Plotly can't find the xvfb-run executable when running from a Gunicorn Flask application. #252

Hi. I have installed Plotly and Orca with conda install -c plotly plotly-orca and xvfb with sudo apt-get install xvfb.

When running a Python script from the terminal that prints or saves a simple figure to file, it works, but when trying the same code from a Flask application running with Gunicorn and Nginx, it fails on .to_image

File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/plotly/io/_orca.py", line 1482, in to_image
ensure_server()
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/plotly/io/_orca.py", line 1344, in ensure_server
validate_executable()
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/plotly/io/_orca.py", line 1067, in validate_executable
formatted_path=formatted_path
ValueError:
The plotly.io.orca.config.use_xvfb property is set to True, but the
xvfb-run executable could not be found on the system path.

Searched for the executable 'xvfb-run' on the following path:
/home/ubuntu/anaconda3/bin

Inside /home/ubuntu/anaconda3/bin I have an orca.sh script with the following code:

#!/bin/bash
xvfb-run -a /home/ubuntu/anaconda3/bin/orca-1.2.1-x86_64.AppImage "$@"

The orca-1.2.1-x86_64.AppImage file is also present on that directory

Related: running orca on the terminal does not print anything, but
xvfb-run orca graph '{ "data": [{"y": [1,2,1]}] }' -o fig.png does work.

here is my $path contents:
/home/ubuntu/bin:/home/ubuntu/.local/bin:/home/ubuntu/anaconda3/bin:/home/ubuntu/anaconda3/condabin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

Any help?
I'm a newbie with unix shell commands, btw.

tl;dr: Plotly can't find xvfb when running inside a Flask-Gunicorn app. Works fine when running from a simple python script from the terminal