traefik/pkg/config/parser/flat_encode.go

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package parser
import (
"fmt"
"reflect"
"sort"
"strconv"
"strings"
"time"
2019-08-03 01:58:23 +00:00
"github.com/containous/traefik/v2/pkg/types"
)
const defaultPtrValue = "false"
// FlatOpts holds options used when encoding to Flat.
type FlatOpts struct {
Case string // "lower" or "upper", defaults to "lower".
Separator string
SkipRoot bool
TagName string
}
// Flat is a configuration item representation.
type Flat struct {
Name string
Description string
Default string
}
// EncodeToFlat encodes a node to a Flat representation.
// Even though the given node argument should have already been augmented with metadata such as kind,
// the element (and its type information) is still needed to treat remaining edge cases.
func EncodeToFlat(element interface{}, node *Node, opts FlatOpts) ([]Flat, error) {
if element == nil || node == nil {
return nil, nil
}
if node.Kind == 0 {
return nil, fmt.Errorf("missing node type: %s", node.Name)
}
elem := reflect.ValueOf(element)
if elem.Kind() == reflect.Struct {
return nil, fmt.Errorf("structs are not supported, use pointer instead")
}
encoder := encoderToFlat{FlatOpts: opts}
var entries []Flat
if encoder.SkipRoot {
for _, child := range node.Children {
field := encoder.getField(elem.Elem(), child)
entries = append(entries, encoder.createFlat(field, child.Name, child)...)
}
} else {
entries = encoder.createFlat(elem, strings.ToLower(node.Name), node)
}
sort.Slice(entries, func(i, j int) bool { return entries[i].Name < entries[j].Name })
return entries, nil
}
type encoderToFlat struct {
FlatOpts
}
func (e encoderToFlat) createFlat(field reflect.Value, name string, node *Node) []Flat {
var entries []Flat
if node.Kind != reflect.Map && node.Description != "-" {
if !(node.Kind == reflect.Ptr && len(node.Children) > 0) ||
(node.Kind == reflect.Ptr && node.Tag.Get(e.TagName) == TagLabelAllowEmpty) {
if node.Name[0] != '[' {
entries = append(entries, Flat{
Name: e.getName(name),
Description: node.Description,
Default: e.getNodeValue(e.getField(field, node), node),
})
}
}
}
for _, child := range node.Children {
if node.Kind == reflect.Map {
fChild := e.getField(field, child)
var v string
if child.Kind == reflect.Struct {
v = defaultPtrValue
} else {
v = e.getNodeValue(fChild, child)
}
if node.Description != "-" {
entries = append(entries, Flat{
Name: e.getName(name, child.Name),
Description: node.Description,
Default: v,
})
}
if child.Kind == reflect.Struct || child.Kind == reflect.Ptr {
for _, ch := range child.Children {
f := e.getField(fChild, ch)
n := e.getName(name, child.Name, ch.Name)
entries = append(entries, e.createFlat(f, n, ch)...)
}
}
} else {
f := e.getField(field, child)
n := e.getName(name, child.Name)
entries = append(entries, e.createFlat(f, n, child)...)
}
}
return entries
}
func (e encoderToFlat) getField(field reflect.Value, node *Node) reflect.Value {
switch field.Kind() {
case reflect.Struct:
return field.FieldByName(node.FieldName)
case reflect.Ptr:
if field.Elem().Kind() == reflect.Struct {
return field.Elem().FieldByName(node.FieldName)
}
return field.Elem()
case reflect.Map:
return field.MapIndex(reflect.ValueOf(node.FieldName))
default:
return field
}
}
func (e encoderToFlat) getNodeValue(field reflect.Value, node *Node) string {
if node.Kind == reflect.Ptr && len(node.Children) > 0 {
return defaultPtrValue
}
if field.Kind() == reflect.Int64 {
i, _ := strconv.ParseInt(node.Value, 10, 64)
switch field.Type() {
case reflect.TypeOf(types.Duration(time.Second)):
return strconv.Itoa(int(i) / int(time.Second))
case reflect.TypeOf(time.Second):
return time.Duration(i).String()
}
}
return node.Value
}
func (e encoderToFlat) getName(names ...string) string {
var name string
if names[len(names)-1][0] == '[' {
name = strings.Join(names, "")
} else {
name = strings.Join(names, e.Separator)
}
if strings.EqualFold(e.Case, "upper") {
return strings.ToUpper(name)
}
return strings.ToLower(name)
}