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|
package config
import (
"fmt"
"os"
"reflect"
"strconv"
"time"
)
func getEnv(key, defaultVal string) string {
if value := os.Getenv(key); value != "" {
return value
}
return defaultVal
}
func getEnvBool(key string, defaultVal bool) bool {
if value := os.Getenv(key); value != "" {
if parsed, err := strconv.ParseBool(value); err == nil {
return parsed
}
}
return defaultVal
}
func getEnvDuration(key string, defaultVal time.Duration) time.Duration {
if value := os.Getenv(key); value != "" {
if parsed, err := time.ParseDuration(value); err == nil {
return parsed
}
}
return defaultVal
}
func getEnvInt64(key string, defaultVal int64) int64 {
if value := os.Getenv(key); value != "" {
if parsed, err := strconv.ParseInt(value, 10, 64); err == nil {
return parsed
}
}
return defaultVal
}
func getEnvFloat64(key string, defaultVal float64) float64 {
if value := os.Getenv(key); value != "" {
if parsed, err := strconv.ParseFloat(value, 64); err == nil {
return parsed
}
}
return defaultVal
}
func setFieldFromEnv(field reflect.Value, envKey, defaultVal string) {
switch field.Kind() {
case reflect.String:
field.SetString(getEnv(envKey, defaultVal))
case reflect.Bool:
defaultBool, _ := strconv.ParseBool(defaultVal)
field.SetBool(getEnvBool(envKey, defaultBool))
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
defaultInt, _ := strconv.ParseInt(defaultVal, 10, 64)
field.SetInt(getEnvInt64(envKey, defaultInt))
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
defaultUint, _ := strconv.ParseUint(defaultVal, 10, 64)
setUintField(field, envKey, defaultUint)
case reflect.Float32, reflect.Float64:
defaultFloat, _ := strconv.ParseFloat(defaultVal, 64)
field.SetFloat(getEnvFloat64(envKey, defaultFloat))
default:
setDurationField(field, envKey, defaultVal)
}
}
func setUintField(field reflect.Value, envKey string, defaultVal uint64) {
if value := os.Getenv(envKey); value != "" {
if parsed, err := strconv.ParseUint(value, 10, 64); err == nil {
field.SetUint(parsed)
return
}
}
field.SetUint(defaultVal)
}
func setDurationField(field reflect.Value, envKey, defaultVal string) {
if field.Type() == reflect.TypeOf(time.Duration(0)) {
defaultDuration, _ := time.ParseDuration(defaultVal)
field.Set(reflect.ValueOf(getEnvDuration(envKey, defaultDuration)))
}
}
func setFieldDefault(field reflect.Value, defaultVal string) {
switch field.Kind() {
case reflect.String:
field.SetString(defaultVal)
case reflect.Bool:
if defaultBool, err := strconv.ParseBool(defaultVal); err == nil {
field.SetBool(defaultBool)
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if defaultInt, err := strconv.ParseInt(defaultVal, 10, 64); err == nil {
field.SetInt(defaultInt)
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if defaultUint, err := strconv.ParseUint(defaultVal, 10, 64); err == nil {
field.SetUint(defaultUint)
}
case reflect.Float32, reflect.Float64:
if defaultFloat, err := strconv.ParseFloat(defaultVal, 64); err == nil {
field.SetFloat(defaultFloat)
}
default:
if field.Type() == reflect.TypeOf(time.Duration(0)) {
if defaultDuration, err := time.ParseDuration(defaultVal); err == nil {
field.Set(reflect.ValueOf(defaultDuration))
}
}
}
}
func validateConfigInput(config any) (reflect.Value, reflect.Type, error) {
v := reflect.ValueOf(config)
if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
return reflect.Value{}, nil, fmt.Errorf("config must be a pointer to struct")
}
elem := v.Elem()
return elem, elem.Type(), nil
}
func Parse(config any) error {
elem, t, err := validateConfigInput(config)
if err != nil {
return err
}
for i := range elem.NumField() {
field := elem.Field(i)
fieldType := t.Field(i)
if !field.CanSet() {
continue
}
envKey := fieldType.Tag.Get("env")
defaultVal := fieldType.Tag.Get("default")
if envKey == "" {
continue
}
setFieldFromEnv(field, envKey, defaultVal)
}
return nil
}
func Defaults[T any](config *T) *T {
v := reflect.ValueOf(config)
if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
return config
}
elem := v.Elem()
t := elem.Type()
newStruct := reflect.New(t)
newElem := newStruct.Elem()
for i := range elem.NumField() {
field := newElem.Field(i)
fieldType := t.Field(i)
if !field.CanSet() {
continue
}
defaultVal := fieldType.Tag.Get("default")
if defaultVal == "" {
continue
}
setFieldDefault(field, defaultVal)
}
return newStruct.Interface().(*T)
}
|
