72 lines
1.7 KiB
Go
72 lines
1.7 KiB
Go
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"log/slog"
|
|
"os"
|
|
"strings"
|
|
|
|
"github.com/fsnotify/fsnotify"
|
|
"github.com/spf13/viper"
|
|
)
|
|
|
|
// === Complete Cobra + Viper Integration ===
|
|
|
|
func initConfigComplete() error {
|
|
// 1. Config file
|
|
if cfgFile != "" {
|
|
viper.SetConfigFile(cfgFile) // explicit path
|
|
} else {
|
|
home, _ := os.UserHomeDir()
|
|
viper.AddConfigPath(home) // search $HOME
|
|
viper.AddConfigPath(".") // search current dir
|
|
viper.SetConfigName(".myapp")
|
|
viper.SetConfigType("yaml")
|
|
}
|
|
|
|
// 2. Environment variables
|
|
viper.SetEnvPrefix("MYAPP") // MYAPP_PORT, MYAPP_LOG_LEVEL
|
|
viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_")) // log-level → MYAPP_LOG_LEVEL
|
|
viper.AutomaticEnv() // bind all env vars automatically
|
|
|
|
// 3. Read config file (ignore "not found")
|
|
if err := viper.ReadInConfig(); err != nil {
|
|
if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
|
|
return fmt.Errorf("reading config: %w", err)
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// === Unmarshaling into Structs ===
|
|
|
|
type Config struct {
|
|
Port int `mapstructure:"port"`
|
|
Host string `mapstructure:"host"`
|
|
LogLevel string `mapstructure:"log-level"`
|
|
Database struct {
|
|
DSN string `mapstructure:"dsn"`
|
|
MaxConn int `mapstructure:"max-conn"`
|
|
} `mapstructure:"database"`
|
|
}
|
|
|
|
func loadConfig() (Config, error) {
|
|
var cfg Config
|
|
if err := viper.Unmarshal(&cfg); err != nil {
|
|
return Config{}, fmt.Errorf("unmarshaling config: %w", err)
|
|
}
|
|
return cfg, nil
|
|
}
|
|
|
|
// === Watching Config File Changes ===
|
|
// For long-running CLIs (servers, daemons):
|
|
|
|
func watchConfig() {
|
|
viper.OnConfigChange(func(e fsnotify.Event) {
|
|
slog.Info("config file changed", "file", e.Name)
|
|
// re-read and apply config
|
|
})
|
|
viper.WatchConfig()
|
|
}
|