[ProtocolSweetHome][Telegram] Send alert message in case of shutdown linux machine

shutdown_alert_bot.sh

#!/bin/bash
# text to @botFather
# get botID, chatID
# set env vars
echo "export ALARM_CHAT=YOUR_ID" >> .bashrc
echo "export ALARM_BOT_TOKEN=YOUR_TOKEN >> .bashrc
source .bashrc
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root@vnaumov-dev:~# cat /etc/systemd/system/start_and_stop.service
[Unit]
Description=UP/DOWN telegram alerts
After=network.target networking.service network-online.target nss-lookup.target systemd-resolved
Requires=network.target networking.service network-online.target nss-lookup.target systemd-resolved

[Service]
Type=oneshot
RemainAfterExit=true
ExecStart=/root/.alert_commands startup
ExecStop=/root/.alert_commands shutdown

[Install]
WantedBy=multi-user.target
###################################################

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root@vnaumov-dev:~# cat .alert_commands
#!/bin/bash
# Initialize our own variables:
ALARM_BOT_TOKEN=
ALARM_CHAT=
shutdown_header="_I am going to shutdown.._"
startup_header="_I am alive_"
header="Check manually"

case "$1" in
shutdown)
    header=$shutdown_header
    ;;
startup)
    header=$startup_header
    ;;
esac

echo $header

msg="\
$header
\`\`\`bash
name: $(hostname)
--------------------------------------------------
addresses: $(hostname -I)
--------------------------------------------------
RAM: $(free -h)
--------------------------------------------------
Space: $(df -h)
--------------------------------------------------
Visitors:
$(who -a)
--------------------------------------------------
alert log saved in /root/telegram_monitor.log
--------------------------------------------------
\`\`\`
"

echo -e "$(date)--------------------------------------------\n" >> /root/telegram_monitor.log
curl -X POST \
       -H 'Content-Type: application/json' \
       -d "{\"chat_id\": $ALARM_CHAT, \"text\": \"$msg\", \"disable_notification\": true, \"parse_mode\": \"Markdown\"}" \
       https://api.telegram.org/bot$ALARM_BOT_TOKEN/sendMessage -vvv >> /root/telegram_monitor.log
echo -e "--------------------------------------------\n" >> /root/telegram_monitor.log
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