/
options.go
163 lines (140 loc) · 3.6 KB
/
options.go
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// Copyright CZ. All rights reserved.
// Author: CZ cz.theng@gmail.com
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file
package options
import (
"errors"
"flag"
"fmt"
"os"
"reflect"
"github.com/BurntSushi/toml"
)
var (
errUnknownStrconvType = errors.New("no a basic type of strconv")
)
const (
configHelp string = "path for config file"
helpHelp string = " for help document"
)
// Parse will parse flag and read config file to option with default values
func Parse(options interface{}) (err error) {
err = parseDefaultValues(options)
if err != nil {
err = fmt.Errorf("parse default value:%w", err)
fmt.Printf("[ERROR]:%s", err.Error())
return err
}
//fmt.Printf("parseDefaultValues:%v\n", options)
err = parseConfigFile(options)
if err != nil {
err = fmt.Errorf("parse config file: %w", err)
fmt.Printf("[ERROR]:%s", err.Error())
return err
}
//fmt.Printf("parseConfigFile:%v\n", options)
err = parseFlags(options)
if err != nil {
err = fmt.Errorf("parse flags:%w", err)
fmt.Printf("[ERROR]:%s", err.Error())
return err
}
//fmt.Printf("parseFlags:%v\n", options)
return nil
}
func parseDefaultValues(options interface{}) (err error) {
val := reflect.ValueOf(options).Elem()
typ := val.Type()
for i := 0; i < typ.NumField(); i++ {
field := typ.Field(i)
dval := field.Tag.Get("default")
fieldVal := val.FieldByName(field.Name)
v, err := strconvParse(dval, fieldVal.Type())
if err != nil {
// Recursively resolve embedded types.
var fieldPtr reflect.Value
fmt.Printf("fieldVal:%v Elem:\n", fieldVal.Type())
if fieldVal.Type().Kind() == reflect.Struct {
fieldPtr = fieldVal.Addr()
if !fieldPtr.IsNil() {
err = parseDefaultValues(fieldPtr.Interface())
}
}
continue
}
fieldVal.Set(reflect.ValueOf(v))
}
return nil
}
func parseConfigFile(options interface{}) (err error) {
configFilePath := ""
if len(os.Args) < 3 {
return nil
}
for i := 1; i < len(os.Args[1:]); i++ {
if os.Args[i] == "-c" || os.Args[i] == "--config" || os.Args[i] == "-config" {
i++
configFilePath = os.Args[i]
}
}
if configFilePath == "" {
return nil
}
_, err = toml.DecodeFile(configFilePath, options)
if err != nil {
return err
}
return nil
}
func parseFlags(options interface{}) (err error) {
val := reflect.ValueOf(options).Elem()
typ := val.Type()
fs := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
var args []string = make([]string, len(os.Args))
if len(os.Args) > 2 {
j := 0
for i := 1; i < len(os.Args); i++ {
if os.Args[i] == "-c" || os.Args[i] == "--config" || os.Args[i] == "-config" {
i++
continue
}
args[j] = os.Args[i]
j++
}
} else {
copy(args, os.Args)
}
// for fake parse to build all the FlagSet.formal map[string]*Flag
for i := 0; i < typ.NumField(); i++ {
field := typ.Field(i)
flagHelp := field.Tag.Get("help")
dval := field.Tag.Get("default")
flagKey := field.Tag.Get("flag")
if flagKey != "" {
fs.String(flagKey, dval, flagHelp)
}
sflagKey := field.Tag.Get("sflag")
if sflagKey != "" {
fs.String(sflagKey, dval, flagHelp)
}
}
fs.Parse(args)
// build option from Flag in FlagSet.formal
for i := 0; i < typ.NumField(); i++ {
field := typ.Field(i)
flagKey := field.Tag.Get("flag")
sflagKey := field.Tag.Get("sflag")
if flagKey == "" && sflagKey == "" {
continue
}
fieldVal := val.FieldByName(field.Name)
fs.Visit(func(f *flag.Flag) {
if f.Name == flagKey || f.Name == sflagKey {
sv, _ := strconvParse(f.Value.String(), fieldVal.Type())
fieldVal.Set(reflect.ValueOf(sv))
}
})
}
return nil
}