[teamai] Push 87 resource(s) from XingfenD

.teamai/skills/common/golang-cli/assets/examples/config.go

@@ -0,0 +1,71 @@
+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()
+}