Docker file to build tasmota firmware

Dockerfile

# Document requirements for building Tasmota firmware by creating a docker image :)
#
# Usage
#   Install docker and git on your os, e.g. on opensuse:
#     sudo zypper install docker git 
#   Start docker service on your os, e.g. on systemd based distros like opensuse:
#     sudo systemctl start docker
#   Build docker image
#     sudo docker build -t tasmota /path/to/this/file/
#   Clone Tasmota git repository or some fork, e.g.
#     git clone https://github.com/arendst/Sonoff-Tasmota
#   Modify platformio.ini if needed, e.g. to
#     select the espressif core version
#     select your default environment (e.g. sonoff-DE)
#     select your upload port and speed
#     ...
#   Modify sonoff/my_user_config.h if needed, e.g. to
#     set your wifi credentials
#     set your mqtt server
#     set your syslog server
#     ...
#   Run docker image and build all environments (or use -e to select one, or replace pio run with whatever)
#     sudo docker run --rm -u $UID -v /full/path/to/git/repo/Sonoff-Tasmota:/tasmota tasmota pio run

# Use a sane, recent os as basis
FROM opensuse/leap:15.1

# Install pip with all requirements and wget on above os
RUN zypper in -y python3-pip

# Upgrade pip to latest
RUN pip install --upgrade pip

# UTF-8 required for PlatformIO
ENV LC_ALL=C.UTF-8
ENV LANG=C.UTF-8

# Install latest PlatformIO
RUN pip install platformio

# Provide external Sonoff-Tasmota git repo with your desired version and optional changes
VOLUME ["/tasmota"]

# Where platformio.ini is expected if you do a pio run
WORKDIR /tasmota

# Some programs need a HOME
ENV HOME=/tmp

# Present options if none given
CMD ["pio", "run", "--help"]