Merge pull request #11738 from daizuozhuo/master

pkg/util/jsonpath/doc.go

+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// package jsonpath is a template engine using jsonpath syntax,
+// which can be seen at http://goessner.net/articles/JsonPath/.
+// In addition, it has {range} {end} function to iterate list and slice.
+package jsonpath

pkg/util/jsonpath/jsonpath_test.go

+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package jsonpath
+
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+)
+
+type jsonpathTest struct {
+	name     string
+	template string
+	input    interface{}
+	expect   string
+}
+
+func testJSONPath(tests []jsonpathTest, t *testing.T) {
+	for _, test := range tests {
+		j := New(test.name)
+		err := j.Parse(test.template)
+		if err != nil {
+			t.Errorf("in %s, parse %s error %v", test.name, test.template, err)
+		}
+		buf := new(bytes.Buffer)
+		err = j.Execute(buf, test.input)
+		if err != nil {
+			t.Errorf("in %s, execute error %v", test.name, err)
+		}
+		out := buf.String()
+		if out != test.expect {
+			t.Errorf(`in %s, expect to get "%s", got "%s"`, test.name, test.expect, out)
+		}
+	}
+}
+
+func testFailJSONPath(tests []jsonpathTest, t *testing.T) {
+	for _, test := range tests {
+		j := New(test.name)
+		err := j.Parse(test.template)
+		if err != nil {
+			t.Errorf("in %s, parse %s error %v", test.name, test.template, err)
+		}
+		buf := new(bytes.Buffer)
+		err = j.Execute(buf, test.input)
+		var out string
+		if err == nil {
+			out = "nil"
+		} else {
+			out = err.Error()
+		}
+		if out != test.expect {
+			t.Errorf("in %s, expect to get error %s, got %s", test.name, test.expect, out)
+		}
+	}
+}
+
+func TestStructInput(t *testing.T) {
+	type book struct {
+		Category string
+		Author   string
+		Title    string
+		Price    float32
+	}
+
+	type bicycle struct {
+		Color string
+		Price float32
+	}
+
+	type store struct {
+		Book    []book
+		Bicycle bicycle
+		Name    string
+		Labels  map[string]int
+	}
+
+	storeData := store{
+		Name: "jsonpath",
+		Book: []book{
+			{"reference", "Nigel Rees", "Sayings of the Centurey", 8.95},
+			{"fiction", "Evelyn Waugh", "Sword of Honour", 12.99},
+			{"fiction", "Herman Melville", "Moby Dick", 8.99},
+		},
+		Bicycle: bicycle{"red", 19.95},
+		Labels: map[string]int{
+			"engieer":  10,
+			"web/html": 15,
+			"k8s-app":  20,
+		},
+	}
+
+	storeTests := []jsonpathTest{
+		{"plain", "hello jsonpath", nil, "hello jsonpath"},
+		{"recursive", "{..}", []int{1, 2, 3}, "[1, 2, 3]"},
+		{"filter", "{[?(@<5)]}", []int{2, 6, 3, 7}, "2 3"},
+		{"quote", `{"{"}`, nil, "{"},
+		{"union", "{[1,3,4]}", []int{0, 1, 2, 3, 4}, "1 3 4"},
+		{"array", "{[0:2]}", []string{"Monday", "Tudesday"}, "Monday Tudesday"},
+		{"variable", "hello {.Name}", storeData, "hello jsonpath"},
+		{"dict/", "{.Labels.web/html}", storeData, "15"},
+		{"dict-", "{.Labels.k8s-app}", storeData, "20"},
+		{"nest", "{.Bicycle.Color}", storeData, "red"},
+		{"allarray", "{.Book[*].Author}", storeData, "Nigel Rees Evelyn Waugh Herman Melville"},
+		{"allfileds", "{.Bicycle.*}", storeData, "red 19.95"},
+		{"recurfileds", "{..Price}", storeData, "8.95 12.99 8.99 19.95"},
+		{"lastarray", "{.Book[-1:]}", storeData,
+			"{Category: fiction, Author: Herman Melville, Title: Moby Dick, Price: 8.99}"},
