executor: add --label flag

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>

pkg/executor/build.go

@@ -21,6 +21,7 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/google/go-containerregistry/pkg/v1/partial"
@@ -82,7 +83,7 @@ func newStageBuilder(opts *config.KanikoOptions, stage config.KanikoStage, cross
 		return nil, err
 	}
 
-	imageConfig, err := initializeConfig(sourceImage)
+	imageConfig, err := initializeConfig(sourceImage, opts)
 	if err != nil {
 		return nil, err
 	}
@@ -134,7 +135,7 @@ func newStageBuilder(opts *config.KanikoOptions, stage config.KanikoStage, cross
 	return s, nil
 }
 
-func initializeConfig(img partial.WithConfigFile) (*v1.ConfigFile, error) {
+func initializeConfig(img partial.WithConfigFile, opts *config.KanikoOptions) (*v1.ConfigFile, error) {
 	imageConfig, err := img.ConfigFile()
 	if err != nil {
 		return nil, err
@@ -143,6 +144,25 @@ func initializeConfig(img partial.WithConfigFile) (*v1.ConfigFile, error) {
 	if imageConfig.Config.Env == nil {
 		imageConfig.Config.Env = constants.ScratchEnvVars
 	}
+
+	if opts == nil {
+		return imageConfig, nil
+	}
+
+	if l := len(opts.Labels); l > 0 {
+		if imageConfig.Config.Labels == nil {
+			imageConfig.Config.Labels = make(map[string]string)
+		}
+		for _, label := range opts.Labels {
+			parts := strings.SplitN(label, "=", 2)
+			if len(parts) != 2 {
+				return nil, fmt.Errorf("labels must be of the form key=value, got %s", label)
+			}
+
+			imageConfig.Config.Labels[parts[0]] = parts[1]
+		}
+	}
+
 	return imageConfig, nil
 }
 
@@ -484,7 +504,7 @@ func CalculateDependencies(opts *config.KanikoOptions) (map[int][]string, error)
 				return nil, err
 			}
 		}
-		cfg, err := initializeConfig(image)
+		cfg, err := initializeConfig(image, opts)
 		if err != nil {
 			return nil, err
 		}

pkg/executor/build_test.go

@@ -462,7 +462,7 @@ func TestInitializeConfig(t *testing.T) {
 			t.Errorf("error seen when running test %s", err)
 			t.Fail()
 		}
-		actual, _ := initializeConfig(img)
+		actual, _ := initializeConfig(img, nil)
 		testutil.CheckDeepEqual(t, tt.expected, actual.Config)
 	}
 }