refactor: migrate from zerolog to zap logging library

Replace github.com/rs/zerolog with go.uber.org/zap throughout the codebase
to improve performance and provide better structured logging capabilities.

Key changes:
- Replace zerolog imports with zap and zapcore
- Implement custom Logger wrapper in log.go to maintain zerolog-like API
- Add LogEvent struct with chained methods (Str, Int, Err, Bool, etc.)
- Update all logging calls to use the new zap-based wrapper
- Replace JSON encoders with Console encoders for better readability

Benefits:
- Better performance with zap's optimized logging
- Consistent structured logging across all components
- Maintained zerolog-like API for easy migration
- Proper field context preservation for debugging
- Multi-core logging architecture for better output control

All tests pass and build succeeds.

cmd/cli/main.go

@@ -5,10 +5,10 @@ import (
 	"os"
 	"path/filepath"
 	"sync/atomic"
-	"time"
 
 	"github.com/kardianos/service"
-	"github.com/rs/zerolog"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 
 	"github.com/Control-D-Inc/ctrld"
 )
@@ -40,9 +40,10 @@ var (
 	cleanup           bool
 	startOnly         bool
 
-	mainLog       atomic.Pointer[ctrld.Logger]
-	consoleWriter zerolog.ConsoleWriter
-	noConfigStart bool
+	mainLog            atomic.Pointer[ctrld.Logger]
+	consoleWriter      zapcore.Core
+	consoleWriterLevel zapcore.Level
+	noConfigStart      bool
 )
 
 const (
@@ -53,8 +54,8 @@ const (
 )
 
 func init() {
-	l := zerolog.New(io.Discard)
-	mainLog.Store(&ctrld.Logger{Logger: &l})
+	l := zap.NewNop()
+	mainLog.Store(&ctrld.Logger{Logger: l})
 }
 
 func Main() {
@@ -82,23 +83,23 @@ func normalizeLogFilePath(logFilePath string) string {
 
 // initConsoleLogging initializes console logging, then storing to mainLog.
 func initConsoleLogging() {
-	consoleWriter = zerolog.NewConsoleWriter(func(w *zerolog.ConsoleWriter) {
-		w.TimeFormat = time.StampMilli
-	})
-	multi := zerolog.MultiLevelWriter(consoleWriter)
-	l := mainLog.Load().Output(multi).With().Timestamp().Logger()
-	mainLog.Store(&ctrld.Logger{Logger: &l})
-
+	consoleWriterLevel = zapcore.InfoLevel
 	switch {
 	case silent:
-		zerolog.SetGlobalLevel(zerolog.NoLevel)
+		// For silent mode, use a no-op logger
+		l := zap.NewNop()
+		mainLog.Store(&ctrld.Logger{Logger: l})
 	case verbose == 1:
-		zerolog.SetGlobalLevel(zerolog.InfoLevel)
+		// Info level is default
 	case verbose > 1:
-		zerolog.SetGlobalLevel(zerolog.DebugLevel)
+		// Debug level
+		consoleWriterLevel = zapcore.DebugLevel
 	default:
-		zerolog.SetGlobalLevel(zerolog.NoticeLevel)
+		// Notice level maps to Info in zap
 	}
+	consoleWriter = newHumanReadableZapCore(os.Stdout, consoleWriterLevel)
+	l := zap.New(consoleWriter)
+	mainLog.Store(&ctrld.Logger{Logger: l})
 }
 
 // initInteractiveLogging is like initLogging, but the ProxyLogger is discarded
@@ -108,7 +109,6 @@ func initConsoleLogging() {
 func initInteractiveLogging() {
 	old := cfg.Service.LogPath
 	cfg.Service.LogPath = ""
-	zerolog.TimeFieldFormat = time.RFC3339 + ".000"
 	initLoggingWithBackup(false)
 	cfg.Service.LogPath = old
 }
@@ -119,7 +119,7 @@ func initInteractiveLogging() {
 // This is only used in runCmd for special handling in case of logging config
 // change in cd mode. Without special reason, the caller should use initLogging
 // wrapper instead of calling this function directly.
-func initLoggingWithBackup(doBackup bool) []io.Writer {
+func initLoggingWithBackup(doBackup bool) []zapcore.Core {
 	var writers []io.Writer
 	if logFilePath := normalizeLogFilePath(cfg.Service.LogPath); logFilePath != "" {
 		// Create parent directory if necessary.
@@ -146,32 +146,53 @@ func initLoggingWithBackup(doBackup bool) []io.Writer {
 		}
 		writers = append(writers, logFile)
 	}
-	writers = append(writers, consoleWriter)
-	multi := zerolog.MultiLevelWriter(writers...)
-	l := mainLog.Load().Output(multi).With().Logger()
-	mainLog.Store(&ctrld.Logger{Logger: &l})
 
-	zerolog.SetGlobalLevel(zerolog.NoticeLevel)
+	// Create zap cores for different writers
+	var cores []zapcore.Core
+	cores = append(cores, consoleWriter)
+
+	// Determine log level
 	logLevel := cfg.Service.LogLevel
 	switch {
 	case silent:
-		zerolog.SetGlobalLevel(zerolog.NoLevel)
-		return writers
+		// For silent mode, use a no-op logger
+		l := zap.NewNop()
+		mainLog.Store(&ctrld.Logger{Logger: l})
+		return cores
 	case verbose == 1:
 		logLevel = "info"
 	case verbose > 1:
 		logLevel = "debug"
 	}
-	if logLevel == "" {
-		return writers
+
+	// Parse log level
+	var level zapcore.Level
+	switch logLevel {
+	case "debug":
+		level = zapcore.DebugLevel
+	case "info":
+		level = zapcore.InfoLevel
+	case "warn":
+		level = zapcore.WarnLevel
+	case "error":
+		level = zapcore.ErrorLevel
+	default:
+		level = zapcore.InfoLevel // default level
 	}
-	level, err := zerolog.ParseLevel(logLevel)
-	if err != nil {
-		mainLog.Load().Warn().Err(err).Msg("could not set log level")
-		return writers
+
+	consoleWriter.Enabled(level)
+	// Add cores for all writers
+	for _, writer := range writers {
+		core := newMachineFriendlyZapCore(writer, level)
+		cores = append(cores, core)
 	}
-	zerolog.SetGlobalLevel(level)
-	return writers
+
+	// Create a multi-core logger
+	multiCore := zapcore.NewTee(cores...)
+	logger := zap.New(multiCore)
+	mainLog.Store(&ctrld.Logger{Logger: logger})
+
+	return cores
 }
 
 func initCache() {