parent/child mode

lib/golang/lib.go

@@ -21,138 +21,16 @@ const ipcSocketArg = "--ipc-socket"
 
 type StdioMode int
 
-type ipcMode int
+type ipcCommon struct {
-
-const (
-	modeParent ipcMode = 1
-	modeChild  ipcMode = 2
-)
-
-type KittenIPC struct {
-	mode     ipcMode
-	cmd      *exec.Cmd
 	localApi     any
-
 	socketPath   string
-	listener   net.Listener
 	conn         net.Conn
 	errCh        chan error
-
 	nextId       int64
 	pendingCalls map[int64]chan callResult
 	mu           sync.Mutex
 }
 
-func NewParent(cmd *exec.Cmd, localApi any) (*KittenIPC, error) {
-	k := KittenIPC{
-		mode:         modeParent,
-		cmd:          cmd,
-		localApi:     localApi,
-		pendingCalls: make(map[int64]chan callResult),
-		errCh:        make(chan error, 1),
-	}
-
-	k.socketPath = filepath.Join(os.TempDir(), fmt.Sprintf("kitten-ipc-%d.sock", os.Getpid()))
-
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
-
-	if slices.Contains(cmd.Args, ipcSocketArg) {
-		return nil, fmt.Errorf("you should not use `%s` argument in your command", ipcSocketArg)
-	}
-	cmd.Args = append(cmd.Args, ipcSocketArg, k.socketPath)
-
-	k.errCh = make(chan error, 1)
-
-	return &k, nil
-}
-
-func NewChild(localApi any) (*KittenIPC, error) {
-	k := KittenIPC{
-		mode:         modeChild,
-		localApi:     localApi,
-		pendingCalls: make(map[int64]chan callResult),
-		errCh:        make(chan error, 1),
-	}
-
-	socketPath := flag.String("ipc-socket", "", "Path to IPC socket")
-	flag.Parse()
-
-	if *socketPath == "" {
-		return nil, fmt.Errorf("ipc socket path is missing")
-	}
-	k.socketPath = *socketPath
-
-	return &k, nil
-}
-
-func (k *KittenIPC) Start() error {
-	if k.mode == modeParent {
-		return k.startParent()
-	}
-	return k.startChild()
-}
-
-func (k *KittenIPC) startParent() error {
-	_ = os.Remove(k.socketPath)
-	listener, err := net.Listen("unix", k.socketPath)
-	if err != nil {
-		return fmt.Errorf("listen unix socket: %w", err)
-	}
-	k.listener = listener
-	defer k.closeSock()
-
-	err = k.cmd.Start()
-	if err != nil {
-		return fmt.Errorf("cmd start: %w", err)
-	}
-
-	if err := k.acceptConn(); err != nil {
-		return fmt.Errorf("accept connection: %w", err)
-	}
-
-	return nil
-}
-
-func (k *KittenIPC) startChild() error {
-	conn, err := net.Dial("unix", k.socketPath)
-	if err != nil {
-		return fmt.Errorf("connect to parent socket: %w", err)
-	}
-	k.conn = conn
-	k.startRcvData()
-	return nil
-}
-
-func (k *KittenIPC) acceptConn() error {
-	const acceptTimeout = time.Second * 10
-
-	res := make(chan mo.Result[net.Conn], 1)
-	go func() {
-		conn, err := k.listener.Accept()
-		if err != nil {
-			res <- mo.Err[net.Conn](err)
-		} else {
-			res <- mo.Ok[net.Conn](conn)
-		}
-		close(res)
-	}()
-
-	select {
-	case <-time.After(acceptTimeout):
-		_ = k.cmd.Process.Kill()
-		return fmt.Errorf("accept timeout")
-	case res := <-res:
-		if res.IsError() {
-			_ = k.cmd.Process.Kill()
-			return fmt.Errorf("accept: %w", res.Error())
-		}
-		k.conn = res.MustGet()
-		k.startRcvData()
-	}
-	return nil
-}
-
 type MsgType int
 
