move cli, session cleanup

cmd/gotelem/cli/root.go

@@ -1,4 +1,4 @@
-package cmd
+package cli
 
 import (
 	"log"

cmd/gotelem/cli/server.go

@@ -1,4 +1,4 @@
-package cmd
+package cli
 
 import (
 	"fmt"

cmd/gotelem/cli/xbee.go

@@ -1,9 +1,10 @@
-package cmd
+package cli
 
 // this file contains xbee utilities.
 // we can do network discovery and netcat-like things.
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -19,6 +20,13 @@ import (
 	"golang.org/x/exp/slog"
 )
 
+// context key stuff to prevent collisions
+type ctxKey int
+
+const (
+	keyIODevice ctxKey = iota
+)
+
 var xbeeCmd = &cli.Command{
 	Name:    "xbee",
 	Aliases: []string{"x"},
@@ -45,6 +53,17 @@ TCP/UDP connections require a port and will fail if one is not provided.
 			EnvVars:  []string{"XBEE_DEVICE"},
 		},
 	},
+	// this parses the device string and creates the io device.
+	// TODO: should we create the session here instead?
+	Before: func(ctx *cli.Context) error {
+		transport, err := parseDeviceString(ctx.String("device"))
+		if err != nil {
+			return err
+		}
+
+		ctx.Context = context.WithValue(ctx.Context, keyIODevice, transport)
+		return nil
+	},
 	Subcommands: []*cli.Command{
 		{
 			Name:            "info",
@@ -72,7 +91,7 @@ writtend to stdout.
 func xbeeInfo(ctx *cli.Context) error {
 
 	logger := slog.New(slog.NewTextHandler(os.Stderr))
-	transport, _ := parseDeviceString(ctx.String("device"))
+	transport := ctx.Context.Value(keyIODevice).(xbeeTransport)
 	xb, err := xbee.NewSession(transport, logger.With("device", transport.Type()))
 	if err != nil {
 		return cli.Exit(err, 1)
@@ -94,10 +113,9 @@ func netcat(ctx *cli.Context) error {
 		return cli.Exit("missing [addr] argument", 1)
 
 	}
-	// basically create two pipes.
 	logger := slog.New(slog.NewTextHandler(os.Stderr))
 
-	transport, _ := parseDeviceString(ctx.String("device"))
+	transport := ctx.Context.Value(keyIODevice).(xbeeTransport)
 	xb, _ := xbee.NewSession(transport, logger.With("devtype", transport.Type()))
 
 	sent := make(chan int64)
@@ -114,7 +132,9 @@ func netcat(ctx *cli.Context) error {
 	go streamCopy(os.Stdin, xb)
 	go streamCopy(xb, os.Stdout)
 
-	<-sent
+	n := <-sent
+
+	fmt.Printf("Sent %d\n", n)
 
 	return nil
 }

cmd/gotelem/gotelem.go

@@ -0,0 +1,9 @@
+package main
+
+import (
+	"github.com/kschamplin/gotelem/cmd/gotelem/cli"
+)
+
+func main() {
+	cli.Execute()
+}

xbee/api_frame.go

@@ -1,10 +1,3 @@
-// Package xbee implements xbee API encoding and decoding.
-
-// It encodes and decodes
-// API frames from io.Writer and io.Reader by providing a WriteFrame function and
-// a scanner.split function. It also includes internal packets for using the API.
-// For end-users, it provides a simple net.Conn-like interface that can write
-// and read arbitrary bytes (to be used by a higher level protocol)
 package xbee
 
 import (

xbee/rxframe_test.go

@@ -15,7 +15,6 @@ func TestParseRxFrame(t *testing.T) {
 		want    *RxFrame
 		wantErr bool
 	}{
-		// TODO: Add test cases.
 		{
 			name: "64-bit unicast",
 			args: args{

xbee/session.go

@@ -1,3 +1,10 @@
+/*
+Package xbee provides communication and configuration of Digi XBee products
+
+(and other Digi products that are similar such as the XLR Pro). It provides
+a net.Conn-like interface as well as AT commands for configuration. The most
+common usage of the package is with a Session, which provides
+*/
 package xbee
 
 import (
@@ -9,39 +16,32 @@ import (
 	"golang.org/x/exp/slog"
 )
 
-// todo: make transport-agnostic (serial port or TCP/IP)
-
-// A session is a simple way to manage an xbee device.
-// it provides io.Reader and io.Writer, as well as some extra functions to handle
-// custom Xbee frames.
-// type Session interface {
-// 	io.ReadWriteCloser
-// 	GetStatus() // todo: figure out signature for this
-
-// 	// Dial takes an address and allows direct communication with that
-// 	// device, without using broadcast.
-// 	Dial(addr uint64) io.ReadWriteCloser
-// 	// AT command related functions - query, set on local, query, set on remote.
-
-// 	ATCommand(cmd ATCmd, queued bool) (resp ATCmd, err error)
-// 	RemoteATCommand(cmd ATCmd, addr uint64) (resp ATCmd, err error)
-// }
+// TODO: implement net.Conn for Session/Conn. We are missing LocalAddr, RemoteAddr,
+// and Deadline related methods.
 
