proxy: add nil check for fix-misdirected (#2040)

* proxy: add nil check for fix-misdirected

* fix test

internal/controlplane/luascripts/fix-misdirected.lua

@@ -12,8 +12,12 @@ function envoy_on_response(response_handle)
     local headers = response_handle:headers()
     local dynamic_meta = response_handle:streamInfo():dynamicMetadata()
 
-    local authority =
+    local filter_meta = dynamic_meta:get("envoy.filters.http.lua")
-        dynamic_meta:get("envoy.filters.http.lua")["request.authority"]
+    if filter_meta == nil then
+        return
+    end
+
+    local authority = filter_meta["request.authority"]
     local expected_authority = "%s"
 
     -- if we got a 404 (no route found) and the authority header doesn't match

internal/controlplane/xds_lua_test.go

@@ -10,6 +10,61 @@ import (
 	lua "github.com/yuin/gopher-lua"
 )
 
+func TestLuaFixMisdirected(t *testing.T) {
+	t.Run("request", func(t *testing.T) {
+		L := lua.NewState()
+		defer L.Close()
+
+		bs, err := luaFS.ReadFile("luascripts/fix-misdirected.lua")
+		require.NoError(t, err)
+
+		err = L.DoString(string(bs))
+		require.NoError(t, err)
+
+		headers := map[string]string{
+			":authority": "TEST",
+		}
+		metadata := map[string]interface{}{}
+		dynamicMetadata := map[string]map[string]interface{}{}
+		handle := newLuaResponseHandle(L, headers, metadata, dynamicMetadata)
+
+		err = L.CallByParam(lua.P{
+			Fn:      L.GetGlobal("envoy_on_request"),
+			NRet:    0,
+			Protect: true,
+		}, handle)
+		require.NoError(t, err)
+
+		assert.Equal(t, map[string]map[string]interface{}{
+			"envoy.filters.http.lua": {
+				"request.authority": "TEST",
+			},
+		}, dynamicMetadata)
+	})
+	t.Run("empty metadata", func(t *testing.T) {
+		L := lua.NewState()
+		defer L.Close()
+
+		bs, err := luaFS.ReadFile("luascripts/fix-misdirected.lua")
+		require.NoError(t, err)
+
+		err = L.DoString(string(bs))
+		require.NoError(t, err)
+
+		headers := map[string]string{}
+		metadata := map[string]interface{}{}
+		dynamicMetadata := map[string]map[string]interface{}{}
+		handle := newLuaResponseHandle(L, headers, metadata, dynamicMetadata)
+
+		err = L.CallByParam(lua.P{
+			Fn:      L.GetGlobal("envoy_on_response"),
+			NRet:    0,
+			Protect: true,
+		}, handle)
+		require.NoError(t, err)
+	})
+}
+
 func TestLuaRewriteHeaders(t *testing.T) {
 	L := lua.NewState()
 	defer L.Close()
@@ -37,7 +92,7 @@ func TestLuaRewriteHeaders(t *testing.T) {
 			},
 		},
 	}
-	handle := newLuaResponseHandle(L, headers, metadata)
+	handle := newLuaResponseHandle(L, headers, metadata, nil)
 
 	err = L.CallByParam(lua.P{
 		Fn:      L.GetGlobal("envoy_on_response"),
@@ -49,9 +104,12 @@ func TestLuaRewriteHeaders(t *testing.T) {
 	assert.Equal(t, "https://frontend/one/some/uri/", headers["Location"])
 }
 
-func newLuaResponseHandle(L *lua.LState, headers map[string]string, metadata map[string]interface{}) lua.LValue {
+func newLuaResponseHandle(L *lua.LState,
-	typ := L.NewTable()
+	headers map[string]string,
-	L.SetFuncs(typ, map[string]lua.LGFunction{
+	metadata map[string]interface{},
+	dynamicMetadata map[string]map[string]interface{},
+) lua.LValue {
+	return newLuaType(L, map[string]lua.LGFunction{
 		"headers": func(L *lua.LState) int {
 			L.Push(newLuaHeaders(L, headers))
 			return 1
@@ -60,12 +118,11 @@ func newLuaResponseHandle(L *lua.LState, headers map[string]string, metadata map
 			L.Push(newLuaMetadata(L, metadata))
 			return 1
 		},
+		"streamInfo": func(L *lua.LState) int {
+			L.Push(newLuaStreamInfo(L, dynamicMetadata))
+			return 1
+		},
 	})
-	L.SetField(typ, "__index", typ)
-
-	tbl := L.NewTable()
-	L.SetMetatable(tbl, typ)
-	return tbl
 }
 
