SMTP2Go Mail Usage Check Plugin for Icinga2

Features

• Real-time usage check: Fetches the current mail usage from the SMTP2Go API
• Configurable thresholds: Set custom warning and critical percentage thresholds
• Performance data output: Returns Icinga-compatible performance data for both absolute mail usage and percentage utilization

Requirements

• Python 3
• requests Python library (install with pip install requests)

Installation

1. Make sure Python 3 is installed on your monitoring server
2. Install the requests library if not already present:

   pip3 install requests 

3. Download or clone this repository and place the script in the plugins folder

   git clone https://github.com/StratoGh0st99/check_smtp2go_usage.git
   cd check_smtp2go_usage
   cp check_smtp2go_usage.py /usr/lib/nagios/plugins/

4. Make the script executable.

   chmod +x /usr/lib/nagios/plugins/check_smtp2go_quota.py

Usage

Test your API credentials

   ./check_smtp2go_quota.py --api-key YOUR_API_KEY --warn 80 --crit 90

Parameters

-a / --api-key (required): Your SMTP2Go API key

-w / --warn (required): Warning threshold in percent (e.g. 80 for 80%)

-c / --crit (required): Critical threshold in percent (e.g. 90 for 90%)

Example Output

OK - 200 of 1000 mails used (20.00%) | mails_used=200;800;900;0;1000 usage_percent=20.00%;80;90;0;100

Integrate in Icinga2

1. Define the CheckCommand in Icinga2

   object CheckCommand "check_smtp2go_quota" {
    import "plugin-check-command"
    command = [ "/usr/lib/nagios/plugins/check_smtp2go_quota.py" ]
    arguments = {
      "--api-key" = "$smtp2go_api_key$"
      "--warn" = "$smtp2go_warn$"
      "--crit" = "$smtp2go_crit$"
      }
   }

2. Apply the service to a host

   apply Service "smtp2go-quota" {
    import "generic-service"
    check_command = "check_smtp2go_quota"
    vars.smtp2go_api_key = "YOUR_API_KEY"
    vars.smtp2go_warn = "80"
    vars.smtp2go_crit = "90"
    assign where host.name == "myhost"
    }

3. Reload Icinga2

   systemctl reload icinga2