+		{"recurarray", "{..Book[2]}", storeData,
+			"{Category: fiction, Author: Herman Melville, Title: Moby Dick, Price: 8.99}"},
+	}
+	testJSONPath(storeTests, t)
+
+	failStoreTests := []jsonpathTest{
+		{"invalid identfier", "{hello}", storeData, "unrecongnized identifier hello"},
+		{"nonexistent field", "{.hello}", storeData, "hello is not found"},
+		{"invalid array", "{.Labels[0]}", storeData, "<map[string]int Value> is not array or slice"},
+		{"invalid filter operator", "{.Book[?(@.Price<>10)]}", storeData, "unrecognized filter operator <>"},
+		{"redundent end", "{range .Labels.*}{@}{end}{end}", storeData, "not in range, nothing to end"},
+	}
+	testFailJSONPath(failStoreTests, t)
+}
+
+func TestJSONInput(t *testing.T) {
+	var pointsJSON = []byte(`[
+		{"id": "i1", "x":4, "y":-5},
+		{"id": "i2", "x":-2, "y":-5, "z":1},
+		{"id": "i3", "x":  8, "y":  3 },
+		{"id": "i4", "x": -6, "y": -1 },
+		{"id": "i5", "x":  0, "y":  2, "z": 1 },
+		{"id": "i6", "x":  1, "y":  4 }
+	]`)
+	var pointsData interface{}
+	err := json.Unmarshal(pointsJSON, &pointsData)
+	if err != nil {
+		t.Error(err)
+	}
+	pointsTests := []jsonpathTest{
+		{"exists filter", "{[?(@.z)].id}", pointsData, "i2 i5"},
+		{"bracket key", "{[0]['id']}", pointsData, "i1"},
+	}
+	testJSONPath(pointsTests, t)
+}
+
+// TestKubenates tests some use cases from kubenates
+func TestKubenates(t *testing.T) {
+	var input = []byte(`{
+	  "kind": "List",
+	  "items":[
+		{
+		  "kind":"None",
+		  "metadata":{"name":"127.0.0.1"},
+		  "status":{
+			"capacity":{"cpu":"4"},
+			"addresses":[{"type": "LegacyHostIP", "address":"127.0.0.1"}]
+		  }
+		},
+		{
+		  "kind":"None",
+		  "metadata":{"name":"127.0.0.2"},
+		  "status":{
+			"capacity":{"cpu":"8"},
+			"addresses":[
+			  {"type": "LegacyHostIP", "address":"127.0.0.2"},
+			  {"type": "another", "address":"127.0.0.3"}
+			]
+		  }
+		}
+	  ],
+	  "users":[
+	    {
+	      "name": "myself",
+	      "user": {}
+	    },
+	    {
+	      "name": "e2e",
+	      "user": {"username": "admin", "password": "secret"}
+	  	}
+	  ]
+	}`)
+	var nodesData interface{}
+	err := json.Unmarshal(input, &nodesData)
+	if err != nil {
+		t.Error(err)
+	}
+	nodesTests := []jsonpathTest{
+		{"range item", "{range .items[*]}{.metadata.name}, {end}{.kind}", nodesData, `127.0.0.1, 127.0.0.2, List`},
+		{"range addresss", "{.items[*].status.addresses[*].address}", nodesData,
+			`127.0.0.1 127.0.0.2 127.0.0.3`},
+		{"double range", "{range .items[*]}{range .status.addresses[*]}{.address}, {end}{end}", nodesData,
+			`127.0.0.1, 127.0.0.2, 127.0.0.3, `},
+		{"item name", "{.items[*].metadata.name}", nodesData, `127.0.0.1 127.0.0.2`},
+		{"union nodes capacity", "{.items[*]['metadata.name', 'status.capacity']}", nodesData,
+			`127.0.0.1 127.0.0.2 {cpu: 4} {cpu: 8}`},
+		{"range nodes capacity", "{range .items[*]}[{.metadata.name}, {.status.capacity}] {end}", nodesData,
+			`[127.0.0.1, {cpu: 4}] [127.0.0.2, {cpu: 8}] `},
+		{"user password", `{.users[?(@.name=="e2e")].user.password}`, nodesData, "secret"},
+	}
+	testJSONPath(nodesTests, t)
+}

pkg/util/jsonpath/node.go

+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package jsonpath
+
+import "fmt"
+
+// NodeType identifies the type of a parse tree node.
