log-alert.sh

#!/bin/bash

BOT_TOKEN="<token>"
CHAT_ID="<id>"
TELEGRAM_USERNAME="<username>"

send_telegram_message() {
    local message="$1"
    curl -s -X POST "https://api.telegram.org/bot$BOT_TOKEN/sendMessage" \
        -d chat_id="$CHAT_ID" \
        -d text="$message" \
        -d parse_mode="HTML"
}

# https://core.telegram.org/bots/api#formatting-options
escape_special_chars() {
    local string="$1"
    echo "$string" | sed 's/[_*[\]()~`>#+=|{}.-]/\\&/g'
}

process_log_line() {
    local line="$1"
    if echo "$line" | grep -q "level=ERROR"; then
        local timestamp=$(echo "$line" | grep -oP 'time=\K[^ ]+')
        local error_msg=$(echo "$line" | sed -E 's/.*msg=("([^"]*)"|([^ ]*)).*/\2\3/')
        local error_details=$(echo "$line" | sed -E 's/.*error=("([^"]*)"|([^ ]*)).*/\2\3/')

        error_msg=$(escape_special_chars "$error_msg")
        error_details=$(escape_special_chars "$error_details")

        local message="⚠️ <b>Error Alert</b> ⚠️
<b>Time:</b> $timestamp
<b>Message:</b> $error_msg
<b>Error:</b> $error_details
@$TELEGRAM_USERNAME"

        send_telegram_message "$message"
    fi
}

journalctl -u ykbot.service -f -n 0 | while read -r line; do
    process_log_line "$line"
done