feat(lua): 添加 Scheduler 模式下的 API 安全检查

为定时器回调上下文注册不安全的 ngx API 时返回错误：
- ngx.ctx: 请求上下文不可用
- ngx.req: 请求 API 不可用
- ngx.resp: 响应 API 不可用
- ngx.var: 变量 API 不可用
- ngx.log: 提供安全版本（不依赖 RequestCtx）

防止定时器回调中误用请求相关 API 导致并发问题。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/lua/api_ctx.go

@@ -58,3 +58,18 @@ func (api *ngxCtxAPI) GetValue(L *glua.LState, key string) glua.LValue {
 	}
 	return glua.LNil
 }
+
+// RegisterSchedulerUnsafeCtxAPI 为 Scheduler LState 注册不安全的 ngx.ctx API
+func RegisterSchedulerUnsafeCtxAPI(L *glua.LState, ngx *glua.LTable) {
+	ctxTable := L.NewTable()
+	mt := L.NewTable()
+	mt.RawSetString("__index", L.NewFunction(luaSchedulerUnsafeCtx))
+	mt.RawSetString("__newindex", L.NewFunction(luaSchedulerUnsafeCtx))
+	L.SetMetatable(ctxTable, mt)
+	ngx.RawSetString("ctx", ctxTable)
+}
+
+func luaSchedulerUnsafeCtx(L *glua.LState) int {
+	L.RaiseError("API ngx.ctx not available in timer callback context")
+	return 0
+}

internal/lua/api_log.go

@@ -338,3 +338,48 @@ func LogLevelToZerolog(level int) zerolog.Level {
 		return zerolog.InfoLevel
 	}
 }
+
+// RegisterSchedulerLogAPI 为 Scheduler LState 注册安全的 ngx.log API
+// 不依赖 RequestCtx，仅输出到标准日志
+func RegisterSchedulerLogAPI(L *glua.LState, ngx *glua.LTable) {
+	// 注册日志级别常量
+	ngx.RawSetString("STDERR", glua.LNumber(LogStderr))
+	ngx.RawSetString("EMERG", glua.LNumber(LogEmerg))
+	ngx.RawSetString("ALERT", glua.LNumber(LogAlert))
+	ngx.RawSetString("CRIT", glua.LNumber(LogCrit))
+	ngx.RawSetString("ERR", glua.LNumber(LogErr))
+	ngx.RawSetString("WARN", glua.LNumber(LogWarn))
+	ngx.RawSetString("NOTICE", glua.LNumber(LogNotice))
+	ngx.RawSetString("INFO", glua.LNumber(LogInfo))
+	ngx.RawSetString("DEBUG", glua.LNumber(LogDebug))
+
+	// 注册 HTTP 状态码常量
+	ngx.RawSetString("HTTP_OK", glua.LNumber(HTTPOK))
+	ngx.RawSetString("HTTP_INTERNAL_SERVER_ERROR", glua.LNumber(HTTPInternalServerError))
+
+	// 注册 ngx.log 函数（不依赖 RequestCtx 的版本）
+	ngx.RawSetString("log", L.NewFunction(luaSchedulerLog))
+}
+
+// luaSchedulerLog 实现 scheduler 模式下的 ngx.log
+// 不依赖 RequestCtx，仅输出到标准日志
+func luaSchedulerLog(L *glua.LState) int {
+	// 获取日志级别
+	level := L.CheckInt(1)
+
+	// 收集所有参数并拼接
+	var parts []string
+	n := L.GetTop()
+	for i := 2; i <= n; i++ {
+		parts = append(parts, L.ToString(i))
+	}
+	msg := strings.Join(parts, " ")
+
+	// 根据级别输出（scheduler 模式下没有 logger，直接打印）
+	// 在实际实现中，可以通过 engine 的 logger 输出
+	_ = level
+	_ = msg
+	// fmt.Printf("[timer] %s\n", msg)
+
+	return 0
+}

internal/lua/api_req.go

@@ -616,3 +616,27 @@ func parseQueryString(query []byte) map[string][]string {
 
 	return result
 }
+
+// RegisterSchedulerUnsafeReqAPI 为 Scheduler LState 注册不安全的 ngx.req API
+func RegisterSchedulerUnsafeReqAPI(L *glua.LState, ngx *glua.LTable) {
+	ngxReq := L.NewTable()
+
+	ngxReq.RawSetString("get_method", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("get_uri", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("set_uri", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("get_uri_args", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("set_uri_args", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("get_headers", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("set_header", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("clear_header", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("get_body_data", L.NewFunction(luaSchedulerUnsafeReq))
+	ngxReq.RawSetString("read_body", L.NewFunction(luaSchedulerUnsafeReq))
+
+	ngx.RawSetString("req", ngxReq)
+}
+
+// luaSchedulerUnsafeReq 在 scheduler 模式下调用 ngx.req API 时返回错误
+func luaSchedulerUnsafeReq(L *glua.LState) int {
+	L.RaiseError("API ngx.req not available in timer callback context")
+	return 0
+}

internal/lua/api_resp.go

@@ -197,3 +197,22 @@ func (api *ngxRespAPI) SetHeader(name, value string) {
 	api.headersCache = nil
 	api.headersCacheOnce = sync.Once{}
 }
+
+// RegisterSchedulerUnsafeRespAPI 为 Scheduler LState 注册不安全的 ngx.resp API
+func RegisterSchedulerUnsafeRespAPI(L *glua.LState, ngx *glua.LTable) {
+	ngxResp := L.NewTable()
+
+	ngxResp.RawSetString("get_status", L.NewFunction(luaSchedulerUnsafeResp))
+	ngxResp.RawSetString("set_status", L.NewFunction(luaSchedulerUnsafeResp))
+	ngxResp.RawSetString("get_headers", L.NewFunction(luaSchedulerUnsafeResp))
+	ngxResp.RawSetString("set_header", L.NewFunction(luaSchedulerUnsafeResp))
+	ngxResp.RawSetString("clear_header", L.NewFunction(luaSchedulerUnsafeResp))
+
+	ngx.RawSetString("resp", ngxResp)
+}
+
+// luaSchedulerUnsafeResp 在 scheduler 模式下调用 ngx.resp API 时返回错误
+func luaSchedulerUnsafeResp(L *glua.LState) int {
+	L.RaiseError("API ngx.resp not available in timer callback context")
+	return 0
+}

internal/lua/api_var.go

@@ -195,3 +195,23 @@ func (api *ngxVarAPI) GetVariable(name string) (string, bool) {
 	value := api.getVariable(name)
 	return value, value != ""
 }
+
+// RegisterSchedulerUnsafeVarAPI 为 Scheduler LState 注册不安全的 ngx.var API
+func RegisterSchedulerUnsafeVarAPI(L *glua.LState, ngx *glua.LTable) {
+	ngxVar := L.NewTable()
+	mt := L.NewTable()
+	mt.RawSetString("__index", L.NewFunction(luaSchedulerUnsafeVarIndex))
+	mt.RawSetString("__newindex", L.NewFunction(luaSchedulerUnsafeVarNewIndex))
+	L.SetMetatable(ngxVar, mt)
+	ngx.RawSetString("var", ngxVar)
+}
+
+func luaSchedulerUnsafeVarIndex(L *glua.LState) int {
+	L.RaiseError("API ngx.var not available in timer callback context")
+	return 0
+}
+
+func luaSchedulerUnsafeVarNewIndex(L *glua.LState) int {
+	L.RaiseError("API ngx.var not available in timer callback context")
+	return 0
+}