Add top-level ELB Attachment resource

Add an aws_elb_attachment resource so that the attment of instances to
an ELB can be managed separately from an aws_elb and prevent dependency
cycles.

builtin/providers/aws/provider.go

@@ -176,6 +176,7 @@ func Provider() terraform.ResourceProvider {
 			"aws_elastic_beanstalk_environment":            resourceAwsElasticBeanstalkEnvironment(),
 			"aws_elasticsearch_domain":                     resourceAwsElasticSearchDomain(),
 			"aws_elb":                                      resourceAwsElb(),
+			"aws_elb_attachment":                           resourceAwsElbAttachment(),
 			"aws_flow_log":                                 resourceAwsFlowLog(),
 			"aws_glacier_vault":                            resourceAwsGlacierVault(),
 			"aws_iam_access_key":                           resourceAwsIamAccessKey(),

builtin/providers/aws/resource_aws_elb_attachment.go

@@ -0,0 +1,121 @@
+package aws
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/elb"
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func resourceAwsElbAttachment() *schema.Resource {
+	return &schema.Resource{
+		Create: resourceAwsElbAttachmentCreate,
+		Read:   resourceAwsElbAttachmentRead,
+		Delete: resourceAwsElbAttachmentDelete,
+
+		Schema: map[string]*schema.Schema{
+			"elb": &schema.Schema{
+				Type:     schema.TypeString,
+				ForceNew: true,
+				Required: true,
+			},
+
+			"instance": &schema.Schema{
+				Type:     schema.TypeString,
+				ForceNew: true,
+				Required: true,
+			},
+		},
+	}
+}
+
+func resourceAwsElbAttachmentCreate(d *schema.ResourceData, meta interface{}) error {
+	elbconn := meta.(*AWSClient).elbconn
+	elbName := d.Get("elb").(string)
+
+	instance := d.Get("instance").(string)
+
+	registerInstancesOpts := elb.RegisterInstancesWithLoadBalancerInput{
+		LoadBalancerName: aws.String(elbName),
+		Instances:        []*elb.Instance{{InstanceId: aws.String(instance)}},
+	}
+
+	log.Printf("[INFO] registering instance %s with ELB %s", instance, elbName)
+
+	_, err := elbconn.RegisterInstancesWithLoadBalancer(&registerInstancesOpts)
+	if err != nil {
+		return fmt.Errorf("Failure registering instances with ELB: %s", err)
+	}
+
+	d.SetId(resource.PrefixedUniqueId(fmt.Sprintf("%s-", elbName)))
+
+	return nil
+}
+
+func resourceAwsElbAttachmentRead(d *schema.ResourceData, meta interface{}) error {
+	elbconn := meta.(*AWSClient).elbconn
+	elbName := d.Get("elb").(string)
+
+	// only add the instance that was previously defined for this resource
+	expected := d.Get("instance").(string)
+
+	// Retrieve the ELB properties to get a list of attachments
+	describeElbOpts := &elb.DescribeLoadBalancersInput{
+		LoadBalancerNames: []*string{aws.String(elbName)},
+	}
+
+	resp, err := elbconn.DescribeLoadBalancers(describeElbOpts)
+	if err != nil {
+		if isLoadBalancerNotFound(err) {
+			log.Printf("[ERROR] ELB %s not found", elbName)
+			d.SetId("")
+			return nil
+		}
+		return fmt.Errorf("Error retrieving ELB: %s", err)
+	}
+	if len(resp.LoadBalancerDescriptions) != 1 {
+		log.Printf("[ERROR] Unable to find ELB: %s", resp.LoadBalancerDescriptions)
+		d.SetId("")
+		return nil
+	}
+
+	// only set the instance Id that this resource manages
+	found := false
+	for _, i := range resp.LoadBalancerDescriptions[0].Instances {
+		if expected == *i.InstanceId {
+			d.Set("instance", expected)
+			found = true
+		}
+	}
+
+	if !found {
+		log.Printf("[WARN] instance %s not found in elb attachments", expected)
+		d.SetId("")
+	}
+
+	return nil
+}
+
+func resourceAwsElbAttachmentDelete(d *schema.ResourceData, meta interface{}) error {
+	elbconn := meta.(*AWSClient).elbconn
+	elbName := d.Get("elb").(string)
+
+	instance := d.Get("instance").(string)
+
+	log.Printf("[INFO] Deleting Attachment %s from: %s", instance, elbName)
+
+	deRegisterInstancesOpts := elb.DeregisterInstancesFromLoadBalancerInput{
+		LoadBalancerName: aws.String(elbName),
+		Instances:        []*elb.Instance{{InstanceId: aws.String(instance)}},
+	}
+
+	_, err := elbconn.DeregisterInstancesFromLoadBalancer(&deRegisterInstancesOpts)
+	if err != nil {
+		return fmt.Errorf("Failure deregistering instances from ELB: %s", err)
+	}
+
+	return nil
+}

