fix(config,server): merge defaults on Load and fix monitoring registration

Two related fixes that must land together:

1. config.Load() now starts from DefaultConfig() before unmarshaling
   YAML. This ensures missing top-level fields (Performance,
   Monitoring, Resolver) use their documented defaults instead of
   zero values. Most importantly, file_cache is no longer silently
   disabled when users omit the performance: section.

2. startSingleMode() now checks Monitoring.Status.Enabled instead of
   Path/Allow to decide whether to register the status endpoint.
   Without this change, fix #1 would have caused a regression where
   the status handler is registered even when monitoring is disabled,
   because DefaultConfig() sets Path and Allow defaults.

Also replace remaining log.Printf in status.go and lua/api_timer.go
with zerolog to follow project logging conventions.

Added tests:
- config/load_test.go: verifies defaults are applied, explicit values
  override defaults, and monitoring stays disabled by default.
- server/monitoring_registration_test.go: verifies /_status is only
  registered when enabled and remains reachable with static handler
  on path: /.

internal/config/config.go

@@ -134,8 +134,12 @@ func Load(path string) (*Config, error) {
 		return nil, fmt.Errorf("读取配置文件失败: %w", err)
 	}
 
-	var cfg Config
-	if err := yaml.Unmarshal(data, &cfg); err != nil {
+	// 从默认值开始，YAML 只覆盖显式配置的字段。
+	// 注意：yaml.v3 对 slice 会整体替换，因此用户显式配置的 Servers[]
+	// 元素不会继承 server-level 默认值；但顶层 struct 字段（Performance、
+	// Monitoring、Resolver）的默认值会被保留。
+	cfg := DefaultConfig()
+	if err := yaml.Unmarshal(data, cfg); err != nil {
 		return nil, fmt.Errorf("解析配置文件失败: %w", err)
 	}
 
@@ -145,16 +149,16 @@ func Load(path string) (*Config, error) {
 			return nil, fmt.Errorf("获取配置文件绝对路径失败: %w", err)
 		}
 		visited := map[string]bool{absPath: true}
-		if err := processIncludes(&cfg, filepath.Dir(path), 0, visited); err != nil {
+		if err := processIncludes(cfg, filepath.Dir(path), 0, visited); err != nil {
 			return nil, fmt.Errorf("处理配置引入失败: %w", err)
 		}
 	}
 
-	if err := Validate(&cfg); err != nil {
+	if err := Validate(cfg); err != nil {
 		return nil, fmt.Errorf("配置验证失败: %w", err)
 	}
 
-	return &cfg, nil
+	return cfg, nil
 }
 
 const maxIncludeDepth = 10

internal/config/load_test.go

@@ -0,0 +1,104 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestLoad_MergesDefaults(t *testing.T) {
+	tmpDir := t.TempDir()
+	path := filepath.Join(tmpDir, "minimal.yaml")
+	content := `
+servers:
+  - listen: ":8080"
+`
+	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("Load failed: %v", err)
+	}
+
+	if cfg.Performance.FileCache.MaxEntries == 0 {
+		t.Error("Performance.FileCache.MaxEntries should have default value")
+	}
+	if cfg.Performance.FileCache.MaxSize == 0 {
+		t.Error("Performance.FileCache.MaxSize should have default value")
+	}
+	if cfg.Performance.FileCache.Inactive == 0 {
+		t.Error("Performance.FileCache.Inactive should have default value")
+	}
+	if cfg.Monitoring.Status.Path != "/_status" {
+		t.Errorf("Monitoring.Status.Path = %q, want %q", cfg.Monitoring.Status.Path, "/_status")
+	}
+	if cfg.Monitoring.Pprof.Path != "/debug/pprof" {
+		t.Errorf("Monitoring.Pprof.Path = %q, want %q", cfg.Monitoring.Pprof.Path, "/debug/pprof")
+	}
+	if cfg.Resolver.Valid == 0 {
+		t.Error("Resolver.Valid should have default value")
+	}
+}
+
+func TestLoad_ExplicitOverridesDefault(t *testing.T) {
+	tmpDir := t.TempDir()
+	path := filepath.Join(tmpDir, "explicit.yaml")
+	content := `
+performance:
+  file_cache:
+    max_entries: 500
+    max_size: 52428800
+    inactive: 120s
+servers:
+  - listen: ":8080"
+`
+	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("Load failed: %v", err)
+	}
+
+	if cfg.Performance.FileCache.MaxEntries != 500 {
+		t.Errorf("MaxEntries = %d, want 500", cfg.Performance.FileCache.MaxEntries)
+	}
+	if cfg.Performance.FileCache.MaxSize != 52428800 {
+		t.Errorf("MaxSize = %d, want 52428800", cfg.Performance.FileCache.MaxSize)
+	}
+	if cfg.Performance.FileCache.Inactive != 120*time.Second {
+		t.Errorf("Inactive = %v, want 120s", cfg.Performance.FileCache.Inactive)
+	}
+}
+
+func TestLoad_MonitoringDisabledByDefault(t *testing.T) {
+	tmpDir := t.TempDir()
+	path := filepath.Join(tmpDir, "minimal.yaml")
+	content := `
+servers:
+  - listen: ":8080"
+`
+	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("Load failed: %v", err)
+	}
+
+	// 默认值 Path 存在，但 Enabled 应为 false
+	if cfg.Monitoring.Status.Enabled {
+		t.Error("Monitoring.Status.Enabled should be false by default")
+	}
+	if cfg.Monitoring.Pprof.Enabled {
+		t.Error("Monitoring.Pprof.Enabled should be false by default")
+	}
+	if cfg.Monitoring.Status.Path != "/_status" {
+		t.Errorf("Monitoring.Status.Path = %q, want %q", cfg.Monitoring.Status.Path, "/_status")
+	}
+}

