Add transformation of SQL DB read error so HandleNotFound works (#3396)

overrides/terraform/resource_override.rb

@@ -75,7 +75,12 @@ def self.attributes
 
           # This enables resources that get their project via a reference to a different resource
           # instead of a project field to use User Project Overrides
-          :supports_indirect_user_project_override
+          :supports_indirect_user_project_override,
+
+          # Function to transform a read error so that handleNotFound recognises
+          # it as a 404. This should be added as a handwritten fn that takes in
+          # an error and returns one.
+          :read_error_transform
         ]
       end
 
@@ -108,6 +113,7 @@ def validate
         check :skip_sweeper, type: :boolean, default: false
         check :skip_delete, type: :boolean, default: false
         check :supports_indirect_user_project_override, type: :boolean, default: false
+        check :read_error_transform, type: String
       end
 
       def apply(resource)

products/sql/terraform.yaml

@@ -16,6 +16,7 @@ client_name: 'SqlAdmin'
 overrides: !ruby/object:Overrides::ResourceOverrides
   Database: !ruby/object:Overrides::Terraform::ResourceOverride
     mutex: "google-sql-database-instance-{{project}}-{{instance}}"
+    read_error_transform: "transformSQLDatabaseReadError"
     import_format: ["projects/{{project}}/instances/{{instance}}/databases/{{name}}",
                     "{{project}}/{{instance}}/{{name}}",
                     "instances/{{instance}}/databases/{{name}}",

templates/terraform/resource.erb

@@ -407,7 +407,11 @@ func resource<%= resource_name -%>Read(d *schema.ResourceData, meta interface{})
 <%  end -%>
     res, err := sendRequest(config, "<%= object.read_verb.to_s.upcase -%>", <% if has_project || object.supports_indirect_user_project_override %>project<% else %>""<% end %>, url, nil<%= object.error_retry_predicates ? ", " + object.error_retry_predicates.join(',') : "" -%>)
     if err != nil {
+<%  if object.read_error_transform -%>
+        return handleNotFoundError(<%= object.read_error_transform %>(err), d, fmt.Sprintf("<%= resource_name -%> %q", d.Id()))
+<%  else -%>
         return handleNotFoundError(err, d, fmt.Sprintf("<%= resource_name -%> %q", d.Id()))
+<%  end -%>
     }
 
 <%  if object.nested_query -%>

third_party/terraform/utils/sql_utils.go

@@ -0,0 +1,26 @@
+package google
+
+import (
+	"log"
+	"strings"
+
+	"github.com/hashicorp/errwrap"
+	"google.golang.org/api/googleapi"
+)
+
+func transformSQLDatabaseReadError(err error) error {
+	if gErr, ok := errwrap.GetType(err, &googleapi.Error{}).(*googleapi.Error); ok {
+		if gErr.Code == 400 && strings.Contains(gErr.Message, "Invalid request since instance is not running") {
+			// This error occurs when attempting a GET after deleting the sql database and sql instance. It leads to to
+			// inconsistent behavior as handleNotFoundError(...) expects an error code of 404 when a resource does not
+			// exist. To get the desired behavior from handleNotFoundError, modify the return code to 404 so that
+			// handleNotFoundError(...) will treat this as a NotFound error
+			gErr.Code = 404
+		}
+
+		log.Printf("[DEBUG] Transformed SQLDatabase error")
+		return gErr
+	}
+
+	return err
+}