Add support for writing maps of literals, used by gce metadata

upup/pkg/fi/cloudup/gcetasks/instance.go

@@ -394,28 +394,25 @@ func ShortenImageURL(defaultProject string, imageURL string) (string, error) {
 }
 
 type terraformInstance struct {
-	Name                  string                        `json:"name" cty:"name"`
+	Name                  string                           `json:"name" cty:"name"`
-	CanIPForward          bool                          `json:"can_ip_forward" cty:"can_ip_forward"`
+	CanIPForward          bool                             `json:"can_ip_forward" cty:"can_ip_forward"`
-	MachineType           string                        `json:"machine_type,omitempty" cty:"machine_type"`
+	MachineType           string                           `json:"machine_type,omitempty" cty:"machine_type"`
-	ServiceAccount        *terraformServiceAccount      `json:"service_account,omitempty" cty:"service_account"`
+	ServiceAccount        *terraformServiceAccount         `json:"service_account,omitempty" cty:"service_account"`
-	Scheduling            *terraformScheduling          `json:"scheduling,omitempty" cty:"scheduling"`
+	Scheduling            *terraformScheduling             `json:"scheduling,omitempty" cty:"scheduling"`
-	Disks                 []*terraformInstanceAttachedDisk      `json:"disk,omitempty" cty:"disk"`
+	Disks                 []*terraformInstanceAttachedDisk `json:"disk,omitempty" cty:"disk"`
-	NetworkInterfaces     []*terraformNetworkInterface  `json:"network_interface,omitempty" cty:"network_interface"`
+	NetworkInterfaces     []*terraformNetworkInterface     `json:"network_interface,omitempty" cty:"network_interface"`
-	Metadata              map[string]*terraform.Literal `json:"metadata,omitempty" cty:"metadata"`
+	Metadata              map[string]*terraform.Literal    `json:"metadata,omitempty" cty:"metadata"`
-	MetadataStartupScript *terraform.Literal            `json:"metadata_startup_script,omitempty" cty:"metadata_startup_script"`
+	MetadataStartupScript *terraform.Literal               `json:"metadata_startup_script,omitempty" cty:"metadata_startup_script"`
-	Tags                  []string                      `json:"tags,omitempty" cty:"tags"`
+	Tags                  []string                         `json:"tags,omitempty" cty:"tags"`
-	Zone                  string                        `json:"zone,omitempty" cty:"zone"`
+	Zone                  string                           `json:"zone,omitempty" cty:"zone"`
 }
 
-
 type terraformInstanceAttachedDisk struct {
 	AutoDelete bool   `json:"auto_delete,omitempty" cty:"auto_delete"`
 	DeviceName string `json:"device_name,omitempty" cty:"device_name"`
 
-	// DANGER - common but different meaning:
+	// 'pd-standard', 'pd-ssd', 'local-ssd' etc
-	//   for an instance template this is scratch vs persistent
+	Type    string `json:"type,omitempty" cty:"type"`
-	//   for an instance this is 'pd-standard', 'pd-ssd', 'local-ssd' etc
-	Type string `json:"type,omitempty" cty:"type"`
 	Disk    string `json:"disk,omitempty" cty:"disk"`
 	Image   string `json:"image,omitempty" cty:"image"`
 	Scratch bool   `json:"scratch,omitempty" cty:"scratch"`

upup/pkg/fi/cloudup/gcetasks/instancetemplate.go

@@ -417,16 +417,16 @@ func (_ *InstanceTemplate) RenderGCE(t *gce.GCEAPITarget, a, e, changes *Instanc
 }
 
 type terraformInstanceTemplate struct {
-	NamePrefix            string                        `json:"name_prefix" cty:"name_prefix"`
+	NamePrefix            string                                   `json:"name_prefix" cty:"name_prefix"`
-	CanIPForward          bool                          `json:"can_ip_forward" cty:"can_ip_forward"`
+	CanIPForward          bool                                     `json:"can_ip_forward" cty:"can_ip_forward"`
-	MachineType           string                        `json:"machine_type,omitempty" cty:"machine_type"`
+	MachineType           string                                   `json:"machine_type,omitempty" cty:"machine_type"`
-	ServiceAccount        *terraformServiceAccount      `json:"service_account,omitempty" cty:"service_account"`
+	ServiceAccount        *terraformServiceAccount                 `json:"service_account,omitempty" cty:"service_account"`
-	Scheduling            *terraformScheduling          `json:"scheduling,omitempty" cty:"scheduling"`
+	Scheduling            *terraformScheduling                     `json:"scheduling,omitempty" cty:"scheduling"`
-	Disks                 []*terraformInstanceTemplateAttachedDisk      `json:"disk,omitempty" cty:"disk"`
+	Disks                 []*terraformInstanceTemplateAttachedDisk `json:"disk,omitempty" cty:"disk"`
-	NetworkInterfaces     []*terraformNetworkInterface  `json:"network_interface,omitempty" cty:"network_interface"`
+	NetworkInterfaces     []*terraformNetworkInterface             `json:"network_interface,omitempty" cty:"network_interface"`
-	Metadata              map[string]*terraform.Literal `json:"metadata,omitempty" cty:"metadata"`
+	Metadata              map[string]*terraform.Literal            `json:"metadata,omitempty" cty:"metadata"`
-	MetadataStartupScript *terraform.Literal            `json:"metadata_startup_script,omitempty" cty:"metadata_startup_script"`
+	MetadataStartupScript *terraform.Literal                       `json:"metadata_startup_script,omitempty" cty:"metadata_startup_script"`
-	Tags                  []string                      `json:"tags,omitempty" cty:"tags"`
+	Tags                  []string                                 `json:"tags,omitempty" cty:"tags"`
 }
 
 type terraformServiceAccount struct {
@@ -444,12 +444,8 @@ type terraformInstanceTemplateAttachedDisk struct {
 	AutoDelete bool   `json:"auto_delete,omitempty" cty:"auto_delete"`
 	DeviceName string `json:"device_name,omitempty" cty:"device_name"`
 
