Merge pull request #1632 from hashicorp/f-generate-sg-names

unique identifier helper for resources / generate AWS security group names

builtin/providers/aws/resource_aws_launch_configuration.go

@@ -364,16 +364,13 @@ func resourceAwsLaunchConfigurationCreate(d *schema.ResourceData, meta interface
 		createLaunchConfigurationOpts.BlockDeviceMappings = blockDevices
 	}
 
-	var id string
+	var lcName string
 	if v, ok := d.GetOk("name"); ok {
-		id = v.(string)
+		lcName = v.(string)
 	} else {
-		hash := sha1.Sum([]byte(fmt.Sprintf("%#v", createLaunchConfigurationOpts)))
-		configName := fmt.Sprintf("terraform-%s", base64.URLEncoding.EncodeToString(hash[:]))
-		log.Printf("[DEBUG] Computed Launch config name: %s", configName)
-		id = configName
+		lcName = resource.UniqueId()
 	}
-	createLaunchConfigurationOpts.LaunchConfigurationName = aws.String(id)
+	createLaunchConfigurationOpts.LaunchConfigurationName = aws.String(lcName)
 
 	log.Printf(
 		"[DEBUG] autoscaling create launch configuration: %#v", createLaunchConfigurationOpts)
@@ -382,7 +379,7 @@ func resourceAwsLaunchConfigurationCreate(d *schema.ResourceData, meta interface
 		return fmt.Errorf("Error creating launch configuration: %s", err)
 	}
 
-	d.SetId(id)
+	d.SetId(lcName)
 	log.Printf("[INFO] launch configuration ID: %s", d.Id())
 
 	// We put a Retry here since sometimes eventual consistency bites

builtin/providers/aws/resource_aws_security_group.go

@@ -24,13 +24,15 @@ func resourceAwsSecurityGroup() *schema.Resource {
 		Schema: map[string]*schema.Schema{
 			"name": &schema.Schema{
 				Type:     schema.TypeString,
-				Required: true,
+				Optional: true,
+				Computed: true,
 				ForceNew: true,
 			},
 
 			"description": &schema.Schema{
 				Type:     schema.TypeString,
-				Required: true,
+				Optional: true,
+				Default:  "Managed by Terraform",
 			},
 
 			"vpc_id": &schema.Schema{
@@ -144,9 +146,7 @@ func resourceAwsSecurityGroup() *schema.Resource {
 func resourceAwsSecurityGroupCreate(d *schema.ResourceData, meta interface{}) error {
 	conn := meta.(*AWSClient).ec2conn
 
-	securityGroupOpts := &ec2.CreateSecurityGroupInput{
-		GroupName: aws.String(d.Get("name").(string)),
-	}
+	securityGroupOpts := &ec2.CreateSecurityGroupInput{}
 
 	if v := d.Get("vpc_id"); v != nil {
 		securityGroupOpts.VPCID = aws.String(v.(string))
@@ -156,6 +156,14 @@ func resourceAwsSecurityGroupCreate(d *schema.ResourceData, meta interface{}) er
 		securityGroupOpts.Description = aws.String(v.(string))
 	}
 
+	var groupName string
+	if v, ok := d.GetOk("name"); ok {
+		groupName = v.(string)
+	} else {
+		groupName = resource.UniqueId()
+	}
+	securityGroupOpts.GroupName = aws.String(groupName)
+
 	log.Printf(
 		"[DEBUG] Security Group create configuration: %#v", securityGroupOpts)
 	createResp, err := conn.CreateSecurityGroup(securityGroupOpts)

builtin/providers/aws/resource_aws_security_group_test.go

@@ -3,6 +3,7 @@ package aws
 import (
 	"fmt"
 	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/awslabs/aws-sdk-go/aws"
@@ -184,6 +185,35 @@ func TestAccAWSSecurityGroup_Change(t *testing.T) {
 	})
 }
 
+func TestAccAWSSecurityGroup_generatedName(t *testing.T) {
+	var group ec2.SecurityGroup
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSSecurityGroupDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccAWSSecurityGroupConfig_generatedName,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSSecurityGroupExists("aws_security_group.web", &group),
+					resource.TestCheckResourceAttr(
+						"aws_security_group.web", "description", "Managed by Terraform"),
+					func(s *terraform.State) error {
+						if group.GroupName == nil {
+							return fmt.Errorf("bad: No SG name")
+						}
+						if !strings.HasPrefix(*group.GroupName, "terraform-") {
+							return fmt.Errorf("No terraform- prefix: %s", *group.GroupName)
+						}
+						return nil
+					},
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckAWSSecurityGroupDestroy(s *terraform.State) error {
 	conn := testAccProvider.Meta().(*AWSClient).ec2conn
 
@@ -518,3 +548,18 @@ resource "aws_security_group" "foo" {
   }
 }
 `
+
+const testAccAWSSecurityGroupConfig_generatedName = `
+resource "aws_security_group" "web" {
+  ingress {
+    protocol = "tcp"
+    from_port = 80
+    to_port = 8000
+    cidr_blocks = ["10.0.0.0/8"]
+  }
+
+	tags {
+		Name = "tf-acc-test"
+	}
+}
+`

helper/resource/id.go

@@ -0,0 +1,41 @@
+package resource
+
+import (
+	"crypto/rand"
+	"encoding/base32"
+	"fmt"
+	"strings"
+)
+
+const UniqueIdPrefix = `terraform-`
+
+// Helper for a resource to generate a unique identifier
+//
+// This uses a simple RFC 4122 v4 UUID with some basic cosmetic filters
+// applied (base32, remove padding, downcase) to make visually distinguishing
+// identifiers easier.
+func UniqueId() string {
+	return fmt.Sprintf("%s%s", UniqueIdPrefix,
+		strings.ToLower(
+			strings.Replace(
+				base32.StdEncoding.EncodeToString(uuidV4()),
+				"=", "", -1)))
+}
+
+func uuidV4() []byte {
+	var uuid [16]byte
+
+	// Set all the other bits to randomly (or pseudo-randomly) chosen
+	// values.
+	rand.Read(uuid[:])
+
+	// Set the two most significant bits (bits 6 and 7) of the
+	// clock_seq_hi_and_reserved to zero and one, respectively.
+	uuid[8] = (uuid[8] | 0x80) & 0x8f
+
+	// Set the four most significant bits (bits 12 through 15) of the
+	// time_hi_and_version field to the 4-bit version number from Section 4.1.3.
+	uuid[6] = (uuid[6] | 0x40) & 0x4f
+
+	return uuid[:]
+}

helper/resource/id_test.go

@@ -0,0 +1,25 @@
+package resource
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestUniqueId(t *testing.T) {
+	iterations := 10000
+	ids := make(map[string]struct{})
+	var id string
+	for i := 0; i < iterations; i++ {
+		id = UniqueId()
+
+		if _, ok := ids[id]; ok {
+			t.Fatalf("Got duplicated id! %s", id)
+		}
+
+		if !strings.HasPrefix(id, "terraform-") {
+			t.Fatalf("Unique ID didn't have terraform- prefix! %s", id)
+		}
+
+		ids[id] = struct{}{}
+	}
+}