icinga2-checks/check_mysql_connections.py

#!/usr/bin/env python
import argparse
import sys
import traceback

import mysql.connector

from checker import nagios
from checker.result import quit_check


def main(args):
    try:
        connection = mysql.connector.connect(host=args.host, user=args.username, password=args.password)
        cursor = connection.cursor()
        cursor.execute("SHOW STATUS LIKE 'Threads_connected'")
        result = cursor.fetchone()
        active_connections = int(result[1])

        cursor.execute("SHOW VARIABLES LIKE 'max_connections'")
        result = cursor.fetchone()
        max_connections = int(result[1])

        cursor.close()
        connection.close()

    except mysql.connector.Error as e:
        quit_check(f'unable to connect to MySQL server: {e}', nagios.STATE_CRIT)
        return  # make pycharm happy

    # ===================================================
    # Parse data

    warn_percent = args.warn_percent / 100
    crit_percent = args.crit_percent / 100
    active_connections_percent = active_connections / max_connections
    active_connections_percent_str = str(int(active_connections_percent * 100))

    if active_connections_percent > crit_percent:
        exit_code = nagios.STATE_CRIT
    elif active_connections_percent > warn_percent:
        exit_code = nagios.STATE_WARN
    else:
        exit_code = nagios.STATE_OK

    perfdata = {
        'percent_active_connections': {
            'value': active_connections_percent_str,
            'min': 0,
            'unit': '%',
            'warn': int(warn_percent * 100),
            'crit': int(crit_percent * 100)
        },
        'active_connections': {
            'value': active_connections,
            'min': 0,
            'max': max_connections,
            'warn': int(max_connections * warn_percent),
            'crit': int(max_connections * crit_percent)
        }
    }
    text_str = f'{active_connections}/{max_connections} ({active_connections_percent_str}%) of available connections used'
    quit_check(text_str, exit_code, perfdata)


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Check MySQL connections to a server.')
    parser.add_argument('--host', required=True, help='The IP of the MySQL server to connect to.')
    parser.add_argument('--username', required=True, help='Username to connect with.')
    parser.add_argument('--password', required=True, help='Password to connect with.')
    parser.add_argument('--warn-percent', default=50, type=int, help='Connections warning percentage. Default: 50%')
    parser.add_argument('--crit-percent', default=75, type=int, help='Connections critical percentage. Default: 75%')
    args = parser.parse_args()

    try:
        main(args)
    except Exception as e:
        print(f"UNKNOWN - {e}")
        traceback.print_exc()
        sys.exit(nagios.STATE_UNKNOWN)