added monitor service implementation

Author: masci

Diff for: commands/daemon/monitor.go

@@ -0,0 +1,111 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2019 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to [email protected].
+
+package daemon
+
+import (
+	"fmt"
+	"io"
+	"log"
+
+	"github.com/arduino/arduino-cli/arduino/monitors"
+	rpc "github.com/arduino/arduino-cli/rpc/monitor"
+)
+
+// MonitorService implements the `Monitor` service
+type MonitorService struct {
+}
+
+// StreamingOpen returns a stream response that can be used to fetch data from the
+// monitor target. The first message passed through the `StreamingOpenReq` must
+// contain monitor configuration params, not data.
+func (s *MonitorService) StreamingOpen(stream rpc.Monitor_StreamingOpenServer) error {
+	// grab the first message
+	msg, err := stream.Recv()
+	if err != nil {
+		return err
+	}
+
+	// ensure it's a config message and not data
+	config := msg.GetMonitorConfig()
+	if config == nil {
+		return fmt.Errorf("first message must contain monitor configuration, not data")
+	}
+
+	// select which type of monitor we need
+	var mon monitors.Monitor
+	switch config.GetType() {
+	case rpc.MonitorConfig_SERIAL:
+		// grab port speed from additional config data
+		var baudRate float64
+		addCfg := config.GetAdditionalConfig()
+		for k, v := range addCfg.GetFields() {
+			if k == "BaudRate" {
+				baudRate = v.GetNumberValue()
+				break
+			}
+		}
+
+		// default baud rate if not provided
+		if baudRate == 0 {
+			baudRate = 9600
+		}
+
+		var err error
+		if mon, err = monitors.OpenSerialMonitor(config.GetTarget(), int(baudRate)); err != nil {
+			return err
+		}
+	}
+
+	// now we can stream the other messages and re-route to the monitor
+	go func() {
+		for {
+			msg, err := stream.Recv()
+			if err == io.EOF {
+				// connection closed, exit
+				break
+			}
+
+			if err != nil {
+				// error, exit
+				log.Fatal(err)
+				break
+			}
+
+			mon.Write(msg.GetData())
+		}
+	}()
+
+	// read from the monitor and forward to the output stream
+
+	buf := make([]byte, 8)
+	for {
+		n, err := mon.Read(buf)
+		if err != nil {
+			return err
+		}
+
+		if n == 0 {
+			// port was closed
+			return nil
+		}
+
+		if err = stream.Send(&rpc.StreamingOpenResp{
+			Data: buf[:n],
+		}); err != nil {
+			return err
+		}
+	}
+}