+type NodeType int
+
+// Type returns itself and provides an easy default implementation
+func (t NodeType) Type() NodeType {
+	return t
+}
+
+func (t NodeType) String() string {
+	return NodeTypeName[t]
+}
+
+const (
+	NodeText NodeType = iota
+	NodeArray
+	NodeList
+	NodeField
+	NodeIdentifier
+	NodeFilter
+	NodeInt
+	NodeFloat
+	NodeWildcard
+	NodeRecursive
+	NodeUnion
+)
+
+var NodeTypeName = map[NodeType]string{
+	NodeText:       "NodeText",
+	NodeArray:      "NodeArray",
+	NodeList:       "NodeList",
+	NodeField:      "NodeField",
+	NodeIdentifier: "NodeIdentifier",
+	NodeFilter:     "NodeFilter",
+	NodeInt:        "NodeInt",
+	NodeFloat:      "NodeFloat",
+	NodeWildcard:   "NodeWildcard",
+	NodeRecursive:  "NodeRecursive",
+	NodeUnion:      "NodeUnion",
+}
+
+type Node interface {
+	Type() NodeType
+	String() string
+}
+
+// ListNode holds a sequence of nodes.
+type ListNode struct {
+	NodeType
+	Nodes []Node // The element nodes in lexical order.
+}
+
+func newList() *ListNode {
+	return &ListNode{NodeType: NodeList}
+}
+
+func (l *ListNode) append(n Node) {
+	l.Nodes = append(l.Nodes, n)
+}
+
+func (l *ListNode) String() string {
+	return fmt.Sprintf("%s", l.Type())
+}
+
+// TextNode holds plain text.
+type TextNode struct {
+	NodeType
+	Text []byte // The text; may span newlines.
+}
+
+func newText(text string) *TextNode {
+	return &TextNode{NodeType: NodeText, Text: []byte(text)}
+}
+
+func (t *TextNode) String() string {
+	return fmt.Sprintf("%s: %s", t.Type(), t.Text)
+}
+
+// FieldNode holds filed of struct
+type FieldNode struct {
+	NodeType
+	Value string
+}
+
+func newField(value string) *FieldNode {
+	return &FieldNode{NodeType: NodeField, Value: value}
+}
+
+func (f *FieldNode) String() string {
+	return fmt.Sprintf("%s: %s", f.Type(), f.Value)
+}
+
+// IdentifierNode holds an identifier
+type IdentifierNode struct {
+	NodeType
+	Name string
+}
+
+func newIdentifier(value string) *IdentifierNode {
+	return &IdentifierNode{
+		NodeType: NodeIdentifier,
+		Name:     value,
+	}
+}
+
+func (f *IdentifierNode) String() string {
+	return fmt.Sprintf("%s: %s", f.Type(), f.Name)
+}
+
+// ParamsEntry holds param information for ArrayNode
+type ParamsEntry struct {
+	Value int
+	Known bool //whether the value is known when parse it
+}
+
+// ArrayNode holds start, end, step information for array index selection
+type ArrayNode struct {
+	NodeType
+	Params [3]ParamsEntry //start, end, step
+}
+
+func newArray(params [3]ParamsEntry) *ArrayNode {
+	return &ArrayNode{
+		NodeType: NodeArray,
+		Params:   params,
+	}
+}
+
+func (a *ArrayNode) String() string {
+	return fmt.Sprintf("%s: %v", a.Type(), a.Params)
+}
+
+// FilterNode holds operand and operator information for filter
+type FilterNode struct {
+	NodeType
+	Left     *ListNode
+	Right    *ListNode
+	Operator string
+}
+
+func newFilter(left, right *ListNode, operator string) *FilterNode {
+	return &FilterNode{
+		NodeType: NodeFilter,
+		Left:     left,
+		Right:    right,
+		Operator: operator,
+	}
+}
+
+func (f *FilterNode) String() string {
+	return fmt.Sprintf("%s: %s %s %s", f.Type(), f.Left, f.Operator, f.Right)
