provider/aws: aws_subnet data source

builtin/providers/aws/data_source_aws_subnet.go

@@ -0,0 +1,123 @@
+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 dataSourceAwsSubnet() *schema.Resource {
+	return &schema.Resource{
+		Read: dataSourceAwsSubnetRead,
+
+		Schema: map[string]*schema.Schema{
+			"availability_zone": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+
+			"cidr_block": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+
+			"default_for_az": &schema.Schema{
+				Type:     schema.TypeBool,
+				Optional: true,
+				Computed: true,
+			},
+
+			"filter": ec2CustomFiltersSchema(),
+
+			"id": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+
+			"state": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+
+			"tags": tagsSchemaComputed(),
+
+			"vpc_id": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				Computed: true,
+			},
+		},
+	}
+}
+
+func dataSourceAwsSubnetRead(d *schema.ResourceData, meta interface{}) error {
+	conn := meta.(*AWSClient).ec2conn
+
+	req := &ec2.DescribeSubnetsInput{}
+
+	if id := d.Get("id"); id != "" {
+		req.SubnetIds = []*string{aws.String(id.(string))}
+	}
+
+	// We specify default_for_az as boolean, but EC2 filters want
+	// it to be serialized as a string. Note that setting it to
+	// "false" here does not actually filter by it *not* being
+	// the default, because Terraform can't distinguish between
+	// "false" and "not set".
+	defaultForAzStr := ""
+	if d.Get("default_for_az").(bool) {
+		defaultForAzStr = "true"
+	}
+
+	req.Filters = buildEC2AttributeFilterList(
+		map[string]string{
+			"availabilityZone": d.Get("availability_zone").(string),
+			"cidrBlock":        d.Get("cidr_block").(string),
+			"defaultForAz":     defaultForAzStr,
+			"state":            d.Get("state").(string),
+			"vpc-id":           d.Get("vpc_id").(string),
+		},
+	)
+	req.Filters = append(req.Filters, buildEC2TagFilterList(
+		tagsFromMap(d.Get("tags").(map[string]interface{})),
+	)...)
+	req.Filters = append(req.Filters, buildEC2CustomFilterList(
+		d.Get("filter").(*schema.Set),
+	)...)
+	if len(req.Filters) == 0 {
+		// Don't send an empty filters list; the EC2 API won't accept it.
+		req.Filters = nil
+	}
+
+	log.Printf("[DEBUG] DescribeSubnets %s\n", req)
+	resp, err := conn.DescribeSubnets(req)
+	if err != nil {
+		return err
+	}
+	if resp == nil || len(resp.Subnets) == 0 {
+		return fmt.Errorf("no matching subnet found")
+	}
+	if len(resp.Subnets) > 1 {
+		return fmt.Errorf("multiple subnets matched; use additional constraints to reduce matches to a single subnet")
+	}
+
+	subnet := resp.Subnets[0]
+
+	d.SetId(*subnet.SubnetId)
+	d.Set("id", subnet.SubnetId)
+	d.Set("vpc_id", subnet.VpcId)
+	d.Set("availability_zone", subnet.AvailabilityZone)
+	d.Set("cidr_block", subnet.CidrBlock)
+	d.Set("default_for_az", subnet.DefaultForAz)
+	d.Set("state", subnet.State)
+	d.Set("tags", tagsToMap(subnet.Tags))
+
+	return nil
+}

builtin/providers/aws/data_source_aws_subnet_test.go

@@ -0,0 +1,125 @@
+package aws
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestAccDataSourceAwsSubnet(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccDataSourceAwsSubnetConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccDataSourceAwsSubnetCheck("data.aws_subnet.by_id"),
+					testAccDataSourceAwsSubnetCheck("data.aws_subnet.by_cidr"),
+					testAccDataSourceAwsSubnetCheck("data.aws_subnet.by_tag"),
+					testAccDataSourceAwsSubnetCheck("data.aws_subnet.by_vpc"),
+					testAccDataSourceAwsSubnetCheck("data.aws_subnet.by_filter"),
+				),
+			},
+		},
+	})
+}
+
+func testAccDataSourceAwsSubnetCheck(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)
+		}
+
+		vpcRs, ok := s.RootModule().Resources["aws_vpc.test"]
+		if !ok {
+			return fmt.Errorf("can't find aws_vpc.test in state")
+		}
+		subnetRs, ok := s.RootModule().Resources["aws_subnet.test"]
+		if !ok {
+			return fmt.Errorf("can't find aws_subnet.test in state")
+		}
+
+		attr := rs.Primary.Attributes
+
+		if attr["id"] != subnetRs.Primary.Attributes["id"] {
+			return fmt.Errorf(
+				"id is %s; want %s",
+				attr["id"],
+				subnetRs.Primary.Attributes["id"],
+			)
+		}
+
+		if attr["vpc_id"] != vpcRs.Primary.Attributes["id"] {
+			return fmt.Errorf(
+				"vpc_id is %s; want %s",
+				attr["vpc_id"],
+				vpcRs.Primary.Attributes["id"],
+			)
+		}
+
+		if attr["cidr_block"] != "172.16.123.0/24" {
+			return fmt.Errorf("bad cidr_block %s", attr["cidr_block"])
+		}
+		if attr["availability_zone"] != "us-west-2a" {
+			return fmt.Errorf("bad availability_zone %s", attr["availability_zone"])
+		}
+		if attr["tags.Name"] != "terraform-testacc-subnet-data-source" {
+			return fmt.Errorf("bad Name tag %s", attr["tags.Name"])
+		}
+
+		return nil
+	}
+}
+
+const testAccDataSourceAwsSubnetConfig = `
+provider "aws" {
+  region = "us-west-2"
+}
+
+resource "aws_vpc" "test" {
+  cidr_block = "172.16.0.0/16"
+
+  tags {
+    Name = "terraform-testacc-subnet-data-source"
+  }
+}
+
+resource "aws_subnet" "test" {
+  vpc_id            = "${aws_vpc.test.id}"
+  cidr_block        = "172.16.123.0/24"
+  availability_zone = "us-west-2a"
+
+  tags {
+    Name = "terraform-testacc-subnet-data-source"
+  }
+}
+
+data "aws_subnet" "by_id" {
+  id = "${aws_subnet.test.id}"
+}
+
+data "aws_subnet" "by_cidr" {
+  cidr_block = "${aws_subnet.test.cidr_block}"
+}
+
+data "aws_subnet" "by_tag" {
+  tags {
+    Name = "${aws_subnet.test.tags["Name"]}"
+  }
+}
+
+data "aws_subnet" "by_vpc" {
+  vpc_id = "${aws_subnet.test.vpc_id}"
+}
+
+data "aws_subnet" "by_filter" {
+  filter {
+    name = "vpc-id"
+    values = ["${aws_subnet.test.vpc_id}"]
+  }
+}
+`

