Add Empty and Apply function to HelmValues

pkg/pipes/helmvalues.go

@@ -23,6 +23,8 @@ import (
 	"github.com/thestormforge/konjure/pkg/pipes/internal/strvals"
 	"sigs.k8s.io/kustomize/kyaml/kio"
 	"sigs.k8s.io/kustomize/kyaml/yaml"
+	"sigs.k8s.io/kustomize/kyaml/yaml/merge2"
+	"sigs.k8s.io/kustomize/kyaml/yaml/walk"
 )
 
 // HelmValues is a reader that emits resource nodes representing Helm values.
@@ -40,6 +42,11 @@ type HelmValues struct {
 	FS fs.FS
 }
 
+// Empty returns true if there are no values configured on the this Helm values instance.
+func (r *HelmValues) Empty() bool {
+	return len(r.ValueFiles)+len(r.Values)+len(r.StringValues)+len(r.FileValues) == 0
+}
+
 // AsMap converts the configured user specified values into a map of values.
 func (r *HelmValues) AsMap() (map[string]any, error) {
 	base := map[string]any{}
@@ -112,6 +119,26 @@ func (r *HelmValues) readFile(spec string) (string, error) {
 	return string(data), err
 }
 
+// Apply merges these Helm values into the filtered nodes without a schema.
+func (r *HelmValues) Apply() yaml.Filter {
+	return yaml.FilterFunc(func(node *yaml.RNode) (*yaml.RNode, error) {
+		if r.Empty() {
+			return node, nil
+		}
+
+		w := walk.Walker{
+			Visitor: merge2.Merger{},
+			Sources: []*yaml.RNode{node},
+		}
+		if nodes, err := r.Read(); err != nil {
+			return nil, err
+		} else {
+			w.Sources = append(w.Sources, nodes...)
+		}
+		return w.Walk()
+	})
+}
+
 // MergeMaps is used to combine results from multiple values.
 func (r *HelmValues) MergeMaps(a, b map[string]any) map[string]any {
 	out := make(map[string]any, len(a))

pkg/pipes/helmvalues_test.go

@@ -80,6 +80,25 @@ c: d`),
 	}
 }
 
+func TestHelmValues_Apply(t *testing.T) {
+	nodes, err := (&filters.Pipeline{
+		Inputs: []kio.Reader{
+			&HelmValues{Values: []string{"a=b"}},
+		},
+		Filters: []kio.Filter{
+			kio.FilterAll((&HelmValues{Values: []string{
+				"c.d=e",
+				"a=z",
+			}}).Apply()),
+		},
+	}).Read()
+	assert.NoError(t, err, "failed to apply")
+
+	actual, err := nodes[0].MarshalJSON()
+	assert.NoError(t, err, "failed to produce JSON")
+	assert.JSONEq(t, `{"a":"z","c":{"d":"e"}}`, string(actual))
+}
+
 func TestHelmValues_Flatten(t *testing.T) {
 	flattened, err := (&filters.Pipeline{
 		Inputs: []kio.Reader{