import: add support for import blocks

In Terraform 1.5+, there is now the option to import resources using a HCL block alongside your resources code[1]. This commit updates the `import` command to support that conditional generation if the `—modern-import-block` flag is used.

CLI compatible output

```
terraform import cloudflare_ruleset.terraform_managed_resource_c311c194ead8414c985c44eb4710d435 zone/0d555506aec9767e661a2e19e6d4e711/c311c194ead8414c985c44eb4710d435
terraform import cloudflare_ruleset.terraform_managed_resource_64a2203f3c0246bebc2f39b886d54982 zone/0d555506aec9767e661a2e19e6d4e711/64a2203f3c0246bebc2f39b886d54982
```

HCL block import output

```
import {
  to = cloudflare_ruleset.terraform_managed_resource_c311c194ead8414c985c44eb4710d435
  id = "zone/0d555506aec9767e661a2e19e6d4e711/c311c194ead8414c985c44eb4710d435"
}

import {
  to = cloudflare_ruleset.terraform_managed_resource_64a2203f3c0246bebc2f39b886d54982
  id = "zone/0d555506aec9767e661a2e19e6d4e711/64a2203f3c0246bebc2f39b886d54982"
}
```

[1]: https://developer.hashicorp.com/terraform/language/import

internal/app/cf-terraforming/cmd/import.go

@@ -9,7 +9,9 @@ import (
 	"time"
 
 	"github.com/cloudflare/cloudflare-go"
+	"github.com/hashicorp/hcl/v2/hclwrite"
 	"github.com/spf13/cobra"
+	"github.com/zclconf/go-cty/cty"
 )
 
 // resourceImportStringFormats contains a mapping of the resource type to the
@@ -483,16 +485,43 @@ func runImport() func(cmd *cobra.Command, args []string) {
 			return
 		}
 
+		importFile := hclwrite.NewEmptyFile()
+		importBody := importFile.Body()
+
 		for _, data := range jsonStructData {
-			fmt.Fprint(cmd.OutOrStdout(), buildCompositeID(resourceType, data.(map[string]interface{})["id"].(string)))
+			id := data.(map[string]interface{})["id"].(string)
+
+			if useModernImportBlock {
+				idvalue := buildRawImportAddress(resourceType, id)
+				imp := importBody.AppendNewBlock("import", []string{}).Body()
+				imp.SetAttributeRaw("to", hclwrite.TokensForIdentifier(fmt.Sprintf("%s.%s", resourceType, fmt.Sprintf("%s_%s", terraformResourceNamePrefix, id))))
+				imp.SetAttributeValue("id", cty.StringVal(idvalue))
+				importFile.Body().AppendNewline()
+			} else {
+				fmt.Fprint(cmd.OutOrStdout(), buildTerraformImportCommand(resourceType, id))
+			}
+		}
+
+		if useModernImportBlock {
+			// don't format the output; there is a bug in hclwrite.Format that
+			// splits incorrectly on certain characters. instead, manually
+			// insert new lines on the block.
+			fmt.Fprint(cmd.OutOrStdout(), string(importFile.Bytes()))
 		}
 	}
 }
 
-// buildCompositeID takes the resourceType and resourceID in order to lookup the
-// resource type import string and then return a suitable composite value that
-// is compatible with `terraform import`.
-func buildCompositeID(resourceType, resourceID string) string {
+// buildTerraformImportCommand takes the resourceType and resourceID in order to
+// lookup the resource type import string and then return a suitable composite
+// value that is compatible with `terraform import`.
+func buildTerraformImportCommand(resourceType, resourceID string) string {
+	resourceImportAddress := buildRawImportAddress(resourceType, resourceID)
+	return fmt.Sprintf("%s %s.%s_%s %s\n", terraformImportCmdPrefix, resourceType, terraformResourceNamePrefix, resourceID, resourceImportAddress)
+}
+
+// buildRawImportAddress takes the resourceType and resourceID in order to lookup
+// the resource type import string and then return a suitable address.
+func buildRawImportAddress(resourceType, resourceID string) string {
 	if _, ok := resourceImportStringFormats[resourceType]; !ok {
 		log.Fatalf("%s does not have an import format defined", resourceType)
 	}
@@ -508,16 +537,14 @@ func buildCompositeID(resourceType, resourceID string) string {
 		identiferValue = zoneID
 	}
 
-	s := ""
-	s += fmt.Sprintf("%s %s.%s_%s %s", terraformImportCmdPrefix, resourceType, terraformResourceNamePrefix, resourceID, resourceImportStringFormats[resourceType])
+	s := resourceImportStringFormats[resourceType]
 	replacer := strings.NewReplacer(
 		":identifier_type", identiferType,
 		":identifier_value", identiferValue,
 		":zone_id", zoneID,
 		":account_id", accountID,
 		":id", resourceID,
 	)
-	s += "\n"
 
 	return replacer.Replace(s)
 }

internal/app/cf-terraforming/cmd/root.go

@@ -10,7 +10,7 @@ import (
 
 var log = logrus.New()
 var cfgFile, zoneID, hostname, apiEmail, apiKey, apiToken, accountID, terraformInstallPath, terraformBinaryPath string
-var verbose bool
+var verbose, useModernImportBlock bool
 var api *cloudflare.API
 var terraformImportCmdPrefix = "terraform import"
 var terraformResourceNamePrefix = "terraform_managed_resource"
@@ -118,6 +118,8 @@ func init() {
 	if err = viper.BindEnv("terraform-install-path", "CLOUDFLARE_TERRAFORM_INSTALL_PATH"); err != nil {
 		log.Fatal(err)
 	}
+
+	rootCmd.PersistentFlags().BoolVarP(&useModernImportBlock, "modern-import-block", "", false, "Whether to generate HCL import blocks for generated resources instead of `terraform import` compatible CLI commands. This is only compatible with Terraform 1.5+")
 }
 
 // initConfig reads in config file and ENV variables if set.