provider/aws: add local name filter to aws_ami datasource

In cases where the filters provided by AWS against the name of an AMI are not
sufficient, allow adding a "local_name_filter" which is a regex that is used
to filter the AMIs returned by amazon.

builtin/providers/aws/data_source_aws_ami.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"log"
+	"regexp"
 	"sort"
 	"time"
 
@@ -43,6 +44,11 @@ func dataSourceAwsAmi() *schema.Resource {
 					},
 				},
 			},
+			"local_name_filter": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				ForceNew: true,
+			},
 			"most_recent": &schema.Schema{
 				Type:     schema.TypeBool,
 				Optional: true,
@@ -206,10 +212,11 @@ func dataSourceAwsAmiRead(d *schema.ResourceData, meta interface{}) error {
 
 	executableUsers, executableUsersOk := d.GetOk("executable_users")
 	filters, filtersOk := d.GetOk("filter")
+	localNameFilter, localNameFilterOk := d.GetOk("local_name_filter")
 	owners, ownersOk := d.GetOk("owners")
 
-	if executableUsersOk == false && filtersOk == false && ownersOk == false {
-		return fmt.Errorf("One of executable_users, filters, or owners must be assigned")
+	if executableUsersOk == false && filtersOk == false && localNameFilterOk == false && ownersOk == false {
+		return fmt.Errorf("One of executable_users, filters, local_name_filter, or owners must be assigned")
 	}
 
 	params := &ec2.DescribeImagesInput{}
@@ -227,20 +234,33 @@ func dataSourceAwsAmiRead(d *schema.ResourceData, meta interface{}) error {
 	if err != nil {
 		return err
 	}
+
+	var filteredImages []*ec2.Image
+	if localNameFilterOk == true {
+		r := regexp.MustCompile(localNameFilter.(string))
+		for _, image := range resp.Images {
+			if r.MatchString(*image.Name) == true {
+				filteredImages = append(filteredImages, image)
+			}
+		}
+	} else {
+		filteredImages = resp.Images[:]
+	}
+
 	var image *ec2.Image
-	if len(resp.Images) < 1 {
+	if len(filteredImages) < 1 {
 		return fmt.Errorf("Your query returned no results. Please change your filters and try again.")
-	} else if len(resp.Images) > 1 {
+	} else if len(filteredImages) > 1 {
 		if (d.Get("most_recent").(bool)) == true {
 			log.Printf("[DEBUG] aws_ami - multiple results found and most_recent is set")
-			image = mostRecentAmi(resp.Images)
+			image = mostRecentAmi(filteredImages)
 		} else {
 			log.Printf("[DEBUG] aws_ami - multiple results found and most_recent not set")
 			return fmt.Errorf("Your query returned more than one result. Please try a more specific search, or set most_recent to true.")
 		}
 	} else {
-		log.Printf("[DEBUG] aws_ami - Single AMI found: %s", *resp.Images[0].ImageId)
-		image = resp.Images[0]
+		log.Printf("[DEBUG] aws_ami - Single AMI found: %s", *filteredImages[0].ImageId)
+		image = filteredImages[0]
 	}
 	return amiDescriptionAttributes(d, image)
 }

builtin/providers/aws/data_source_aws_ami_test.go

@@ -139,6 +139,22 @@ func TestAccAWSAmiDataSource_owners(t *testing.T) {
 	})
 }
 
+func TestAccAWSAmiDataSource_localNameFilter(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccCheckAwsAmiDataSourceLocalNameFilterConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAwsAmiDataSourceID("data.aws_ami.local_filtered_ami"),
+					resource.TestMatchResourceAttr("data.aws_ami.local_filtered_ami", "image_id", regexp.MustCompile("^ami-")),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckAwsAmiDataSourceDestroy(s *terraform.State) error {
 	return nil
 }
@@ -245,3 +261,16 @@ data "aws_ami" "amazon_ami" {
 	owners = ["amazon"]
 }
 `
+
+// Testing local_name_filter parameter
+const testAccCheckAwsAmiDataSourceLocalNameFilterConfig = `
+data "aws_ami" "local_filtered_ami" {
+	most_recent = true
+	owners = ["amazon"]
+	filter {
+		name = "name"
+		values = ["amzn-ami-*"]
+	}
+	local_name_filter = "^amzn-ami-\\d{3}[5].*-ecs-optimized"
+}
+`

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

@@ -25,6 +25,7 @@ data "aws_ami" "nat_ami" {
     name = "name"
     values = ["amzn-ami-vpc-nat*"]
   }
+  local_name_filter = "^myami-\\d{3}"
   owners = ["self"]
 }
 ```
@@ -41,6 +42,9 @@ recent AMI.
 several valid keys, for a full reference, check out
 [describe-images in the AWS CLI reference][1].
 
+* `local_name_filter` - (Optional) A regex string to apply to the AMI list returned
+by AWS. This allows more advanced filtering not supported from the AWS API.
+
 * `owners` - (Optional) Limit search to specific AMI owners. Valid items are the numeric
 account ID, `amazon`, or `self`.