Support JSON configuration output

cmd/gokc/gokc.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"flag"
 	"fmt"
 	"os"
@@ -35,11 +36,15 @@ func init() {
 }
 
 func main() {
-	var filepath string
-	var isVersion bool
+	var (
+		filepath  string
+		isVersion bool
+		printJSON bool
+	)
 	flag.StringVar(&filepath, "f", "/etc/keepalived/keepalived.conf", "keepalived.conf file path")
 	flag.BoolVar(&isVersion, "v", false, "print the version")
 	flag.BoolVar(&log.IsVerbose, "V", false, "verbose log mode")
+	flag.BoolVar(&printJSON, "json", false, "print configuration as json")
 	flag.Parse()
 
 	if isVersion {
@@ -57,14 +62,24 @@ func main() {
 	}
 	defer file.Close()
 
-	if err := parser.Parse(file, filepath); err != nil {
+	result, err := parser.Parse(file, filepath)
+	if err != nil {
 		if e, ok := err.(*parser.Error); ok {
 			msg := colorstring.Color(fmt.Sprintf("[white]%s:%d:%d: [red]%s[reset]", e.Filename, e.Line, e.Column, e.Message))
 			log.Error(msg)
 		} else {
 			log.Error(err)
 		}
 	}
+	log.Debugf("%#v\n", result)
 
-	log.Infof("gokc: the configuration file %s syntax is ok", filepath)
+	if printJSON {
+		j, err := json.Marshal(result)
+		if err != nil {
+			log.Error(err)
+		}
+		fmt.Println(string(j))
+	} else {
+		log.Infof("gokc: the configuration file %s syntax is ok", filepath)
+	}
 }

parser/ast.go

@@ -0,0 +1,50 @@
+package parser
+
+// Token represents the token of the configuration.
+type Token struct {
+	tok      int
+	lit      string
+	filename string
+	line     int
+	column   int
+}
+
+type Configuration struct {
+	Blocks []BlockAny
+}
+
+type BlockAny interface{} //FIXME
+
+type Block struct {
+	name  string // <STRING>: vrrp_script <STRING> { ... }
+	stmts []StmtAny
+}
+
+type BlockArgs struct { // virtual_server <IP ADDRESS> <PORT> { }
+	Name  string    `json:"name"`
+	Args  []string  `json:"args"`
+	Stmts []StmtAny `json:"stmts"`
+}
+
+type SubBlockArgs BlockArgs // real_server <IP ADDRESS> <PORT> { ... }
+
+type StmtAny interface{} //FIXME
+
+type Stmt struct { // state: MASTER
+	Key string `json:"key"`
+	Val Value  `json:"value"`
+}
+
+type StmtMulti struct { // virtual_ipaddress { vips }
+	Key  string  `json:"key"`
+	Vals []Value `json:"values"`
+}
+
+type StmtValue = Value // static_ipaddress { address_options }
+
+type Value interface{}
+
+// VIPAddr represents virtual_ipaddress
+type VIPAddr struct {
+	Addr string `json:"addr"`
+}

parser/json.go

@@ -0,0 +1,21 @@
+package parser
+
+import "encoding/json"
+
+func (conf Configuration) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Blocks []BlockAny `json:"blocks"`
+	}{
+		Blocks: conf.Blocks,
+	})
+}
+
+func (b Block) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Name  string    `json:"name"`
+		Stmts []StmtAny `json:"stmts"`
+	}{
+		Name:  b.name,
+		Stmts: b.stmts,
+	})
+}

parser/lexer.go

@@ -258,7 +258,8 @@ func (t *Tokenizer) NextAll() ([]*Token, error) {
 		}
 
 		result = append(result, &Token{
-			value:    token,
+			tok:      token,
+			lit:      s,
 			filename: t.filename,
 			line:     t.scanner.Line,
 			column:   t.scanner.Column,
@@ -332,17 +333,11 @@ func (t *Tokenizer) scanInclude(rawfilename string) ([]*Token, error) {
 	return result, nil
 }
 
-type Token struct {
-	value    int
-	filename string
-	line     int
-	column   int
-}
-
 type Lexer struct {
 	tokens []*Token
 	pos    int
 	e      error
+	result []BlockAny
 }
 
 type Error struct {
@@ -378,7 +373,8 @@ func (l *Lexer) Lex(lval *yySymType) int {
 		return EOF
 	}
 	token := l.nextToken()
-	return token.value
+	lval.token = *token
+	return token.tok
 }
 
 func (l *Lexer) Error(msg string) {
@@ -391,16 +387,16 @@ func (l *Lexer) Error(msg string) {
 	}
 }
 
-func Parse(src io.Reader, filename string) error {
+func Parse(src io.Reader, filename string) (Configuration, error) {
 	yyErrorVerbose = true
 	t := NewTokenizer(src, filename)
 	tokens, err := t.NextAll()
 	if err != nil {
-		return err
+		return Configuration{}, err
 	}
 	l := NewLexer(tokens)
 	if ret := yyParse(l); ret != 0 {
-		return l.e
+		return Configuration{}, l.e
 	}
-	return l.e
+	return Configuration{Blocks: l.result}, l.e
 }

parser/lexer_test.go

@@ -57,7 +57,7 @@ func TestTokenizer_NextAll(t *testing.T) {
 		}
 		fmt.Printf("%+v", len(tokens))
 		for i, token := range tokens {
-			got, want := token.value, tt.toks[i]
+			got, want := token.tok, tt.toks[i]
 			if got != want {
 				t.Errorf("token got %v, want %v (%v)", got, want, i)
 			}
@@ -67,7 +67,7 @@ func TestTokenizer_NextAll(t *testing.T) {
 
 func TestNewLexer(t *testing.T) {
 	tokens := []*Token{
-		{VRRP_INSTANCE, "dummy.conf", 2, 10},
+		{VRRP_INSTANCE, "vrrp_instance", "dummy.conf", 2, 10},
 	}
 	l := NewLexer(tokens)
 	if !reflect.DeepEqual(l.tokens, tokens) {