 const (
@@ -174,40 +52,40 @@ type callResult struct {
 	err    error
 }
 
-func (k *KittenIPC) startRcvData() {
+func (ipc *ipcCommon) startRcvData() {
-	scn := bufio.NewScanner(k.conn)
+	scn := bufio.NewScanner(ipc.conn)
 	for scn.Scan() {
 		var msg Message
 		if err := json.Unmarshal(scn.Bytes(), &msg); err != nil {
-			k.raiseErr(fmt.Errorf("unmarshal message: %w", err))
+			ipc.raiseErr(fmt.Errorf("unmarshal message: %w", err))
 			break
 		}
-		k.processMsg(msg)
+		ipc.processMsg(msg)
 	}
 	if err := scn.Err(); err != nil {
-		k.raiseErr(err)
+		ipc.raiseErr(err)
 	}
 }
 
-func (k *KittenIPC) processMsg(msg Message) {
+func (ipc *ipcCommon) processMsg(msg Message) {
 	switch msg.Type {
 	case MsgCall:
-		k.handleCall(msg)
+		ipc.handleCall(msg)
 	case MsgResponse:
-		k.handleResponse(msg)
+		ipc.handleResponse(msg)
 	}
 }
 
-func (k *KittenIPC) handleCall(msg Message) {
+func (ipc *ipcCommon) handleCall(msg Message) {
 
-	if k.localApi == nil {
+	if ipc.localApi == nil {
-		k.sendResponse(msg.Id, nil, fmt.Errorf("remote side does not accept ipc calls"))
+		ipc.sendResponse(msg.Id, nil, fmt.Errorf("remote side does not accept ipc calls"))
 	}
-	localApi := reflect.ValueOf(k.localApi)
+	localApi := reflect.ValueOf(ipc.localApi)
 
 	method := localApi.MethodByName(msg.Method)
 	if !method.IsValid() {
-		k.sendResponse(msg.Id, nil, fmt.Errorf("method not found: %s", msg.Method))
+		ipc.sendResponse(msg.Id, nil, fmt.Errorf("method not found: %s", msg.Method))
 		return
 	}
 
@@ -215,7 +93,7 @@ func (k *KittenIPC) handleCall(msg Message) {
 	argsCount := methodType.NumIn()
 
 	if len(msg.Params) != argsCount {
-		k.sendResponse(msg.Id, nil, fmt.Errorf("argument count mismatch: expected %d, got %d", argsCount, len(msg.Params)))
+		ipc.sendResponse(msg.Id, nil, fmt.Errorf("argument count mismatch: expected %d, got %d", argsCount, len(msg.Params)))
 		return
 	}
 
@@ -233,20 +111,20 @@ func (k *KittenIPC) handleCall(msg Message) {
 		res = append(res, resVal)
 	}
 
-	k.sendResponse(msg.Id, res, resErr.Interface().(error))
+	ipc.sendResponse(msg.Id, res, resErr.Interface().(error))
 }
 
-func (k *KittenIPC) handleResponse(msg Message) {
+func (ipc *ipcCommon) handleResponse(msg Message) {
 
-	k.mu.Lock()
+	ipc.mu.Lock()
-	ch, ok := k.pendingCalls[msg.Id]
+	ch, ok := ipc.pendingCalls[msg.Id]
 	if ok {
-		delete(k.pendingCalls, msg.Id)
+		delete(ipc.pendingCalls, msg.Id)
 	}
-	k.mu.Unlock()
+	ipc.mu.Unlock()
 
 	if !ok {
-		k.raiseErr(fmt.Errorf("received response for unknown call id: %d", msg.Id))
+		ipc.raiseErr(fmt.Errorf("received response for unknown call id: %d", msg.Id))
 		return
 	}
 
