provider/aws: Add aws_eip data source (#9833)

* provider/aws: Add the aws_eip data source

* Document the aws_eip data source on the website

* provider/aws: support query by public_ip for aws_eip data source

builtin/providers/aws/data_source_aws_eip.go

@@ -0,0 +1,64 @@
+package aws
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/ec2"
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func dataSourceAwsEip() *schema.Resource {
+	return &schema.Resource{
+		Read: dataSourceAwsEipRead,
+
+		Schema: map[string]*schema.Schema{
+			"id": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+
+			"public_ip": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+		},
+	}
+}
+
+func dataSourceAwsEipRead(d *schema.ResourceData, meta interface{}) error {
+	conn := meta.(*AWSClient).ec2conn
+
+	req := &ec2.DescribeAddressesInput{}
+
+	if id := d.Get("id"); id != "" {
+		req.AllocationIds = []*string{aws.String(id.(string))}
+	}
+
+	if public_ip := d.Get("public_ip"); public_ip != "" {
+		req.PublicIps = []*string{aws.String(public_ip.(string))}
+	}
+
+	log.Printf("[DEBUG] DescribeAddresses %s\n", req)
+	resp, err := conn.DescribeAddresses(req)
+	if err != nil {
+		return err
+	}
+	if resp == nil || len(resp.Addresses) == 0 {
+		return fmt.Errorf("no matching Elastic IP found")
+	}
+	if len(resp.Addresses) > 1 {
+		return fmt.Errorf("multiple Elastic IPs matched; use additional constraints to reduce matches to a single Elastic IP")
+	}
+
+	eip := resp.Addresses[0]
+
+	d.SetId(*eip.AllocationId)
+	d.Set("id", eip.AllocationId)
+	d.Set("public_ip", eip.PublicIp)
+
+	return nil
+}

builtin/providers/aws/data_source_aws_eip_test.go

@@ -0,0 +1,77 @@
+package aws
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestAccDataSourceAwsEip(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccDataSourceAwsEipConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccDataSourceAwsEipCheck("data.aws_eip.by_id"),
+					testAccDataSourceAwsEipCheck("data.aws_eip.by_public_ip"),
+				),
+			},
+		},
+	})
+}
+
+func testAccDataSourceAwsEipCheck(name string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		rs, ok := s.RootModule().Resources[name]
+		if !ok {
+			return fmt.Errorf("root module has no resource called %s", name)
+		}
+
+		eipRs, ok := s.RootModule().Resources["aws_eip.test"]
+		if !ok {
+			return fmt.Errorf("can't find aws_eip.test in state")
+		}
+
+		attr := rs.Primary.Attributes
+
+		if attr["id"] != eipRs.Primary.Attributes["id"] {
+			return fmt.Errorf(
+				"id is %s; want %s",
+				attr["id"],
+				eipRs.Primary.Attributes["id"],
+			)
+		}
+
+		if attr["public_ip"] != eipRs.Primary.Attributes["public_ip"] {
+			return fmt.Errorf(
+				"public_ip is %s; want %s",
+				attr["public_ip"],
+				eipRs.Primary.Attributes["public_ip"],
+			)
+		}
+
+		return nil
+	}
+}
+
+const testAccDataSourceAwsEipConfig = `
+provider "aws" {
+  region = "us-west-2"
+}
+
+resource "aws_eip" "wrong1" {}
+resource "aws_eip" "test" {}
+resource "aws_eip" "wrong2" {}
+
+data "aws_eip" "by_id" {
+  id = "${aws_eip.test.id}"
+}
+
+data "aws_eip" "by_public_ip" {
+  public_ip = "${aws_eip.test.public_ip}"
+}
+`

builtin/providers/aws/provider.go

@@ -155,6 +155,7 @@ func Provider() terraform.ResourceProvider {
 			"aws_ebs_snapshot":             dataSourceAwsEbsSnapshot(),
 			"aws_ebs_volume":               dataSourceAwsEbsVolume(),
 			"aws_ecs_container_definition": dataSourceAwsEcsContainerDefinition(),
+			"aws_eip":                      dataSourceAwsEip(),
 			"aws_elb_service_account":      dataSourceAwsElbServiceAccount(),
 			"aws_iam_policy_document":      dataSourceAwsIamPolicyDocument(),
 			"aws_iam_server_certificate":   dataSourceAwsIAMServerCertificate(),

website/source/docs/providers/aws/d/eip.html.markdown

@@ -0,0 +1,50 @@
+---
+layout: "aws"
+page_title: "AWS: aws_eip"
+sidebar_current: "docs-aws-datasource-eip"
+description: |-
+    Provides details about a specific Elastic IP
+---
+
+# aws\_eip
+
+`aws_eip` provides details about a specific Elastic IP.
+
+This resource can prove useful when a module accepts an allocation ID or
+public IP as an input variable and needs to determine the other.
+
+## Example Usage
+
+The following example shows how one might accept a public IP as a variable
+and use this data source to obtain the allocation ID.
+
+```
+variable "instance_id" {}
+variable "public_ip" {}
+
+data "aws_eip" "proxy_ip" {
+  public_ip = "${var.public_ip}"
+}
+
+aws_eip_association "proxy_eip" {
+  instance_id = "${var.instance_id}"
+  allocation_id = "${data.aws_eip.proxy_ip.id}"
+}
+```
+
+## Argument Reference
+
+The arguments of this data source act as filters for querying the available
+Elastic IPs in the current region. The given filters must match exactly one
+Elastic IP whose data will be exported as attributes.
+
+* `id` - (Optional) The allocation id of the specific EIP to retrieve.
+
+* `public_ip` - (Optional) The public IP of the specific EIP to retrieve.
+
+## Attributes Reference
+
+All of the argument attributes are also exported as result attributes. This
+data source will complete the data by populating any fields that are not
+included in the configuration with the data for the selected Elastic IP.
+