Check for already-existing image before building image

commands/build.go

@@ -4,6 +4,7 @@ import (
 	"log"
 	"path"
 
+	"github.com/bravetools/bravetools/platform"
 	"github.com/spf13/cobra"
 )
 
@@ -40,7 +41,11 @@ func build(cmd *cobra.Command, args []string) {
 	}
 
 	err = host.BuildImage(bravefile)
-	if err != nil {
+	switch errType := err.(type) {
+	case nil:
+	case *platform.ImageExistsError:
+		log.Fatalf("image %q already exists - if you want to rebuild it, first delete the existing image with: `brave remove -i [IMAGE]`", errType.Name)
+	default:
 		log.Fatal(err)
 	}
 }

platform/helpers.go

@@ -462,3 +462,9 @@ func checkUnits(unitName string, bh *BraveHost) error {
 
 	return nil
 }
+
+func imageExists(imageNameAndVersion string) bool {
+	homeDir, _ := os.UserHomeDir()
+	image := path.Join(homeDir, shared.ImageStore, imageNameAndVersion+".tar.gz")
+	return shared.FileExists(image)
+}

platform/host_api.go

@@ -530,6 +530,14 @@ func (bh *BraveHost) DeleteUnit(name string) error {
 	return nil
 }
 
+type ImageExistsError struct {
+	Name string
+}
+
+func (e *ImageExistsError) Error() string {
+	return fmt.Sprintf("image %q already exists", e.Name)
+}
+
 // BuildImage creates an image based on Bravefile
 func (bh *BraveHost) BuildImage(bravefile *shared.Bravefile) error {
 	if strings.ContainsAny(bravefile.PlatformService.Name, "/_. !@£$%^&*(){}:;`~,?") {
@@ -544,6 +552,9 @@ func (bh *BraveHost) BuildImage(bravefile *shared.Bravefile) error {
 	if err != nil {
 		return err
 	}
+	if imageExists(bravefile.PlatformService.Image) {
+		return &ImageExistsError{Name: bravefile.PlatformService.Image}
+	}
 
 	// Intercept SIGINT, propagate cancel and cleanup artefacts
 	var imageFingerprint string
@@ -797,6 +808,9 @@ func (bh *BraveHost) InitUnit(backend Backend, unitParams *shared.Bravefile) (er
 	if err != nil {
 		return err
 	}
+	if !imageExists(unitParams.PlatformService.Image) {
+		return fmt.Errorf("image %q does not exist", unitParams.PlatformService.Image)
+	}
 
 	var fingerprint string