internal/lua/api_timer.go

@@ -21,12 +21,12 @@ package lua
 
 import (
 	"fmt"
-	"log"
 	"sync"
 	"sync/atomic"
 	"time"
 
 	glua "github.com/yuin/gopher-lua"
+	"rua.plus/lolly/internal/logging"
 )
 
 // CallbackEntry 回调队列条目，封装定时器触发的 Lua 回调。
@@ -261,7 +261,7 @@ func (m *TimerManager) executeTimer(entry *TimerEntry) {
 			m.queueMu.Unlock()
 		default:
 			m.queueMu.Unlock()
-			log.Printf("[lua] timer callback dropped: queue full")
+			logging.Warn().Msg("[lua] timer callback dropped: queue full")
 		}
 	}
 }
@@ -277,7 +277,7 @@ func (m *TimerManager) schedulerLoop() {
 		// 从字节码重建函数并执行
 		fn := m.schedulerL.NewFunctionFromProto(entry.proto)
 		if fn == nil {
-			log.Printf("[lua] timer callback: failed to create function from proto")
+			logging.Error().Msg("[lua] timer callback: failed to create function from proto")
 			continue
 		}
 
@@ -286,7 +286,7 @@ func (m *TimerManager) schedulerLoop() {
 			Fn:   fn,
 			NRet: 0,
 		}, entry.args...); err != nil {
-			log.Printf("[lua] timer callback error: %v", err)
+			logging.Error().Err(err).Msg("[lua] timer callback error")
 		}
 	}
 }
@@ -405,7 +405,7 @@ func (m *TimerManager) gracefulShutdown(timeout time.Duration) {
 	case <-time.After(timeout):
 		abandoned := len(m.callbackQueue)
 		if abandoned > 0 {
-			log.Printf("[lua] shutdown timeout: %d callbacks abandoned", abandoned)
+			logging.Warn().Int("abandoned", abandoned).Msg("[lua] shutdown timeout: callbacks abandoned")
 		}
 	}
 }