@@ -259,7 +137,7 @@ func (k *KittenIPC) handleResponse(msg Message) {
 	close(ch)
 }
 
-func (k *KittenIPC) sendResponse(id int64, result []any, err error) {
+func (ipc *ipcCommon) sendResponse(id int64, result []any, err error) {
 	msg := Message{
 		Type:   MsgResponse,
 		Id:     id,
@@ -270,12 +148,12 @@ func (k *KittenIPC) sendResponse(id int64, result []any, err error) {
 		msg.Error = err.Error()
 	}
 
-	if err := k.sendMsg(msg); err != nil {
+	if err := ipc.sendMsg(msg); err != nil {
-		k.raiseErr(fmt.Errorf("send response for id=%d: %w", id, err))
+		ipc.raiseErr(fmt.Errorf("send response for id=%d: %w", id, err))
 	}
 }
 
-func (k *KittenIPC) sendMsg(msg Message) error {
+func (ipc *ipcCommon) sendMsg(msg Message) error {
 
 	data, err := json.Marshal(msg)
 	if err != nil {
@@ -284,20 +162,20 @@ func (k *KittenIPC) sendMsg(msg Message) error {
 
 	data = append(data, '\n')
 
-	if _, err := k.conn.Write(data); err != nil {
+	if _, err := ipc.conn.Write(data); err != nil {
 		return fmt.Errorf("write message: %w", err)
 	}
 
 	return nil
 }
 
-func (k *KittenIPC) Call(method string, params ...any) ([]any, error) {
+func (ipc *ipcCommon) Call(method string, params ...any) ([]any, error) {
-	k.mu.Lock()
+	ipc.mu.Lock()
-	id := k.nextId
+	id := ipc.nextId
-	k.nextId++
+	ipc.nextId++
 	resChan := make(chan callResult, 1)
-	k.pendingCalls[id] = resChan
+	ipc.pendingCalls[id] = resChan
-	k.mu.Unlock()
+	ipc.mu.Unlock()
 
 	msg := Message{
 		Type:   MsgCall,
@@ -306,10 +184,10 @@ func (k *KittenIPC) Call(method string, params ...any) ([]any, error) {
 		Params: params,
 	}
 
-	if err := k.sendMsg(msg); err != nil {
+	if err := ipc.sendMsg(msg); err != nil {
-		k.mu.Lock()
+		ipc.mu.Lock()
-		delete(k.pendingCalls, id)
+		delete(ipc.pendingCalls, id)
-		k.mu.Unlock()
+		ipc.mu.Unlock()
 		return nil, fmt.Errorf("send call: %w", err)
 	}
 
@@ -317,38 +195,111 @@ func (k *KittenIPC) Call(method string, params ...any) ([]any, error) {
 	return result.result, result.err
 }
 
-func (k *KittenIPC) raiseErr(err error) {
+func (ipc *ipcCommon) raiseErr(err error) {
 	select {
-	case k.errCh <- err:
+	case ipc.errCh <- err:
 	default:
 	}
 }
 
