From 3f472eb2b932fb81b4ad16a2d87c88560a87917a Mon Sep 17 00:00:00 2001
From: Dirk Avery <dirk.avery@gmail.com>
Date: Wed, 22 Aug 2018 17:39:33 -0400
Subject: [PATCH] Fix route table importing to avoid route deletion

Import route tables using inline routes in the resource data. This
is the same way resource data is structured when routes tables are
read (and created) which enables imports to line up properly with
existing resources.

Previously, if you applied a state that included the import of a
route table, all routes in the route table would be deleted. This
bug occurred because the import function
(resourceAwsRouteTableImportState()) would return a target state
including both a route table resource and separate route resources
for each route. The route table read function
(resourceAwsRouteTableRead()) returns a state with a route table
resource having inline routes. Despite being equivalent, since the
states did not match, Terraform would delete all routes in the
route table when applying the change plan.

Fixes #5631

Update functions names to comply with convention

This commit is planned to occur after PR #5687 which changes the
names of these functions. In order to avoid merge conflicts at that
time, this pre-emptively renames the functions.
---
 aws/import_aws_route_table.go   | 107 --------------------------------
 aws/resource_aws_route_table.go |  13 +++-
 2 files changed, 12 insertions(+), 108 deletions(-)
 delete mode 100644 aws/import_aws_route_table.go

diff --git a/aws/import_aws_route_table.go b/aws/import_aws_route_table.go
deleted file mode 100644
index 6934245a299..00000000000
--- a/aws/import_aws_route_table.go
+++ /dev/null
@@ -1,107 +0,0 @@
-package aws
-
-import (
-	"fmt"
-	"log"
-
-	"github.com/aws/aws-sdk-go/service/ec2"
-	"github.com/hashicorp/terraform/helper/schema"
-)
-
-// Route table import also imports all the rules
-func resourceAwsRouteTableImportState(
-	d *schema.ResourceData,
-	meta interface{}) ([]*schema.ResourceData, error) {
-	conn := meta.(*AWSClient).ec2conn
-
-	// First query the resource itself
-	id := d.Id()
-	resp, err := conn.DescribeRouteTables(&ec2.DescribeRouteTablesInput{
-		RouteTableIds: []*string{&id},
-	})
-	if err != nil {
-		return nil, err
-	}
-	if len(resp.RouteTables) < 1 || resp.RouteTables[0] == nil {
-		return nil, fmt.Errorf("route table %s is not found", id)
-	}
-	table := resp.RouteTables[0]
-
-	// Start building our results
-	results := make([]*schema.ResourceData, 1,
-		2+len(table.Associations)+len(table.Routes))
-	results[0] = d
-	log.Print("[WARN] RouteTable imports will be handled differently in a future version.")
-	log.Printf("[WARN] This import will create %d resources (aws_route_table, aws_route, aws_route_table_association).", len(results))
-	log.Print("[WARN] In the future, only 1 aws_route_table resource will be created with inline routes.")
-
-	{
-		// Construct the routes
-		subResource := resourceAwsRoute()
-		for _, route := range table.Routes {
-			// Ignore the local/default route
-			if route.GatewayId != nil && *route.GatewayId == "local" {
-				continue
-			}
-
-			if route.Origin != nil && *route.Origin == "EnableVgwRoutePropagation" {
-				continue
-			}
-
-			if route.DestinationPrefixListId != nil {
-				// Skipping because VPC endpoint routes are handled separately
-				// See aws_vpc_endpoint
-				continue
-			}
-
-			// Minimal data for route
-			d := subResource.Data(nil)
-			d.SetType("aws_route")
-			d.Set("route_table_id", id)
-			d.Set("destination_cidr_block", route.DestinationCidrBlock)
-			d.Set("destination_ipv6_cidr_block", route.DestinationIpv6CidrBlock)
-			d.SetId(resourceAwsRouteID(d, route))
-			results = append(results, d)
-		}
-	}
-
-	{
-		// Construct the associations
-		subResource := resourceAwsRouteTableAssociation()
-		for _, assoc := range table.Associations {
-			if *assoc.Main {
-				// Ignore
-				continue
-			}
-
-			// Minimal data for route
-			d := subResource.Data(nil)
-			d.SetType("aws_route_table_association")
-			d.Set("route_table_id", assoc.RouteTableId)
-			d.SetId(*assoc.RouteTableAssociationId)
-			results = append(results, d)
-		}
-	}
-
-	{
-		// Construct the main associations. We could do this above but
-		// I keep this as a separate section since it is a separate resource.
-		subResource := resourceAwsMainRouteTableAssociation()
-		for _, assoc := range table.Associations {
-			if !*assoc.Main {
-				// Ignore
-				continue
-			}
-
-			// Minimal data for route
-			d := subResource.Data(nil)
-			d.SetType("aws_main_route_table_association")
-			d.Set("route_table_id", id)
-			d.Set("vpc_id", table.VpcId)
-			d.SetId(*assoc.RouteTableAssociationId)
-			results = append(results, d)
-		}
-	}
-
-	return results, nil
-}
diff --git a/aws/resource_aws_route_table.go b/aws/resource_aws_route_table.go
index a2010ce09f9..fb4b5b7e90f 100644
--- a/aws/resource_aws_route_table.go
+++ b/aws/resource_aws_route_table.go
@@ -21,7 +21,18 @@ func resourceAwsRouteTable() *schema.Resource {
 		Update: resourceAwsRouteTableUpdate,
 		Delete: resourceAwsRouteTableDelete,
 		Importer: &schema.ResourceImporter{
-			State: resourceAwsRouteTableImportState,
+			State: func(d *schema.ResourceData, meta interface{}) ([]*schema.ResourceData, error) {
+				log.Printf("[INFO] Importing Route Table ID: %s", d.Id())
+
+				err := resourceAwsRouteTableRead(d, meta)
+				if err != nil {
+					return nil, err
+				}
+
+				results := make([]*schema.ResourceData, 1)
+				results[0] = d
+				return results, nil
+			},
 		},
 
 		Schema: map[string]*schema.Schema{