 func newLuaHeaders(L *lua.LState, headers map[string]string) lua.LValue {
@@ -102,8 +159,7 @@ func newLuaHeaders(L *lua.LState, headers map[string]string) lua.LValue {
 }
 
 func newLuaMetadata(L *lua.LState, metadata map[string]interface{}) lua.LValue {
-	typ := L.NewTable()
+	return newLuaType(L, map[string]lua.LGFunction{
-	L.SetFuncs(typ, map[string]lua.LGFunction{
 		"get": func(L *lua.LState) int {
 			_ = L.CheckTable(1)
 			key := L.CheckString(2)
@@ -118,6 +174,53 @@ func newLuaMetadata(L *lua.LState, metadata map[string]interface{}) lua.LValue {
 			return 1
 		},
 	})
+}
+
+func newLuaDynamicMetadata(L *lua.LState, metadata map[string]map[string]interface{}) lua.LValue {
+	return newLuaType(L, map[string]lua.LGFunction{
+		"get": func(L *lua.LState) int {
+			_ = L.CheckTable(1)
+			key := L.CheckString(2)
+
+			obj, ok := metadata[key]
+			if !ok {
+				L.Push(lua.LNil)
+				return 0
+			}
+
+			L.Push(toLua(L, obj))
+			return 1
+		},
+		"set": func(L *lua.LState) int {
+			_ = L.CheckTable(1)
+			filterName := L.CheckString(2)
+			key := L.CheckString(3)
+			value := L.CheckAny(4)
+
+			m, ok := metadata[filterName]
+			if !ok {
+				m = make(map[string]interface{})
+				metadata[filterName] = m
+			}
+			m[key] = fromLua(L, value)
+
+			return 0
+		},
+	})
+}
+
+func newLuaStreamInfo(L *lua.LState, dynamicMetadata map[string]map[string]interface{}) lua.LValue {
+	return newLuaType(L, map[string]lua.LGFunction{
+		"dynamicMetadata": func(L *lua.LState) int {
+			L.Push(newLuaDynamicMetadata(L, dynamicMetadata))
+			return 1
+		},
+	})
+}
+
+func newLuaType(L *lua.LState, funcs map[string]lua.LGFunction) lua.LValue {
+	typ := L.NewTable()
+	L.SetFuncs(typ, funcs)
 	L.SetField(typ, "__index", typ)
 
 	tbl := L.NewTable()
@@ -125,6 +228,35 @@ func newLuaMetadata(L *lua.LState, metadata map[string]interface{}) lua.LValue {
 	return tbl
 }
 
+func fromLua(L *lua.LState, v lua.LValue) interface{} {
+	switch v.Type() {
+	case lua.LTNil:
+		return nil
+	case lua.LTBool:
+		return bool(v.(lua.LBool))
+	case lua.LTNumber:
+		return float64(v.(lua.LNumber))
+	case lua.LTString:
+		return string(v.(lua.LString))
+	case lua.LTTable:
+		a := []interface{}{}
+		m := map[string]interface{}{}
+		v.(*lua.LTable).ForEach(func(key, value lua.LValue) {
+			if key.Type() == lua.LTNumber {
+				a = append(a, fromLua(L, value))
+			} else {
+				m[lua.LVAsString(key)] = fromLua(L, value)
+			}
+		})
+		if len(a) > 0 {
+			return a
+		}
+		return m
+	default:
+		panic("not supported")
+	}
+}
+
 func toLua(L *lua.LState, obj interface{}) lua.LValue {
 	// send the object through JSON to remove custom types
 	var normalized interface{}