feat: PC-11815 add budget adjustments terraform support (#175)

## Motivation

Add support for the new `BudgetAdjustment` kind.

## Release Notes

New BudgetAdjustment kind which allows customers to schedule recurring
future events that should be excluded from the Error Budget calculations
in their SLOs. This PR introduces new `budget_adjustment` resource.

---------

Co-authored-by: kubaceg <jakub.cegielka@nobl9.com>

cspell.yaml

@@ -26,6 +26,7 @@ ignorePaths:
   - bin/**
 words:
   - apdex
+  - bymonthday
   - dbslo
   - dynatrace
   - endef
@@ -46,6 +47,7 @@ words:
   - opentsdb
   - plantuml
   - promql
+  - rrule
   - securego
   - sloctl
   - slos

docs/resources/budget_adjustment.md

@@ -0,0 +1,96 @@
+---
+page_title: "nobl9_budget_adjustment Resource - terraform-provider-nobl9"
+description: |-
+  Budget adjustment configuration documentation https://docs.nobl9.com/features/budget-adjustment
+---
+
+# nobl9_budget_adjustment (Resource)
+
+The budget adjustment feature allows you to define future periods where planned maintenance, releases, and similar activities won't affect your budget in specific SLOs.
+
+For more details, refer to the [Budget adjustment configuration documentation](https://docs.nobl9.com/features/budget-adjustment).
+
+## Example Usage
+
+Here's an example of Budget Adjustment resource configuration:
+
+```terraform
+resource "nobl9_budget_adjustment" "single-budget-adjustment-event" {
+  name              = "single-budget-adjustment-event"
+  display_name      = "Single Budget Adjustment Event"
+  first_event_start = "2022-01-01T00:00:00Z"
+  duration          = "1h"
+  description       = "Single budget adjustment event"
+  filters {
+    slos {
+      slo {
+        name    = "my-slo"
+        project = "default"
+      }
+    }
+  }
+}
+
+resource "nobl9_budget_adjustment" "recurring-budget-adjustment-event" {
+  name              = "recurring-budget-adjustment-event"
+  display_name      = "Recurring Budget Adjustment Event"
+  first_event_start = "2022-01-01T16:00:00Z"
+  duration          = "1h"
+  rrule             = "FREQ=WEEKLY"
+  description       = "Recurring budget adjustment event"
+  filters {
+    slos {
+      slo {
+        name    = "my-slo"
+        project = "default"
+      }
+    }
+  }
+}
+```
+
+<!-- schema generated by tfplugindocs -->
+## Schema
+
+### Required
+
+- `duration` (String) The duration of the budget adjustment event. The expected value for this field is a string formatted as a time duration. The duration must be defined with a precision of 1 minute. Example: `1h10m`
+- `first_event_start` (String) The time at which the first event is scheduled to start. The expected value must be a string representing the date and time in RFC3339 format. Example: `2022-12-31T00:00:00Z`
+- `name` (String) Unique name of the resource, must conform to the naming convention from [DNS RFC1123](https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#names).
+
+### Optional
+
+- `description` (String) Optional description of the resource. Here, you can add details about who is responsible for the integration (team/owner) or the purpose of creating it.
+- `display_name` (String) User-friendly display name of the resource.
+- `filters` (Block Set) Filters are used to select SLOs for the budget adjustment event. (see [below for nested schema](#nestedblock--filters))
+- `rrule` (String) The recurrence rule for the budget adjustment event. The expected value is a string in RRULE format. Example: `FREQ=MONTHLY;BYMONTHDAY=1`
+
+### Read-Only
+
+- `id` (String) The ID of this resource.
+
+<a id="nestedblock--filters"></a>
+### Nested Schema for `filters`
+
+Required:
+
+- `slos` (Block Set, Min: 1) (see [below for nested schema](#nestedblock--filters--slos))
+
+<a id="nestedblock--filters--slos"></a>
+### Nested Schema for `filters.slos`
+
+Required:
+
+- `slo` (Block List, Min: 1) SLO where budget adjustment event will be applied. (see [below for nested schema](#nestedblock--filters--slos--slo))
+
+<a id="nestedblock--filters--slos--slo"></a>
+### Nested Schema for `filters.slos.slo`
+
+Required:
+
+- `name` (String) Unique name of the resource, must conform to the naming convention from [DNS RFC1123](https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#names).
+- `project` (String) Name of the Nobl9 project the resource sits in, must conform to the naming convention from [DNS RFC1123](https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#names).
+
+## Useful Links
+
+[Budget Adjustment configuration | Nobl9 Documentation](https://docs.nobl9.com/yaml-guide#budget-adjustment)

examples/resources/nobl9_budget_adjustment/resource.tf

@@ -0,0 +1,32 @@
+resource "nobl9_budget_adjustment" "single-budget-adjustment-event" {
+  name              = "single-budget-adjustment-event"
+  display_name      = "Single Budget Adjustment Event"
+  first_event_start = "2022-01-01T00:00:00Z"
+  duration          = "1h"
+  description       = "Single budget adjustment event"
+  filters {
+    slos {
+      slo {
+        name    = "my-slo"
+        project = "default"
+      }
+    }
+  }
+}
+
+resource "nobl9_budget_adjustment" "recurring-budget-adjustment-event" {
+  name              = "recurring-budget-adjustment-event"
+  display_name      = "Recurring Budget Adjustment Event"
+  first_event_start = "2022-01-01T16:00:00Z"
+  duration          = "1h"
+  rrule             = "FREQ=WEEKLY"
+  description       = "Recurring budget adjustment event"
+  filters {
+    slos {
+      slo {
+        name    = "my-slo"
+        project = "default"
+      }
+    }
+  }
+}

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/hashicorp/terraform-plugin-sdk/v2 v2.33.0
 	github.com/nobl9/nobl9-go v0.81.0
 	github.com/stretchr/testify v1.9.0
+	github.com/teambition/rrule-go v1.8.2
 )
 
 require (
@@ -71,7 +72,6 @@ require (
 	github.com/posener/complete v1.2.3 // indirect
 	github.com/shopspring/decimal v1.3.1 // indirect
 	github.com/spf13/cast v1.5.0 // indirect
-	github.com/teambition/rrule-go v1.8.2 // indirect
 	github.com/vmihailenco/msgpack v4.0.4+incompatible // indirect
 	github.com/vmihailenco/msgpack/v5 v5.4.1 // indirect
 	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect

nobl9/provider.go

@@ -109,6 +109,7 @@ func Provider() *schema.Provider {
 			"nobl9_project":                                 resourceProject(),
 			"nobl9_role_binding":                            resourceRoleBinding(),
 			"nobl9_slo":                                     resourceSLO(),
+			"nobl9_budget_adjustment":                       budgetAdjustment(),
 		},
 
 		ConfigureContextFunc: providerConfigure,