add supports for cmd: terraform add (#209)

* add supports for cmd: terraform add

* refine per review comments

* tiny fix

* use strings.Builder as writer as we returns string

tfexec/add.go

@@ -0,0 +1,101 @@
+package tfexec
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+type addConfig struct {
+	fromState       bool
+	out             string
+	includeOptional bool
+	provider        string
+	reattachInfo    ReattachInfo
+}
+
+var defaultAddOptions = addConfig{}
+
+type AddOption interface {
+	configureAdd(*addConfig)
+}
+
+func (opt *FromStateOption) configureAdd(conf *addConfig) {
+	conf.fromState = opt.fromState
+}
+
+func (opt *OutOption) configureAdd(conf *addConfig) {
+	conf.out = opt.path
+}
+
+func (opt *IncludeOptionalOption) configureAdd(conf *addConfig) {
+	conf.includeOptional = opt.includeOptional
+}
+
+func (opt *ProviderOption) configureAdd(conf *addConfig) {
+	conf.provider = opt.provider
+}
+
+func (opt *ReattachOption) configureAdd(conf *addConfig) {
+	conf.reattachInfo = opt.info
+}
+
+// Add represents the `terraform add` subcommand (added in 1.1.0).
+//
+// Note that this function signature and behaviour is subject
+// to breaking changes including removal of that function
+// until final 1.1.0 Terraform version (with this command) is released.
+func (tf *Terraform) Add(ctx context.Context, address string, opts ...AddOption) (string, error) {
+	cmd, err := tf.addCmd(ctx, address, opts...)
+	if err != nil {
+		return "", err
+	}
+
+	var outBuf strings.Builder
+	cmd.Stdout = mergeWriters(cmd.Stdout, &outBuf)
+
+	if err := tf.runTerraformCmd(ctx, cmd); err != nil {
+		return "", err
+	}
+
+	return outBuf.String(), nil
+}
+
+func (tf *Terraform) addCmd(ctx context.Context, address string, opts ...AddOption) (*exec.Cmd, error) {
+	err := tf.compatible(ctx, tf1_1_0, nil)
+	if err != nil {
+		return nil, fmt.Errorf("terraform add was added in 1.1.0: %w", err)
+	}
+
+	c := defaultAddOptions
+
+	for _, o := range opts {
+		o.configureAdd(&c)
+	}
+
+	args := []string{"add"}
+
+	args = append(args, "-from-state="+strconv.FormatBool(c.fromState))
+	if c.out != "" {
+		args = append(args, "-out="+c.out)
+	}
+	args = append(args, "-optional="+strconv.FormatBool(c.includeOptional))
+	if c.provider != "" {
+		args = append(args, "-provider="+c.provider)
+	}
+
+	args = append(args, address)
+
+	mergeEnv := map[string]string{}
+	if c.reattachInfo != nil {
+		reattachStr, err := c.reattachInfo.marshalString()
+		if err != nil {
+			return nil, err
+		}
+		mergeEnv[reattachEnvVar] = reattachStr
+	}
+
+	return tf.buildTerraformCmd(ctx, mergeEnv, args...), nil
+}

tfexec/add_test.go

@@ -0,0 +1,56 @@
+package tfexec
+
+import (
+	"context"
+	"testing"
+
+	"github.com/hashicorp/terraform-exec/tfexec/internal/testutil"
+)
+
+func TestAddCmd(t *testing.T) {
+	td := testTempDir(t)
+
+	tf, err := NewTerraform(td, tfVersion(t, testutil.Latest_v1_1))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// empty env, to avoid environ mismatch in testing
+	tf.SetEnv(map[string]string{})
+
+	t.Run("default", func(t *testing.T) {
+		addCmd, err := tf.addCmd(context.Background(), "my-addr")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assertCmd(t, []string{
+			"add",
+			"-from-state=false",
+			"-optional=false",
+			"my-addr",
+		}, nil, addCmd)
+	})
+
+	t.Run("override-default", func(t *testing.T) {
+		addCmd, err := tf.addCmd(context.Background(),
+			"my-addr",
+			FromState(true),
+			Out("out"),
+			IncludeOptional(true),
+			Provider("my-provider"),
+		)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assertCmd(t, []string{
+			"add",
+			"-from-state=true",
+			"-out=out",
+			"-optional=true",
+			"-provider=my-provider",
+			"my-addr",
+		}, nil, addCmd)
+	})
+}

tfexec/internal/testutil/tfcache.go

@@ -9,12 +9,13 @@ import (
 )
 
 const (
-	Latest011 = "0.11.15"
-	Latest012 = "0.12.31"
-	Latest013 = "0.13.7"
-	Latest014 = "0.14.11"
-	Latest015 = "0.15.5"
-	Latest_v1 = "1.0.0"
+	Latest011   = "0.11.15"
+	Latest012   = "0.12.31"
+	Latest013   = "0.13.7"
+	Latest014   = "0.14.11"
+	Latest015   = "0.15.5"
+	Latest_v1   = "1.0.0"
+	Latest_v1_1 = "1.1.0-alpha20210811"
 )
 
 const appendUserAgent = "tfexec-testutil"

tfexec/options.go

@@ -365,3 +365,21 @@ type VerifyPluginsOption struct {
 func VerifyPlugins(verifyPlugins bool) *VerifyPluginsOption {
 	return &VerifyPluginsOption{verifyPlugins}
 }
+
+// FromStateOption represents the -from-state option of the "terraform add" command.
+type FromStateOption struct {
+	fromState bool
+}
+
+func FromState(fromState bool) *FromStateOption {
+	return &FromStateOption{fromState}
+}
+
+// IncludeOptionalOption represents the -optional option of the "terraform add" command.
+type IncludeOptionalOption struct {
+	includeOptional bool
+}
+
+func IncludeOptional(includeOptional bool) *IncludeOptionalOption {
+	return &IncludeOptionalOption{includeOptional}
+}

tfexec/version.go

@@ -19,6 +19,7 @@ var (
 	tf0_13_0 = version.Must(version.NewVersion("0.13.0"))
 	tf0_14_0 = version.Must(version.NewVersion("0.14.0"))
 	tf0_15_0 = version.Must(version.NewVersion("0.15.0"))
+	tf1_1_0  = version.Must(version.NewVersion("1.1.0"))
 )
 
 // Version returns structured output from the terraform version command including both the Terraform CLI version