+}
+
+// IntNode holds integer value
+type IntNode struct {
+	NodeType
+	Value int
+}
+
+func newInt(num int) *IntNode {
+	return &IntNode{NodeType: NodeInt, Value: num}
+}
+
+func (i *IntNode) String() string {
+	return fmt.Sprintf("%s: %d", i.Type(), i.Value)
+}
+
+// FloatNode holds float value
+type FloatNode struct {
+	NodeType
+	Value float64
+}
+
+func newFloat(num float64) *FloatNode {
+	return &FloatNode{NodeType: NodeFloat, Value: num}
+}
+
+func (i *FloatNode) String() string {
+	return fmt.Sprintf("%s: %f", i.Type(), i.Value)
+}
+
+// WildcardNode means a wildcard
+type WildcardNode struct {
+	NodeType
+}
+
+func newWildcard() *WildcardNode {
+	return &WildcardNode{NodeType: NodeWildcard}
+}
+
+func (i *WildcardNode) String() string {
+	return fmt.Sprintf("%s", i.Type())
+}
+
+// RecursiveNode means a recursive descent operator
+type RecursiveNode struct {
+	NodeType
+}
+
+func newRecursive() *RecursiveNode {
+	return &RecursiveNode{NodeType: NodeRecursive}
+}
+
+func (r *RecursiveNode) String() string {
+	return fmt.Sprintf("%s", r.Type())
+}
+
+// UnionNode is union of ListNode
+type UnionNode struct {
+	NodeType
+	Nodes []*ListNode
+}
+
+func newUnion(nodes []*ListNode) *UnionNode {
+	return &UnionNode{NodeType: NodeUnion, Nodes: nodes}
+}
+
+func (u *UnionNode) String() string {
+	return fmt.Sprintf("%s", u.Type())
+}

pkg/util/jsonpath/parser.go

+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package jsonpath
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+const eof = -1
+
+const (
+	leftDelim  = "{"
+	rightDelim = "}"
+)
+
+type Parser struct {
+	Name  string
+	Root  *ListNode
+	input string
+	cur   *ListNode
+	pos   int
+	start int
+	width int
+}
+
+// Parse parsed the given text and return a node Parser.
+// If an error is encountered, parsing stops and an empty
+// Parser is returned with the error
+func Parse(name, text string) (*Parser, error) {
+	p := NewParser(name)
+	err := p.Parse(text)
+	if err != nil {
+		p = nil
+	}
+	return p, err
+}
+
+func NewParser(name string) *Parser {
+	return &Parser{
+		Name: name,
+	}
+}
+
+// parseAction parsed the expression inside delimiter
+func parseAction(name, text string) (*Parser, error) {
+	p, err := Parse(name, fmt.Sprintf("%s%s%s", leftDelim, text, rightDelim))
+	p.Root = p.Root.Nodes[0].(*ListNode)
+	return p, err
+}
+
+func (p *Parser) Parse(text string) error {
+	p.input = text
+	p.Root = newList()
+	p.pos = 0
+	return p.parseText(p.Root)
+}
+
+// consumeText return the parsed text since last cosumeText
+func (p *Parser) consumeText() string {
+	value := p.input[p.start:p.pos]
+	p.start = p.pos
+	return value
+}
+
+// next returns the next rune in the input.
+func (p *Parser) next() rune {
+	if int(p.pos) >= len(p.input) {
+		p.width = 0
+		return eof
+	}
+	r, w := utf8.DecodeRuneInString(p.input[p.pos:])
+	p.width = w
+	p.pos += p.width
+	return r
+}
+
+// peek returns but does not consume the next rune in the input.
+func (p *Parser) peek() rune {
+	r := p.next()
+	p.backup()
+	return r
+}
+
+// backup steps back one rune. Can only be called once per call of next.
