Support Terraform backend

README.md

@@ -30,6 +30,10 @@ Then you can go ahead and run `aztfy`:
 aztfy [option] <resource group name>
 
   -b    Batch mode (i.e. Non-interactive mode)
+  -backend-config value
+        The Terraform backend config
+  -backend-type string
+        The Terraform backend used to store the state (default "local")
   -f    Whether to overwrite the out dir if it is not empty, use with caution
   -k    Whether continue on import error (batch mode only)
   -m string

internal/config/config.go

@@ -1,13 +1,15 @@
 package config
 
 type Config struct {
-	ResourceGroupName   string // specified via CLI
-	Logfile             string `env:"AZTFY_LOGFILE" default:""`
-	Debug               bool   `env:"AZTFY_DEBUG" default:"false"`
-	MockClient          bool   `env:"AZTFY_MOCK_CLIENT" default:"false"`
-	OutputDir           string // specified via CLI option
-	ResourceMappingFile string // specified via CLI option
-	ResourceNamePattern string // specified via CLI option
-	Overwrite           bool   // specified via CLI option
-	BatchMode           bool   // specified via CLI option
+	ResourceGroupName   string   // specified via CLI
+	Logfile             string   `env:"AZTFY_LOGFILE" default:""`
+	Debug               bool     `env:"AZTFY_DEBUG" default:"false"`
+	MockClient          bool     `env:"AZTFY_MOCK_CLIENT" default:"false"`
+	OutputDir           string   // specified via CLI option
+	ResourceMappingFile string   // specified via CLI option
+	ResourceNamePattern string   // specified via CLI option
+	Overwrite           bool     // specified via CLI option
+	BatchMode           bool     // specified via CLI option
+	BackendType         string   // specified via CLI option
+	BackendConfig       []string // specified via CLI option
 }

internal/meta/config_info.go

@@ -1,7 +1,6 @@
 package meta
 
 import (
-	"bytes"
 	"io"
 
 	"github.com/hashicorp/hcl/v2/hclwrite"
@@ -16,8 +15,5 @@ type ConfigInfo struct {
 
 func (cfg ConfigInfo) DumpHCL(w io.Writer) (int, error) {
 	out := hclwrite.Format(cfg.hcl.Bytes())
-	// Hack: removing the leading warning comments before each resource config,
-	// which is generated via "terraform add".
-	out = out[bytes.Index(out, []byte(`resource "`)):]
 	return w.Write(out)
 }

internal/meta/meta_impl.go

@@ -40,6 +40,9 @@ type MetaImpl struct {
 
 	resourceNamePrefix string
 	resourceNameSuffix string
+
+	backendType   string
+	backendConfig []string
 }
 
 func newMetaImpl(cfg config.Config) (Meta, error) {
@@ -127,6 +130,8 @@ func newMetaImpl(cfg config.Config) (Meta, error) {
 		outdir:          outdir,
 		auth:            auth,
 		resourceMapping: m,
+		backendType:     cfg.BackendType,
+		backendConfig:   cfg.BackendConfig,
 	}
 
 	if pos := strings.LastIndex(cfg.ResourceNamePattern, "*"); pos != -1 {
@@ -221,6 +226,7 @@ func (meta MetaImpl) Import(item *ImportItem) {
 		item.ImportError = fmt.Errorf("generating resource template for %s: %w", item.TFAddr, err)
 		return
 	}
+	tpl = meta.cleanupTerraformAdd(tpl)
 	if err := os.WriteFile(cfgFile, []byte(tpl), 0644); err != nil {
 		item.ImportError = fmt.Errorf("generating resource template file: %w", err)
 		return
@@ -266,8 +272,9 @@ func (meta MetaImpl) ExportResourceMapping(l ImportList) error {
 	return nil
 }
 
-func providerConfig() string {
+func (meta *MetaImpl) providerConfig() string {
 	return fmt.Sprintf(`terraform {
+  backend %q {}
   required_providers {
     azurerm = {
       source = "hashicorp/azurerm"
@@ -279,18 +286,22 @@ func providerConfig() string {
 provider "azurerm" {
   features {}
 }
-`, schema.ProviderVersion)
+`, meta.backendType, schema.ProviderVersion)
 }
 
 func (meta *MetaImpl) initProvider(ctx context.Context) error {
 	cfgFile := filepath.Join(meta.outdir, "provider.tf")
 
