Heartbeat monitoring (#7)

* Ask user about heartbeat monitoring
* Monitoring logic
* Add a work about heartbeat monitoring to README

README.md

@@ -15,3 +15,6 @@ This repository contains the MicroMPX set-up for [ZuidWest FM](https://www.zuidw
 - Download and run the VPN script with the command `/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/oszuidwest/rpi-umpx-decoder/main/vpn.sh)"`
 - Check with `ip a` if you have an interface named `wg0` with the correct IP
 - If the `wg0` interface is not showing, enable debugging with `modprobe wireguard && echo module wireguard +p > /sys/kernel/debug/dynamic_debug/control` and `tail -f /var/log/syslog` to look for errors
+
+## Optional heartbeat monitoring
+You can optionally integrate heartbeat monitoring. In this case the Pi will `wget --spider` a given url every minute, acting as a heartbeat. This can be any url, but we tested with Uptime Robot. A paid account is required at Uptime Robot for heartbeat monitoring.

setup.sh

@@ -23,7 +23,7 @@ is_this_linux
 is_this_os_64bit
 
 # Check if we are running on a Raspberry Pi 3 or newer
-check_rpi_model 3
+check_rpi_model 4
 
 # Something fancy for the sysadmin
 cat << "EOF"
@@ -87,6 +87,17 @@ curl -s -o /etc/systemd/system/micrompx.service https://raw.githubusercontent.co
 systemctl daemon-reload > /dev/null
 systemctl enable micrompx > /dev/null
 
+# Heartbeat monitoring
+ask_user "ENABLE_HEARTBEAT" "n" "Do you want to integrate heartbeat monitoring via UptimeRobot (y/n)" "y/n"
+if [ "$ENABLE_HEARTBEAT" == "y" ]; then
+  ask_user "HEARTBEAT_URL" "https://heartbeat.uptimerobot.com/xxx" "Enter the URL to get every minute for heartbeat monitoring" "str"
+
+  # Add a cronjob that calls the HEARTBEAT_URL every minute
+  echo -e "${BLUE}►► Setting up heartbeat monitoring cronjob...${NC}"
+  (crontab -l 2>/dev/null; echo "* * * * * wget --spider $HEARTBEAT_URL > /dev/null 2>&1") | crontab -
+  echo -e "${GREEN}Heartbeat monitoring cronjob added.${NC}"
+fi
+
 # Disable only the hdmi audio so we can use the minijack for monitoring
 echo -e "${BLUE}►► Disabling onboard audio...${NC}"
 readonly CONFIG_FILE="/boot/firmware/config.txt"