init

1 files changed, 236 insertions, 0 deletions

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..01027e7
--- /dev/null
+++ b/main.go
@@ -0,0 +1,236 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+)
+/*
+#cgo LDFLAGS: -llua
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+
+int
+luna_load_file(lua_State *L, char *file) {
+	if (luaL_dofile(L, file) != LUA_OK) {
+		return -1;
+	}
+	if (!lua_istable(L, -1)) {
+
+		return -1;
+	}
+	return luaL_ref(L, LUA_REGISTRYINDEX);
+}
+
+int
+luna_isfunction(lua_State *L, int n) {
+	return lua_isfunction(L, n);
+}
+
+void
+luna_push_table_item(lua_State *L, int ref, char *key) {
+	lua_rawgeti(L, LUA_REGISTRYINDEX, ref);
+	lua_pushstring(L, key);
+	lua_gettable(L, -2);
+}
+
+void
+luna_pop(lua_State *L, int n) {
+	lua_pop(L, n);
+}
+
+const char *
+luna_tostring(lua_State *L, int n) {
+	return lua_tostring(L, n);
+}
+
+int
+luna_tonumber(lua_State *L, int n) {
+	return lua_tonumber(L, n);
+}
+
+void
+luna_push_ref(lua_State *L, int ref) {
+	lua_rawgeti(L, LUA_REGISTRYINDEX, ref);
+}
+
+int
+luna_pop_ref(lua_State *L) {
+	return luaL_ref(L, LUA_REGISTRYINDEX);
+}
+
+const char *
+luna_pcall(lua_State *L, int nargs, int nresults) {
+	if (lua_pcall(L, nargs, nresults, 0) != LUA_OK) {
+		// FIXME: check for errors
+		return NULL;
+	}
+}
+*/
+import "C"
+
+type WorkerRequest struct {
+	Request *http.Request
+	Route string
+	result chan *WorkerResponse
+}
+
+type WorkerResponse struct {
+	Code int
+	Headers map[string]string
+	Body string
+}
+
+type Worker struct {
+	read chan *WorkerRequest
+	L *C.lua_State
+	routes map[string]C.int
+	api C.int
+	started bool
+}
+
+func NewWorker(read chan *WorkerRequest) *Worker {
+	return &Worker {
+		read: read,
+		routes: make(map[string]C.int),
+	}
+}
+
+func (w *Worker) Start (filename string) error {
+	if w.started {
+		return errors.New("already started")
+	}
+
+	w.L = C.luaL_newstate()
+	C.luaL_openlibs(w.L)
+	// FIXME: C.luna_load_file should return an error.
+	w.api = C.luna_load_file(w.L, C.CString(filename))
+	w.initRoutes()
+
+	return nil
+}
+
+func (w *Worker) Listen () {
+	for {
+		r := <- w.read
+		handlerRef := w.routes[r.Route]
+		C.luna_push_ref(w.L, handlerRef)
+		C.lua_pushstring(w.L, C.CString(r.Request.Method))
+		C.lua_pushstring(w.L, C.CString(r.Request.URL.Path))
+
+		// table for headers
+		C.lua_createtable(w.L, 0, C.int(len(r.Request.Header)))
+		
+		for k := range r.Request.Header {
+			h := r.Request.Header.Get(k)
+			C.lua_pushstring(w.L, C.CString(h))
+			C.lua_setfield(w.L, -2, C.CString(k))
+		}
+
+		body, err := io.ReadAll(r.Request.Body)
+		if err != nil {
+			C.luna_pop(w.L, 4);
+			// TODO: 500
+			return
+		}
+
+		C.lua_pushstring(w.L, C.CString(string(body)))
+		C.luna_pcall(w.L, 4, 3)
+		code := C.luna_tonumber(w.L, -3)
+		rbody := C.GoString(C.luna_tostring(w.L, -1))
+
+		// parse headers
+		headers := make(map[string]string)
+		C.luna_pop(w.L, 1)
+		C.lua_pushnil(w.L)
+		for C.lua_next(w.L, -2) != 0 {
+			if C.lua_isstring(w.L, -2) == 0 || C.lua_isstring(w.L, -1) == 0 {
+				C.luna_pop(w.L, 1)
+				continue
+			}
+			v := C.GoString(C.luna_tostring(w.L, -1))
+			C.luna_pop(w.L, 1)
+			// we must not pop the item key from the stack because
+			// otherwise C.lua_next won't work properly
+			k := C.GoString(C.luna_tostring(w.L, -1))
+			headers[k] = v
+		}
+		C.luna_pop(w.L, 2)
+
+		r.result <- &WorkerResponse {
+			Code: int(code),
+			Headers: headers,
+			Body: rbody,
+		}
+	}
+}
+
+func (w *Worker) Request (route string, r *http.Request,) chan *WorkerResponse {
+	res := make(chan *WorkerResponse)
+	w.read <- &WorkerRequest{
+		Request: r,
+		Route: route,
+		result: res,
+	}
+	return res
+}
+
+func (w *Worker) ListRoutes() []string {
+	res := []string{}
+	for route, _ := range w.routes {
+		res = append(res, route)
+	}
+	return res
+}
+
+func (w *Worker) Stop () {
+	C.lua_close(w.L)
+}
+
+func (w *Worker) initRoutes() {
+	C.luna_push_table_item(w.L, w.api, C.CString("routes"))
+	C.lua_pushnil(w.L)
+	for C.lua_next(w.L, -2) != 0 {
+		if C.lua_isstring(w.L, -2) == 0 || C.luna_isfunction(w.L, -1) == 0 {
+			C.luna_pop(w.L, 1)
+			continue
+		}
+		handlerRef := C.luna_pop_ref(w.L)
+		// we must not pop the item key from the stack because
+		// otherwise C.lua_next won't work properly
+		route := C.GoString(C.luna_tostring(w.L, -1))
+		w.routes[route] = handlerRef
+	}
+}
+
+func main() {
+	rch := make(chan *WorkerRequest, 4096)
+	for i := 0; i < 8; i++ {
+		log.Printf("worker %d started\n", i)
+		w := NewWorker(rch)
+		w.Start("init.lua")
+		if i == 0 {
+			for _, route := range w.ListRoutes() {
+				http.HandleFunc(
+					route,
+					func (wr http.ResponseWriter, r *http.Request) {
+						resCh := w.Request(route, r)
+						res := <- resCh
+						for k, h := range res.Headers {
+							wr.Header().Set(k, h)
+						}
+						wr.WriteHeader(int(res.Code))
+						fmt.Fprint(wr, string(res.Body))
+					},
+				)
+			}
+		}
+		go w.Listen()
+		defer w.Stop()
+	}
+	fmt.Println("running")
+	log.Fatal(http.ListenAndServe("127.0.0.1:3001", nil))
+}