From d6bb88f92479cb5d42da960fb056de34eb686ca0 Mon Sep 17 00:00:00 2001
From: Priya Wadhwa <priyawadhwa@google.com>
Date: Mon, 21 May 2018 14:51:00 -0700
Subject: [PATCH] Resolve environment replacement for arg

---
 integration/dockerfiles/Dockerfile_test_scratch |  4 +++-
 pkg/commands/arg.go                             | 16 +++++++++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/integration/dockerfiles/Dockerfile_test_scratch b/integration/dockerfiles/Dockerfile_test_scratch
index e2a1383ee..340d05532 100644
--- a/integration/dockerfiles/Dockerfile_test_scratch
+++ b/integration/dockerfiles/Dockerfile_test_scratch
@@ -6,7 +6,9 @@ COPY $file /foo
 ARG file2=context/bar/bat
 COPY $file2 /bat
 # Check that overriding a default value works
-ARG file3=context/bar/baz
+ENV baz baz
+ENV src file3
+ARG ${src}=context/bar/${baz}
 COPY $file3 /baz
 # Check that setting an ENV will override the ARG
 ENV file context/bar/bam/bat
diff --git a/pkg/commands/arg.go b/pkg/commands/arg.go
index cf4dcd525..e91489eb9 100644
--- a/pkg/commands/arg.go
+++ b/pkg/commands/arg.go
@@ -18,6 +18,7 @@ package commands
 
 import (
 	"github.com/GoogleContainerTools/kaniko/pkg/dockerfile"
+	"github.com/GoogleContainerTools/kaniko/pkg/util"
 	"github.com/docker/docker/builder/dockerfile/instructions"
 	"github.com/google/go-containerregistry/v1"
 	"github.com/sirupsen/logrus"
@@ -31,7 +32,20 @@ type ArgCommand struct {
 // ExecuteCommand only needs to add this ARG key/value as seen
 func (r *ArgCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.BuildArgs) error {
 	logrus.Info("ARG")
-	buildArgs.AddArg(r.cmd.Key, r.cmd.Value)
+	replacementEnvs := buildArgs.ReplacementEnvs(config.Env)
+	resolvedKey, err := util.ResolveEnvironmentReplacement(r.cmd.Key, replacementEnvs, false)
+	if err != nil {
+		return err
+	}
+	var resolvedValue *string
+	if r.cmd.Value != nil {
+		value, err := util.ResolveEnvironmentReplacement(*r.cmd.Value, replacementEnvs, false)
+		if err != nil {
+			return err
+		}
+		resolvedValue = &value
+	}
+	buildArgs.AddArg(resolvedKey, resolvedValue)
 	return nil
 }