-func (k *KittenIPC) closeSock() error {
+type ParentIPC struct {
-	if err := k.listener.Close(); err != nil {
+	*ipcCommon
+	cmd      *exec.Cmd
+	listener net.Listener
+}
+
+func NewParent(cmd *exec.Cmd, localApi any) (*ParentIPC, error) {
+	p := ParentIPC{
+		ipcCommon: &ipcCommon{
+			localApi:     localApi,
+			pendingCalls: make(map[int64]chan callResult),
+			errCh:        make(chan error, 1),
+			socketPath:   filepath.Join(os.TempDir(), fmt.Sprintf("kitten-ipc-%d.sock", os.Getpid())),
+		},
+		cmd: cmd,
+	}
+
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	if slices.Contains(cmd.Args, ipcSocketArg) {
+		return nil, fmt.Errorf("you should not use `%s` argument in your command", ipcSocketArg)
+	}
+	cmd.Args = append(cmd.Args, ipcSocketArg, p.socketPath)
+
+	p.errCh = make(chan error, 1)
+
+	return &p, nil
+}
+
+func (p *ParentIPC) Start() error {
+	_ = os.Remove(p.socketPath)
+	listener, err := net.Listen("unix", p.socketPath)
+	if err != nil {
+		return fmt.Errorf("listen unix socket: %w", err)
+	}
+	p.listener = listener
+	defer p.closeSock()
+
+	err = p.cmd.Start()
+	if err != nil {
+		return fmt.Errorf("cmd start: %w", err)
+	}
+
+	if err := p.acceptConn(); err != nil {
+		return fmt.Errorf("accept connection: %w", err)
+	}
+
+	return nil
+}
+
+func (p *ParentIPC) acceptConn() error {
+	const acceptTimeout = time.Second * 10
+
+	res := make(chan mo.Result[net.Conn], 1)
+	go func() {
+		conn, err := p.listener.Accept()
+		if err != nil {
+			res <- mo.Err[net.Conn](err)
+		} else {
+			res <- mo.Ok[net.Conn](conn)
+		}
+		close(res)
+	}()
+
+	select {
+	case <-time.After(acceptTimeout):
+		_ = p.cmd.Process.Kill()
+		return fmt.Errorf("accept timeout")
+	case res := <-res:
+		if res.IsError() {
+			_ = p.cmd.Process.Kill()
+			return fmt.Errorf("accept: %w", res.Error())
+		}
+		p.conn = res.MustGet()
+		p.startRcvData()
+	}
+	return nil
+}
+
+func (p *ParentIPC) closeSock() error {
+	if err := p.listener.Close(); err != nil {
 		return fmt.Errorf("close socket listener: %w", err)
 	}
 	return nil
 }
 
-func (k *KittenIPC) Wait() error {
+func (p *ParentIPC) Wait() error {
-	if k.mode == modeParent {
-		return k.waitParent()
-	}
-	return k.waitChild()
-}
-
-func (k *KittenIPC) waitParent() error {
 	waitErrCh := make(chan error, 1)
 
 	go func() {
-		waitErrCh <- k.cmd.Wait()
+		waitErrCh <- p.cmd.Wait()
 	}()
 
 	select {
-	case err := <-k.errCh:
+	case err := <-p.errCh:
 		runtimeErr := fmt.Errorf("runtime error: %w", err)
-		killErr := k.cmd.Process.Kill()
+		killErr := p.cmd.Process.Kill()
 		return mergeErr(runtimeErr, killErr)
 	case err := <-waitErrCh:
 		if err != nil {
@@ -359,8 +310,42 @@ func (k *KittenIPC) waitParent() error {
 	return nil
 }
 
-func (k *KittenIPC) waitChild() error {
+type ChildIPC struct {
-	err := <-k.errCh
+	*ipcCommon
+}
+
+func NewChild(localApi any) (*ChildIPC, error) {
+	c := ChildIPC{
+		ipcCommon: &ipcCommon{
+			localApi:     localApi,
+			pendingCalls: make(map[int64]chan callResult),
+			errCh:        make(chan error, 1),
+		},
+	}
+
+	socketPath := flag.String("ipc-socket", "", "Path to IPC socket")
+	flag.Parse()
+
+	if *socketPath == "" {
+		return nil, fmt.Errorf("ipc socket path is missing")
+	}
+	c.socketPath = *socketPath
+
+	return &c, nil
+}
+
+func (c *ChildIPC) Start() error {
+	conn, err := net.Dial("unix", c.socketPath)
+	if err != nil {
+		return fmt.Errorf("connect to parent socket: %w", err)
+	}
+	c.conn = conn
+	c.startRcvData()
+	return nil
+}
+
+func (c *ChildIPC) Wait() error {
+	err := <-c.errCh
 	if err != nil {
 		return fmt.Errorf("ipc error: %w", err)
 	}