+func (p *Parser) backup() {
+	p.pos -= p.width
+}
+
+func (p *Parser) parseText(cur *ListNode) error {
+	for {
+		if strings.HasPrefix(p.input[p.pos:], leftDelim) {
+			if p.pos > p.start {
+				cur.append(newText(p.consumeText()))
+			}
+			return p.parseLeftDelim(cur)
+		}
+		if p.next() == eof {
+			break
+		}
+	}
+	// Correctly reached EOF.
+	if p.pos > p.start {
+		cur.append(newText(p.consumeText()))
+	}
+	return nil
+}
+
+// parseLeftDelim scans the left delimiter, which is known to be present.
+func (p *Parser) parseLeftDelim(cur *ListNode) error {
+	p.pos += len(leftDelim)
+	p.consumeText()
+	newNode := newList()
+	cur.append(newNode)
+	cur = newNode
+	return p.parseInsideAction(cur)
+}
+
+func (p *Parser) parseInsideAction(cur *ListNode) error {
+	prefixMap := map[string]func(*ListNode) error{
+		rightDelim: p.parseRightDelim,
+		"[?(":      p.parseFilter,
+		"..":       p.parseRecursive,
+	}
+	for prefix, parseFunc := range prefixMap {
+		if strings.HasPrefix(p.input[p.pos:], prefix) {
+			return parseFunc(cur)
+		}
+	}
+
+	switch r := p.next(); {
+	case r == eof || isEndOfLine(r):
+		return fmt.Errorf("unclosed action")
+	case r == ' ':
+		p.consumeText()
+	case r == '@': //the current object, just pass it
+		p.consumeText()
+	case r == '[':
+		return p.parseArray(cur)
+	case r == '"':
+		return p.parseQuote(cur)
+	case r == '.':
+		return p.parseField(cur)
+	case r == '+' || r == '-' || unicode.IsDigit(r):
+		p.backup()
+		return p.parseNumber(cur)
+	case isAlphaNumeric(r):
+		p.backup()
+		return p.parseIdentifier(cur)
+	default:
+		return fmt.Errorf("unrecognized charactor in action: %#U", r)
+	}
+	return p.parseInsideAction(cur)
+}
+
+// parseRightDelim scans the right delimiter, which is known to be present.
+func (p *Parser) parseRightDelim(cur *ListNode) error {
+	p.pos += len(rightDelim)
+	p.consumeText()
+	cur = p.Root
+	return p.parseText(cur)
+}
+
+// parseIdentifier scans build-in keywords, like "range" "end"
+func (p *Parser) parseIdentifier(cur *ListNode) error {
+	var r rune
+	for {
+		r = p.next()
+		if isTerminator(r) {
+			p.backup()
+			break
+		}
+	}
+	value := p.consumeText()
+	cur.append(newIdentifier(value))
+	return p.parseInsideAction(cur)
+}
+
+// parseRecursive scans the recursive desent operator ..
+func (p *Parser) parseRecursive(cur *ListNode) error {
+	p.pos += len("..")
+	p.consumeText()
+	cur.append(newRecursive())
+	if r := p.peek(); isAlphaNumeric(r) {
+		return p.parseField(cur)
+	}
+	return p.parseInsideAction(cur)
+}
+
+// parseNumber scans number
+func (p *Parser) parseNumber(cur *ListNode) error {
+	r := p.peek()
+	if r == '+' || r == '-' {
+		r = p.next()
+	}
+	for {
+		r = p.next()
+		if r != '.' && !unicode.IsDigit(r) {
+			p.backup()
+			break
+		}
+	}
+	value := p.consumeText()
+	i, err := strconv.Atoi(value)
+	if err == nil {
+		cur.append(newInt(i))
+		return p.parseInsideAction(cur)
+	}
+	d, err := strconv.ParseFloat(value, 64)
+	if err == nil {
+		cur.append(newFloat(d))
+		return p.parseInsideAction(cur)
+	}
+	return fmt.Errorf("cannot parse number %s", value)
+}
+
+// parseArray scans array index selection
+func (p *Parser) parseArray(cur *ListNode) error {
+Loop:
+	for {
+		switch p.next() {
+		case eof, '\n':
+			return fmt.Errorf("unterminated array")
+		case ']':
+			break Loop
+		}
+	}
+	text := p.consumeText()
+	text = string(text[1 : len(text)-1])
+	if text == "*" {
+		text = ":"
+	}
