Beego/core/config/config.go

// Copyright 2014 beego Author. All Rights Reserved.
//
// 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 config is used to parse config.
// Usage:
//  import "github.com/astaxie/beego/config"
// Examples.
//
//  cnf, err := config.NewConfig("ini", "config.conf")
//
//  cnf APIS:
//
//  cnf.Set(key, val string) error
//  cnf.String(key string) string
//  cnf.Strings(key string) []string
//  cnf.Int(key string) (int, error)
//  cnf.Int64(key string) (int64, error)
//  cnf.Bool(key string) (bool, error)
//  cnf.Float(key string) (float64, error)
//  cnf.DefaultString(key string, defaultVal string) string
//  cnf.DefaultStrings(key string, defaultVal []string) []string
//  cnf.DefaultInt(key string, defaultVal int) int
//  cnf.DefaultInt64(key string, defaultVal int64) int64
//  cnf.DefaultBool(key string, defaultVal bool) bool
//  cnf.DefaultFloat(key string, defaultVal float64) float64
//  cnf.DIY(key string) (interface{}, error)
//  cnf.GetSection(section string) (map[string]string, error)
//  cnf.SaveConfigFile(filename string) error
// More docs http://beego.me/docs/module/config.md
package config

import (
	"context"
	"errors"
	"fmt"
	"os"
	"reflect"
	"strconv"
	"strings"
	"time"
)

// Configer defines how to get and set value from configuration raw data.
type Configer interface {
	// support section::key type in given key when using ini type.
	Set(ctx context.Context, key, val string) error

	// support section::key type in key string when using ini and json type; Int,Int64,Bool,Float,DIY are same.
	String(ctx context.Context, key string) (string, error)
	// get string slice
	Strings(ctx context.Context, key string) ([]string, error)
	Int(ctx context.Context, key string) (int, error)
	Int64(ctx context.Context, key string) (int64, error)
	Bool(ctx context.Context, key string) (bool, error)
	Float(ctx context.Context, key string) (float64, error)
	// support section::key type in key string when using ini and json type; Int,Int64,Bool,Float,DIY are same.
	DefaultString(ctx context.Context, key string, defaultVal string) string
	// get string slice
	DefaultStrings(ctx context.Context, key string, defaultVal []string) []string
	DefaultInt(ctx context.Context, key string, defaultVal int) int
	DefaultInt64(ctx context.Context, key string, defaultVal int64) int64
	DefaultBool(ctx context.Context, key string, defaultVal bool) bool
	DefaultFloat(ctx context.Context, key string, defaultVal float64) float64
	DIY(ctx context.Context, key string) (interface{}, error)

	GetSection(ctx context.Context, section string) (map[string]string, error)

	Unmarshaler(ctx context.Context, prefix string, obj interface{}, opt ...DecodeOption) error
	Sub(ctx context.Context, key string) (Configer, error)
	OnChange(ctx context.Context, key string, fn func(value string))
	SaveConfigFile(ctx context.Context, filename string) error
}

type BaseConfiger struct {
	// The reader should support key like "a.b.c"
	reader func(ctx context.Context, key string) (string, error)
}

func NewBaseConfiger(reader func(ctx context.Context, key string) (string, error)) BaseConfiger {
	return BaseConfiger{
		reader: reader,
	}
}

func (c *BaseConfiger) Int(ctx context.Context, key string) (int, error) {
	res, err := c.reader(context.TODO(), key)
	if err != nil {
		return 0, err
	}
	return strconv.Atoi(res)
}

func (c *BaseConfiger) Int64(ctx context.Context, key string) (int64, error) {
	res, err := c.reader(context.TODO(), key)
	if err != nil {
		return 0, err
	}
	return strconv.ParseInt(res, 10, 64)
}

func (c *BaseConfiger) Bool(ctx context.Context, key string) (bool, error) {
	res, err := c.reader(context.TODO(), key)
	if err != nil {
		return false, err
	}
	return ParseBool(res)
}

func (c *BaseConfiger) Float(ctx context.Context, key string) (float64, error) {
	res, err := c.reader(context.TODO(), key)
	if err != nil {
		return 0, err
	}
	return strconv.ParseFloat(res, 64)
}

