## Time Periods

Time Periods define time ranges in Icinga where event actions are
triggered, for example if a service check is executed or not within
the `check_period` attribute. Or a notification should be sent to
users or not, filtered by the `notification_period` configuration
attribute for `Notification` and `User` objects.

> **Note**
>
> If you are familar with Icinga 1.x - these time period definitions
> are called `legacy timeperiods` in Icinga 2.
>
> An Icinga 2 legacy timeperiod requires the `ITL` provided template
>`legacy-timeperiod`.

The `TimePeriod` attribute `ranges` may contain multiple directives,
including weekdays, days of the month, and calendar dates.
These types may overlap/override other types in your ranges dictionary.

The descending order of precedence is as follows:

* Calendar date (2008-01-01)
* Specific month date (January 1st)
* Generic month date (Day 15)
* Offset weekday of specific month (2nd Tuesday in December)
* Offset weekday (3rd Monday)
* Normal weekday (Tuesday)

If you don't set any `check_period` or `notification_period` attribute
on your configuration objects Icinga 2 assumes `24x7` as time period
as shown below.

    object TimePeriod "24x7" inherits "legacy-timeperiod" {
      display_name = "Icinga 2 24x7 TimePeriod",
      ranges = {
        "monday"    = "00:00-24:00",
        "tuesday"   = "00:00-24:00",
        "wednesday" = "00:00-24:00",
        "thursday"  = "00:00-24:00",
        "friday"    = "00:00-24:00",
        "saturday"  = "00:00-24:00",
        "sunday"    = "00:00-24:00",
      }
    }
    
If your operation staff should only be notified during workhours
create a new timeperiod named `workhours` defining a work day with
09:00 to 17:00.

    object TimePeriod "workhours" inherits "legacy-timeperiod" {
      display_name = "Icinga 2 8x5 TimePeriod",
      ranges = {
        "monday"    = "09:00-17:00",
        "tuesday"   = "09:00-17:00",
        "wednesday" = "09:00-17:00",
        "thursday"  = "09:00-17:00",
        "friday"    = "09:00-17:00",
      }
    }

Assign the timeperiod as `notification_period` to the `Notification`
object then.

    object Host "localhost" {
      services["ping4"] = {
        notifications["mail"] = {
          templates = [ "generic-notification" ],
          notification_command = "mail-notification",
          users = [ "icingaadmin" ],
          notification_period = "workhours"
        }      
      }
    }