+// Session represents a connection to a locally-attached XBee. The connection can be through
+// serial/USB or TCP/IP depending on what is supported by the device.
 type Session struct {
 	ioDev io.ReadWriteCloser
 	ct    connTrack
-	slog.Logger
+	log   slog.Logger
 	// this buffer is used for storing data that must be read at some point.
-	rxBuf     *bufio.ReadWriter
+	rxBuf *bufio.ReadWriter
+
 	writeLock sync.Mutex // prevents multiple writers from accessing the port at once.
+
+	// conns contain a map of addresses to connections. This means that there
+	// can only be one direct connection to a device. This is pretty reasonable IMO.
+	// but needs to be documented very clearly.
+	conns map[uint64]*Conn
 }
 
+// NewSession takes an IO device and a logger and returns a new XBee session.
 func NewSession(dev io.ReadWriteCloser, baseLog *slog.Logger) (*Session, error) {
-	// make the session with the port/mode given, and set up the conntrack.
 	sess := &Session{
-		ioDev:  dev,
-		Logger: *baseLog,
-		ct:     *NewConnTrack(),
+		ioDev: dev,
+		log:   *baseLog,
+		ct:    *NewConnTrack(),
 	}
 
 	// setup io readwriter with a pipe.
@@ -69,10 +69,12 @@ func (sess *Session) rxHandler() {
 	scan := bufio.NewScanner(sess.ioDev)
 	scan.Split(xbeeFrameSplit)
 
+	// scan.Scan() will return false when there's EOF, i.e the io device is closed.
+	// this is activated by sess.Close()
 	for scan.Scan() {
 		data, err := parseFrame(scan.Bytes())
 		if err != nil {
-			sess.Logger.Warn("error parsing frame", "error", err, "data", data)
+			sess.log.Warn("error parsing frame", "error", err, "data", data)
 			continue
 		}
 
@@ -82,13 +84,13 @@ func (sess *Session) rxHandler() {
 			//TODO: if we have multiple remotes on the network, we need to track them here.
 			frame, err := ParseRxFrame(data)
 			if err != nil {
-				sess.Logger.Warn("error parsing rx packet", "error", err, "data", data)
+				sess.log.Warn("error parsing rx packet", "error", err, "data", data)
 				break //continue?
 			}
 			// take the data and write it to our internal rx packet buffer.
 			_, err = sess.rxBuf.Write(frame.Payload)
 			if err != nil {
-				sess.Logger.Warn("error writing data", "error", err, "payload", frame.Payload)
+				sess.log.Warn("error writing data", "error", err, "payload", frame.Payload)
 			}
 
 		case TxStatusType, ATCmdResponseType, RemoteCmdRespType:
@@ -99,17 +101,18 @@ func (sess *Session) rxHandler() {
 			err := sess.ct.ClearMark(idx, data)
 			if err != nil {
 				// we got a rogue packet lol
-				sess.Logger.Warn("rogue frame ID", "id", idx, "error", err)
+				sess.log.Warn("rogue frame ID", "id", idx, "error", err)
 			}
 
 		default:
 			// we don't know what to do with it.
-			sess.Logger.Info("unhandled packet type", "type", data[0], "id", data[1])
+			sess.log.Info("unhandled packet type", "type", data[0], "id", data[1])
 
 		}
 
 	}
 	// if we get here, the serial port has closed. this is fine.
+	sess.log.Debug("closing rx handler", "err", scan.Err())
 }
 
 // This implements io.Reader for the UART Session.
@@ -118,27 +121,34 @@ func (sess *Session) Read(p []byte) (int, error) {
 	return sess.rxBuf.Read(p)
 }
 
-func (sess *Session) Write(p []byte) (n int, err error) {
-	sess.Warn("hello")
+// Write sends a message to all XBees listening on the network. To send a message to a specific
+// XBee, use Dial() to get a Conn
+func (sess *Session) Write(p []byte) (int, error) {
+
+	return sess.writeAddr(p, 0xFFFF)
+
+}
+
+func (sess *Session) writeAddr(p []byte, dest uint64) (n int, err error) {
+
 	idx, ch, err := sess.ct.GetMark()
 	if err != nil {
 		return
 	}
 
-	n = len(p)
 	wf := &TxFrame{
 		Id:          idx,
-		Destination: BroadcastAddr,
+		Destination: dest,
 		Payload:     p,
 	}
-	// write the actual packet
 
 	sess.writeLock.Lock()
-	_, err = writeXBeeFrame(sess.ioDev, wf.Bytes())
+	n, err = writeXBeeFrame(sess.ioDev, wf.Bytes())
 	sess.writeLock.Unlock()
 	if err != nil {
 		return
 	}
+	n = n - 4
 
 	// finally, wait for the channel we got to return. this means that
 	// the matching response frame was received, so we can parse it.
@@ -210,6 +220,15 @@ func (sess *Session) Close() error {
 	return sess.ioDev.Close()
 }
 
-// next, we define AT commands. These are functions that take in a Session and
-// provide wrappers around AT command information, like type checking.
-//
+// Conn is a connection to a specific remote XBee. Conn allows for the user to
+// contact one Xbee for point-to-point communications. This enables ACK packets
+// for reliable transmission.
+type Conn struct {
+	parent *Session
+	log    slog.Logger
+	addr   uint64
+}
+
+func (c *Conn) Write(p []byte) (int, error) {
+	return c.parent.writeAddr(p, c.addr)
+}