 	// Always use the latest provider version here, as this is a one shot tool, which should guarantees to work with the latest version.
-	if err := os.WriteFile(cfgFile, []byte(providerConfig()), 0644); err != nil {
+	if err := os.WriteFile(cfgFile, []byte(meta.providerConfig()), 0644); err != nil {
 		return fmt.Errorf("error creating provider config: %w", err)
 	}
 
-	if err := meta.tf.Init(ctx); err != nil {
+	var opts []tfexec.InitOption
+	for _, opt := range meta.backendConfig {
+		opts = append(opts, tfexec.BackendConfig(opt))
+	}
+	if err := meta.tf.Init(ctx, opts...); err != nil {
 		return fmt.Errorf("error running terraform init: %s", err)
 	}
 
@@ -340,6 +351,7 @@ func (meta MetaImpl) stateToConfig(ctx context.Context, list ImportList) (Config
 		if err != nil {
 			return nil, fmt.Errorf("converting terraform state to config for resource %s: %w", item.TFAddr, err)
 		}
+		tpl = meta.cleanupTerraformAdd(tpl)
 		f, diag := hclwrite.ParseConfig([]byte(tpl), "", hcl.InitialPos)
 		if diag.HasErrors() {
 			return nil, fmt.Errorf("parsing the HCL generated by \"terraform add\" of %s: %s", item.TFAddr, diag.Error())
@@ -434,6 +446,23 @@ func (meta MetaImpl) generateConfig(cfgs ConfigInfos) error {
 	return nil
 }
 
+func (meta MetaImpl) cleanupTerraformAdd(tpl string) string {
+	segs := strings.Split(tpl, "\n")
+	// Removing:
+	// - preceding/trailing state lock related log when TF backend is used.
+	// - preceding warning comments.
+	for len(segs) != 0 && (strings.HasPrefix(segs[0], "Acquiring state lock.") || strings.HasPrefix(segs[0], "#")) {
+		segs = segs[1:]
+	}
+
+	last := len(segs) - 1
+	for last != -1 && (segs[last] == "" || strings.HasPrefix(segs[last], "Releasing state lock.")) {
+		segs = segs[:last]
+		last = len(segs) - 1
+	}
+	return strings.Join(segs, "\n")
+}
+
 func removeEverythingUnder(path string) error {
 	dir, err := os.Open(path)
 	if err != nil {

main.go

@@ -23,6 +23,7 @@ var (
 	flagBatchMode   *bool
 	flagPattern     *string
 	flagOverwrite   *bool
+	flagBackendType *string
 )
 
 func init() {
@@ -33,6 +34,7 @@ func init() {
 	flagBatchMode = flag.Bool("b", false, "Batch mode (i.e. Non-interactive mode)")
 	flagPattern = flag.String("p", "res-", `The pattern of the resource name. The resource name is generated by taking the pattern and adding an auto-incremental integer to the end. If pattern includes a "*", the auto-incremental integer replaces the last "*"`)
 	flagOverwrite = flag.Bool("f", false, "Whether to overwrite the out dir if it is not empty, use with caution")
+	flagBackendType = flag.String("backend-type", "local", "The Terraform backend used to store the state")
 }
 
 const usage = `aztfy [option] <resource group name>
@@ -43,11 +45,27 @@ func fatal(err error) {
 	os.Exit(1)
 }
 
+type strSliceFlag struct {
+	values *[]string
+}
+
+func (o *strSliceFlag) String() string { return "" }
+func (o *strSliceFlag) Set(val string) error {
+	*o.values = append(*o.values, val)
+	return nil
+}
+
 func main() {
 	flag.Usage = func() {
 		fmt.Fprintf(flag.CommandLine.Output(), "%s\n", usage)
 		flag.PrintDefaults()
 	}
+
+	var backendConfig []string
+	flag.Var(&strSliceFlag{
+		values: &backendConfig,
+	}, "backend-config", "The Terraform backend config")
+
 	flag.Parse()
 
 	if *flagVersion {
@@ -80,6 +98,8 @@ func main() {
 	cfg.OutputDir = *flagOutputDir
 	cfg.Overwrite = *flagOverwrite
 	cfg.BatchMode = *flagBatchMode
+	cfg.BackendType = *flagBackendType
+	cfg.BackendConfig = backendConfig
 
 	if cfg.BatchMode {
 		if err := batchImport(cfg, *flagContinue); err != nil {