added new generic parser interface

krm-functions/lib/parser/parser.go

@@ -17,11 +17,218 @@ limitations under the License.
 package parser
 
 import (
+	"fmt"
+
 	"github.com/GoogleContainerTools/kpt-functions-sdk/go/fn"
+	"sigs.k8s.io/yaml"
+)
+
+const (
+	// errors
+	errKubeObjectNotInitialized = "KubeObject not initialized"
 )
 
-type Parser interface {
-	// ParseKubeObject returns a fn sdk KubeObject; if something failed an error
-	// is returned
-	ParseKubeObject() (*fn.KubeObject, error)
+type Parser[T1 any] interface {
+	// GetKubeObject returns the present kubeObject
+	GetKubeObject() *fn.KubeObject
+	// GetGoStruct returns a go struct representing the present KRM resource
+	GetGoStruct() (T1, error)
+	// GetStringValue is a generic utility function that returns a string from
+	// a string slice representing the path in the yaml doc
+	GetStringValue(fields ...string) string
+	// GetIntValue is a generic utility function that returns a int from
+	// a string slice representing the path in the yaml doc
+	GetIntValue(fields ...string) int
+	// GetBoolValue is a generic utility function that returns a bool from
+	// a string slice representing the path in the yaml doc
+	GetBoolValue(fields ...string) bool
+	// GetStringMap is a generic utility function that returns a map[string]string from
+	// a string slice representing the path in the yaml doc
+	GetStringMap(fields ...string) map[string]string
+	// SetNestedString is a generic utility function that sets a string on
+	// a string slice representing the path in the yaml doc
+	SetNestedString(s string, fields ...string) error
+	// SetNestedInt is a generic utility function that sets a int on
+	// a string slice representing the path in the yaml doc
+	SetNestedInt(s int, fields ...string) error
+	// SetNestedBool is a generic utility function that sets a bool on
+	// a string slice representing the path in the yaml doc
+	SetNestedBool(s bool, fields ...string) error
+	// SetNestedMap is a generic utility function that sets a map[string]string on
+	// a string slice representing the path in the yaml doc
+	SetNestedMap(s map[string]string, fields ...string) error
+	// DeleteNestedField is a generic utility function that deletes
+	// a string slice representing the path from the yaml doc
+	DeleteNestedField(fields ...string) error
+}
+
+// NewFromKubeObject creates a new parser interface
+// It expects a *fn.KubeObject as input representing the serialized yaml file
+func NewFromKubeObject[T1 any](o *fn.KubeObject) Parser[T1] {
+	return &obj[T1]{
+		o: o,
+	}
+}
+
+// NewFromYaml creates a new parser interface
+// It expects raw byte slice as input representing the serialized yaml file
+func NewFromYaml[T1 any](b []byte) (Parser[T1], error) {
+	o, err := fn.ParseKubeObject(b)
+	if err != nil {
+		return nil, err
+	}
+	return NewFromKubeObject[T1](o), nil
+}
+
+// NewFromGoStruct creates a new parser interface
+// It expects a go struct representing the interface krm resource
+func NewFromGoStruct[T1 any](x any) (Parser[T1], error) {
+	b, err := yaml.Marshal(x)
+	if err != nil {
+		return nil, err
+	}
+	return NewFromYaml[T1](b)
+}
+
+type obj[T1 any] struct {
+	o *fn.KubeObject
+}
+
+// GetKubeObject returns the present kubeObject
+func (r *obj[T1]) GetKubeObject() *fn.KubeObject {
+	return r.o
+}
+
+// GetGoStruct returns a go struct representing the present KRM resource
+func (r *obj[T1]) GetGoStruct() (T1, error) {
+	var x T1
+	if err := yaml.Unmarshal([]byte(r.o.String()), &x); err != nil {
+		return x, err
+	}
+	return x, nil
+}
+
+// GetStringValue is a generic utility function that returns a string from
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) GetStringValue(fields ...string) string {
+	if r.o == nil {
+		return ""
+	}
+	s, ok, err := r.o.NestedString(fields...)
+	if err != nil {
+		return ""
+	}
+	if !ok {
+		return ""
+	}
+	return s
+}
+
+// GetIntValue is a generic utility function that returns a int from
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) GetIntValue(fields ...string) int {
+	if r.o == nil {
+		return 0
+	}
+	i, ok, err := r.o.NestedInt(fields...)
+	if err != nil {
+		return 0
+	}
+	if !ok {
+		return 0
+	}
+	return i
+}
+
+// GetBoolValue is a generic utility function that returns a bool from
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) GetBoolValue(fields ...string) bool {
+	if r.o == nil {
+		return false
+	}
+	b, ok, err := r.o.NestedBool(fields...)
+	if err != nil {
+		return false
+	}
+	if !ok {
+		return false
+	}
+	return b
+}
+
+// GetStringMap is a generic utility function that returns a map[string]string from
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) GetStringMap(fields ...string) map[string]string {
+	if r.o == nil {
+		return map[string]string{}
+	}
+	m, ok, err := r.o.NestedStringMap(fields...)
+	if err != nil {
+		return map[string]string{}
+	}
+	if !ok {
+		return map[string]string{}
+	}
+	return m
+}
+
+// SetNestedString is a generic utility function that sets a string on
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) SetNestedString(s string, fields ...string) error {
+	if r.o == nil {
+		return fmt.Errorf(errKubeObjectNotInitialized)
+	}
+	if err := r.o.SetNestedField(s, fields...); err != nil {
+		return err
+	}
+	return nil
+}
+
+// SetNestedInt is a generic utility function that sets a int on
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) SetNestedInt(s int, fields ...string) error {
+	if r.o == nil {
+		return fmt.Errorf(errKubeObjectNotInitialized)
+	}
+	if err := r.o.SetNestedInt(s, fields...); err != nil {
+		return err
+	}
+	return nil
+}
+
+// SetNestedBool is a generic utility function that sets a bool on
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) SetNestedBool(s bool, fields ...string) error {
+	if r.o == nil {
+		return fmt.Errorf(errKubeObjectNotInitialized)
+	}
+	if err := r.o.SetNestedBool(s, fields...); err != nil {
+		return err
+	}
+	return nil
+}
+
+// SetNestedMap is a generic utility function that sets a map[string]string on
+// a string slice representing the path in the yaml doc
+func (r *obj[T1]) SetNestedMap(s map[string]string, fields ...string) error {
+	if r.o == nil {
+		return fmt.Errorf(errKubeObjectNotInitialized)
+	}
+	if err := r.o.SetNestedStringMap(s, fields...); err != nil {
+		return err
+	}
+	return nil
+}
+
+// DeleteNestedField is a generic utility function that deletes
+// a string slice representing the path from the yaml doc
+func (r *obj[T1]) DeleteNestedField(fields ...string) error {
+	if r.o == nil {
+		return fmt.Errorf(errKubeObjectNotInitialized)
+	}
+	_, err := r.o.RemoveNestedField(fields...)
+	if err != nil {
+		return err
+	}
+	return nil
 }