-	// DANGER - common but different meaning:
+	// scratch vs persistent
-	//   for an instance template this is scratch vs persistent
+	Type        string `json:"type,omitempty" cty:"type"`
-	//   for an instance this is 'pd-standard', 'pd-ssd', 'local-ssd' etc
-	Type string `json:"type,omitempty" cty:"type"`
-
-	// These values are only for instance templates:
 	Boot        bool   `json:"boot,omitempty" cty:"boot"`
 	DiskName    string `json:"disk_name,omitempty" cty:"disk_name"`
 	SourceImage string `json:"source_image,omitempty" cty:"source_image"`

upup/pkg/fi/cloudup/terraform/BUILD.bazel

@@ -40,5 +40,6 @@ go_test(
         "//pkg/diff:go_default_library",
         "//vendor/github.com/hashicorp/hcl/v2/hclwrite:go_default_library",
         "//vendor/github.com/zclconf/go-cty/cty:go_default_library",
+        "//vendor/github.com/zclconf/go-cty/cty/gocty:go_default_library",
     ],
 )

upup/pkg/fi/cloudup/terraform/hcl2.go

@@ -177,17 +177,32 @@ func writeMap(body *hclwrite.Body, key string, values map[string]cty.Value) {
 	}
 	sort.Strings(keys)
 	for _, k := range keys {
-		v := values[k]
 		tokens = append(tokens, []*hclwrite.Token{
 			{Type: hclsyntax.TokenOQuote, Bytes: []byte{'"'}, SpacesBefore: 1},
 			{Type: hclsyntax.TokenQuotedLit, Bytes: []byte(k)},
 			{Type: hclsyntax.TokenCQuote, Bytes: []byte{'"'}, SpacesBefore: 1},
 			{Type: hclsyntax.TokenEqual, Bytes: []byte("="), SpacesBefore: 1},
-			{Type: hclsyntax.TokenOQuote, Bytes: []byte{'"'}, SpacesBefore: 1},
-			{Type: hclsyntax.TokenQuotedLit, Bytes: []byte(v.AsString())},
-			{Type: hclsyntax.TokenCQuote, Bytes: []byte{'"'}, SpacesBefore: 1},
-			{Type: hclsyntax.TokenNewline, Bytes: []byte("\n")},
 		}...)
+
+		v := values[k]
+
+		refLiteral := reflect.New(reflect.TypeOf(Literal{}))
+		err := gocty.FromCtyValue(v, refLiteral.Interface())
+		// If this is a map of literals then do not surround the value with quotes
+		if literal, ok := refLiteral.Interface().(*Literal); err == nil && ok {
+			// For maps of literals we currently only support file references
+			// If we ever need to support a map of strings to resource property references that can be added here
+			if literal.FilePath != "" {
+				tokens = append(tokens, &hclwrite.Token{Type: hclsyntax.TokenIdent, Bytes: []byte(fmt.Sprintf("file(%q)", literal.FilePath))})
+			}
+		} else {
+			tokens = append(tokens, []*hclwrite.Token{
+				{Type: hclsyntax.TokenOQuote, Bytes: []byte{'"'}, SpacesBefore: 1},
+				{Type: hclsyntax.TokenQuotedLit, Bytes: []byte(v.AsString())},
+				{Type: hclsyntax.TokenOQuote, Bytes: []byte{'"'}, SpacesBefore: 1},
+			}...)
+		}
+		tokens = append(tokens, &hclwrite.Token{Type: hclsyntax.TokenNewline, Bytes: []byte("\n")})
 	}
 	tokens = append(tokens,
 		&hclwrite.Token{Type: hclsyntax.TokenCBrace, Bytes: []byte("}")},

upup/pkg/fi/cloudup/terraform/hcl2_test.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/hashicorp/hcl/v2/hclwrite"
 	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/gocty"
 	"k8s.io/kops/pkg/diff"
 )
 
@@ -262,3 +263,53 @@ tags = {
 		})
 	}
 }
+
+func TestWriteMapLiterals(t *testing.T) {
+	cases := []struct {
+		name     string
+		values   map[string]Literal
+		expected string
+	}{
+		{
+			name: "literal values",
+			values: map[string]Literal{
+				"key1": {FilePath: "${module.path}/path/to/value1"},
+				"key2": {FilePath: "${module.path}/path/to/value2"},
+			},
+			expected: `
+metadata = {
+  "key1" = file("${module.path}/path/to/value1")
+  "key2" = file("${module.path}/path/to/value2")
+}
+			`,
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			literalMap := make(map[string]cty.Value)
+			for k, v := range tc.values {
+				literalType, err := gocty.ImpliedType(v)
+				if err != nil {
+					t.Errorf("unexpected error %v", err)
+				}
+				literalVal, err := gocty.ToCtyValue(v, literalType)
+
+				if err != nil {
+					t.Errorf("unexpected error %v", err)
+				}
+				literalMap[k] = literalVal
+			}
+
+			f := hclwrite.NewEmptyFile()
+			root := f.Body()
+			writeMap(root, "metadata", literalMap)
+			actual := strings.TrimSpace(string(f.Bytes()))
+			expected := strings.TrimSpace(tc.expected)
+			if actual != expected {
+				diffString := diff.FormatDiff(expected, string(actual))
+				t.Logf("diff:\n%s\n", diffString)
+				t.Errorf("expected: '%s', got: '%s'\n", expected, actual)
+			}
+		})
+	}
+}