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parse.go
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parse.go
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// Copyright 2013-2018 The NATS Authors
// 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 conf supports a configuration file format used by gnatsd. It is
// a flexible format that combines the best of traditional
// configuration formats and newer styles such as JSON and YAML.
package conf
// The format supported is less restrictive than today's formats.
// Supports mixed Arrays [], nested Maps {}, multiple comment types (# and //)
// Also supports key value assignments using '=' or ':' or whiteSpace()
// e.g. foo = 2, foo : 2, foo 2
// maps can be assigned with no key separator as well
// semicolons as value terminators in key/value assignments are optional
//
// see parse_test.go for more examples.
import (
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
"time"
"unicode"
)
type parser struct {
mapping map[string]interface{}
lx *lexer
// The current scoped context, can be array or map
ctx interface{}
// stack of contexts, either map or array/slice stack
ctxs []interface{}
// Keys stack
keys []string
// Keys stack as items
ikeys []item
// The config file path, empty by default.
fp string
// pedantic reports error when configuration is not correct.
pedantic bool
}
// Parse will return a map of keys to interface{}, although concrete types
// underly them. The values supported are string, bool, int64, float64, DateTime.
// Arrays and nested Maps are also supported.
func Parse(data string) (map[string]interface{}, error) {
p, err := parse(data, "", false)
if err != nil {
return nil, err
}
return p.mapping, nil
}
// ParseFile is a helper to open file, etc. and parse the contents.
func ParseFile(fp string) (map[string]interface{}, error) {
data, err := os.ReadFile(fp)
if err != nil {
return nil, fmt.Errorf("error opening config file: %v", err)
}
p, err := parse(string(data), fp, false)
if err != nil {
return nil, err
}
return p.mapping, nil
}
// ParseFileWithChecks is equivalent to ParseFile but runs in pedantic mode.
func ParseFileWithChecks(fp string) (map[string]interface{}, error) {
data, err := os.ReadFile(fp)
if err != nil {
return nil, err
}
p, err := parse(string(data), fp, true)
if err != nil {
return nil, err
}
return p.mapping, nil
}
type token struct {
item item
value interface{}
usedVariable bool
sourceFile string
}
func (t *token) Value() interface{} {
return t.value
}
func (t *token) Line() int {
return t.item.line
}
func (t *token) IsUsedVariable() bool {
return t.usedVariable
}
func (t *token) SourceFile() string {
return t.sourceFile
}
func (t *token) Position() int {
return t.item.pos
}
func parse(data, fp string, pedantic bool) (p *parser, err error) {
p = &parser{
mapping: make(map[string]interface{}),
lx: lex(data),
ctxs: make([]interface{}, 0, 4),
keys: make([]string, 0, 4),
ikeys: make([]item, 0, 4),
fp: filepath.Dir(fp),
pedantic: pedantic,
}
p.pushContext(p.mapping)
var prevItem item
for {
it := p.next()
if it.typ == itemEOF {
// Here we allow the final character to be a bracket '}'
// in order to support JSON like configurations.
if prevItem.typ == itemKey && prevItem.val != mapEndString {
return nil, fmt.Errorf("config is invalid (%s:%d:%d)", fp, it.line, it.pos)
}
break
}
prevItem = it
if err := p.processItem(it, fp); err != nil {
return nil, err
}
}
return p, nil
}
func (p *parser) next() item {
return p.lx.nextItem()
}
func (p *parser) pushContext(ctx interface{}) {
p.ctxs = append(p.ctxs, ctx)
p.ctx = ctx
}
func (p *parser) popContext() interface{} {
if len(p.ctxs) == 0 {
panic("BUG in parser, context stack empty")
}
li := len(p.ctxs) - 1
last := p.ctxs[li]
p.ctxs = p.ctxs[0:li]
p.ctx = p.ctxs[len(p.ctxs)-1]
return last
}
func (p *parser) pushKey(key string) {
p.keys = append(p.keys, key)
}
func (p *parser) popKey() string {
if len(p.keys) == 0 {
panic("BUG in parser, keys stack empty")
}
li := len(p.keys) - 1
last := p.keys[li]
p.keys = p.keys[0:li]
return last
}
func (p *parser) pushItemKey(key item) {
p.ikeys = append(p.ikeys, key)
}
func (p *parser) popItemKey() item {
if len(p.ikeys) == 0 {
panic("BUG in parser, item keys stack empty")
}
li := len(p.ikeys) - 1
last := p.ikeys[li]
p.ikeys = p.ikeys[0:li]
return last
}
func (p *parser) processItem(it item, fp string) error {
setValue := func(it item, v interface{}) {
if p.pedantic {
p.setValue(&token{it, v, false, fp})
} else {
p.setValue(v)
}
}
switch it.typ {
case itemError:
return fmt.Errorf("Parse error on line %d: '%s'", it.line, it.val)
case itemKey:
// Keep track of the keys as items and strings,
// we do this in order to be able to still support
// includes without many breaking changes.
p.pushKey(it.val)
if p.pedantic {
p.pushItemKey(it)
}
case itemMapStart:
newCtx := make(map[string]interface{})
p.pushContext(newCtx)
case itemMapEnd:
setValue(it, p.popContext())
case itemString:
// FIXME(dlc) sanitize string?
