add jsonpath to kubectl

pkg/util/jsonpath/jsonpath.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"io"
 	"reflect"
-	"strconv"
 
 	"k8s.io/kubernetes/third_party/golang/template"
 )
@@ -214,10 +213,9 @@ func (j *JSONPath) evalIdentifier(input []reflect.Value, node *IdentifierNode) (
 func (j *JSONPath) evalArray(input []reflect.Value, node *ArrayNode) ([]reflect.Value, error) {
 	result := []reflect.Value{}
 	for _, value := range input {
-		if value.Kind() == reflect.Interface {
-			value = reflect.ValueOf(value.Interface())
-		}
-		if value.Kind() != reflect.Array && value.Kind() != reflect.Slice {
+
+		value, isNil := template.Indirect(value)
+		if isNil || (value.Kind() != reflect.Array && value.Kind() != reflect.Slice) {
 			return input, fmt.Errorf("%v is not array or slice", value)
 		}
 		params := node.Params
@@ -265,9 +263,11 @@ func (j *JSONPath) evalField(input []reflect.Value, node *FieldNode) ([]reflect.
 	results := []reflect.Value{}
 	for _, value := range input {
 		var result reflect.Value
-		if value.Kind() == reflect.Interface {
-			value = reflect.ValueOf(value.Interface())
+		value, isNil := template.Indirect(value)
+		if isNil {
+			continue
 		}
+
 		if value.Kind() == reflect.Struct {
 			result = value.FieldByName(node.Value)
 		} else if value.Kind() == reflect.Map {
@@ -287,6 +287,11 @@ func (j *JSONPath) evalField(input []reflect.Value, node *FieldNode) ([]reflect.
 func (j *JSONPath) evalWildcard(input []reflect.Value, node *WildcardNode) ([]reflect.Value, error) {
 	results := []reflect.Value{}
 	for _, value := range input {
+		value, isNil := template.Indirect(value)
+		if isNil {
+			continue
+		}
+
 		kind := value.Kind()
 		if kind == reflect.Struct {
 			for i := 0; i < value.NumField(); i++ {
@@ -310,6 +315,11 @@ func (j *JSONPath) evalRecursive(input []reflect.Value, node *RecursiveNode) ([]
 	result := []reflect.Value{}
 	for _, value := range input {
 		results := []reflect.Value{}
+		value, isNil := template.Indirect(value)
+		if isNil {
+			continue
+		}
+
 		kind := value.Kind()
 		if kind == reflect.Struct {
 			for i := 0; i < value.NumField(); i++ {
@@ -340,9 +350,8 @@ func (j *JSONPath) evalRecursive(input []reflect.Value, node *RecursiveNode) ([]
 func (j *JSONPath) evalFilter(input []reflect.Value, node *FilterNode) ([]reflect.Value, error) {
 	results := []reflect.Value{}
 	for _, value := range input {
-		if value.Kind() == reflect.Interface {
-			value = reflect.ValueOf(value.Interface())
-		}
+		value, _ = template.Indirect(value)
+
 		if value.Kind() != reflect.Array && value.Kind() != reflect.Slice {
 			return input, fmt.Errorf("%v is not array or slice", value)
 		}
@@ -407,77 +416,11 @@ func (j *JSONPath) evalFilter(input []reflect.Value, node *FilterNode) ([]reflec
 
 // evalToText translates reflect value to corresponding text
 func (j *JSONPath) evalToText(v reflect.Value) ([]byte, error) {
-	if v.Kind() == reflect.Interface {
-		v = reflect.ValueOf(v.Interface())
+	iface, ok := template.PrintableValue(v)
+	if !ok {
+		return nil, fmt.Errorf("can't print type %s", v.Type())
 	}
 	var buffer bytes.Buffer
-	switch v.Kind() {
-	case reflect.Invalid:
-		//pass
-	case reflect.Ptr:
-		text, err := j.evalToText(reflect.Indirect(v))
-		if err != nil {
-			return nil, err
-		}
-		buffer.Write(text)
-	case reflect.Bool:
-		if variable := v.Bool(); variable {
-			buffer.WriteString("True")
-		} else {
-			buffer.WriteString("False")
-		}
-	case reflect.Float32:
-		buffer.WriteString(strconv.FormatFloat(v.Float(), 'f', -1, 32))
-	case reflect.Float64:
-		buffer.WriteString(strconv.FormatFloat(v.Float(), 'f', -1, 64))
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		buffer.WriteString(strconv.FormatInt(v.Int(), 10))
-	case reflect.String:
-		buffer.WriteString(v.String())
-	case reflect.Array, reflect.Slice:
-		buffer.WriteString("[")
-		for i := 0; i < v.Len(); i++ {
-			text, err := j.evalToText(v.Index(i))
-			if err != nil {
-				return nil, err
-			}
-			buffer.Write(text)
-			if i != v.Len()-1 {
-				buffer.WriteString(", ")
-			}
-		}
-		buffer.WriteString("]")
-	case reflect.Struct:
-		buffer.WriteString("{")
-		for i := 0; i < v.NumField(); i++ {
-			text, err := j.evalToText(v.Field(i))
-			if err != nil {
-				return nil, err
-			}
-			pair := fmt.Sprintf("%s: %s", v.Type().Field(i).Name, text)
-			buffer.WriteString(pair)
-			if i != v.NumField()-1 {
-				buffer.WriteString(", ")
-			}
-		}
-		buffer.WriteString("}")
-	case reflect.Map:
-		buffer.WriteString("{")
-		for i, key := range v.MapKeys() {
-			text, err := j.evalToText(v.MapIndex(key))
-			if err != nil {
-				return nil, err
-			}
-			pair := fmt.Sprintf("%s: %s", key, text)
-			buffer.WriteString(pair)
-			if i != len(v.MapKeys())-1 {
-				buffer.WriteString(", ")
-			}
-		}
-		buffer.WriteString("}")
-
-	default:
-		return nil, fmt.Errorf("%v is not printable", v.Kind())
-	}
+	fmt.Fprint(&buffer, iface)
 	return buffer.Bytes(), nil
 }