Add CreateContextWithOptions for lintcontext

Allows users to provide options for creating lint context.

Related Issue: #141

Signed-off-by: Arvind Iyengar <[email protected]>

Author: Arvind Iyengar

pkg/lintcontext/context.go

@@ -2,6 +2,7 @@ package lintcontext
 
 import (
 	"golang.stackrox.io/kube-linter/internal/k8sutil"
+	"k8s.io/apimachinery/pkg/runtime"
 )
 
 // ObjectMetadata is metadata about an object.
@@ -31,6 +32,8 @@ type LintContext interface {
 type lintContextImpl struct {
 	objects        []Object
 	invalidObjects []InvalidObject
+
+	customDecoder runtime.Decoder
 }
 
 // Objects returns the (valid) objects loaded from this LintContext.

pkg/lintcontext/create_contexts.go

@@ -9,19 +9,30 @@ import (
 	"github.com/pkg/errors"
 	"golang.stackrox.io/kube-linter/internal/set"
 	"helm.sh/helm/v3/pkg/chartutil"
+	"k8s.io/apimachinery/pkg/runtime"
 )
 
 var (
 	knownYAMLExtensions = set.NewFrozenStringSet(".yaml", ".yml")
 )
 
+// Options represent values that can be provided to modify how objects are parsed to create lint contexts
+type Options struct {
+	// CustomDecoder allows users to supply a non-default decoder to parse k8s objects. This can be used
+	// to allow the linter to create contexts for k8s custom resources
+	CustomDecoder runtime.Decoder
+}
+
 // CreateContexts creates a context. Each context contains a set of files that should be linted
 // as a group.
 // Currently, each directory of Kube YAML files (or Helm charts) are treated as a separate context.
 // TODO: Figure out if it's useful to allow people to specify that files spanning different directories
 // should be treated as being in the same context.
 func CreateContexts(filesOrDirs ...string) ([]LintContext, error) {
+	return CreateContextsWithOptions(Options{}, filesOrDirs...)
+}
 
+func CreateContextsWithOptions(options Options, filesOrDirs ...string) ([]LintContext, error) {
 	contextsByDir := make(map[string]*lintContextImpl)
 	for _, fileOrDir := range filesOrDirs {
 		// Stdin
@@ -30,6 +41,7 @@ func CreateContexts(filesOrDirs ...string) ([]LintContext, error) {
 				continue
 			}
 			ctx := new()
+			ctx.customDecoder = options.CustomDecoder
 			if err := ctx.loadObjectsFromReader("<standard input>", os.Stdin); err != nil {
 				return nil, err
 			}
@@ -49,6 +61,7 @@ func CreateContexts(filesOrDirs ...string) ([]LintContext, error) {
 			if !info.IsDir() {
 				if strings.HasSuffix(strings.ToLower(currentPath), ".tgz") {
 					ctx := new()
+					ctx.customDecoder = options.CustomDecoder
 					if err := ctx.loadObjectsFromTgzHelmChart(currentPath); err != nil {
 						return err
 					}
@@ -63,6 +76,7 @@ func CreateContexts(filesOrDirs ...string) ([]LintContext, error) {
 					ctx := contextsByDir[dirName]
 					if ctx == nil {
 						ctx = new()
+						ctx.customDecoder = options.CustomDecoder
 						contextsByDir[dirName] = ctx
 					}
 					if err := ctx.loadObjectsFromYAMLFile(currentPath, info); err != nil {
@@ -77,6 +91,7 @@ func CreateContexts(filesOrDirs ...string) ([]LintContext, error) {
 					return nil
 				}
 				ctx := new()
+				ctx.customDecoder = options.CustomDecoder
 				contextsByDir[currentPath] = ctx
 				if err := ctx.loadObjectsFromHelmChart(currentPath); err != nil {
 					return err

pkg/lintcontext/parse_yaml.go

@@ -18,6 +18,7 @@ import (
 	"helm.sh/helm/v3/pkg/cli/values"
 	"helm.sh/helm/v3/pkg/engine"
 	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
 	"k8s.io/apimachinery/pkg/util/yaml"
 	"k8s.io/client-go/kubernetes/scheme"
@@ -34,15 +35,18 @@ var (
 	decoder      = serializer.NewCodecFactory(clientSchema).UniversalDeserializer()
 )
 
-func parseObjects(data []byte) ([]k8sutil.Object, error) {
-	obj, _, err := decoder.Decode(data, nil, nil)
+func parseObjects(data []byte, d runtime.Decoder) ([]k8sutil.Object, error) {
+	if d == nil {
+		d = decoder
+	}
+	obj, _, err := d.Decode(data, nil, nil)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to decode")
 	}
 	if list, ok := obj.(*v1.List); ok {
 		objs := make([]k8sutil.Object, 0, len(list.Items))
 		for i, item := range list.Items {
-			obj, _, err := decoder.Decode(item.Raw, nil, nil)
+			obj, _, err := d.Decode(item.Raw, nil, nil)
 			if err != nil {
 				return nil, errors.Wrapf(err, "decoding item %d in the list", i)
 			}
@@ -197,7 +201,7 @@ func (l *lintContextImpl) loadObjectFromYAMLReader(filePath string, r *yaml.YAML
 		Raw:      doc,
 	}
 
-	objs, err := parseObjects(doc)
+	objs, err := parseObjects(doc, l.customDecoder)
 	if err != nil {
 		l.addInvalidObjects(InvalidObject{
 			Metadata: metadata,