Alert Modules
=============

Alert scripts are located in the directory `scripts/alerts` in the git repository of your NetSpyGlass cluster.

.. code-block:: none

  ├── scripts
  │   ├── aggregation
  │   │   ├── example.py
  │   │   └── __init__.py
  │   ├── alerts
  │   │   ├── __init__.py
  │   │   ├── nsg_bgp_session_down.py
  │   │   ├── nsg_device_down.py
  │   │   ├── nsg_high_cpu_util.py
  │   │   ├── nsg_high_mem_util.py
  │   │   ├── nsg_interface_down.py
  │   │   └── nsg_snmp_timeout.py

A module in directory `alerts` might look like this (this is a file "alerts/alert_busy_cpu.py")::


    import nw2rules
    from nw2functions import *


    def alert_busy_cpu(log):
        alert(
            name='busyCpuAlert',
            input=import_var('cpuUtil'),
            condition=lambda _, value: value > 75,
            description='CPU utilization is over 75% for 20% of time for the last 10 min',
            duration=600,
            percent_duration=20,
            notification_time=600,
            streams=['log'],
            fan_out=True
        )


NetSpyGlass monitors all python scripts in directory `scripts` and reloads them when they change.
You do not need to restart the server for this. As usual, watch logs in the panel System/Logs/Python
for errors when you modify and save one of these script files.