+
+	//union operator
+	strs := strings.Split(text, ",")
+	if len(strs) > 1 {
+		union := []*ListNode{}
+		for _, str := range strs {
+			parser, err := parseAction("union", fmt.Sprintf("[%s]", strings.Trim(str, " ")))
+			if err != nil {
+				return err
+			}
+			union = append(union, parser.Root)
+		}
+		cur.append(newUnion(union))
+		return p.parseInsideAction(cur)
+	}
+
+	// dict key
+	reg := regexp.MustCompile(`^'([^']*)'$`)
+	value := reg.FindStringSubmatch(text)
+	if value != nil {
+		parser, err := parseAction("arraydict", fmt.Sprintf(".%s", value[1]))
+		if err != nil {
+			return err
+		}
+		for _, node := range parser.Root.Nodes {
+			cur.append(node)
+		}
+		return p.parseInsideAction(cur)
+	}
+
+	//slice operator
+	reg = regexp.MustCompile(`^(-?[\d]*)(:-?[\d]*)?(:[\d]*)?$`)
+	value = reg.FindStringSubmatch(text)
+	if value == nil {
+		return fmt.Errorf("invalid array index %s", text)
+	}
+	value = value[1:]
+	params := [3]ParamsEntry{}
+	for i := 0; i < 3; i++ {
+		if value[i] != "" {
+			if i > 0 {
+				value[i] = value[i][1:]
+			}
+			if i > 0 && value[i] == "" {
+				params[i].Known = false
+			} else {
+				var err error
+				params[i].Known = true
+				params[i].Value, err = strconv.Atoi(value[i])
+				if err != nil {
+					return fmt.Errorf("array index %s is not a number", params[i].Value)
+				}
+			}
+		} else {
+			if i == 1 {
+				params[i].Known = true
+				params[i].Value = params[0].Value + 1
+			} else {
+				params[i].Known = false
+				params[i].Value = 0
+			}
+		}
+	}
+	cur.append(newArray(params))
+	return p.parseInsideAction(cur)
+}
+
+// parseFilter scans filter inside array selection
+func (p *Parser) parseFilter(cur *ListNode) error {
+	p.pos += len("[?(")
+	p.consumeText()
+Loop:
+	for {
+		switch p.next() {
+		case eof, '\n':
+			return fmt.Errorf("unterminated filter")
+		case ')':
+			break Loop
+		}
+	}
+	if p.next() != ']' {
+		return fmt.Errorf("unclosed array expect ]")
+	}
+	reg := regexp.MustCompile(`^([^!<>=]+)([!<>=]+)(.+?)$`)
+	text := p.consumeText()
+	text = string(text[:len(text)-2])
+	value := reg.FindStringSubmatch(text)
+	if value == nil {
+		parser, err := parseAction("text", text)
+		if err != nil {
+			return err
+		}
+		cur.append(newFilter(parser.Root, newList(), "exists"))
+	} else {
+		leftParser, err := parseAction("left", value[1])
+		if err != nil {
+			return err
+		}
+		rightParser, err := parseAction("right", value[3])
+		if err != nil {
+			return err
+		}
+		cur.append(newFilter(leftParser.Root, rightParser.Root, value[2]))
+	}
+	return p.parseInsideAction(cur)
+}
+
+// parseQuote scans array index selection
+func (p *Parser) parseQuote(cur *ListNode) error {
+Loop:
+	for {
+		switch p.next() {
+		case eof, '\n':
+			return fmt.Errorf("unterminated quoted string")
+		case '"':
+			break Loop
+		}
+	}
+	value := p.consumeText()
+	cur.append(newText(value[1 : len(value)-1]))
+	return p.parseInsideAction(cur)
+}
+
+// parseField scans a field until a terminator
+func (p *Parser) parseField(cur *ListNode) error {
+	p.consumeText()
+	var r rune
+	for {
+		r = p.next()
+		if isTerminator(r) {
+			p.backup()
+			break
+		}
+	}
+	value := p.consumeText()
+	if value == "*" {
+		cur.append(newWildcard())
+	} else {
+		cur.append(newField(value))
+	}
+	return p.parseInsideAction(cur)
+}
+
+// isTerminator reports whether the input is at valid termination character to appear after an identifier.