builtin/providers/aws/resource_aws_elb_attachment_test.go

@@ -0,0 +1,232 @@
+package aws
+
+import (
+	"fmt"
+	"log"
+	"testing"
+
+	"github.com/aws/aws-sdk-go/service/elb"
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestAccAWSELBAttachment_basic(t *testing.T) {
+	var conf elb.LoadBalancerDescription
+
+	testCheckInstanceAttached := func(count int) resource.TestCheckFunc {
+		return func(*terraform.State) error {
+			if len(conf.Instances) != count {
+				return fmt.Errorf("instance count does not match")
+			}
+			return nil
+		}
+	}
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:      func() { testAccPreCheck(t) },
+		IDRefreshName: "aws_elb.bar",
+		Providers:     testAccProviders,
+		CheckDestroy:  testAccCheckAWSELBDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccAWSELBAttachmentConfig1,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSELBExists("aws_elb.bar", &conf),
+					testCheckInstanceAttached(1),
+				),
+			},
+
+			resource.TestStep{
+				Config: testAccAWSELBAttachmentConfig2,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSELBExists("aws_elb.bar", &conf),
+					testCheckInstanceAttached(2),
+				),
+			},
+
+			resource.TestStep{
+				Config: testAccAWSELBAttachmentConfig3,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSELBExists("aws_elb.bar", &conf),
+					testCheckInstanceAttached(2),
+				),
+			},
+
+			resource.TestStep{
+				Config: testAccAWSELBAttachmentConfig4,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSELBExists("aws_elb.bar", &conf),
+					testCheckInstanceAttached(0),
+				),
+			},
+		},
+	})
+}
+
+// remove and instance and check that it's correctly re-attached.
+func TestAccAWSELBAttachment_drift(t *testing.T) {
+	var conf elb.LoadBalancerDescription
+
+	deregInstance := func() {
+		conn := testAccProvider.Meta().(*AWSClient).elbconn
+
+		deRegisterInstancesOpts := elb.DeregisterInstancesFromLoadBalancerInput{
+			LoadBalancerName: conf.LoadBalancerName,
+			Instances:        conf.Instances,
+		}
+
+		log.Printf("[DEBUG] deregistering instance %s from ELB", conf.Instances[0].InstanceId)
+
+		_, err := conn.DeregisterInstancesFromLoadBalancer(&deRegisterInstancesOpts)
+		if err != nil {
+			t.Fatalf("Failure deregistering instances from ELB: %s", err)
+		}
+
+	}
+
+	testCheckInstanceAttached := func(count int) resource.TestCheckFunc {
+		return func(*terraform.State) error {
+			if len(conf.Instances) != count {
+				return fmt.Errorf("instance count does not match")
+			}
+			return nil
+		}
+	}
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:      func() { testAccPreCheck(t) },
+		IDRefreshName: "aws_elb.bar",
+		Providers:     testAccProviders,
+		CheckDestroy:  testAccCheckAWSELBDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccAWSELBAttachmentConfig1,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSELBExists("aws_elb.bar", &conf),
+					testCheckInstanceAttached(1),
+				),
+			},
+
+			// remove an instance from the ELB, and make sure it gets re-added
+			resource.TestStep{
+				Config:    testAccAWSELBAttachmentConfig1,
+				PreConfig: deregInstance,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSELBExists("aws_elb.bar", &conf),
+					testCheckInstanceAttached(1),
+				),
+			},
+		},
+	})
+}
+
+// add one attachment
+const testAccAWSELBAttachmentConfig1 = `
+resource "aws_elb" "bar" {
+  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]
+
+  listener {
+    instance_port     = 8000
+    instance_protocol = "http"
+    lb_port           = 80
+    lb_protocol       = "http"
+  }
+}
+
+resource "aws_instance" "foo1" {
+  # us-west-2
+  ami           = "ami-043a5034"
+  instance_type = "t1.micro"
+}
+
+resource "aws_elb_attachment" "foo1" {
+  elb      = "${aws_elb.bar.id}"
+  instance = "${aws_instance.foo1.id}"
+}
+`
+
+// add a second attachment
+const testAccAWSELBAttachmentConfig2 = `
+resource "aws_elb" "bar" {
+  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]
+
+  listener {
+    instance_port     = 8000
+    instance_protocol = "http"
+    lb_port           = 80
+    lb_protocol       = "http"
+  }
+}
+
+resource "aws_instance" "foo1" {
+  # us-west-2
+  ami           = "ami-043a5034"
+  instance_type = "t1.micro"
+}
+
+resource "aws_instance" "foo2" {
+  # us-west-2
+  ami           = "ami-043a5034"
+  instance_type = "t1.micro"
+}
+
+resource "aws_elb_attachment" "foo1" {
+  elb      = "${aws_elb.bar.id}"
+  instance = "${aws_instance.foo1.id}"
+}
+
+resource "aws_elb_attachment" "foo2" {
+  elb      = "${aws_elb.bar.id}"
+  instance = "${aws_instance.foo2.id}"
+}
+`
+
+// swap attachments between resources
+const testAccAWSELBAttachmentConfig3 = `
+resource "aws_elb" "bar" {
+  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]
+
+  listener {
+    instance_port     = 8000
+    instance_protocol = "http"
+    lb_port           = 80
+    lb_protocol       = "http"
+  }
+}
+
+resource "aws_instance" "foo1" {
+  # us-west-2
+  ami           = "ami-043a5034"
+  instance_type = "t1.micro"
+}
+
+resource "aws_instance" "foo2" {
+  # us-west-2
+  ami           = "ami-043a5034"
+  instance_type = "t1.micro"
+}
+
+resource "aws_elb_attachment" "foo1" {
+  elb      = "${aws_elb.bar.id}"
+  instance = "${aws_instance.foo2.id}"
+}
+
+resource "aws_elb_attachment" "foo2" {
+  elb      = "${aws_elb.bar.id}"
+  instance = "${aws_instance.foo1.id}"
+}
+`
+
+// destroy attachments
+const testAccAWSELBAttachmentConfig4 = `
+resource "aws_elb" "bar" {
+  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]
+
+  listener {
+    instance_port     = 8000
+    instance_protocol = "http"
+    lb_port           = 80
+    lb_protocol       = "http"
+  }
+}
+`

