overwriteOutput flag

Author: lantoli

internal/cli/cluster/cluster.go

@@ -3,45 +3,51 @@ package cluster
 import (
 	"fmt"
 
+	"github.com/mongodb-labs/atlas-cli-plugin-terraform/internal/file"
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 )
 
 func Builder() *cobra.Command {
-	opts := &Opts{fs: afero.NewOsFs()}
+	o := &opts{fs: afero.NewOsFs()}
 	cmd := &cobra.Command{
 		Use:     "cluster_to_advanced",
 		Short:   "Upgrade cluster to advanced_cluster",
 		Long:    "Upgrade Terraform config from mongodbatlas_cluster to mongodbatlas_advanced_cluster",
 		Aliases: []string{"clu2adv"},
 		PreRunE: func(cmd *cobra.Command, args []string) error {
-			if exists, err := afero.Exists(opts.fs, opts.file); !exists || err != nil {
-				return fmt.Errorf("input file not found: %s", opts.file)
-			}
-			if exists, err := afero.Exists(opts.fs, opts.output); exists || err != nil {
-				return fmt.Errorf("output file can't exist: %s", opts.output)
-			}
-			return nil
+			return o.PreRun()
 		},
 		RunE: func(_ *cobra.Command, _ []string) error {
-			return opts.Run()
+			return o.Run()
 		},
 	}
-	cmd.Flags().StringVarP(&opts.file, "file", "f", "", "input file")
-	cmd.Flags().StringVarP(&opts.output, "output", "o", "", "output file")
-	_ = cmd.MarkFlagFilename("file")
+	cmd.Flags().StringVarP(&o.file, "file", "f", "", "input file")
 	_ = cmd.MarkFlagRequired("file")
+	cmd.Flags().StringVarP(&o.output, "output", "o", "", "output file")
 	_ = cmd.MarkFlagRequired("output")
+	cmd.Flags().BoolVarP(&o.overwriteOutput, "overwriteOutput", "w", false, "overwrite output file if exists")
 	return cmd
 }
 
-type Opts struct {
-	fs     afero.Fs
-	file   string
-	output string
+type opts struct {
+	fs              afero.Fs
+	file            string
+	output          string
+	overwriteOutput bool
 }
 
-func (o *Opts) Run() error {
+func (o *opts) PreRun() error {
+	if err := file.MustExist(o.fs, o.file); err != nil {
+		return err
+	}
+	if !o.overwriteOutput {
+		return file.MustNotExist(o.fs, o.output)
+	}
+	return nil
+}
+
+func (o *opts) Run() error {
 	content, err := afero.ReadFile(o.fs, o.file)
 	if err != nil {
 		return fmt.Errorf("failed to read file %s: %w", o.file, err)

internal/file/file.go

@@ -0,0 +1,41 @@
+package file
+
+import (
+	"fmt"
+
+	"github.com/spf13/afero"
+)
+
+func Exists(fs afero.Fs, filename string) (exists bool, err error) {
+	exists, err = afero.Exists(fs, filename)
+	if err != nil {
+		return false, newError(err, filename)
+	}
+	return
+}
+
+func MustExist(fs afero.Fs, filename string) error {
+	exists, err := Exists(fs, filename)
+	if err != nil {
+		return err
+	}
+	if !exists {
+		return fmt.Errorf("file must exist: %s", filename)
+	}
+	return nil
+}
+
+func MustNotExist(fs afero.Fs, filename string) error {
+	exists, err := Exists(fs, filename)
+	if err != nil {
+		return err
+	}
+	if exists {
+		return fmt.Errorf("file must not exist: %s", filename)
+	}
+	return nil
+}
+
+func newError(err error, filename string) error {
+	return fmt.Errorf("error in file %s: %w", filename, err)
+}