setValue(it, it.val)
case itemInteger:
lastDigit := 0
for _, r := range it.val {
if !unicode.IsDigit(r) && r != '-' {
break
}
lastDigit++
}
numStr := it.val[:lastDigit]
num, err := strconv.ParseInt(numStr, 10, 64)
if err != nil {
if e, ok := err.(*strconv.NumError); ok &&
e.Err == strconv.ErrRange {
return fmt.Errorf("integer '%s' is out of the range", it.val)
}
return fmt.Errorf("expected integer, but got '%s'", it.val)
}
// Process a suffix
suffix := strings.ToLower(strings.TrimSpace(it.val[lastDigit:]))
switch suffix {
case "":
setValue(it, num)
case "k":
setValue(it, num*1000)
case "kb", "ki", "kib":
setValue(it, num*1024)
case "m":
setValue(it, num*1000*1000)
case "mb", "mi", "mib":
setValue(it, num*1024*1024)
case "g":
setValue(it, num*1000*1000*1000)
case "gb", "gi", "gib":
setValue(it, num*1024*1024*1024)
case "t":
setValue(it, num*1000*1000*1000*1000)
case "tb", "ti", "tib":
setValue(it, num*1024*1024*1024*1024)
case "p":
setValue(it, num*1000*1000*1000*1000*1000)
case "pb", "pi", "pib":
setValue(it, num*1024*1024*1024*1024*1024)
case "e":
setValue(it, num*1000*1000*1000*1000*1000*1000)
case "eb", "ei", "eib":
setValue(it, num*1024*1024*1024*1024*1024*1024)
}
case itemFloat:
num, err := strconv.ParseFloat(it.val, 64)
if err != nil {
if e, ok := err.(*strconv.NumError); ok &&
e.Err == strconv.ErrRange {
return fmt.Errorf("float '%s' is out of the range", it.val)
}
return fmt.Errorf("expected float, but got '%s'", it.val)
}
setValue(it, num)
case itemBool:
switch strings.ToLower(it.val) {
case "true", "yes", "on":
setValue(it, true)
case "false", "no", "off":
setValue(it, false)
default:
return fmt.Errorf("expected boolean value, but got '%s'", it.val)
}
case itemDatetime:
dt, err := time.Parse("2006-01-02T15:04:05Z", it.val)
if err != nil {
return fmt.Errorf(
"expected Zulu formatted DateTime, but got '%s'", it.val)
}
setValue(it, dt)
case itemArrayStart:
var array = make([]interface{}, 0)
p.pushContext(array)
case itemArrayEnd:
array := p.ctx
p.popContext()
setValue(it, array)
case itemVariable:
value, found, err := p.lookupVariable(it.val)
if err != nil {
return fmt.Errorf("variable reference for '%s' on line %d could not be parsed: %s",
it.val, it.line, err)
}
if !found {
return fmt.Errorf("variable reference for '%s' on line %d can not be found",
it.val, it.line)
}
if p.pedantic {
switch tk := value.(type) {
case *token:
// Mark the looked up variable as used, and make
// the variable reference become handled as a token.
tk.usedVariable = true
p.setValue(&token{it, tk.Value(), false, fp})
default:
// Special case to add position context to bcrypt references.
p.setValue(&token{it, value, false, fp})
}
} else {
p.setValue(value)
}
case itemInclude:
var (
m map[string]interface{}
err error
)
if p.pedantic {
m, err = ParseFileWithChecks(filepath.Join(p.fp, it.val))
} else {
m, err = ParseFile(filepath.Join(p.fp, it.val))
}
if err != nil {
return fmt.Errorf("error parsing include file '%s', %v", it.val, err)
}
for k, v := range m {
p.pushKey(k)
if p.pedantic {
switch tk := v.(type) {
case *token:
p.pushItemKey(tk.item)
}
}
p.setValue(v)
}
}
return nil
}
// Used to map an environment value into a temporary map to pass to secondary Parse call.
const pkey = "pk"
// We special case raw strings here that are bcrypt'd. This allows us not to force quoting the strings
const bcryptPrefix = "2a$"
// lookupVariable will lookup a variable reference. It will use block scoping on keys
// it has seen before, with the top level scoping being the environment variables. We
// ignore array contexts and only process the map contexts..
//
// Returns true for ok if it finds something, similar to map.
func (p *parser) lookupVariable(varReference string) (interface{}, bool, error) {
// Do special check to see if it is a raw bcrypt string.
if strings.HasPrefix(varReference, bcryptPrefix) {
return "$" + varReference, true, nil
}
// Loop through contexts currently on the stack.
for i := len(p.ctxs) - 1; i >= 0; i-- {
ctx := p.ctxs[i]
// Process if it is a map context
if m, ok := ctx.(map[string]interface{}); ok {
if v, ok := m[varReference]; ok {
return v, ok, nil
}
}
}
// If we are here, we have exhausted our context maps and still not found anything.
// Parse from the environment.
if vStr, ok := os.LookupEnv(varReference); ok {
// Everything we get here will be a string value, so we need to process as a parser would.
if vmap, err := Parse(fmt.Sprintf("%s=%s", pkey, vStr)); err == nil {
v, ok := vmap[pkey]
return v, ok, nil
} else {
return nil, false, err
}
}
return nil, false, nil
}
func (p *parser) setValue(val interface{}) {
// Test to see if we are on an array or a map
// Array processing
if ctx, ok := p.ctx.([]interface{}); ok {
p.ctx = append(ctx, val)
p.ctxs[len(p.ctxs)-1] = p.ctx
}
// Map processing
if ctx, ok := p.ctx.(map[string]interface{}); ok {
key := p.popKey()
if p.pedantic {
// Change the position to the beginning of the key
// since more useful when reporting errors.
switch v := val.(type) {
case *token:
it := p.popItemKey()
v.item.pos = it.pos
v.item.line = it.line
ctx[key] = v
}
} else {
// FIXME(dlc), make sure to error if redefining same key?
ctx[key] = val
}
}
}