+func isTerminator(r rune) bool {
+	if isSpace(r) || isEndOfLine(r) {
+		return true
+	}
+	switch r {
+	case eof, '.', ',', '[', ']', '$', '@', '{', '}':
+		return true
+	}
+	return false
+}
+
+// isSpace reports whether r is a space character.
+func isSpace(r rune) bool {
+	return r == ' ' || r == '\t'
+}
+
+// isEndOfLine reports whether r is an end-of-line character.
+func isEndOfLine(r rune) bool {
+	return r == '\r' || r == '\n'
+}
+
+// isAlphaNumeric reports whether r is an alphabetic, digit, or underscore.
+func isAlphaNumeric(r rune) bool {
+	return r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r)
+}

pkg/util/jsonpath/parser_test.go

+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package jsonpath
+
+import (
+	"testing"
+)
+
+type parserTest struct {
+	name  string
+	text  string
+	nodes []Node
+}
+
+var parserTests = []parserTest{
+	{"plain", `hello jsonpath`, []Node{newText("hello jsonpath")}},
+	{"variable", `hello {.jsonpath}`,
+		[]Node{newText("hello "), newList(), newField("jsonpath")}},
+	{"arrayfiled", `hello {['jsonpath']}`,
+		[]Node{newText("hello "), newList(), newField("jsonpath")}},
+	{"quote", `{"{"}`, []Node{newList(), newText("{")}},
+	{"array", `{[1:3]}`, []Node{newList(),
+		newArray([3]ParamsEntry{{1, true}, {3, true}, {0, false}})}},
+	{"allarray", `{.book[*].author}`,
+		[]Node{newList(), newField("book"),
+			newArray([3]ParamsEntry{{0, false}, {0, false}, {0, false}}), newField("author")}},
+	{"wildcard", `{.bicycle.*}`,
+		[]Node{newList(), newField("bicycle"), newWildcard()}},
+	{"filter", `{[?(@.price<3)]}`,
+		[]Node{newList(), newFilter(newList(), newList(), "<"),
+			newList(), newField("price"), newList(), newInt(3)}},
+	{"recursive", `{..}`, []Node{newList(), newRecursive()}},
+	{"recurField", `{..price}`,
+		[]Node{newList(), newRecursive(), newField("price")}},
+	{"arraydict", `{['book.price']}`, []Node{newList(),
+		newField("book"), newField("price"),
+	}},
+	{"union", `{['bicycle.price', 3, 'book.price']}`, []Node{newList(), newUnion([]*ListNode{}),
+		newList(), newField("bicycle"), newField("price"),
+		newList(), newArray([3]ParamsEntry{{3, true}, {4, true}, {0, false}}),
+		newList(), newField("book"), newField("price"),
+	}},
+	{"range", `{range .items}{.name},{end}`, []Node{
+		newList(), newIdentifier("range"), newField("items"),
+		newList(), newField("name"), newText(","),
+		newList(), newIdentifier("end"),
+	}},
+}
+
+func collectNode(nodes []Node, cur Node) []Node {
+	nodes = append(nodes, cur)
+	switch cur.Type() {
+	case NodeList:
+		for _, node := range cur.(*ListNode).Nodes {
+			nodes = collectNode(nodes, node)
+		}
+	case NodeFilter:
+		nodes = collectNode(nodes, cur.(*FilterNode).Left)
+		nodes = collectNode(nodes, cur.(*FilterNode).Right)
+	case NodeUnion:
+		for _, node := range cur.(*UnionNode).Nodes {
+			nodes = collectNode(nodes, node)
+		}
+	}
+	return nodes
+}
+
+func TestParser(t *testing.T) {
+	for _, test := range parserTests {
+		parser, err := Parse(test.name, test.text)
+		if err != nil {
+			t.Errorf("parse %s error %v", test.name, err)
+		}
+		result := collectNode([]Node{}, parser.Root)[1:]
+		if len(result) != len(test.nodes) {
+			t.Errorf("in %s, expect to get %d nodes, got %d nodes", test.name, len(test.nodes), len(result))
+			t.Error(result)
+		}
+		for i, expect := range test.nodes {
+			if result[i].String() != expect.String() {
+				t.Errorf("in %s, %dth node, expect %v, got %v", test.name, i, expect, result[i])
+			}
+		}
+	}
+}
