resource/aws_vpc_dhcp_options_association: Handle read-after-create e…

…ventual consistency (hashicorp#18472)

* resource/aws_vpc_dhcp_options_association: Handle read-after-create eventual consistency

Reference: hashicorp#16142
Reference: hashicorp#16796

Output from acceptance testing in AWS Commercial:

```
--- PASS: TestAccAWSDHCPOptionsAssociation_disappears_vpc (19.27s)
--- PASS: TestAccAWSDHCPOptionsAssociation_disappears_dhcp (25.61s)
--- PASS: TestAccAWSDHCPOptionsAssociation_basic (25.84s)
```

Output from acceptance testing in AWS GovCloud (US):

```
--- PASS: TestAccAWSDHCPOptionsAssociation_disappears_vpc (21.51s)
--- PASS: TestAccAWSDHCPOptionsAssociation_disappears_dhcp (27.55s)
--- PASS: TestAccAWSDHCPOptionsAssociation_basic (28.10s)
```

* Update CHANGELOG for hashicorp#18472

* r/vpc_dhcp_options_association: Tweak delete

Co-authored-by: Dirk Avery <dirk.avery@gmail.com>

.changelog/18472.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_vpc_dhcp_options_association: Handle read-after-create eventual consistency
+```

aws/resource_aws_vpc_dhcp_options_association.go

@@ -7,6 +7,12 @@ import (
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/helper/resource"
+	"github.com/hashicorp/aws-sdk-go-base/tfawserr"
+	tfec2 "github.com/terraform-providers/terraform-provider-aws/aws/internal/service/ec2"
+	"github.com/terraform-providers/terraform-provider-aws/aws/internal/service/ec2/finder"
+	"github.com/terraform-providers/terraform-provider-aws/aws/internal/service/ec2/waiter"
+	"github.com/terraform-providers/terraform-provider-aws/aws/internal/tfresource"
 )
 
 func resourceAwsVpcDhcpOptionsAssociation() *schema.Resource {
@@ -23,6 +29,7 @@ func resourceAwsVpcDhcpOptionsAssociation() *schema.Resource {
 			"vpc_id": {
 				Type:     schema.TypeString,
 				Required: true,
+				ForceNew: true,
 			},
 
 			"dhcp_options_id": {
@@ -79,22 +86,47 @@ func resourceAwsVpcDhcpOptionsAssociationCreate(d *schema.ResourceData, meta int
 
 func resourceAwsVpcDhcpOptionsAssociationRead(d *schema.ResourceData, meta interface{}) error {
 	conn := meta.(*AWSClient).ec2conn
-	// Get the VPC that this association belongs to
-	vpcRaw, _, err := VPCStateRefreshFunc(conn, d.Get("vpc_id").(string))()
 
-	if err != nil {
-		return err
-	}
+	var vpc *ec2.Vpc
+
+	err := resource.Retry(waiter.PropagationTimeout, func() *resource.RetryError {
+		var err error
+
+		vpc, err = finder.VpcByID(conn, d.Get("vpc_id").(string))
+
+		if d.IsNewResource() && tfawserr.ErrCodeEquals(err, tfec2.ErrCodeInvalidVpcIDNotFound) {
+			return resource.RetryableError(err)
+		}
+
+		if err != nil {
+			return resource.NonRetryableError(err)
+		}
+
+		if d.IsNewResource() && aws.StringValue(vpc.DhcpOptionsId) != d.Get("dhcp_options_id").(string) {
+			return resource.RetryableError(&resource.NotFoundError{
+				LastError: fmt.Errorf("EC2 VPC DHCP Options Association (%s) not found", d.Id()),
+			})
+		}
 
-	if vpcRaw == nil {
 		return nil
+	})
+
+	if tfresource.TimedOut(err) {
+		vpc, err = finder.VpcByID(conn, d.Get("vpc_id").(string))
 	}
 
