add open() and close() implementation along with other useful stuff

Author: umbynos

dummy-monitor/dummy_port.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"io"
+)
+
+type dummyPort struct {
+	echo     chan string
+	portName string
+}
+
+func newDummyPort(portName string) *dummyPort {
+	return &dummyPort{
+		echo:     make(chan string, 20),
+		portName: portName,
+	}
+}
+
+func (d *dummyPort) Close() error {
+	close(d.echo)
+	return nil
+}
+
+func (d *dummyPort) Read(p []byte) (int, error) {
+	data, ok := <-d.echo
+	if !ok {
+		return 0, io.EOF
+	}
+	n := copy(p, []byte(data))
+	// if p is too small data loss may happen.. ¯\_(ツ)_/¯
+	return n, nil
+}
+
+func (d *dummyPort) Write(p []byte) (int, error) {
+	d.echo <- string(p)
+	return len(p), nil
+}

dummy-monitor/main.go

@@ -18,10 +18,11 @@
 package main
 
 import (
+	"errors"
 	"fmt"
+	"io"
 	"os"
 
-	"github.com/arduino/go-properties-orderedmap"
 	monitor "github.com/arduino/pluggable-monitor-protocol-handler"
 	"github.com/arduino/pluggable-monitor-protocol-handler/dummy-monitor/args"
 )
@@ -53,6 +54,8 @@ var settings = &monitor.PortDescriptor{
 	},
 }
 
+var openedPort *dummyPort
+
 func main() {
 	args.Parse()
 	dummy := &dummyMonitor{}
@@ -87,13 +90,20 @@ func (d *dummyMonitor) Configure(parameterName string, value string) error {
 	return fmt.Errorf("invalid value for parameter %s: %s", parameterName, value)
 }
 
-//TODO implement
-func (d *dummyMonitor) Open(ipAddress string, boardPort string) error {
-	return nil
+func (d *dummyMonitor) Open(boardPort string) (io.ReadWriter, error) {
+	if openedPort != nil {
+		return nil, fmt.Errorf("port already opened: %s", openedPort.portName)
+	}
+	openedPort = newDummyPort(boardPort)
+	return openedPort, nil
 }
 
-//TODO implement
 func (d *dummyMonitor) Close() error {
+	if openedPort == nil {
+		return errors.New("port already closed")
+	}
+	openedPort.Close()
+	openedPort = nil
 	return nil
 }
 

go.mod

@@ -2,4 +2,7 @@ module github.com/arduino/pluggable-monitor-protocol-handler
 
 go 1.16
 
-require github.com/arduino/go-properties-orderedmap v1.4.0
+require (
+	github.com/arduino/go-properties-orderedmap v1.4.0
+	github.com/hashicorp/go-multierror v1.1.1
+)

go.sum

@@ -4,6 +4,10 @@ github.com/arduino/go-properties-orderedmap v1.4.0 h1:YEbbzPqm1gXWDM/Jaq8tlvmh09
 github.com/arduino/go-properties-orderedmap v1.4.0/go.mod h1:DKjD2VXY/NZmlingh4lSFMEYCVubfeArCsGPGDwb2yk=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
+github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
+github.com/hashicorp/go-multierror v1.1.1 h1:H5DkEtf6CXdFp0N0Em5UCwQpXMWke8IA0+lD48awMYo=
+github.com/hashicorp/go-multierror v1.1.1/go.mod h1:iw975J/qwKPdAO1clOe2L8331t/9/fmwbPZ6JB6eMoM=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

monitor.go

@@ -31,11 +31,14 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"net"
 	"regexp"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/arduino/go-properties-orderedmap"
+	"github.com/hashicorp/go-multierror"
 )
 
 // Port is a descriptor for a board port
@@ -62,7 +65,7 @@ type Monitor interface {
 	Configure(parameterName string, value string) error
 
 	// Open allows to open a communication with the board using TCP/IP
-	Open(ipAddress string, boardPort string) error
+	Open(boardPort string) (io.ReadWriter, error)
 
 	// Close will close the currently open port and TCP/IP connection
 	Close() error
@@ -80,6 +83,8 @@ type Server struct {
 	userAgent          string
 	reqProtocolVersion int
 	initialized        bool
+	clientConn         net.Conn
+	closeFuncMutex     sync.Mutex
 }
 
 // NewServer creates a new monitor server backed by the
@@ -126,7 +131,7 @@ func (d *Server) Run(in io.Reader, out io.Writer) error {
 		case "OPEN":
 			d.open(fullCmd[5:])
 		case "CLOSE":
-			d.close()
+			d.close("")
 		case "QUIT":
 			d.impl.Quit()
 			d.outputChan <- messageOk("quit")
@@ -208,13 +213,76 @@ func (d *Server) configure(cmd string) {
 }
 
 func (d *Server) open(cmd string) {
-
-}
-
-func (d *Server) close() {
-
+	if !d.initialized {
+		d.outputChan <- messageError("open", "Monitor not initialized")
+		return
+	}
+	parameters := strings.SplitN(cmd, " ", 2)
+	if len(parameters) != 2 {
+		d.outputChan <- messageError("open", "Invalid OPEN command")
+		return
+	}
+	address := parameters[0]
+	portName := parameters[1]
+	port, err := d.impl.Open(portName)
+	if err != nil {
+		d.outputChan <- messageError("open", err.Error())
+		return
+	}
+	d.clientConn, err = net.Dial("tcp", address)
+	if err != nil {
+		d.impl.Close()
+		d.outputChan <- messageError("open", err.Error())
+		return
+	}
+	// io.Copy is used to bridge the Client's TCP connection to the port one and vice versa
+	go func() {
+		_, err := io.Copy(port, d.clientConn) // Copy is blocking, so we run it insiede a gorutine
+		if err != nil {
+			d.close(err.Error())
+		} else {
+			d.close("lost TCP/IP connection with the client!")
+		}
+	}()
+	go func() {
+		_, err := io.Copy(d.clientConn, port) // Copy is blocking, so we run it insiede a gorutine
+		if err != nil {
+			d.close(err.Error())
+		} else {
+			d.close("lost connection with the port")
+		}
+	}()
+	d.outputChan <- &message{
+		EventType: "open",
+		Message:   "OK",
+	}
 }
 
+func (d *Server) close(messageErr string) {
+	d.closeFuncMutex.Lock()
+	defer d.closeFuncMutex.Unlock()
+	if d.clientConn == nil {
+		// TODO
+		// d.outputChan <- messageError("close", "port already closed")
+		return
+	}
+	connErr := d.clientConn.Close()
+	portErr := d.impl.Close()
+	d.clientConn = nil
+	if messageErr != "" {
+		d.outputChan <- messageError("port_closed", messageErr)
+		return
+	}
+	if connErr != nil || portErr != nil {
+		var errs *multierror.Error
+		errs = multierror.Append(errs, connErr, portErr)
+		d.outputChan <- messageError("close", errs.Error())
+		return
+	}
+	d.outputChan <- &message{
+		EventType: "close",
+		Message:   "OK",
+	}
 }
 
 func (d *Server) outputProcessor(outWriter io.Writer) {