provider/aws: Adding a datasource for aws_ebs_volume

This will allows us to filter a specific ebs_volume for attachment to an
aws_instance

```
make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSEbsVolumeDataSource_'✹
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2016/11/01 12:39:19 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v
-run=TestAccAWSEbsVolumeDataSource_ -timeout 120m
=== RUN   TestAccAWSEbsVolumeDataSource_basic
--- PASS: TestAccAWSEbsVolumeDataSource_basic (28.74s)
=== RUN   TestAccAWSEbsVolumeDataSource_multipleFilters
--- PASS: TestAccAWSEbsVolumeDataSource_multipleFilters (28.37s)
PASS
ok      github.com/hashicorp/terraform/builtin/providers/aws57.145s
```

builtin/providers/aws/data_source_aws_ebs_volume.go

@@ -0,0 +1,216 @@
+package aws
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"sort"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/ec2"
+	"github.com/davecgh/go-spew/spew"
+	"github.com/hashicorp/terraform/helper/hashcode"
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func dataSourceAwsEbsVolume() *schema.Resource {
+	return &schema.Resource{
+		Read: dataSourceAwsEbsVolumeRead,
+
+		Schema: map[string]*schema.Schema{
+			"filter": {
+				Type:     schema.TypeSet,
+				Optional: true,
+				ForceNew: true,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"name": {
+							Type:     schema.TypeString,
+							Required: true,
+						},
+
+						"values": {
+							Type:     schema.TypeList,
+							Required: true,
+							Elem:     &schema.Schema{Type: schema.TypeString},
+						},
+					},
+				},
+			},
+			"most_recent": {
+				Type:     schema.TypeBool,
+				Optional: true,
+				Default:  false,
+				ForceNew: true,
+			},
+			"availability_zone": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"encrypted": {
+				Type:     schema.TypeBool,
+				Computed: true,
+			},
+			"iops": {
+				Type:     schema.TypeInt,
+				Computed: true,
+			},
+			"volume_type": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"size": {
+				Type:     schema.TypeInt,
+				Computed: true,
+			},
+			"snapshot_id": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"kms_key_id": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"volume_id": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"tags": {
+				Type:     schema.TypeSet,
+				Computed: true,
+				Set:      volumeTagsHash,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"key": {
+							Type:     schema.TypeString,
+							Computed: true,
+						},
+						"value": {
+							Type:     schema.TypeString,
+							Computed: true,
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func dataSourceAwsEbsVolumeRead(d *schema.ResourceData, meta interface{}) error {
+	conn := meta.(*AWSClient).ec2conn
+
+	filters, filtersOk := d.GetOk("filter")
+
+	params := &ec2.DescribeVolumesInput{}
+	if filtersOk {
+		params.Filters = buildVolumeFilters(filters.(*schema.Set))
+	}
+
+	resp, err := conn.DescribeVolumes(params)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("Found These Volumes %s", spew.Sdump(resp.Volumes))
+
+	filteredVolumes := resp.Volumes[:]
+
+	var volume *ec2.Volume
+	if len(filteredVolumes) < 1 {
+		return fmt.Errorf("Your query returned no results. Please change your search criteria and try again.")
+	}
+
+	if len(filteredVolumes) > 1 {
+		recent := d.Get("most_recent").(bool)
+		log.Printf("[DEBUG] aws_ebs_volume - multiple results found and `most_recent` is set to: %t", recent)
+		if recent {
+			volume = mostRecentVolume(filteredVolumes)
+		} else {
+			return fmt.Errorf("Your query returned more than one result. Please try a more " +
+				"specific search criteria, or set `most_recent` attribute to true.")
+		}
+	} else {
+		// Query returned single result.
+		volume = filteredVolumes[0]
+	}
+
+	log.Printf("[DEBUG] aws_volume - Single Volume found: %s", *volume.VolumeId)
+	return volumeDescriptionAttributes(d, volume)
+}
+
+// Build a slice of AMI filter options from the filters provided.
+func buildVolumeFilters(set *schema.Set) []*ec2.Filter {
+	var filters []*ec2.Filter
+	for _, v := range set.List() {
+		m := v.(map[string]interface{})
+		var filterValues []*string
+		for _, e := range m["values"].([]interface{}) {
+			filterValues = append(filterValues, aws.String(e.(string)))
+		}
+		filters = append(filters, &ec2.Filter{
+			Name:   aws.String(m["name"].(string)),
+			Values: filterValues,
+		})
+	}
+	return filters
+}
+
+type volumeSort []*ec2.Volume
+
+func (a volumeSort) Len() int      { return len(a) }
+func (a volumeSort) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
+func (a volumeSort) Less(i, j int) bool {
+	itime := *a[i].CreateTime
+	jtime := *a[j].CreateTime
+	return itime.Unix() < jtime.Unix()
+}
+
+func mostRecentVolume(volumes []*ec2.Volume) *ec2.Volume {
+	sortedVolumes := volumes
+	sort.Sort(volumeSort(sortedVolumes))
+	return sortedVolumes[len(sortedVolumes)-1]
+}
+
+// populate the numerous fields that the image description returns.
+func volumeDescriptionAttributes(d *schema.ResourceData, volume *ec2.Volume) error {
+	// Simple attributes first
+	d.SetId(*volume.VolumeId)
+	d.Set("volume_id", volume.VolumeId)
+	d.Set("availability_zone", volume.AvailabilityZone)
+	d.Set("encrypted", volume.Encrypted)
+	d.Set("iops", volume.Iops)
+	d.Set("kms_key_id", volume.KmsKeyId)
+	d.Set("size", volume.Size)
+	d.Set("snapshot_id", volume.SnapshotId)
+	d.Set("volume_type", volume.VolumeType)
+
+	if err := d.Set("tags", volumeTags(volume.Tags)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Returns a set of tags.
+func volumeTags(m []*ec2.Tag) *schema.Set {
+	s := &schema.Set{
+		F: volumeTagsHash,
+	}
+	for _, v := range m {
+		tag := map[string]interface{}{
+			"key":   *v.Key,
+			"value": *v.Value,
+		}
+		s.Add(tag)
+	}
+	return s
+}
+
+func volumeTagsHash(v interface{}) int {
+	var buf bytes.Buffer
+	m := v.(map[string]interface{})
+	// All keys added in alphabetical order.
+	buf.WriteString(fmt.Sprintf("%s-", m["key"].(string)))
+	buf.WriteString(fmt.Sprintf("%s-", m["value"].(string)))
+	return hashcode.String(buf.String())
+}

