feat(log): B-03 日志轮转配置 - 添加 lumberjack 支持

- 添加 lumberjack.v2 依赖实现日志轮转
- 支持配置文件输出（stdout/stderr/file）
- 支持文件轮转（100MB/3备份/7天/压缩）
- 添加 Config 结构体灵活配置
- 添加完整测试用例

测试验证：
- TestInitWithConfig PASS
- TestInitWithConfigFileOutput PASS
- TestDefaultConfig PASS
- 全量日志测试通过

go.mod

@@ -13,6 +13,7 @@ require (
 	golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac // indirect
 	golang.org/x/tools v0.0.0-20201124115921-2c860bdd6e78 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect
 	lukechampine.com/uint128 v1.1.1 // indirect
 	modernc.org/cc/v3 v3.36.0 // indirect
 	modernc.org/ccgo/v3 v3.16.8 // indirect

go.sum

@@ -42,6 +42,8 @@ golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1 h1:bBRl1b0OH9s/DuPhuXpNl+VtCaJXFZ5/uEFST95x9zc=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1/go.mod h1:YD8tP3GAjkrDg1eZH7EGmyESg/lsYskCTPBJVb9jqSc=
 lukechampine.com/uint128 v1.1.1 h1:pnxCASz787iMf+02ssImqk6OLt+Z5QHMoZyUXR4z6JU=
 lukechampine.com/uint128 v1.1.1/go.mod h1:c4eWIwlEGaxC/+H1VguhU4PHXNWDCDMUlWdIWl2j1gk=
 modernc.org/cc/v3 v3.36.0 h1:0kmRkTmqNidmu3c7BNDSdVHCxXCkWLmWmCIVX4LUboo=

internal/log/log.go

@@ -9,10 +9,35 @@ import (
 	"time"
 
 	"log/slog"
+	"gopkg.in/natefinch/lumberjack.v2"
 )
 
 var logger *slog.Logger
 
+// Config holds logging configuration
+type Config struct {
+	Level      string
+	Output     string // "stdout", "stderr", or file path
+	Rotation   bool   // enable file rotation
+	MaxSize    int    // MB
+	MaxBackups int
+	MaxAge     int    // days
+	Compress   bool
+}
+
+// DefaultConfig returns default logging configuration
+func DefaultConfig() Config {
+	return Config{
+		Level:      "INFO",
+		Output:     "stdout",
+		Rotation:   false,
+		MaxSize:    100,
+		MaxBackups: 3,
+		MaxAge:     7,
+		Compress:   true,
+	}
+}
+
 // sensitiveFields contains field names that should be sanitized in logs
 var sensitiveFields = []string{
 	"token",
@@ -35,14 +60,47 @@ func Init() {
 
 // InitWithLevel initializes the logger with specified level
 func InitWithLevel(level string) {
-	levelVar := parseLevel(level)
+	cfg := DefaultConfig()
+	cfg.Level = level
+	InitWithConfig(cfg)
+}
+
+// InitWithConfig initializes the logger with full configuration
+func InitWithConfig(cfg Config) {
+	levelVar := parseLevel(cfg.Level)
 
 	opts := &slog.HandlerOptions{
 		Level:       levelVar,
 		ReplaceAttr: sanitizeAttrs,
 	}
 
-	handler := slog.NewJSONHandler(os.Stdout, opts)
+	var handler slog.Handler
+	
+	switch cfg.Output {
+	case "stdout":
+		handler = slog.NewJSONHandler(os.Stdout, opts)
+	case "stderr":
+		handler = slog.NewJSONHandler(os.Stderr, opts)
+	default:
+		// File output with optional rotation
+		if cfg.Rotation {
+			lumberjackLogger := &lumberjack.Logger{
+				Filename:   cfg.Output,
+				MaxSize:    cfg.MaxSize,
+				MaxBackups: cfg.MaxBackups,
+				MaxAge:     cfg.MaxAge,
+				Compress:   cfg.Compress,
+			}
+			handler = slog.NewJSONHandler(lumberjackLogger, opts)
+		} else {
+			file, err := os.OpenFile(cfg.Output, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
+			if err != nil {
+				panic(err)
+			}
+			handler = slog.NewJSONHandler(file, opts)
+		}
+	}
+	
 	logger = slog.New(handler)
 	slog.SetDefault(logger)
 }

internal/log/log_test.go

@@ -2,6 +2,7 @@ package log
 
 import (
 	"log/slog"
+	"os"
 	"testing"
 )
 
@@ -130,3 +131,59 @@ func TestRequestLogger(t *testing.T) {
 		t.Error("RequestLogger should not return nil")
 	}
 }
+
+func TestInitWithConfig(t *testing.T) {
+	// Test with stdout output
+	cfg := DefaultConfig()
+	cfg.Output = "stdout"
+	cfg.Level = "DEBUG"
+	InitWithConfig(cfg)
+	
+	if logger == nil {
+		t.Error("logger should not be nil after InitWithConfig")
+	}
+}
+
+func TestInitWithConfigFileOutput(t *testing.T) {
+	// Test with file output (no rotation)
+	tmpFile := t.TempDir() + "/test.log"
+	cfg := DefaultConfig()
+	cfg.Output = tmpFile
+	cfg.Rotation = false
+	InitWithConfig(cfg)
+	
+	Info("test message for file")
+	
+	// Verify file was created
+	if _, err := os.Stat(tmpFile); os.IsNotExist(err) {
+		t.Errorf("log file %s should exist", tmpFile)
+	}
+}
+
+func TestDefaultConfig(t *testing.T) {
+	cfg := DefaultConfig()
+	
+	if cfg.Level != "INFO" {
+		t.Errorf("default Level = %s, want INFO", cfg.Level)
+	}
+	
+	if cfg.Output != "stdout" {
+		t.Errorf("default Output = %s, want stdout", cfg.Output)
+	}
+	
+	if cfg.MaxSize != 100 {
+		t.Errorf("default MaxSize = %d, want 100", cfg.MaxSize)
+	}
+	
+	if cfg.MaxBackups != 3 {
+		t.Errorf("default MaxBackups = %d, want 3", cfg.MaxBackups)
+	}
+	
+	if cfg.MaxAge != 7 {
+		t.Errorf("default MaxAge = %d, want 7", cfg.MaxAge)
+	}
+	
+	if !cfg.Compress {
+		t.Error("default Compress should be true")
+	}
+}