feat: logging environment variables

app/cmd/root.go

@@ -3,10 +3,12 @@ package cmd
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
 const (
@@ -33,7 +35,11 @@ var (
 var logger *zap.Logger
 
 // Flags
-var cfgFile string
+var (
+	cfgFile   string
+	logLevel  string
+	logFormat string
+)
 
 var rootCmd = &cobra.Command{
 	Use:   "hysteria",
@@ -42,6 +48,36 @@ var rootCmd = &cobra.Command{
 	Run:   runClient, // Default to client mode
 }
 
+var logLevelMap = map[string]zapcore.Level{
+	"debug": zapcore.DebugLevel,
+	"info":  zapcore.InfoLevel,
+	"warn":  zapcore.WarnLevel,
+	"error": zapcore.ErrorLevel,
+}
+
+var logFormatMap = map[string]zapcore.EncoderConfig{
+	"console": {
+		TimeKey:        "time",
+		LevelKey:       "level",
+		NameKey:        "logger",
+		MessageKey:     "msg",
+		LineEnding:     zapcore.DefaultLineEnding,
+		EncodeLevel:    zapcore.CapitalColorLevelEncoder,
+		EncodeTime:     zapcore.RFC3339TimeEncoder,
+		EncodeDuration: zapcore.SecondsDurationEncoder,
+	},
+	"json": {
+		TimeKey:        "time",
+		LevelKey:       "level",
+		NameKey:        "logger",
+		MessageKey:     "msg",
+		LineEnding:     zapcore.DefaultLineEnding,
+		EncodeLevel:    zapcore.LowercaseLevelEncoder,
+		EncodeTime:     zapcore.EpochMillisTimeEncoder,
+		EncodeDuration: zapcore.SecondsDurationEncoder,
+	},
+}
+
 func Execute() {
 	err := rootCmd.Execute()
 	if err != nil {
@@ -50,22 +86,15 @@ func Execute() {
 }
 
 func init() {
-	initLogger()
 	initFlags()
 	cobra.OnInitialize(initConfig)
-}
-
-func initLogger() {
-	// TODO: Configurable logging
-	l, err := zap.NewDevelopment()
-	if err != nil {
-		panic(err)
-	}
-	logger = l
+	cobra.OnInitialize(initLogger) // initLogger must come after initConfig as it depends on config
 }
 
 func initFlags() {
 	rootCmd.PersistentFlags().StringVarP(&cfgFile, "config", "c", "", "config file")
+	rootCmd.PersistentFlags().StringVarP(&logLevel, "log-level", "l", envOrDefault("LOG_LEVEL", "info"), "log level")
+	rootCmd.PersistentFlags().StringVarP(&logFormat, "log-format", "f", envOrDefault("LOG_FORMAT", "console"), "log format")
 }
 
 func initConfig() {
@@ -79,3 +108,38 @@ func initConfig() {
 		viper.AddConfigPath(".")
 	}
 }
+
+func initLogger() {
+	level, ok := logLevelMap[strings.ToLower(logLevel)]
+	if !ok {
+		fmt.Printf("unsupported log level: %s\n", logLevel)
+		os.Exit(1)
+	}
+	enc, ok := logFormatMap[strings.ToLower(logFormat)]
+	if !ok {
+		fmt.Printf("unsupported log format: %s\n", logFormat)
+		os.Exit(1)
+	}
+	c := zap.Config{
+		Level:             zap.NewAtomicLevelAt(level),
+		DisableCaller:     true,
+		DisableStacktrace: true,
+		Encoding:          strings.ToLower(logFormat),
+		EncoderConfig:     enc,
+		OutputPaths:       []string{"stderr"},
+		ErrorOutputPaths:  []string{"stderr"},
+	}
+	var err error
+	logger, err = c.Build()
+	if err != nil {
+		fmt.Printf("failed to initialize logger: %s\n", err)
+		os.Exit(1)
+	}
+}
+
+func envOrDefault(key, def string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return def
+}