builtin/providers/aws/data_source_aws_ebs_volume_test.go

@@ -0,0 +1,106 @@
+package aws
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestAccAWSEbsVolumeDataSource_basic(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccCheckAwsEbsVolumeDataSourceConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAwsEbsVolumeDataSourceID("data.aws_ebs_volume.ebs_volume"),
+					resource.TestCheckResourceAttr("data.aws_ebs_volume.ebs_volume", "size", "40"),
+				),
+			},
+		},
+	})
+}
+
+func TestAccAWSEbsVolumeDataSource_multipleFilters(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccCheckAwsEbsVolumeDataSourceConfigWithMultipleFilters,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAwsEbsVolumeDataSourceID("data.aws_ebs_volume.ebs_volume"),
+					resource.TestCheckResourceAttr("data.aws_ebs_volume.ebs_volume", "size", "10"),
+					resource.TestCheckResourceAttr("data.aws_ebs_volume.ebs_volume", "volume_type", "gp2"),
+				),
+			},
+		},
+	})
+}
+
+func testAccCheckAwsEbsVolumeDataSourceID(n string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		rs, ok := s.RootModule().Resources[n]
+		if !ok {
+			return fmt.Errorf("Can't find Volume data source: %s", n)
+		}
+
+		if rs.Primary.ID == "" {
+			return fmt.Errorf("Volume data source ID not set")
+		}
+		return nil
+	}
+}
+
+const testAccCheckAwsEbsVolumeDataSourceConfig = `
+resource "aws_ebs_volume" "example" {
+    availability_zone = "us-west-2a"
+    type = "gp2"
+    size = 40
+    tags {
+        Name = "External Volume"
+    }
+}
+
+data "aws_ebs_volume" "ebs_volume" {
+    most_recent = true
+    filter {
+	name = "tag:Name"
+	values = ["External Volume"]
+    }
+    filter {
+	name = "volume-type"
+	values = ["${aws_ebs_volume.example.type}"]
+    }
+}
+`
+
+const testAccCheckAwsEbsVolumeDataSourceConfigWithMultipleFilters = `
+resource "aws_ebs_volume" "external1" {
+    availability_zone = "us-west-2a"
+    type = "gp2"
+    size = 10
+    tags {
+        Name = "External Volume 1"
+    }
+}
+
+data "aws_ebs_volume" "ebs_volume" {
+    most_recent = true
+    filter {
+	name = "tag:Name"
+	values = ["External Volume 1"]
+    }
+    filter {
+	name = "size"
+	values = ["${aws_ebs_volume.external1.size}"]
+    }
+    filter {
+	name = "volume-type"
+	values = ["${aws_ebs_volume.external1.type}"]
+    }
+}
+`

builtin/providers/aws/provider.go

@@ -149,6 +149,7 @@ func Provider() terraform.ResourceProvider {
 			"aws_billing_service_account":  dataSourceAwsBillingServiceAccount(),
 			"aws_caller_identity":          dataSourceAwsCallerIdentity(),
 			"aws_cloudformation_stack":     dataSourceAwsCloudFormationStack(),
+			"aws_ebs_volume":               dataSourceAwsEbsVolume(),
 			"aws_ecs_container_definition": dataSourceAwsEcsContainerDefinition(),
 			"aws_elb_service_account":      dataSourceAwsElbServiceAccount(),
 			"aws_iam_policy_document":      dataSourceAwsIamPolicyDocument(),
@@ -159,7 +160,8 @@ func Provider() terraform.ResourceProvider {
 			"aws_s3_bucket_object":         dataSourceAwsS3BucketObject(),
 			"aws_subnet":                   dataSourceAwsSubnet(),
 			"aws_security_group":           dataSourceAwsSecurityGroup(),
-			"aws_vpc":                      dataSourceAwsVpc(),
+
+			"aws_vpc": dataSourceAwsVpc(),
 		},
 
 		ResourcesMap: map[string]*schema.Resource{

helper/resource/testing.go

@@ -252,6 +252,7 @@ func Test(t TestT, c TestCase) {
 		if err != nil {
 			// Perhaps we expected an error? Check if it matches
 			if step.ExpectError != nil {
+				log.Printf("ERROR: %s", spew.Sdump(err.Error()))
 				if !step.ExpectError.MatchString(err.Error()) {
 					errored = true
 					t.Error(fmt.Sprintf(