WIP: kubernetes#7052 TF 12 feature flagged - update output support

docs/advanced/experimental.md

@@ -10,6 +10,7 @@ The following experimental features are currently available:
 * `+EnableExternalDNS` - Enable external-dns with default settings (ingress sources only).
 * `+VPCSkipEnableDNSSupport` - Enables creation of a VPC that does not need DNSSupport enabled.
 * `+SkipTerraformFormat` - Do not `terraform fmt` the generated terraform files.
+* `+Terraform012` - Use HCL2 output for terraform versions 0.12+.
 * `+EnableExternalCloudController` - Enables the use of cloud-controller-manager introduced in v1.7.
 * `+EnableSeparateConfigBase` - Allow a config-base that is different from the state store.
 * `+SpecOverrideFlag` - Allow setting spec values on `kops create`.

pkg/featureflag/featureflag.go

@@ -72,6 +72,8 @@ var (
 	// In particular, this is the only (?) way to grant the bucket.list permission
 	// It allows for experiments with alternative DNS configurations - in particular local proxies.
 	SkipTerraformFormat = New("SkipTerraformFormat", Bool(false))
+	// Enable TF 0.12.x update -target=terraform output
+	Terraform012 = New("Terraform012", Bool(false))
 	// SpecOverrideFlag allows setting spec values on create
 	SpecOverrideFlag = New("SpecOverrideFlag", Bool(false))
 	// Spotinst toggles the use of Spotinst integration.

upup/pkg/fi/cloudup/terraform/hcl_printer.go

@@ -21,24 +21,25 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/hashicorp/hcl/hcl/ast"
-	hcl_printer "github.com/hashicorp/hcl/hcl/printer"
+	hcl1_ast "github.com/hashicorp/hcl/hcl/ast"
+	hcl1_printer "github.com/hashicorp/hcl/hcl/printer"
+
 	"k8s.io/klog"
 	"k8s.io/kops/pkg/featureflag"
 )
 
 const safeChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_"
 
 // sanitizer fixes up an invalid HCL AST, as produced by the HCL parser for JSON
-type astSanitizer struct {
+type hcl1_astSanitizer struct {
 }
 
 // output prints creates b printable HCL output and returns it.
-func (v *astSanitizer) visit(n interface{}) {
+func (v *hcl1_astSanitizer) visit(n interface{}) {
 	switch t := n.(type) {
-	case *ast.File:
+	case *hcl1_ast.File:
 		v.visit(t.Node)
-	case *ast.ObjectList:
+	case *hcl1_ast.ObjectList:
 		var index int
 		for {
 			if index == len(t.Items) {
@@ -48,20 +49,20 @@ func (v *astSanitizer) visit(n interface{}) {
 			v.visit(t.Items[index])
 			index++
 		}
-	case *ast.ObjectKey:
-	case *ast.ObjectItem:
+	case *hcl1_ast.ObjectKey:
+	case *hcl1_ast.ObjectItem:
 		v.visitObjectItem(t)
-	case *ast.LiteralType:
-	case *ast.ListType:
-	case *ast.ObjectType:
+	case *hcl1_ast.LiteralType:
+	case *hcl1_ast.ListType:
+	case *hcl1_ast.ObjectType:
 		v.visit(t.List)
 	default:
 		klog.Warningf(" unknown type: %T\n", n)
 	}
 
 }
 
-func (v *astSanitizer) visitObjectItem(o *ast.ObjectItem) {
+func (v *hcl1_astSanitizer) visitObjectItem(o *hcl1_ast.ObjectItem) {
 	for i, k := range o.Keys {
 		if i == 0 {
 			text := k.Token.Text
@@ -88,12 +89,12 @@ func (v *astSanitizer) visitObjectItem(o *ast.ObjectItem) {
 	v.visit(o.Val)
 }
 
-func hclPrint(node ast.Node) ([]byte, error) {
-	var sanitizer astSanitizer
+func hcl1Print(node hcl1_ast.Node) ([]byte, error) {
+	var sanitizer hcl1_astSanitizer
 	sanitizer.visit(node)
 
 	var b bytes.Buffer
-	err := hcl_printer.Fprint(&b, node)
+	err := hcl1_printer.Fprint(&b, node)
 	if err != nil {
 		return nil, fmt.Errorf("error writing HCL: %v", err)
 	}
@@ -120,7 +121,7 @@ func hclPrint(node ast.Node) ([]byte, error) {
 	}
 
 	// Apply Terraform style (alignment etc.)
-	formatted, err := hcl_printer.Format([]byte(s))
+	formatted, err := hcl1_printer.Format([]byte(s))
 	if err != nil {
 		klog.Errorf("Invalid HCL follows:")
 		for i, line := range strings.Split(s, "\n") {

upup/pkg/fi/cloudup/terraform/target.go

@@ -25,10 +25,12 @@ import (
 	"strings"
 	"sync"
 
-	hcl_parser "github.com/hashicorp/hcl/json/parser"
+	hcl1_parser "github.com/hashicorp/hcl/json/parser"
+
 	"k8s.io/klog"
 	"k8s.io/kops/pkg/apis/kops"
 	"k8s.io/kops/upup/pkg/fi"
+	"k8s.io/kops/pkg/featureflag"
 )
 
 type TerraformTarget struct {
@@ -255,9 +257,15 @@ func (t *TerraformTarget) Finish(taskMap map[string]fi.Task) error {
 		}
 	}
 
-	// See https://github.com/kubernetes/kops/pull/2424 for why we require 0.9.3
 	terraformConfiguration := make(map[string]interface{})
-	terraformConfiguration["required_version"] = ">= 0.9.3"
+	if featureflag.Terraform012.Enabled() {
+		// TF 12 / HCL2 is not the default yet
+		klog.Infof("feature-flag Terraform012 was set; terraform required_version >= 0.12.0")
+		terraformConfiguration["required_version"] = ">= 0.12.0"
+	} else {
+		// See https://github.com/kubernetes/kops/pull/2424 for why we require 0.9.3
+		terraformConfiguration["required_version"] = ">= 0.9.3"
+	}
 
 	data := make(map[string]interface{})
 	data["terraform"] = terraformConfiguration
@@ -282,12 +290,12 @@ func (t *TerraformTarget) Finish(taskMap map[string]fi.Task) error {
 	if useJson {
 		t.files["kubernetes.tf"] = jsonBytes
 	} else {
-		f, err := hcl_parser.Parse(jsonBytes)
+		ast, err := hcl1_parser.Parse(jsonBytes)
 		if err != nil {
 			return fmt.Errorf("error parsing terraform json: %v", err)
 		}
 
-		b, err := hclPrint(f)
+		b, err := hcl1Print(ast)
 		if err != nil {
 			return fmt.Errorf("error writing terraform data to output: %v", err)
 		}