support passing CLI arguments to lua script

2 files changed, 26 insertions, 9 deletions

diff --git a/main.go b/main.go
index eaa3ec6..9a2ad52 100644
--- a/main.go
+++ b/main.go
@@ -23,11 +23,11 @@ func main() {
 	wrksNum := flag.Int("n", runtime.NumCPU(), "Number of HTTP-workers to start")
 	flag.Parse()
 
-	if flag.NArg() != 1 {
+	if flag.NArg() == 0 {
 		printUsage()
 	}
-	luaExe := flag.Arg(0)
-	mustExist(luaExe)
+	luaArgv := flag.Args()
+	mustExist(luaArgv[0])
 
 	httpClient := &http.Client{}
 
@@ -346,7 +346,7 @@ func main() {
 		wrk := NewWorker()
 		wrks = append(wrks, wrk)
 		go func () {
-			err := wrk.Start(luaExe, module)
+			err := wrk.Start(luaArgv, module)
 			if err != nil {
 				log.Fatal(err)
 			}
diff --git a/worker.go b/worker.go
index 2df98a0..88737f7 100644
--- a/worker.go
+++ b/worker.go
@@ -52,10 +52,13 @@ func NewWorker() *Worker {
 
 // Start starts the worker:
 // 1) creates a Lua context
-// 2) executes the filename in it
+// 2) executes the argv in it
 // 3) initiates the the "luna" module so it's possible to call Go functions
 // from Lua
-func (w *Worker) Start(filename string, module map[string]any) error {
+func (w *Worker) Start(argv []string, module map[string]any) error {
+	if len(argv) == 0 {
+		return errors.New("argv must at least contain lua file name")
+	}
 	w.mu.Lock()
 	defer w.mu.Unlock()
 
@@ -65,14 +68,28 @@ func (w *Worker) Start(filename string, module map[string]any) error {
 	w.lua.Start()
 	defer w.lua.RestoreStackFunc()()
 
-	// registers the module in the Lua context
-	err := w.lua.PushObject(module)
+	// emulate passing arguments to the loaded chunk
+	args := []any{}
+	if len(argv) > 1 {
+		for _, arg := range argv[1:] {
+			args = append(args, arg)
+		}
+	}
+	err := w.lua.PushArray(args)
+	if err != nil {
+		return err
+	}
+	w.lua.SetGlobal("arg")
+
+	// register the module in the Lua context
+	err = w.lua.PushObject(module)
 	if err != nil {
 		return err
 	}
 	w.lua.SetGlobal("luna")
 
-	err = w.lua.Require(filename)
+	err = w.lua.Require(argv[0])
+
 	if err != nil {
 		return err
 	}