builtin/providers/aws/provider.go

@@ -153,6 +153,7 @@ func Provider() terraform.ResourceProvider {
 			"aws_ip_ranges":                dataSourceAwsIPRanges(),
 			"aws_redshift_service_account": dataSourceAwsRedshiftServiceAccount(),
 			"aws_s3_bucket_object":         dataSourceAwsS3BucketObject(),
+			"aws_subnet":                   dataSourceAwsSubnet(),
 		},
 
 		ResourcesMap: map[string]*schema.Resource{

builtin/providers/aws/tags.go

@@ -18,6 +18,14 @@ func tagsSchema() *schema.Schema {
 	}
 }
 
+func tagsSchemaComputed() *schema.Schema {
+	return &schema.Schema{
+		Type:     schema.TypeMap,
+		Optional: true,
+		Computed: true,
+	}
+}
+
 func setElbV2Tags(conn *elbv2.ELBV2, d *schema.ResourceData) error {
 	if d.HasChange("tags") {
 		oraw, nraw := d.GetChange("tags")

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

@@ -0,0 +1,81 @@
+---
+layout: "aws"
+page_title: "AWS: aws_subnet"
+sidebar_current: "docs-aws-datasource-subnet"
+description: |-
+    Provides details about a specific VPC subnet
+---
+
+# aws\_subnet
+
+`aws_subnet` provides details about a specific VPC subnet.
+
+This resource can prove useful when a module accepts a subnet id as
+an input variable and needs to, for example, determine the id of the
+VPC that the subnet belongs to.
+
+## Example Usage
+
+The following example shows how one might accept a subnet id as a variable
+and use this data source to obtain the data necessary to create a security
+group that allows connections from hosts in that subnet.
+
+```
+variable "subnet_id" {}
+
+data "aws_subnet" "selected" {
+  id = "${var.subnet_id}"
+}
+
+resource "aws_security_group" "subnet" {
+  vpc_id = "${aws_subnet.selected.vpc_id}"
+
+  ingress {
+    cidr_blocks = ["${aws_subnet.selected.cidr_block}"]
+    from_port   = 80
+    to_port     = 80
+    protocol    = "tcp"
+  }
+}
+```
+
+## Argument Reference
+
+The arguments of this data source act as filters for querying the available
+subnets in the current region. The given filters must match exactly one
+subnet whose data will be exported as attributes.
+
+* `availability_zone` - (Optional) The availability zone where the
+  subnet must reside.
+
+* `cidr_block` - (Optional) The cidr block of the desired subnet.
+
+* `default_for_az` - (Optional) Boolean constraint for whether the desired
+  subnet must be the default subnet for its associated availability zone.
+
+* `filter` - (Optional) Custom filter block as described below.
+
+* `id` - (Optional) The id of the specific subnet to retrieve.
+
+* `state` - (Optional) The state that the desired subnet must have.
+
+* `tags` - (Optional) A mapping of tags, each pair of which must exactly match
+  a pair on the desired subnet.
+
+* `vpc_id` - (Optional) The id of the VPC that the desired subnet belongs to.
+
+More complex filters can be expressed using one or more `filter` sub-blocks,
+which take the following arguments:
+
+* `name` - (Required) The name of the field to filter by, as defined by
+  [the underlying AWS API](http://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeSubnets.html).
+
+* `values` - (Required) Set of values that are accepted for the given field.
+  A subnet will be selected if any one of the given values matches.
+
+## Attributes Reference
+
+All of the argument attributes except `filter` blocks 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 subnet.

website/source/layouts/aws.erb

@@ -44,6 +44,9 @@
                         <li<%= sidebar_current("docs-aws-datasource-s3-bucket-object") %>>
                             <a href="/docs/providers/aws/d/s3_bucket_object.html">aws_s3_bucket_object</a>
                         </li>
+                        <li<%= sidebar_current("docs-aws-datasource-subnet") %>>
+                            <a href="/docs/providers/aws/d/subnet.html">aws_subnet</a>
+                        </li>
                     </ul>
                 </li>