textual and textual dev in the python installed on the system.

[greendavegreen]

ok, conclusion. driver error. :-) I tried again while slowly working through the steps and realized that the first sweep through when I was trying to clean out, I didn't uninstall my first attempt at textual-dev. once I had deleted textual, textual-dev, and httpx, and then installed them all into my virtualenv and nowhere else, all is well.

thanks for the clarity and the helpful hints for collecting the extra info I needed to get through!