-	vpc := vpcRaw.(*ec2.Vpc)
-	if aws.StringValue(vpc.VpcId) != d.Get("vpc_id") ||
-		aws.StringValue(vpc.DhcpOptionsId) != d.Get("dhcp_options_id") {
-		log.Printf("[INFO] It seems the DHCP Options association is gone. Deleting reference from Graph...")
+	if !d.IsNewResource() && tfawserr.ErrCodeEquals(err, tfec2.ErrCodeInvalidVpcIDNotFound) {
+		log.Printf("[WARN] EC2 VPC DHCP Options Association (%s) not found, removing from state", d.Id())
 		d.SetId("")
+		return nil
+	}
+
+	if err != nil {
+		return fmt.Errorf("error reading EC2 VPC DHCP Options Association (%s): %w", d.Id(), err)
+	}
+
+	if vpc == nil {
+		return fmt.Errorf("error reading EC2 VPC DHCP Options Association (%s): empty response", d.Id())
 	}
 
 	d.Set("vpc_id", vpc.VpcId)
@@ -108,18 +140,26 @@ func resourceAwsVpcDhcpOptionsAssociationUpdate(d *schema.ResourceData, meta int
 	return resourceAwsVpcDhcpOptionsAssociationCreate(d, meta)
 }
 
+const VPCDefaultOptionsID = "default"
+
 // AWS does not provide an API to disassociate a DHCP Options set from a VPC.
 // So, we do this by setting the VPC to the default DHCP Options Set.
 func resourceAwsVpcDhcpOptionsAssociationDelete(d *schema.ResourceData, meta interface{}) error {
 	conn := meta.(*AWSClient).ec2conn
 
 	log.Printf("[INFO] Disassociating DHCP Options Set %s from VPC %s...", d.Get("dhcp_options_id"), d.Get("vpc_id"))
+
+	if d.Get("dhcp_options_id").(string) == VPCDefaultOptionsID {
+		// definition of deleted is DhcpOptionsId being equal to "default", nothing to do
+		return nil
+	}
+
 	_, err := conn.AssociateDhcpOptions(&ec2.AssociateDhcpOptionsInput{
-		DhcpOptionsId: aws.String("default"),
+		DhcpOptionsId: aws.String(VPCDefaultOptionsID),
 		VpcId:         aws.String(d.Get("vpc_id").(string)),
 	})
 
-	if isAWSErr(err, "InvalidVpcID.NotFound", "") {
+	if tfawserr.ErrCodeEquals(err, tfec2.ErrCodeInvalidVpcIDNotFound) {
 		return nil
 	}
 

aws/resource_aws_vpc_dhcp_options_association_test.go

@@ -86,6 +86,31 @@ func TestAccAWSDHCPOptionsAssociation_disappears_dhcp(t *testing.T) {
 	})
 }
 
+func TestAccAWSDHCPOptionsAssociation_disappears(t *testing.T) {
+	var v ec2.Vpc
+	var d ec2.DhcpOptions
+	resourceName := "aws_vpc_dhcp_options_association.test"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		ErrorCheck:   testAccErrorCheck(t, ec2.EndpointsID),
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckDHCPOptionsAssociationDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccDHCPOptionsAssociationConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckDHCPOptionsExists("aws_vpc_dhcp_options.test", &d),
+					testAccCheckVpcExists("aws_vpc.test", &v),
+					testAccCheckDHCPOptionsAssociationExist(resourceName, &v),
+					testAccCheckResourceDisappears(testAccProvider, resourceAwsVpcDhcpOptionsAssociation(), resourceName),
+				),
+				ExpectNonEmptyPlan: true,
+			},
+		},
+	})
+}
+
 func testAccDHCPOptionsAssociationVPCImportIdFunc(resourceName string) resource.ImportStateIdFunc {
 	return func(s *terraform.State) (string, error) {
 		rs, ok := s.RootModule().Resources[resourceName]
@@ -111,8 +136,8 @@ func testAccCheckDHCPOptionsAssociationDestroy(s *terraform.State) error {
 			return err
 		}
 
-		if len(vpcs) > 0 {
-			return fmt.Errorf("DHCP Options association is still associated to %d VPCs.", len(vpcs))
+		if rs.Primary.Attributes["dhcp_options_id"] != VPCDefaultOptionsID && len(vpcs) > 0 {
+			return fmt.Errorf("vpc_dhcp_options_association (%s) is still associated to %d VPCs.", rs.Primary.Attributes["dhcp_options_id"], len(vpcs))
 		}
 	}