// DefaultString returns the string value for a given key.
// if err != nil or value is empty return defaultval
func (c *BaseConfiger) DefaultString(ctx context.Context, key string, defaultVal string) string {
	if res, err := c.String(ctx, key); res != "" && err == nil {
		return res
	}
	return defaultVal
}

// DefaultStrings returns the []string value for a given key.
// if err != nil return defaultval
func (c *BaseConfiger) DefaultStrings(ctx context.Context, key string, defaultVal []string) []string {
	if res, err := c.Strings(ctx, key); len(res) > 0 && err == nil {
		return res
	}
	return defaultVal
}

func (c *BaseConfiger) DefaultInt(ctx context.Context, key string, defaultVal int) int {
	if res, err := c.Int(ctx, key); err == nil {
		return res
	}
	return defaultVal
}

func (c *BaseConfiger) DefaultInt64(ctx context.Context, key string, defaultVal int64) int64 {
	if res, err := c.Int64(ctx, key); err == nil {
		return res
	}
	return defaultVal
}

func (c *BaseConfiger) DefaultBool(ctx context.Context, key string, defaultVal bool) bool {
	if res, err := c.Bool(ctx, key); err == nil {
		return res
	}
	return defaultVal
}
func (c *BaseConfiger) DefaultFloat(ctx context.Context, key string, defaultVal float64) float64 {
	if res, err := c.Float(ctx, key); err == nil {
		return res
	}
	return defaultVal
}

func (c *BaseConfiger) String(ctx context.Context, key string) (string, error) {
	return c.reader(context.TODO(), key)
}

// Strings returns the []string value for a given key.
// Return nil if config value does not exist or is empty.
func (c *BaseConfiger) Strings(ctx context.Context, key string) ([]string, error) {
	res, err := c.String(nil, key)
	if err != nil || res == "" {
		return nil, err
	}
	return strings.Split(res, ";"), nil
}

func (c *BaseConfiger) Unmarshaler(ctx context.Context, prefix string, obj interface{}, opt ...DecodeOption) error {
	return errors.New("unsupported operation")
}

func (c *BaseConfiger) Sub(ctx context.Context, key string) (Configer, error) {
	return nil, errors.New("unsupported operation")
}

func (c *BaseConfiger) OnChange(ctx context.Context, key string, fn func(value string)) {
	// do nothing
}

// Config is the adapter interface for parsing config file to get raw data to Configer.
type Config interface {
	Parse(key string) (Configer, error)
	ParseData(data []byte) (Configer, error)
}

var adapters = make(map[string]Config)

// Register makes a config adapter available by the adapter name.
// If Register is called twice with the same name or if driver is nil,
// it panics.
func Register(name string, adapter Config) {
	if adapter == nil {
		panic("config: Register adapter is nil")
	}
	if _, ok := adapters[name]; ok {
		panic("config: Register called twice for adapter " + name)
	}
	adapters[name] = adapter
}

// NewConfig adapterName is ini/json/xml/yaml.
// filename is the config file path.
func NewConfig(adapterName, filename string) (Configer, error) {
	adapter, ok := adapters[adapterName]
	if !ok {
		return nil, fmt.Errorf("config: unknown adaptername %q (forgotten import?)", adapterName)
	}
	return adapter.Parse(filename)
}

// NewConfigData adapterName is ini/json/xml/yaml.
// data is the config data.
func NewConfigData(adapterName string, data []byte) (Configer, error) {
	adapter, ok := adapters[adapterName]
	if !ok {
		return nil, fmt.Errorf("config: unknown adaptername %q (forgotten import?)", adapterName)
	}
	return adapter.ParseData(data)
}

