# 安装 viper

go get github.com/spf13/viper

# 读取配置

# 直接读取

	# config.yaml

	app_name: My Go App
	app_port: 8080
	debug_mode: true

	package main

	import (
	"fmt"
	"github.com/spf13/viper"
	)

	func main() {
	// 设置配置文件的名称和路径（可选）
	viper.SetConfigName("config")
	viper.SetConfigType("yaml")
	viper.AddConfigPath(".")

	// 读取配置文件
	err := viper.ReadInConfig()
	if err != nil {
	panic(fmt.Errorf("Failed to read config file: %s", err))
	}

	// 读取配置项
	appName := viper.GetString("app_name")
	appPort := viper.GetInt("app_port")
	debugMode := viper.GetBool("debug_mode")

	// 使用读取到的配置项
	fmt.Println("App Name:", appName)
	fmt.Println("App Port:", appPort)
	fmt.Println("Debug Mode:", debugMode)
	}

	/*
	App Name: My Go App
	App Port: 8080
	Debug Mode: true
	*/

# 结构体映射

	# config.yaml

	app:
	name: My Go App
	port: 8080
	debug_mode: true
	database:
	host: localhost
	port: 3306
	username: root
	password: password
	dbname: mydb

	package main

	import (
	"fmt"
	"github.com/spf13/viper"
	)

	type Config struct {
	App AppConfig `mapstructure:"app"`
	Database DatabaseConfig `mapstructure:"database"`
	}

	type AppConfig struct {
	Name string `mapstructure:"name"`
	Port int `mapstructure:"port"`
	DebugMode bool `mapstructure:"debug_mode"`
	}

	type DatabaseConfig struct {
	Host string `mapstructure:"host"`
	Port int `mapstructure:"port"`
	Username string `mapstructure:"username"`
	Password string `mapstructure:"password"`
	DBName string `mapstructure:"dbname"`
	}

	func main() {
	// 设置配置文件的名称和路径（可选）
	viper.SetConfigName("config")
	viper.SetConfigType("yaml")
	viper.AddConfigPath(".")

	// 读取配置文件
	err := viper.ReadInConfig()
	if err != nil {
	panic(fmt.Errorf("failed to read config file: %s", err))
	}

	// 解析配置文件到结构体
	var config Config
	err = viper.Unmarshal(&config)
	if err != nil {
	panic(fmt.Errorf("Failed to unmarshal config: %s", err))
	}

	// 使用解析后的结构体
	fmt.Println("App Name:", config.App.Name)
	fmt.Println("App Port:", config.App.Port)
	fmt.Println("Debug Mode:", config.App.DebugMode)
	fmt.Println("Database Host:", config.Database.Host)
	fmt.Println("Database Port:", config.Database.Port)
	fmt.Println("Database Username:", config.Database.Username)
	fmt.Println("Database Password:", config.Database.Password)
	fmt.Println("Database Name:", config.Database.DBName)
	}

	/*
	App Name: My Go App
	App Port: 8080
	Debug Mode: true
	Database Host: localhost
	Database Port: 3306
	Database Username: root
	Database Password: password
	Database Name: mydb
	*/

# 配置中心读取 content

	package main

	import (
	"fmt"
	"github.com/spf13/viper"
	)

	type Config struct {
	App AppConfig `mapstructure:"app"`
	Database DatabaseConfig `mapstructure:"database"`
	}

	type AppConfig struct {
	Name string `mapstructure:"name"`
	Port int `mapstructure:"port"`
	DebugMode bool `mapstructure:"debug_mode"`
	}

	type DatabaseConfig struct {
	Host string `mapstructure:"host"`
	Port int `mapstructure:"port"`
	Username string `mapstructure:"username"`
	Password string `mapstructure:"password"`
	DBName string `mapstructure:"dbname"`
	}

	func main() {
	// 假设已经从配置中心获取了配置文件内容，并将其保存在 content 变量中
	content := `
	app:
	name: My Go App
	port: 8080
	debug_mode: true
	database:
	host: localhost
	port: 3306
	username: root
	password: password
	dbname: mydb
	`

	// 使用 viper.ReadConfigFromReader 来解析配置文件字符串
	viper.SetConfigType("yaml")
	err := viper.ReadConfig(strings.NewReader(content))
	if err != nil {
	panic(fmt.Errorf("Failed to read config: %s", err))
	}

	// 解析配置文件到结构体
	var config Config
	err = viper.Unmarshal(&config)
	if err != nil {
	panic(fmt.Errorf("Failed to unmarshal config: %s", err))
	}

	// 使用解析后的结构体
	fmt.Println("App Name:", config.App.Name)
	fmt.Println("App Port:", config.App.Port)
	fmt.Println("Debug Mode:", config.App.DebugMode)
	fmt.Println("Database Host:", config.Database.Host)
	fmt.Println("Database Port:", config.Database.Port)
	fmt.Println("Database Username:", config.Database.Username)
	fmt.Println("Database Password:", config.Database.Password)
	fmt.Println("Database Name:", config.Database.DBName)
	}

	/*
	App Name: My Go App
	App Port: 8080
	Debug Mode: true
	Database Host: localhost
	Database Port: 3306
	Database Username: root
	Database Password: password
	Database Name: mydb
	*/

# 多环境支持

	package main

	import (
	"fmt"
	"github.com/spf13/viper"
	"os"
	)

	func main() {
	var value string
	fmt.Scan(&value)
	// 设置环境变量
	os.Setenv("env", value)

	// 获取设置的环境变量的值
	env := os.Getenv("env")
	// 设置配置文件的名称和路径（可选）
	viper.SetConfigName("config")
	viper.SetConfigType("yaml")
	viper.AddConfigPath(".")

	// 根据不同的环境加载不同的配置文件
	viper.SetConfigName("config_" + env)

	// 读取配置文件
	err := viper.ReadInConfig()
	if err != nil {
	panic(fmt.Errorf("failed to read config file: %s", err))
	}

	// 读取配置项
	appName := viper.GetString("app.name")
	appPort := viper.GetInt("app.port")
	debugMode := viper.GetBool("app.debug_mode")

	// 使用读取到的配置项
	fmt.Println("App Name:", appName)
	fmt.Println("App Port:", appPort)
	fmt.Println("Debug Mode:", debugMode)
	}