parse arg commands at the top of dockerfiles (#404)

* parse arg commands at the top of dockerfiles

* fix pointer reference bug and remove debugging

* fixing tests

* account for meta args with no value

* don't take fs snapshot if / is the only changed path

* move metaArgs inside KanikoStage

* removing unused property

* check for any directory instead of just /

* remove unnecessary check

pkg/util/image_util.go

@@ -18,6 +18,7 @@ package util
 
 import (
 	"crypto/tls"
+	"fmt"
 	"net/http"
 	"path/filepath"
 	"strconv"
@@ -44,7 +45,13 @@ var (
 )
 
 // RetrieveSourceImage returns the base image of the stage at index
-func RetrieveSourceImage(stage config.KanikoStage, buildArgs []string, opts *config.KanikoOptions) (v1.Image, error) {
+func RetrieveSourceImage(stage config.KanikoStage, opts *config.KanikoOptions) (v1.Image, error) {
+	buildArgs := opts.BuildArgs
+	var metaArgsString []string
+	for _, arg := range stage.MetaArgs {
+		metaArgsString = append(metaArgsString, fmt.Sprintf("%s=%s", arg.Key, arg.ValueString()))
+	}
+	buildArgs = append(buildArgs, metaArgsString...)
 	currentBaseName, err := ResolveEnvironmentReplacement(stage.BaseName, buildArgs, false)
 	if err != nil {
 		return nil, err

pkg/util/image_util_test.go

@@ -57,7 +57,7 @@ func Test_StandardImage(t *testing.T) {
 	retrieveRemoteImage = mock
 	actual, err := RetrieveSourceImage(config.KanikoStage{
 		Stage: stages[0],
-	}, nil, &config.KanikoOptions{})
+	}, &config.KanikoOptions{})
 	testutil.CheckErrorAndDeepEqual(t, false, err, nil, actual)
 }
 func Test_ScratchImage(t *testing.T) {
@@ -67,7 +67,7 @@ func Test_ScratchImage(t *testing.T) {
 	}
 	actual, err := RetrieveSourceImage(config.KanikoStage{
 		Stage: stages[1],
-	}, nil, &config.KanikoOptions{})
+	}, &config.KanikoOptions{})
 	expected := empty.Image
 	testutil.CheckErrorAndDeepEqual(t, false, err, expected, actual)
 }
@@ -89,7 +89,7 @@ func Test_TarImage(t *testing.T) {
 		BaseImageStoredLocally: true,
 		BaseImageIndex:         0,
 		Stage:                  stages[2],
-	}, nil, &config.KanikoOptions{})
+	}, &config.KanikoOptions{})
 	testutil.CheckErrorAndDeepEqual(t, false, err, nil, actual)
 }