support -var-file option (#137)

* support `-var-file` option

* fix golint

CHANGELOG.md

@@ -1,6 +1,7 @@
-## v2.0.1
+## v2.1.0 (unreleased)
 
 FEATURES:
+- Support `-var-file` option to specify the path to the terraform variable file.
 - Support migrating resources from `azurerm` provider to `azapi` provider.
 
 ## v2.0.0-beta

cmd/migrate_command.go

@@ -24,6 +24,7 @@ type MigrateCommand struct {
 	Verbose        bool
 	Strict         bool
 	workingDir     string
+	varFile        string
 	TargetProvider string
 }
 
@@ -32,6 +33,7 @@ func (c *MigrateCommand) flags() *flag.FlagSet {
 	fs.BoolVar(&c.Verbose, "v", false, "whether show terraform logs")
 	fs.BoolVar(&c.Strict, "strict", false, "strict mode: API versions must be matched")
 	fs.StringVar(&c.workingDir, "working-dir", "", "path to Terraform configuration files")
+	fs.StringVar(&c.varFile, "var-file", "", "path to the terraform variable file")
 	fs.StringVar(&c.TargetProvider, "to", "", "Specify the provider to migrate to. The allowed values are: azurerm and azapi. Default is azurerm.")
 
 	fs.Usage = func() { c.Ui.Error(c.Help()) }
@@ -76,6 +78,8 @@ func (c *MigrateCommand) Run(args []string) int {
 		Ui:             c.Ui,
 		Verbose:        c.Verbose,
 		Strict:         c.Strict,
+		workingDir:     c.workingDir,
+		varFile:        c.varFile,
 		TargetProvider: c.TargetProvider,
 	}
 	allResources := planCommand.Plan(terraform, false)

cmd/migrate_command_test.go

@@ -111,7 +111,7 @@ provider "azurerm" {
 			ErrorWriter: os.Stderr,
 		},
 	}
-	p, err := terraform.Plan()
+	p, err := terraform.Plan(nil)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -182,7 +182,7 @@ provider "azurerm" {
 	}
 
 	// check no plan-diff
-	plan, err := terraform.Plan()
+	plan, err := terraform.Plan(nil)
 	if err != nil {
 		t.Fatal(err)
 	}

cmd/plan_command.go

@@ -20,6 +20,7 @@ type PlanCommand struct {
 	Verbose        bool
 	Strict         bool
 	workingDir     string
+	varFile        string
 	TargetProvider string
 }
 
@@ -28,6 +29,7 @@ func (c *PlanCommand) flags() *flag.FlagSet {
 	fs.BoolVar(&c.Verbose, "v", false, "whether show terraform logs")
 	fs.BoolVar(&c.Strict, "strict", false, "strict mode: API versions must be matched")
 	fs.StringVar(&c.workingDir, "working-dir", "", "path to Terraform configuration files")
+	fs.StringVar(&c.varFile, "var-file", "", "path to the terraform variable file")
 	fs.StringVar(&c.TargetProvider, "to", "", "Specify the provider to migrate to. The allowed values are: azurerm and azapi. Default is azurerm.")
 	fs.Usage = func() { c.Ui.Error(c.Help()) }
 	return fs
@@ -78,7 +80,7 @@ func (c *PlanCommand) Synopsis() string {
 func (c *PlanCommand) Plan(terraform *tf.Terraform, isPlanOnly bool) []types.AzureResource {
 	// get azapi resource from state
 	log.Printf("[INFO] running terraform plan...")
-	p, err := terraform.Plan()
+	p, err := terraform.Plan(&c.varFile)
 	if err != nil {
 		log.Fatal(err)
 	}

tf/terraform.go

@@ -69,8 +69,12 @@ func (t *Terraform) Show() (*tfjson.State, error) {
 	return t.exec.Show(context.TODO())
 }
 
-func (t *Terraform) Plan() (*tfjson.Plan, error) {
-	_, err := t.exec.Plan(context.TODO(), tfexec.Out(planfile))
+func (t *Terraform) Plan(varFile *string) (*tfjson.Plan, error) {
+	planOptions := []tfexec.PlanOption{tfexec.Out(planfile)}
+	if varFile != nil && *varFile != "" {
+		planOptions = append(planOptions, tfexec.VarFile(*varFile))
+	}
+	_, err := t.exec.Plan(context.TODO(), planOptions...)
 	if err != nil {
 		return nil, err
 	}