// ExpandValueEnvForMap convert all string value with environment variable.
func ExpandValueEnvForMap(m map[string]interface{}) map[string]interface{} {
	for k, v := range m {
		switch value := v.(type) {
		case string:
			m[k] = ExpandValueEnv(value)
		case map[string]interface{}:
			m[k] = ExpandValueEnvForMap(value)
		case map[string]string:
			for k2, v2 := range value {
				value[k2] = ExpandValueEnv(v2)
			}
			m[k] = value
		}
	}
	return m
}

// ExpandValueEnv returns value of convert with environment variable.
//
// Return environment variable if value start with "${" and end with "}".
// Return default value if environment variable is empty or not exist.
//
// It accept value formats "${env}" , "${env||}}" , "${env||defaultValue}" , "defaultvalue".
// Examples:
//	v1 := config.ExpandValueEnv("${GOPATH}")			// return the GOPATH environment variable.
//	v2 := config.ExpandValueEnv("${GOAsta||/usr/local/go}")	// return the default value "/usr/local/go/".
//	v3 := config.ExpandValueEnv("Astaxie")				// return the value "Astaxie".
func ExpandValueEnv(value string) (realValue string) {
	realValue = value

	vLen := len(value)
	// 3 = ${}
	if vLen < 3 {
		return
	}
	// Need start with "${" and end with "}", then return.
	if value[0] != '$' || value[1] != '{' || value[vLen-1] != '}' {
		return
	}

	key := ""
	defaultV := ""
	// value start with "${"
	for i := 2; i < vLen; i++ {
		if value[i] == '|' && (i+1 < vLen && value[i+1] == '|') {
			key = value[2:i]
			defaultV = value[i+2 : vLen-1] // other string is default value.
			break
		} else if value[i] == '}' {
			key = value[2:i]
			break
		}
	}

	realValue = os.Getenv(key)
	if realValue == "" {
		realValue = defaultV
	}

	return
}

// ParseBool returns the boolean value represented by the string.
//
// It accepts 1, 1.0, t, T, TRUE, true, True, YES, yes, Yes,Y, y, ON, on, On,
// 0, 0.0, f, F, FALSE, false, False, NO, no, No, N,n, OFF, off, Off.
// Any other value returns an error.
func ParseBool(val interface{}) (value bool, err error) {
	if val != nil {
		switch v := val.(type) {
		case bool:
			return v, nil
		case string:
			switch v {
			case "1", "t", "T", "true", "TRUE", "True", "YES", "yes", "Yes", "Y", "y", "ON", "on", "On":
				return true, nil
			case "0", "f", "F", "false", "FALSE", "False", "NO", "no", "No", "N", "n", "OFF", "off", "Off":
				return false, nil
			}
		case int8, int32, int64:
			strV := fmt.Sprintf("%d", v)
			if strV == "1" {
				return true, nil
			} else if strV == "0" {
				return false, nil
			}
		case float64:
			if v == 1.0 {
				return true, nil
			} else if v == 0.0 {
				return false, nil
			}
		}
		return false, fmt.Errorf("parsing %q: invalid syntax", val)
	}
	return false, fmt.Errorf("parsing <nil>: invalid syntax")
}

// ToString converts values of any type to string.
func ToString(x interface{}) string {
	switch y := x.(type) {

	// Handle dates with special logic
	// This needs to come above the fmt.Stringer
	// test since time.Time's have a .String()
	// method
	case time.Time:
		return y.Format("A Monday")

	// Handle type string
	case string:
		return y

	// Handle type with .String() method
	case fmt.Stringer:
		return y.String()

	// Handle type with .Error() method
	case error:
		return y.Error()

	}

	// Handle named string type
	if v := reflect.ValueOf(x); v.Kind() == reflect.String {
		return v.String()
	}

	// Fallback to fmt package for anything else like numeric types
	return fmt.Sprint(x)
}

type DecodeOption func(options decodeOptions)

type decodeOptions struct {
}