Check if SSH connection is working, useful for crontab

ssh_check

#!/bin/bash

HOST="$1"
PORT="$2"
BARK_KEY="$3"
USER="$(whoami)"
IP="$(dig +short $HOST)"
KEY_PATH="$HOME/.ssh/id_ed25519"
LOG_FILE="$HOME/logs/connection_check.log"

mkdir -p $HOME/logs

encode() {
    python3 -c "import urllib.parse; print(urllib.parse.quote('''$1'''))"
}

send_msg() {
    title="$USER@$HOST:$PORT"
    message="[hostname=$(hostname) ip=$IP] $1"
    message="$(encode "$title")/$(encode "$message")"
    curl -w "\n" "https://api.day.app/$BARK_KEY/$message"
    if [ $? -ne 0 ]; then
        echo "$(date): Failed to send message '$1'"
    fi
}

{
    if ssh -i "$KEY_PATH" "$USER"@"$HOST" -p "$PORT" true; then
        if echo `tail -n 1 $LOG_FILE` | grep -q "failed"; then
            send_msg "back online"
            echo "$(date) [$IP]: SSH connection back online"
        fi
        echo "$(date) [$IP]: SSH connection successful"
    else
        send_msg "offline"
        echo "$(date) [$IP]: SSH connection failed"
    fi
} 2>&1 | tee -a $LOG_FILE

ssh_check_crontab

0 * * * * /home/USER/connection_check.sh HOST PORT BARK_KEY