+
+type failParserTest struct {
+	name string
+	text string
+	err  string
+}
+
+func TestFailParser(t *testing.T) {
+	failParserTests := []failParserTest{
+		{"unclosed action", "{.hello", "unclosed action"},
+		{"unrecognized charactor", "{*}", "unrecognized charactor in action: U+002A '*'"},
+		{"invalid number", "{+12.3.0}", "cannot parse number +12.3.0"},
+		{"unterminated array", "{[1}", "unterminated array"},
+		{"invalid index", "{[::-1]}", "invalid array index ::-1"},
+		{"unterminated filter", "{[?(.price]}", "unterminated filter"},
+	}
+	for _, test := range failParserTests {
+		_, err := Parse(test.name, test.text)
+		var out string
+		if err == nil {
+			out = "nil"
+		} else {
+			out = err.Error()
+		}
+		if out != test.err {
+			t.Errorf("in %s, expect to get error %v, got %v", test.name, test.err, out)
+		}
+	}
+}

third_party/golang/template/exec.go

+package template
+import (
+	"reflect"
+	"fmt"
+)
+
+
+var (
+	errorType       = reflect.TypeOf((*error)(nil)).Elem()
+	fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
+)
+
+
+// indirect returns the item at the end of indirection, and a bool to indicate if it's nil.
+// We indirect through pointers and empty interfaces (only) because
+// non-empty interfaces have methods we might need.
+func indirect(v reflect.Value) (rv reflect.Value, isNil bool) {
+	for ; v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface; v = v.Elem() {
+		if v.IsNil() {
+			return v, true
+		}
+		if v.Kind() == reflect.Interface && v.NumMethod() > 0 {
+			break
+		}
+	}
+	return v, false
+}
+
+// printableValue returns the, possibly indirected, interface value inside v that
+// is best for a call to formatted printer.
+func printableValue(v reflect.Value) (interface{}, bool) {
+	if v.Kind() == reflect.Ptr {
+		v, _ = indirect(v) // fmt.Fprint handles nil.
+	}
+	if !v.IsValid() {
+		return "<no value>", true
+	}
+
+	if !v.Type().Implements(errorType) && !v.Type().Implements(fmtStringerType) {
+		if v.CanAddr() && (reflect.PtrTo(v.Type()).Implements(errorType) || reflect.PtrTo(v.Type()).Implements(fmtStringerType)) {
+			v = v.Addr()
+		} else {
+			switch v.Kind() {
+			case reflect.Chan, reflect.Func:
+				return nil, false
+			}
+		}
+	}
+	return v.Interface(), true
+}
+
+// canBeNil reports whether an untyped nil can be assigned to the type. See reflect.Zero.
+func canBeNil(typ reflect.Type) bool {
+	switch typ.Kind() {
+	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
+		return true
+	}
+	return false
+}
+
+// isTrue reports whether the value is 'true', in the sense of not the zero of its type,
+// and whether the value has a meaningful truth value.
+func isTrue(val reflect.Value) (truth, ok bool) {
+	if !val.IsValid() {
+		// Something like var x interface{}, never set. It's a form of nil.
+		return false, true
+	}
+	switch val.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		truth = val.Len() > 0
+	case reflect.Bool:
+		truth = val.Bool()
+	case reflect.Complex64, reflect.Complex128:
+		truth = val.Complex() != 0
+	case reflect.Chan, reflect.Func, reflect.Ptr, reflect.Interface:
+		truth = !val.IsNil()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		truth = val.Int() != 0
+	case reflect.Float32, reflect.Float64:
+		truth = val.Float() != 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		truth = val.Uint() != 0
+	case reflect.Struct:
+		truth = true // Struct values are always true.
+	default:
+		return
+	}
+	return truth, true
+}
\ No newline at end of file