From 8c958a318f24a6259f0325d2d39507431e0d31a1 Mon Sep 17 00:00:00 2001
From: Jakub Kania <jakubkania@blackcat.rocks>
Date: Thu, 9 Aug 2018 00:54:42 +0200
Subject: [PATCH] Add arn for aws_subnet and data.aws_subnet

---
 aws/data_source_aws_subnet.go       | 15 +++++++++++++++
 aws/data_source_aws_subnet_test.go  |  8 ++++++++
 aws/resource_aws_subnet.go          | 16 ++++++++++++++++
 aws/resource_aws_subnet_test.go     |  5 +++++
 website/docs/d/subnet.html.markdown |  4 ++++
 website/docs/r/subnet.html.markdown |  1 +
 6 files changed, 49 insertions(+)

diff --git a/aws/data_source_aws_subnet.go b/aws/data_source_aws_subnet.go
index bdea59c4688..f8fffa26478 100644
--- a/aws/data_source_aws_subnet.go
+++ b/aws/data_source_aws_subnet.go
@@ -5,6 +5,7 @@ import (
 	"log"
 
 	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/arn"
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/hashicorp/terraform/helper/schema"
 )
@@ -74,6 +75,11 @@ func dataSourceAwsSubnet() *schema.Resource {
 				Type:     schema.TypeString,
 				Computed: true,
 			},
+
+			"arn": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
 		},
 	}
 }
@@ -155,5 +161,14 @@ func dataSourceAwsSubnetRead(d *schema.ResourceData, meta interface{}) error {
 		}
 	}
 
+	arn := arn.ARN{
+		Partition: meta.(*AWSClient).partition,
+		Region:    meta.(*AWSClient).region,
+		Service:   "ec2",
+		AccountID: meta.(*AWSClient).accountid,
+		Resource:  fmt.Sprintf("subnet/%s", d.Id()),
+	}
+	d.Set("arn", arn.String())
+
 	return nil
 }
diff --git a/aws/data_source_aws_subnet_test.go b/aws/data_source_aws_subnet_test.go
index 39eb35e4163..347a38453ee 100644
--- a/aws/data_source_aws_subnet_test.go
+++ b/aws/data_source_aws_subnet_test.go
@@ -7,6 +7,7 @@ import (
 	"github.com/hashicorp/terraform/helper/acctest"
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/terraform"
+	"regexp"
 )
 
 func TestAccDataSourceAwsSubnet_basic(t *testing.T) {
@@ -117,6 +118,13 @@ func testAccDataSourceAwsSubnetCheck(name string, rInt int) resource.TestCheckFu
 			return fmt.Errorf("bad Name tag %s", attr["tags.Name"])
 		}
 
+		arnformat := `^arn:[^:]+:ec2:[^:]+:\d{12}:subnet/subnet-.+`
+		arnregex := regexp.MustCompile(arnformat)
+
+		if !arnregex.MatchString(attr["arn"]) {
+			return fmt.Errorf("arn doesn't match format %s", attr["arn"])
+		}
+
 		return nil
 	}
 }
diff --git a/aws/resource_aws_subnet.go b/aws/resource_aws_subnet.go
index 88d23e829fb..b356d31b69b 100644
--- a/aws/resource_aws_subnet.go
+++ b/aws/resource_aws_subnet.go
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/arn"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/hashicorp/terraform/helper/resource"
@@ -68,6 +69,11 @@ func resourceAwsSubnet() *schema.Resource {
 				Computed: true,
 			},
 
+			"arn": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+
 			"tags": tagsSchema(),
 		},
 	}
@@ -154,6 +160,16 @@ func resourceAwsSubnetRead(d *schema.ResourceData, meta interface{}) error {
 			d.Set("ipv6_cidr_block", "")
 		}
 	}
+
+	arn := arn.ARN{
+		Partition: meta.(*AWSClient).partition,
+		Region:    meta.(*AWSClient).region,
+		Service:   "ec2",
+		AccountID: meta.(*AWSClient).accountid,
+		Resource:  fmt.Sprintf("subnet/%s", d.Id()),
+	}
+	d.Set("arn", arn.String())
+
 	d.Set("tags", tagsToMap(subnet.Tags))
 
 	return nil
diff --git a/aws/resource_aws_subnet_test.go b/aws/resource_aws_subnet_test.go
index ea57f64551d..27044f9992a 100644
--- a/aws/resource_aws_subnet_test.go
+++ b/aws/resource_aws_subnet_test.go
@@ -10,6 +10,7 @@ import (
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/terraform"
+	"regexp"
 )
 
 // add sweeper to delete known test subnets
@@ -111,6 +112,10 @@ func TestAccAWSSubnet_basic(t *testing.T) {
 					testAccCheckSubnetExists(
 						"aws_subnet.foo", &v),
 					testCheck,
+					resource.TestMatchResourceAttr(
+						"aws_subnet.foo",
+						"arn",
+						regexp.MustCompile(`^arn:[^:]+:ec2:[^:]+:\d{12}:subnet/subnet-.+`)),
 				),
 			},
 		},
diff --git a/website/docs/d/subnet.html.markdown b/website/docs/d/subnet.html.markdown
index 440f5b20fb6..0e1ba3bd266 100644
--- a/website/docs/d/subnet.html.markdown
+++ b/website/docs/d/subnet.html.markdown
@@ -89,3 +89,7 @@ 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.
+
+In addition the following attributes are exported:
+
+* `arn` - The ARN of the subnet.
\ No newline at end of file
diff --git a/website/docs/r/subnet.html.markdown b/website/docs/r/subnet.html.markdown
index 32a6a0e41cb..6e9ce2c16dc 100644
--- a/website/docs/r/subnet.html.markdown
+++ b/website/docs/r/subnet.html.markdown
@@ -64,6 +64,7 @@ The following arguments are supported:
 In addition to all arguments above, the following attributes are exported:
 
 * `id` - The ID of the subnet
+* `arn` - The ARN of the subnet.
 * `availability_zone`- The AZ for the subnet.
 * `cidr_block` - The CIDR block for the subnet.
 * `vpc_id` - The VPC ID.