From 15b85ecb5223db2193738e27c64f7dcb66f21b13 Mon Sep 17 00:00:00 2001
From: Nick Kubala <kubala.nick@gmail.com>
Date: Wed, 11 Sep 2019 16:36:10 -0700
Subject: [PATCH 1/2] Duck-type k8s manifests instead of actually parsing when
 running skaffold init

---
 pkg/skaffold/initializer/kubectl/kubectl.go | 22 +++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/pkg/skaffold/initializer/kubectl/kubectl.go b/pkg/skaffold/initializer/kubectl/kubectl.go
index 9784cf2be00..d288610bb47 100644
--- a/pkg/skaffold/initializer/kubectl/kubectl.go
+++ b/pkg/skaffold/initializer/kubectl/kubectl.go
@@ -25,9 +25,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	yaml "gopkg.in/yaml.v2"
-	"k8s.io/apimachinery/pkg/runtime"
 	k8syaml "k8s.io/apimachinery/pkg/util/yaml"
-	"k8s.io/client-go/kubernetes/scheme"
 )
 
 // ValidSuffixes are the supported file formats for kubernetes manifests
@@ -89,7 +87,7 @@ func parseImagesFromKubernetesYaml(filepath string) ([]string, error) {
 	}
 	r := k8syaml.NewYAMLReader(bufio.NewReader(f))
 
-	objects := []runtime.Object{}
+	yamlsFound := 0
 	images := []string{}
 
 	for {
@@ -100,21 +98,25 @@ func parseImagesFromKubernetesYaml(filepath string) ([]string, error) {
 		if err != nil {
 			return nil, errors.Wrap(err, "reading config file")
 		}
-		d := scheme.Codecs.UniversalDeserializer()
-		obj, _, err := d.Decode(doc, nil, nil)
-		if err != nil {
-			return nil, errors.Wrap(err, "decoding kubernetes yaml")
-		}
 
 		m := make(map[interface{}]interface{})
 		if err := yaml.Unmarshal(doc, &m); err != nil {
 			return nil, errors.Wrap(err, "reading kubernetes YAML")
 		}
 
+		if _, ok := m["apiVersion"]; !ok {
+			logrus.Debugf("'apiVersion' not present in yaml, continuing")
+			continue
+		}
+		if _, ok := m["kind"]; !ok {
+			logrus.Debugf("'kind' not present in yaml, continuing")
+			continue
+		}
+		yamlsFound++
+
 		images = append(images, parseImagesFromYaml(m)...)
-		objects = append(objects, obj)
 	}
-	if len(objects) == 0 {
+	if yamlsFound == 0 {
 		return nil, errors.New("no valid kubernetes objects decoded")
 	}
 	return images, nil

From e7b2603ad7deccfe66d2d67a532e7f0050dc2019 Mon Sep 17 00:00:00 2001
From: Nick Kubala <kubala.nick@gmail.com>
Date: Thu, 12 Sep 2019 10:59:11 -0700
Subject: [PATCH 2/2] check for metadata field and add test

---
 pkg/skaffold/initializer/kubectl/kubectl.go   | 26 +++++++++++++------
 .../initializer/kubectl/kubectl_test.go       | 13 ++++++++++
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/pkg/skaffold/initializer/kubectl/kubectl.go b/pkg/skaffold/initializer/kubectl/kubectl.go
index d288610bb47..e4804938e5a 100644
--- a/pkg/skaffold/initializer/kubectl/kubectl.go
+++ b/pkg/skaffold/initializer/kubectl/kubectl.go
@@ -31,6 +31,8 @@ import (
 // ValidSuffixes are the supported file formats for kubernetes manifests
 var ValidSuffixes = []string{".yml", ".yaml", ".json"}
 
+var requiredFields = []string{"apiVersion", "kind", "metadata"}
+
 // Kubectl holds parameters to run kubectl.
 type Kubectl struct {
 	configs []string
@@ -77,8 +79,10 @@ func (k *Kubectl) GetImages() []string {
 	return k.images
 }
 
-// parseImagesFromKubernetesYaml attempts to parse k8s objects from a yaml file
-// if successful, it will return the images referenced in the k8s config
+// parseImagesFromKubernetesYaml uses required fields from the k8s spec
+// to determine if a provided yaml file is a valid k8s manifest, as detailed in
+// https://kubernetes.io/docs/concepts/overview/working-with-objects/kubernetes-objects/#required-fields.
+// if so, it will return the images referenced in the k8s config
 // so they can be built by the generated skaffold yaml
 func parseImagesFromKubernetesYaml(filepath string) ([]string, error) {
 	f, err := os.Open(filepath)
@@ -104,14 +108,10 @@ func parseImagesFromKubernetesYaml(filepath string) ([]string, error) {
 			return nil, errors.Wrap(err, "reading kubernetes YAML")
 		}
 
-		if _, ok := m["apiVersion"]; !ok {
-			logrus.Debugf("'apiVersion' not present in yaml, continuing")
-			continue
-		}
-		if _, ok := m["kind"]; !ok {
-			logrus.Debugf("'kind' not present in yaml, continuing")
+		if !isKubernetesYaml(m) {
 			continue
 		}
+
 		yamlsFound++
 
 		images = append(images, parseImagesFromYaml(m)...)
@@ -122,6 +122,16 @@ func parseImagesFromKubernetesYaml(filepath string) ([]string, error) {
 	return images, nil
 }
 
+func isKubernetesYaml(doc map[interface{}]interface{}) bool {
+	for _, field := range requiredFields {
+		if _, ok := doc[field]; !ok {
+			logrus.Debugf("%s not present in yaml, continuing", field)
+			return false
+		}
+	}
+	return true
+}
+
 // adapted from pkg/skaffold/deploy/kubectl/recursiveReplaceImage()
 func parseImagesFromYaml(doc interface{}) []string {
 	images := []string{}
diff --git a/pkg/skaffold/initializer/kubectl/kubectl_test.go b/pkg/skaffold/initializer/kubectl/kubectl_test.go
index 02f907c35ae..53f2be89aed 100644
--- a/pkg/skaffold/initializer/kubectl/kubectl_test.go
+++ b/pkg/skaffold/initializer/kubectl/kubectl_test.go
@@ -98,6 +98,19 @@ subjects:
 			images:    []string{},
 			shouldErr: false,
 		},
+		{
+			description: "crd",
+			contents: `apiVersion: my.crd.io/v1
+kind: CustomType
+metadata:
+  name: test crd
+spec:
+  containers:
+  - name: container
+    image: gcr.io/my/image`,
+			images:    []string{"gcr.io/my/image"},
+			shouldErr: false,
+		},
 	}
 	for _, test := range tests {
 		testutil.Run(t, test.description, func(t *testutil.T) {