internal/server/monitoring_registration_test.go

@@ -0,0 +1,129 @@
+package server
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/valyala/fasthttp"
+	"rua.plus/lolly/internal/config"
+	"rua.plus/lolly/internal/matcher"
+)
+
+func TestMonitoringEndpoints_OnlyRegisteredWhenEnabled(t *testing.T) {
+	// Case 1: monitoring 未启用时，/_status 不应注册
+	cfg := &config.Config{
+		Servers: []config.ServerConfig{{
+			Listen: "127.0.0.1:0",
+			Static: []config.StaticConfig{{
+				Path: "/",
+				Root: t.TempDir(),
+			}},
+		}},
+	}
+
+	srv := New(cfg)
+	go srv.Start()
+	defer srv.StopWithTimeout(5 * time.Second)
+
+	var addr string
+	for start := time.Now(); time.Since(start) < 2*time.Second; time.Sleep(10 * time.Millisecond) {
+		listeners := srv.GetListeners()
+		if len(listeners) > 0 {
+			addr = listeners[0].Addr().String()
+			break
+		}
+	}
+	if addr == "" {
+		t.Fatal("server has no listeners")
+	}
+
+	client := &fasthttp.Client{}
+	req := fasthttp.AcquireRequest()
+	resp := fasthttp.AcquireResponse()
+	defer fasthttp.ReleaseRequest(req)
+	defer fasthttp.ReleaseResponse(resp)
+
+	req.SetRequestURI("http://" + addr + "/_status")
+	req.Header.SetMethod("GET")
+
+	if err := client.Do(req, resp); err != nil {
+		t.Fatalf("request failed: %v", err)
+	}
+
+	// 未启用时应返回 404（被 static handler 处理，找不到文件）
+	assert.Equal(t, fasthttp.StatusNotFound, resp.StatusCode(),
+		"status endpoint should NOT be registered when monitoring is disabled")
+}
+
+func TestMonitoringEndpoints_ReachableWhenEnabled(t *testing.T) {
+	cfg := &config.Config{
+		Monitoring: config.MonitoringConfig{
+			Status: config.StatusConfig{
+				Enabled: true,
+				Path:    "/_status",
+				Allow:   []string{"127.0.0.1"},
+			},
+		},
+		Servers: []config.ServerConfig{{
+			Listen: "127.0.0.1:0",
+			Static: []config.StaticConfig{{
+				Path: "/",
+				Root: t.TempDir(),
+			}},
+		}},
+	}
+
+	srv := New(cfg)
+	go srv.Start()
+	defer srv.StopWithTimeout(5 * time.Second)
+
+	var addr string
+	for start := time.Now(); time.Since(start) < 2*time.Second; time.Sleep(10 * time.Millisecond) {
+		listeners := srv.GetListeners()
+		if len(listeners) > 0 {
+			addr = listeners[0].Addr().String()
+			break
+		}
+	}
+	if addr == "" {
+		t.Fatal("server has no listeners")
+	}
+
+	client := &fasthttp.Client{}
+	req := fasthttp.AcquireRequest()
+	resp := fasthttp.AcquireResponse()
+	defer fasthttp.ReleaseRequest(req)
+	defer fasthttp.ReleaseResponse(resp)
+
+	req.SetRequestURI("http://" + addr + "/_status")
+	req.Header.SetMethod("GET")
+
+	if err := client.Do(req, resp); err != nil {
+		t.Fatalf("request failed: %v", err)
+	}
+
+	assert.Equal(t, fasthttp.StatusOK, resp.StatusCode(),
+		"status endpoint should be reachable when enabled, even with static handler on /")
+}
+
+func TestLocationEngine_StatusExactBeatsStaticPrefix(t *testing.T) {
+	// 独立验证 location engine 的优先级：exact match 应该 beat prefix /
+	engine := matcher.NewLocationEngine()
+
+	engine.AddExact("/_status", func(ctx *fasthttp.RequestCtx) {
+		ctx.SetStatusCode(fasthttp.StatusOK)
+	}, false)
+	engine.AddPrefix("/", func(ctx *fasthttp.RequestCtx) {
+		ctx.SetStatusCode(fasthttp.StatusNotFound)
+	}, false)
+	engine.MarkInitialized()
+
+	result := engine.Match([]byte("/_status"))
+	if result == nil {
+		t.Fatal("expected match")
+	}
+	if result.LocationType != matcher.LocationTypeExact {
+		t.Errorf("expected exact match, got %s", result.LocationType)
+	}
+}

internal/server/server.go

@@ -476,7 +476,7 @@ func (s *Server) startSingleMode() error {
 	s.locationEngine = matcher.NewLocationEngine()
 
 	// 注册状态监控端点（如果配置）
-	if s.config.Monitoring.Status.Path != "" || len(s.config.Monitoring.Status.Allow) > 0 {
+	if s.config.Monitoring.Status.Enabled {
 		statusHandler, err := NewStatusHandler(s, &s.config.Monitoring.Status)
 		if err != nil {
 			logging.Error().Msg("Failed to create status handler: " + err.Error())

internal/server/status.go

@@ -14,13 +14,13 @@ package server
 import (
 	"encoding/json"
 	"fmt"
-	"log"
 	"net"
 	"strings"
 	"time"
 
 	"github.com/valyala/fasthttp"
 	"rua.plus/lolly/internal/config"
+	"rua.plus/lolly/internal/logging"
 	"rua.plus/lolly/internal/utils"
 	"rua.plus/lolly/internal/version"
 )
@@ -299,7 +299,7 @@ func (h *StatusHandler) servePrometheus(ctx *fasthttp.RequestCtx, status *Status
 	}
 
 	if _, err := ctx.WriteString(buf.String()); err != nil {
-		log.Printf("failed to write metrics response: %v", err)
+		logging.Error().Err(err).Msg("failed to write metrics response")
 	}
 }
 
@@ -315,7 +315,7 @@ func (h *StatusHandler) serveJSON(ctx *fasthttp.RequestCtx, status *Status) {
 	}
 
 	if _, err := ctx.Write(data); err != nil {
-		log.Printf("failed to write status response: %v", err)
+		logging.Error().Err(err).Msg("failed to write status response")
 	}
 }
 
@@ -372,7 +372,7 @@ func (h *StatusHandler) serveText(ctx *fasthttp.RequestCtx, status *Status) {
 	}
 
 	if _, err := ctx.WriteString(buf.String()); err != nil {
-		log.Printf("failed to write text response: %v", err)
+		logging.Error().Err(err).Msg("failed to write text response")
 	}
 }
 
@@ -477,7 +477,7 @@ func (h *StatusHandler) serveHTML(ctx *fasthttp.RequestCtx, status *Status) {
 	buf.WriteString("</html>\n")
 
 	if _, err := ctx.WriteString(buf.String()); err != nil {
-		log.Printf("failed to write html response: %v", err)
+		logging.Error().Err(err).Msg("failed to write html response")
 	}
 }