cloudinit/config/config.go
Alex Crawford 667dbd8fb7 update: refactor config
- Explicitly specify all of the valid options for Update
- Seperate the config from File() and Units()
- Add YAML tags for the fields
2014-09-23 17:57:43 -07:00

67 lines
1.5 KiB
Go

package config
import (
"fmt"
"reflect"
"strings"
)
// IsZero returns whether or not the parameter is the zero value for its type.
// If the parameter is a struct, only the exported fields are considered.
func IsZero(c interface{}) bool {
return isZero(reflect.ValueOf(c))
}
// AssertValid checks the fields in the structure and makes sure that they
// contain valid values as specified by the 'valid' flag. Empty fields are
// implicitly valid.
func AssertValid(c interface{}) error {
ct := reflect.TypeOf(c)
cv := reflect.ValueOf(c)
for i := 0; i < ct.NumField(); i++ {
ft := ct.Field(i)
if !isFieldExported(ft) {
continue
}
valid := ft.Tag.Get("valid")
val := cv.Field(i)
if !isValid(val, valid) {
return fmt.Errorf("invalid value \"%v\" for option %q (valid options: %q)", val.Interface(), ft.Name, valid)
}
}
return nil
}
func isZero(v reflect.Value) bool {
switch v.Kind() {
case reflect.Struct:
vt := v.Type()
for i := 0; i < v.NumField(); i++ {
if isFieldExported(vt.Field(i)) && !isZero(v.Field(i)) {
return false
}
}
return true
default:
return v.Interface() == reflect.Zero(v.Type()).Interface()
}
}
func isFieldExported(f reflect.StructField) bool {
return f.PkgPath == ""
}
func isValid(v reflect.Value, valid string) bool {
if valid == "" || isZero(v) {
return true
}
vs := fmt.Sprintf("%v", v.Interface())
for _, valid := range strings.Split(valid, ",") {
if vs == valid {
return true
}
}
return false
}