New resource "random_integer"

This is similar to "random_string" but produces a single integer within a given range.

random/provider.go

@@ -15,6 +15,7 @@ func Provider() terraform.ResourceProvider {
 			"random_shuffle": resourceShuffle(),
 			"random_pet":     resourcePet(),
 			"random_string":  resourceString(),
+			"random_integer": resourceInteger(),
 		},
 	}
 }

random/resource_integer.go

@@ -0,0 +1,68 @@
+package random
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func resourceInteger() *schema.Resource {
+	return &schema.Resource{
+		Create: CreateInteger,
+		Read:   RepopulateInteger,
+		Delete: schema.RemoveFromState,
+
+		Schema: map[string]*schema.Schema{
+			"keepers": {
+				Type:     schema.TypeMap,
+				Optional: true,
+				ForceNew: true,
+			},
+
+			"min": {
+				Type:     schema.TypeInt,
+				Required: true,
+				ForceNew: true,
+			},
+
+			"max": {
+				Type:     schema.TypeInt,
+				Required: true,
+				ForceNew: true,
+			},
+
+			"seed": {
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+
+			"result": {
+				Type:     schema.TypeInt,
+				Computed: true,
+			},
+		},
+	}
+}
+
+func CreateInteger(d *schema.ResourceData, meta interface{}) error {
+	min := d.Get("min").(int)
+	max := d.Get("max").(int)
+	seed := d.Get("seed").(string)
+
+	if max <= min {
+		return fmt.Errorf("Minimum value needs to be smaller than maximum value")
+	}
+	rand := NewRand(seed)
+	number := rand.Intn((max+1)-min) + min
+
+	d.Set("result", number)
+	d.SetId(strconv.Itoa(number))
+
+	return nil
+}
+
+func RepopulateInteger(d *schema.ResourceData, _ interface{}) error {
+	return nil
+}

random/resource_integer_test.go

@@ -0,0 +1,58 @@
+package random
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestAccResourceIntegerBasic(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: testRandomIntegerBasic,
+				Check: resource.ComposeTestCheckFunc(
+					testAccResourceIntegerBasic("random_integer.integer_1"),
+				),
+			},
+		},
+	})
+}
+
+func testAccResourceIntegerBasic(id string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		rs, ok := s.RootModule().Resources[id]
+		if !ok {
+			return fmt.Errorf("Not found: %s", id)
+		}
+		result := rs.Primary.Attributes["result"]
+
+		if rs.Primary.ID == "" {
+			return fmt.Errorf("No ID is set")
+		}
+
+		if result == "" {
+			return fmt.Errorf("Result not found")
+		}
+
+		if result != "3" {
+			return fmt.Errorf("Invalid result %s. Seed does not result in correct value", result)
+		}
+		return nil
+	}
+}
+
+const (
+	testRandomIntegerBasic = `
+resource "random_integer" "integer_1" {
+   min  = 1
+   max  = 3
+   seed = "12345"
+}
+`
+)

website/docs/r/integer.html.md

@@ -0,0 +1,65 @@
+---
+layout: "random"
+page_title: "Random: random_integer"
+sidebar_current: "docs-random-resource-integer"
+description: |-
+  Generates a random integer values.
+---
+
+# random\_integer
+
+The resource `random_integer` generates random values from a given range, described by the `min` and `max` attributes of a given resource.
+
+This resource can be used in conjunction with resources that have
+the `create_before_destroy` lifecycle flag set, to avoid conflicts with
+unique names during the brief period where both the old and new resources
+exist concurrently.
+
+## Example Usage
+
+The following example shows how to generate a random priority between 1 and 99999 for
+a `aws_alb_listener_rule` resource:
+```hcl
+resource "random_integer" "priority" {
+  min     = 1
+  max     = 99999
+  keepers = {
+    # Generate a new integer each time we switch to a new listener ARN
+    listener_arn = "${var.listener_arn}"
+  }
+}
+
+resource "aws_alb_listener_rule" "main" {
+  listener_arn = "${var.listener_arn}"
+  priority     = "${random_integer.priority.result}"
+
+  action {
+    type             = "forward"
+    target_group_arn = "${var.target_group_arn}"
+  }
+  # ... (other aws_alb_listener_rule arguments) ...
+}
+```
+
+The result of the above will set a random priority.
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `min` - (int) The minimum inclusive value of the range.
+
+* `max` - (int) The maximum inclusive value of the range.
+
+* `keepers` - (Optional) Arbitrary map of values that, when changed, will
+  trigger a new id to be generated. See
+  [the main provider documentation](../index.html) for more information.
+
+* `seed` - (Optional) A custom seed to always produce the same value.
+
+## Attribute Reference
+
+The following attributes are supported:
+
+* `id` - (string) An internal id.
+* `result` - (int) The random Integer result.

website/random.erb

@@ -25,6 +25,9 @@
             <li<%= sidebar_current("docs-random-resource-string") %>>
               <a href="/docs/providers/random/r/string.html">random_string</a>
             </li>
+            <li<%= sidebar_current("docs-random-resource-integer") %>>
+              <a href="/docs/providers/random/r/integer.html">random_integer</a>
+            </li>
           </ul>
         </li>
       </ul>