Add `name_prefix` to `aws_autoscaling_group` and `aws_elb` resources (#12629)

Adds support for `name_prefix` to the `aws_autoscaling_group` and `aws_elb` resources. Unfortunately when using `name_prefix` with `aws_elb`, this means that the specified prefix can only be a maximum of 6 characters in length. This is because the maximum length for an ELB name is 32 characters, and `resource.PrefixedUniqueId` generates a 26-character unique identifier. I was considering truncating the unique identifier to allow for a longer `name_prefix`, but I worried that doing so would increase the risk of collisions.

builtin/providers/aws/resource_aws_autoscaling_group.go

@@ -33,6 +33,7 @@ func resourceAwsAutoscalingGroup() *schema.Resource {
 				Optional:      true,
 				Computed:      true,
 				ForceNew:      true,
+				ConflictsWith: []string{"name_prefix"},
 				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
 					// https://github.com/boto/botocore/blob/9f322b1/botocore/data/autoscaling/2011-01-01/service-2.json#L1862-L1873
 					value := v.(string)
@@ -43,6 +44,19 @@ func resourceAwsAutoscalingGroup() *schema.Resource {
 					return
 				},
 			},
+			"name_prefix": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				ForceNew: true,
+				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
+					value := v.(string)
+					if len(value) > 229 {
+						errors = append(errors, fmt.Errorf(
+							"%q cannot be longer than 229 characters, name is limited to 255", k))
+					}
+					return
+				},
+			},
 
 			"launch_configuration": &schema.Schema{
 				Type:     schema.TypeString,
@@ -281,8 +295,12 @@ func resourceAwsAutoscalingGroupCreate(d *schema.ResourceData, meta interface{})
 	var asgName string
 	if v, ok := d.GetOk("name"); ok {
 		asgName = v.(string)
+	} else {
+		if v, ok := d.GetOk("name_prefix"); ok {
+			asgName = resource.PrefixedUniqueId(v.(string))
 		} else {
 			asgName = resource.PrefixedUniqueId("tf-asg-")
+		}
 		d.Set("name", asgName)
 	}
 

builtin/providers/aws/resource_aws_autoscaling_group_test.go

@@ -84,6 +84,27 @@ func TestAccAWSAutoScalingGroup_basic(t *testing.T) {
 	})
 }
 
+func TestAccAWSAutoScalingGroup_namePrefix(t *testing.T) {
+	nameRegexp := regexp.MustCompile("^test-")
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSAutoScalingGroupDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccAWSAutoScalingGroupConfig_namePrefix,
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestMatchResourceAttr(
+						"aws_autoscaling_group.test", "name", nameRegexp),
+					resource.TestCheckResourceAttrSet(
+						"aws_autoscaling_group.test", "arn"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAWSAutoScalingGroup_autoGeneratedName(t *testing.T) {
 	asgNameRegexp := regexp.MustCompile("^tf-asg-")
 
@@ -748,6 +769,22 @@ resource "aws_autoscaling_group" "bar" {
 }
 `
 
+const testAccAWSAutoScalingGroupConfig_namePrefix = `
+resource "aws_launch_configuration" "test" {
+  image_id = "ami-21f78e11"
+  instance_type = "t1.micro"
+}
+
+resource "aws_autoscaling_group" "test" {
+  availability_zones = ["us-west-2a"]
+  desired_capacity = 0
+  max_size = 0
+  min_size = 0
+  name_prefix = "test-"
+  launch_configuration = "${aws_launch_configuration.test.name}"
+}
+`
+
 const testAccAWSAutoScalingGroupConfig_terminationPoliciesEmpty = `
 resource "aws_launch_configuration" "foobar" {
   image_id = "ami-21f78e11"

builtin/providers/aws/resource_aws_elb.go

@@ -34,8 +34,15 @@ func resourceAwsElb() *schema.Resource {
 				Optional:      true,
 				Computed:      true,
 				ForceNew:      true,
+				ConflictsWith: []string{"name_prefix"},
 				ValidateFunc:  validateElbName,
 			},
+			"name_prefix": &schema.Schema{
+				Type:         schema.TypeString,
+				Optional:     true,
+				ForceNew:     true,
+				ValidateFunc: validateElbNamePrefix,
+			},
 
 			"internal": &schema.Schema{
 				Type:     schema.TypeBool,
@@ -246,8 +253,12 @@ func resourceAwsElbCreate(d *schema.ResourceData, meta interface{}) error {
 	var elbName string
 	if v, ok := d.GetOk("name"); ok {
 		elbName = v.(string)
+	} else {
+		if v, ok := d.GetOk("name_prefix"); ok {
+			elbName = resource.PrefixedUniqueId(v.(string))
 		} else {
 			elbName = resource.PrefixedUniqueId("tf-lb-")
+		}
 		d.Set("name", elbName)
 	}
 

builtin/providers/aws/resource_aws_elb_test.go

@@ -172,6 +172,28 @@ func TestAccAWSELB_AccessLogs_disabled(t *testing.T) {
 	})
 }
 