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

@@ -10,6 +10,12 @@ description: |-
 
 Provides an Elastic Load Balancer resource.
 
+~> **NOTE on ELB Instances and ELB Attachments:** Terraform currently
+provides both a standalone [ELB Attachment resource](elb_attachment.html)
+(describing an instance attached to an ELB), and an ELB resource with
+`instances` defined in-line. At this time you cannot use an ELB with in-line
+instaces in conjunction with a ELB Attachment resources. Doing so will cause a
+conflict and will overwrite attachments.
 ## Example Usage
 
 ```

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

@@ -0,0 +1,34 @@
+---
+layout: "aws"
+page_title: "AWS: aws_elb_attachment"
+sidebar_current: "docs-aws-resource-elb-attachment"
+description: |-
+  Provides an Elastic Load Balancer Attachment resource.
+---
+
+# aws\_elb\_attachment
+
+Provides an Elastic Load Balancer Attachment resource.
+
+~> **NOTE on ELB Instances and ELB Attachments:** Terraform currently provides
+both a standalone ELB Attachment resource (describing an instance attached to
+an ELB), and an [Elastic Load Balancer resource](elb.html) with
+`instances` defined in-line. At this time you cannot use an ELB with in-line
+instaces in conjunction with an ELB Attachment resource. Doing so will cause a
+conflict and will overwrite attachments.
+## Example Usage
+
+```
+# Create a new load balancer attachment
+resource "aws_elb_attachment" "baz" {
+  elb      = "${aws_elb.bar.id}"
+  instance = ["${aws_instance.foo.id}"]
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `elb` - (Required) The name of the ELB.
+* `instance` - (Required) Instance ID to place in the ELB pool.