Get alerts when someone connects to wireguard

Routers
1

This sends alerts to discord to know when someone connects.

First i created a script called check_wg_peer.sh in /cfg so its persistent between reboots.

#!/bin/sh

# -------- Configuration --------
PEER=""
NAME="Dale"
WEBHOOK_URL=""
STATE_FILE="/cfg/wg_${NAME}_state"
TIMEOUT=180  # seconds, longer than handshake interval

# -------- Get latest handshake timestamp --------
HANDSHAKE=$(wg show wg latest-handshakes | grep "$PEER" | awk '{print $2}')
NOW=$(date +%s)
DIFF=$((NOW - HANDSHAKE))

# -------- Read previous state --------
PREV_STATE="disconnected"
[ -f "$STATE_FILE" ] && PREV_STATE=$(cat "$STATE_FILE")

# -------- Determine current state --------
if [ "$DIFF" -le "$TIMEOUT" ]; then
    CURR_STATE="connected"
else
    CURR_STATE="disconnected"
fi

# -------- Send alert on transition --------
if [ "$CURR_STATE" = "connected" ] && [ "$PREV_STATE" != "connected" ]; then
    curl -s -H "Content-Type: application/json" \
         -X POST \
         -d "{\"content\": \"Peer $NAME just connected to WireGuard!\"}" \
         "$WEBHOOK_URL"
    echo "Alert sent for $NAME"
fi

# -------- Save current state --------
echo "$CURR_STATE" > "$STATE_FILE"

Then I added this to my rc.local within /cfg

# === WireGuard Discord Alert Cron Job ===
WG_ALERT_SCRIPT="/cfg/check_wg_peer.sh"

# Make sure the script is executable
chmod +x "$WG_ALERT_SCRIPT"

# Add cron job if it doesn't already exist
grep -q "$WG_ALERT_SCRIPT" /etc/crontabs/root || echo "* * * * * $WG_ALERT_SCRIPT" >> /etc/crontabs/root

You can get your peer id from running wg show

This is still a work in progress but does seem to be working, hopefully someone finds it useful.

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