installation of packages as python library setting environment variables in docker compose

[donmart85]

Hi,
i would like to have a feature for installing linux package automatically with docker compose.
I'm using a script for monitoring Proxmox because the librenms included app doesn't work (check_pve.py).
I have inserted this file in the dir /data/monitoring-plugins/check_pve.py with chmod +x permission.
This script uses python3 and needs py3-requests library that isn't included in the image.
I also use nano for editing text ,not included in standard image.
I can install these packages from commandline with apk add action and the script works correctly.
The problem is that every time that i upgrade librenms image, i must re-apply these changes.
It would be useful to set a environment variables for package installation in compose file that, when i start container, will do a check of installed package and install automatically if not present.

For example, i'm using linuxserver image for another service with docker-mods.
One docker-mod permits to install other packages with standard image with environment variables INSTALL_PACKAGES and INSTALL_PIP_PACKAGES.
I would like to have a similar feature in librenms.

Thanks.