feat: update dependencies and improve caching mechanism

- Added Prometheus client library for metrics collection.
- Refactored garbage collection strategy from random deletion to LRU (Least Recently Used) deletion.
- Introduced per-key locking in cache to prevent race conditions.
- Enhanced logging with structured log messages for cache hits and misses.
- Implemented a retry mechanism for upstream requests with exponential backoff.
- Updated Go modules and indirect dependencies for better compatibility and performance.
- Removed unused sync filesystem implementation.
- Added version initialization to ensure a default version string.

cmd/root.go

@@ -3,6 +3,8 @@ package cmd
 import (
 	"os"
 	"s1d3sw1ped/SteamCache2/steamcache"
+	"s1d3sw1ped/SteamCache2/steamcache/logger"
+	"s1d3sw1ped/SteamCache2/version"
 
 	"github.com/rs/zerolog"
 	"github.com/spf13/cobra"
@@ -16,8 +18,9 @@ var (
 	diskpath         string
 	upstream         string
 
-	pprof   bool
-	verbose bool
+	pprof     bool
+	logLevel  string
+	logFormat string
 )
 
 var rootCmd = &cobra.Command{
@@ -29,9 +32,27 @@ var rootCmd = &cobra.Command{
 	By caching game files, SteamCache2 ensures that subsequent downloads of the same files are served from the local cache, 
 	significantly improving download times and reducing the load on the internet connection.`,
 	Run: func(cmd *cobra.Command, args []string) {
-		if verbose {
+		// Configure logging
+		switch logLevel {
+		case "debug":
 			zerolog.SetGlobalLevel(zerolog.DebugLevel)
+		case "error":
+			zerolog.SetGlobalLevel(zerolog.ErrorLevel)
+		case "info":
+			zerolog.SetGlobalLevel(zerolog.InfoLevel)
+		default:
+			zerolog.SetGlobalLevel(zerolog.InfoLevel) // Default to info level if not specified
 		}
+		var writer zerolog.ConsoleWriter
+		if logFormat == "json" {
+			writer = zerolog.ConsoleWriter{Out: os.Stderr, NoColor: true}
+		} else {
+			writer = zerolog.ConsoleWriter{Out: os.Stderr}
+		}
+		logger.Logger = zerolog.New(writer).With().Timestamp().Logger()
+
+		logger.Logger.Info().
+			Msg("starting SteamCache2 " + version.Version)
 
 		sc := steamcache.New(
 			":80",
@@ -43,7 +64,14 @@ var rootCmd = &cobra.Command{
 			upstream,
 			pprof,
 		)
+
+		logger.Logger.Info().
+			Msg("starting SteamCache2 on port 80")
+
 		sc.Run()
+
+		logger.Logger.Info().Msg("SteamCache2 stopped")
+		os.Exit(0)
 	},
 }
 
@@ -67,5 +95,7 @@ func init() {
 
 	rootCmd.Flags().BoolVarP(&pprof, "pprof", "P", false, "Enable pprof")
 	rootCmd.Flags().MarkHidden("pprof")
-	rootCmd.Flags().BoolVarP(&verbose, "verbose", "v", false, "Enable verbose logging")
+
+	rootCmd.Flags().StringVarP(&logLevel, "log-level", "l", "info", "Logging level: debug, info, error")
+	rootCmd.Flags().StringVarP(&logFormat, "log-format", "f", "console", "Logging format: json, console")
 }