feat: enhance logging capabilities with zerolog integration and command-line support

cmd/cbzoptimizer/commands/rootcmd.go

@@ -2,14 +2,31 @@ package commands
 
 import (
 	"fmt"
-	"github.com/rs/zerolog/log"
-	"github.com/spf13/cobra"
-	"github.com/spf13/viper"
 	"os"
 	"path/filepath"
 	"runtime"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"github.com/thediveo/enumflag/v2"
 )
 
+// Map zerolog levels to their textual representations
+var LogLevelIds = map[zerolog.Level][]string{
+	zerolog.PanicLevel: {"panic"},
+	zerolog.FatalLevel: {"fatal"},
+	zerolog.ErrorLevel: {"error"},
+	zerolog.WarnLevel:  {"warn", "warning"},
+	zerolog.InfoLevel:  {"info"},
+	zerolog.DebugLevel: {"debug"},
+	zerolog.TraceLevel: {"trace"},
+}
+
+// Global log level variable with default
+var logLevel zerolog.Level = zerolog.InfoLevel
+
 var rootCmd = &cobra.Command{
 	Use:   "cbzconverter",
 	Short: "Convert CBZ files using a specified converter",
@@ -35,6 +52,17 @@ func init() {
 	viper.AddConfigPath(configFolder)
 	viper.SetEnvPrefix("CBZ")
 	viper.AutomaticEnv()
+
+	// Add log level flag (accepts zerolog levels: panic, fatal, error, warn, info, debug, trace)
+	rootCmd.PersistentFlags().VarP(
+		enumflag.New(&logLevel, "log", LogLevelIds, enumflag.EnumCaseInsensitive),
+		"log", "l",
+		"Set log level; can be 'panic', 'fatal', 'error', 'warn', 'info', 'debug', or 'trace'")
+
+	// Add log level environment variable support
+	viper.SetEnvPrefix("")
+	viper.BindEnv("LOG_LEVEL")
+
 	err := os.MkdirAll(configFolder, os.ModePerm)
 	if err != nil {
 		panic(fmt.Errorf("fatal error config file: %w", err))
@@ -60,3 +88,32 @@ func Execute() {
 func AddCommand(cmd *cobra.Command) {
 	rootCmd.AddCommand(cmd)
 }
+
+// ConfigureLogging sets up zerolog based on command-line flags and environment variables
+func ConfigureLogging() {
+	// Start with default log level (info)
+	level := zerolog.InfoLevel
+
+	// Check LOG_LEVEL environment variable first
+	envLogLevel := viper.GetString("LOG_LEVEL")
+	if envLogLevel != "" {
+		if parsedLevel, err := zerolog.ParseLevel(envLogLevel); err == nil {
+			level = parsedLevel
+		}
+	}
+
+	// Command-line log flag takes precedence over environment variable
+	// The logLevel variable will be set by the flag parsing, so if it's different from default, use it
+	if logLevel != zerolog.InfoLevel {
+		level = logLevel
+	}
+
+	// Set the global log level
+	zerolog.SetGlobalLevel(level)
+
+	// Configure console writer for readable output
+	log.Logger = log.Output(zerolog.ConsoleWriter{
+		Out:     os.Stderr,
+		NoColor: false,
+	})
+}