Exemplo n.º 1
0
// handleExecConn reads a command from the connection and executes it.
func (s *Store) handleExecConn(conn net.Conn) {
	defer s.wg.Done()

	// Read and execute command.
	err := func() error {
		// Read marker message.
		b := make([]byte, 4)
		if _, err := io.ReadFull(conn, b); err != nil {
			return fmt.Errorf("read magic: %s", err)
		} else if string(b) != ExecMagic {
			return fmt.Errorf("invalid exec magic: %q", string(b))
		}

		// Read command size.
		var sz uint64
		if err := binary.Read(conn, binary.BigEndian, &sz); err != nil {
			return fmt.Errorf("read size: %s", err)
		}

		// Read command.
		buf := make([]byte, sz)
		if _, err := io.ReadFull(conn, buf); err != nil {
			return fmt.Errorf("read command: %s", err)
		}

		// Ensure command can be deserialized before applying.
		if err := proto.Unmarshal(buf, &internal.Command{}); err != nil {
			return fmt.Errorf("unable to unmarshal command: %s", err)
		}

		// Apply against the raft log.
		if err := s.apply(buf); err != nil {
			return fmt.Errorf("apply: %s", err)
		}
		return nil
	}()

	// Build response message.
	var resp internal.Response
	resp.OK = proto.Bool(err == nil)
	resp.Index = proto.Uint64(s.raft.LastIndex())
	if err != nil {
		resp.Error = proto.String(err.Error())
	}

	// Encode response back to connection.
	if b, err := proto.Marshal(&resp); err != nil {
		panic(err)
	} else if err = binary.Write(conn, binary.BigEndian, uint64(len(b))); err != nil {
		s.Logger.Printf("unable to write exec response size: %s", err)
	} else if _, err = conn.Write(b); err != nil {
		s.Logger.Printf("unable to write exec response: %s", err)
	}
	conn.Close()
}
Exemplo n.º 2
0
// remoteExec sends an encoded command to the remote leader.
func (s *Store) remoteExec(b []byte) error {
	// Retrieve the current known leader.
	leader := s.raft.Leader()
	if leader == "" {
		return errors.New("no leader")
	}

	// Create a connection to the leader.
	conn, err := net.DialTimeout("tcp", leader, 10*time.Second)
	if err != nil {
		return err
	}
	defer conn.Close()

	// Write a marker byte for exec messages.
	_, err = conn.Write([]byte{MuxExecHeader})
	if err != nil {
		return err
	}

	// Write a marker message.
	_, err = conn.Write([]byte(ExecMagic))
	if err != nil {
		return err
	}

	// Write command size & bytes.
	if err := binary.Write(conn, binary.BigEndian, uint64(len(b))); err != nil {
		return fmt.Errorf("write command size: %s", err)
	} else if _, err := conn.Write(b); err != nil {
		return fmt.Errorf("write command: %s", err)
	}

	// Read response bytes.
	var sz uint64
	if err := binary.Read(conn, binary.BigEndian, &sz); err != nil {
		return fmt.Errorf("read response size: %s", err)
	}
	buf := make([]byte, sz)
	if _, err := io.ReadFull(conn, buf); err != nil {
		return fmt.Errorf("read response: %s", err)
	}

	// Unmarshal response.
	var resp internal.Response
	if err := proto.Unmarshal(buf, &resp); err != nil {
		return fmt.Errorf("unmarshal response: %s", err)
	} else if !resp.GetOK() {
		return fmt.Errorf("exec failed: %s", resp.GetError())
	}

	// Wait for local FSM to sync to index.
	if err := s.sync(resp.GetIndex(), 5*time.Second); err != nil {
		return fmt.Errorf("sync: %s", err)
	}

	return nil
}