Setup Home Assistant easily on Raspberry Pi with venv. Improved from https://www.home-assistant.io/docs/installation/virtualenv

homeassistant_setup_script.sh

#!/bin/bash

#############################################
# WARNING: DO NOT RUN THIS SCRIPT DIRECTLY. #
# THIS SHOULD BE RUN AS ROOT IN A RPI       #
#############################################

if [ ! "$(whoami)" == "root" ];
then
    echo "YOU MUST RUN THIS AS ROOT"
    exit 1
fi

if [ ! "$1" == "confirm" ];
then
    echo "WARNING: DO NOT RUN THIS SCRIPT DIRECTLY. IF YOU ARE SURE WHAT YOU ARE DOING, RUN THIS AS:"
    echo "setup_script.sh confirm"
    exit 1
fi

apt-get update && \
apt-get -y upgrade && \
apt-get -y install python3 python3-dev python3-venv python3-pip libffi-dev libssl-dev && \

# It's okay if this fails, attempt to create the group so useradd will work
groupadd dialout
groupadd gpio
groupadd i2c

useradd -rm homeassistant -G dialout,gpio,i2c

mkdir -p /srv/homeassistant
chown -R homeassistant.homeassistant /srv/homeassistant

runuser -l homeassistant -c "cd /srv/homeassistant && python3 -m venv ." && \
runuser -l homeassistant -c "cd /srv/homeassistant && . bin/activate && python3 -m pip install wheel" && \
runuser -l homeassistant -c "cd /srv/homeassistant && . bin/activate && pip3 install homeassistant"

SYSTEMCTL=`which systemctl`

if [ "$SYSTEMCTL" ];
then
    echo
    echo "************************************************************"
    echo "* Setting up service: home-assistant@homeassistant.service *"
    echo "************************************************************"

    # Setup systemd
    echo "[Unit]
Description=Home Assistant
After=network-online.target

[Service]
Type=simple
User=%i
ExecStart=/srv/homeassistant/bin/hass -c \"/home/%i/.homeassistant\"
Restart=on-failure
RestartSec=5s

[Install]
WantedBy=multi-user.target
" > /etc/systemd/system/home-assistant@homeassistant.service

    $SYSTEMCTL --system daemon-reload && \
    $SYSTEMCTL enable home-assistant@homeassistant.service
else
    echo
    echo "***************************************************"
    echo "* Systemd not found. Skipping installing service. *"
    echo "***************************************************"
fi

if [ $? ];
then
    echo
    echo "**********************************************************"
    echo "* Successfully installed Home Assistant                  *"

    if [ "$SYSTEMCTL" ];
    then
        echo "* Systemd was installed. Start Home Assistant by         *"
        echo "* systemctl start home-assistant@homeassistant.service   *"
    else
        echo "* Systemd not installed. You can start Home Assistant by *"
        echo "* su homeassistant                                       *"
        echo "* cd /srv/homeassistant                                  *"
        echo "* . bin/activate                                         *"
        echo "* bin/hass                                               *"
    fi

    echo "**********************************************************"

    exit 0
else
    echo
    echo "***********************"
    echo "* Installation FAILED *"
    echo "***********************"

    exit 1
fi

This is to automate the long list of instructions from https://www.home-assistant.io/docs/installation/virtualenv