+func TestAccAWSELB_namePrefix(t *testing.T) {
+	var conf elb.LoadBalancerDescription
+	nameRegex := regexp.MustCompile("^test-")
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:      func() { testAccPreCheck(t) },
+		IDRefreshName: "aws_elb.test",
+		Providers:     testAccProviders,
+		CheckDestroy:  testAccCheckAWSELBDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccAWSELB_namePrefix,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSELBExists("aws_elb.test", &conf),
+					resource.TestMatchResourceAttr(
+						"aws_elb.test", "name", nameRegex),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAWSELB_generatedName(t *testing.T) {
 	var conf elb.LoadBalancerDescription
 	generatedNameRegexp := regexp.MustCompile("^tf-lb-")
@@ -1138,6 +1160,20 @@ resource "aws_elb" "foo" {
 `, r, r)
 }
 
+const testAccAWSELB_namePrefix = `
+resource "aws_elb" "test" {
+  name_prefix = "test-"
+  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]
+
+  listener {
+    instance_port = 8000
+    instance_protocol = "http"
+    lb_port = 80
+    lb_protocol = "http"
+  }
+}
+`
+
 const testAccAWSELBGeneratedName = `
 resource "aws_elb" "foo" {
   availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]

builtin/providers/aws/validators.go

@@ -141,7 +141,24 @@ func validateElbName(v interface{}, k string) (ws []string, errors []error) {
 			"%q cannot end with a hyphen: %q", k, value))
 	}
 	return
+}
 
+func validateElbNamePrefix(v interface{}, k string) (ws []string, errors []error) {
+	value := v.(string)
+	if !regexp.MustCompile(`^[0-9A-Za-z-]+$`).MatchString(value) {
+		errors = append(errors, fmt.Errorf(
+			"only alphanumeric characters and hyphens allowed in %q: %q",
+			k, value))
+	}
+	if len(value) > 6 {
+		errors = append(errors, fmt.Errorf(
+			"%q cannot be longer than 6 characters: %q", k, value))
+	}
+	if regexp.MustCompile(`^-`).MatchString(value) {
+		errors = append(errors, fmt.Errorf(
+			"%q cannot begin with a hyphen: %q", k, value))
+	}
+	return
 }
 
 func validateEcrRepositoryName(v interface{}, k string) (ws []string, errors []error) {

builtin/providers/aws/validators_test.go

@@ -1732,3 +1732,56 @@ func TestValidateApiGatewayUsagePlanQuotaSettings(t *testing.T) {
 		}
 	}
 }
+
+func TestValidateElbName(t *testing.T) {
+	validNames := []string{
+		"tf-test-elb",
+	}
+
+	for _, s := range validNames {
+		_, errors := validateElbName(s, "name")
+		if len(errors) > 0 {
+			t.Fatalf("%q should be a valid ELB name: %v", s, errors)
+		}
+	}
+
+	invalidNames := []string{
+		"tf.test.elb.1",
+		"tf-test-elb-tf-test-elb-tf-test-elb",
+		"-tf-test-elb",
+		"tf-test-elb-",
+	}
+
+	for _, s := range invalidNames {
+		_, errors := validateElbName(s, "name")
+		if len(errors) == 0 {
+			t.Fatalf("%q should not be a valid ELB name: %v", s, errors)
+		}
+	}
+}
+
+func TestValidateElbNamePrefix(t *testing.T) {
+	validNamePrefixes := []string{
+		"test-",
+	}
+
+	for _, s := range validNamePrefixes {
+		_, errors := validateElbNamePrefix(s, "name_prefix")
+		if len(errors) > 0 {
+			t.Fatalf("%q should be a valid ELB name prefix: %v", s, errors)
+		}
+	}
+
+	invalidNamePrefixes := []string{
+		"tf.test.elb.",
+		"tf-test",
+		"-test",
+	}
+
+	for _, s := range invalidNamePrefixes {
+		_, errors := validateElbNamePrefix(s, "name_prefix")
+		if len(errors) == 0 {
+			t.Fatalf("%q should not be a valid ELB name prefix: %v", s, errors)
+		}
+	}
+}

website/source/docs/providers/aws/r/autoscaling_group.html.markdown

@@ -64,7 +64,9 @@ EOF
 
 The following arguments are supported:
 
-* `name` - (Optional) The name of the auto scale group. By default generated by terraform.
+* `name` - (Optional) The name of the auto scaling group. By default generated by Terraform.
+* `name_prefix` - (Optional) Creates a unique name beginning with the specified
+  prefix. Conflicts with `name`.
 * `max_size` - (Required) The maximum size of the auto scale group.
 * `min_size` - (Required) The minimum size of the auto scale group.
     (See also [Waiting for Capacity](#waiting-for-capacity) below.)

website/source/docs/providers/aws/r/elb.html.markdown

@@ -72,7 +72,9 @@ resource "aws_elb" "bar" {
 
 The following arguments are supported:
 
-* `name` - (Optional) The name of the ELB. By default generated by terraform.
+* `name` - (Optional) The name of the ELB. By default generated by Terraform.
+* `name_prefix` - (Optional, Forces new resource) Creates a unique name beginning with the specified
+  prefix. Conflicts with `name`.
 * `access_logs` - (Optional) An Access Logs block. Access Logs documented below.
 * `availability_zones` - (Required for an EC2-classic ELB) The AZ's to serve traffic in.
 * `security_groups` - (Optional) A list of security group IDs to assign to the ELB.