--debug option for printing debug info

README.md

@@ -77,6 +77,7 @@ Flags:
   -m, --main=NAMESPACE          Call the -main function for a namespace.
       --init-ns=NAMESPACE       Initialize REPL with the specified namespace. Defaults to "user".
   -C, --color=auto              When to use colors. Possible values: always, auto, none. Defaults to auto.
+      --debug                   Print debug information
       --version                 Show application version.
 
 Args:

client/client.go

@@ -47,6 +47,7 @@ type (
 	OutputHandler interface {
 		Out(s string)
 		Err(s string)
+		Debug(s string)
 	}
 )
 

client/mock_server.go

@@ -44,6 +44,8 @@ func (m *MockServer) Err(s string) {
 	m.errs = append(m.errs, s)
 }
 
+func (m *MockServer) Debug(s string) {}
+
 func (m *MockServer) HandleErr(err error) {
 	m.handledErr = err
 }

cmd/trench/helper.go

@@ -18,6 +18,7 @@ var unixUrlRegex = regexp.MustCompile(`^nrepl\+unix:(.+)$`)
 
 type setupHelper struct {
 	errHandler client.ErrorHandler
+	debug      bool
 }
 
 func readPortFromFile(protocol, portFile string) (int, bool, error) {
@@ -50,6 +51,7 @@ func (h setupHelper) nReplFactory(connBuilder client.ConnBuilder, initNS string)
 			InitNS:        initNS,
 			OutputHandler: outHandler,
 			ErrorHandler:  h.errHandler,
+			Debug:         h.debug,
 		})
 		if err != nil {
 			h.errHandler.HandleErr(err)
@@ -65,6 +67,7 @@ func (h setupHelper) pReplFactory(connBuilder client.ConnBuilder, initNS string)
 			InitNS:        initNS,
 			OutputHandler: outHandler,
 			ErrorHandler:  h.errHandler,
+			Debug:         h.debug,
 		})
 		if err != nil {
 			h.errHandler.HandleErr(err)

cmd/trench/main.go

@@ -34,6 +34,7 @@ type cmdArgs struct {
 	mainNS        *string
 	initNS        *string
 	colorOption   *string
+	debug         *bool
 	args          *[]string
 }
 
@@ -66,6 +67,7 @@ var args = cmdArgs{
 	mainNS:        kingpin.Flag("main", "Call the -main function for a namespace.").Short('m').PlaceHolder("NAMESPACE").String(),
 	initNS:        kingpin.Flag("init-ns", "Initialize REPL with the specified namespace. Defaults to \"user\".").PlaceHolder("NAMESPACE").String(),
 	colorOption:   kingpin.Flag("color", "When to use colors. Possible values: always, auto, none. Defaults to auto.").Default(COLOR_AUTO).Short('C').Enum(COLOR_NONE, COLOR_AUTO, COLOR_ALWAYS),
+	debug:         kingpin.Flag("debug", "Print debug information.").Bool(),
 	args:          kingpin.Arg("args", "Arguments to pass to -main. These will be ignored unless -m is specified.").Strings(),
 }
 
@@ -99,7 +101,7 @@ func main() {
 
 	printer := repl.NewPrinter(colorized(*args.colorOption))
 	errHandler := errorHandler{printer}
-	helper := setupHelper{errHandler}
+	helper := setupHelper{errHandler, *args.debug}
 	protocol, connBuilder := helper.resolveConnection(&args)
 	initFile := strings.TrimSpace(*args.init)
 	filename := strings.TrimSpace(*args.file)

nrepl/client.go

@@ -32,6 +32,7 @@ type (
 		OutputHandler client.OutputHandler
 		ErrorHandler  client.ErrorHandler
 		ConnBuilder   client.ConnBuilder
+		Debug         bool
 		idGenerator   func() string
 	}
 )
@@ -49,7 +50,7 @@ func NewClient(opts *Opts) (*Client, error) {
 		pending:       map[string]chan client.EvalResult{},
 		idGenerator:   opts.idGenerator,
 	}
-	conn, err := Connect(&ConnOpts{opts.ConnBuilder})
+	conn, err := Connect(&ConnOpts{opts.ConnBuilder, opts.Debug, c})
 	if err != nil {
 		return nil, err
 	}
@@ -76,6 +77,10 @@ func (c *Client) Close() error {
 	return nil
 }
 
+func (c *Client) HandleDebugMessage(s string) {
+	c.outputHandler.Debug(s)
+}
+
 func (c *Client) CurrentNS() string {
 	return c.ns
 }

nrepl/nrepl.go

@@ -17,14 +17,23 @@ type (
 	Handler    func(Response)
 	ErrHandler func(error)
 
+	DebugHandler interface {
+		HandleDebugMessage(string)
+	}
+	DebugHandlerFunc func(string)
+
 	Conn struct {
-		socket  net.Conn
-		encoder *bencode.Encoder
-		decoder *bencode.Decoder
+		socket       net.Conn
+		encoder      *bencode.Encoder
+		decoder      *bencode.Decoder
+		debug        bool
+		debugHandler DebugHandler
 	}
 
 	ConnOpts struct {
 		ConnBuilder client.ConnBuilder
+		Debug       bool
+		DebugHandler
 	}
 
 	SessionInfo struct {
@@ -33,20 +42,33 @@ type (
 	}
 )
 
+func (fn DebugHandlerFunc) HandleDebugMessage(s string) {
+	fn(s)
+}
+
 func Connect(opts *ConnOpts) (conn *Conn, err error) {
 	connBuilder := opts.ConnBuilder
 	socket, err := connBuilder.Connect()
 	if err != nil {
 		return
 	}
+	debugHandler := opts.DebugHandler
+	if debugHandler == nil {
+		debugHandler = DebugHandlerFunc(func(_ string) {})
+	}
 	return &Conn{
-		socket:  socket,
-		encoder: bencode.NewEncoder(socket),
-		decoder: bencode.NewDecoder(socket),
+		socket:       socket,
+		encoder:      bencode.NewEncoder(socket),
+		decoder:      bencode.NewDecoder(socket),
+		debug:        opts.Debug,
+		debugHandler: debugHandler,
 	}, nil
 }
 
 func (conn *Conn) Send(req client.Request) error {
+	if conn.debug {
+		conn.debugHandler.HandleDebugMessage(fmt.Sprintf("[DEBUG:SEND] %q\n", req))
+	}
 	return conn.encoder.Encode(map[string]bencode.Datum(req.(Request)))
 }
 
@@ -58,6 +80,9 @@ func (conn *Conn) Recv() (client.Response, error) {
 		}
 		return nil, err
 	}
+	if conn.debug {
+		conn.debugHandler.HandleDebugMessage(fmt.Sprintf("[DEBUG:RECV] %q\n", datum))
+	}
 	dict, ok := datum.(map[string]bencode.Datum)
 	if !ok {
 		return nil, errors.New("response must be a dictionary")

prepl/prepl.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"strings"
 	"sync"
 
 	"github.com/athos/trenchman/client"
@@ -31,16 +32,23 @@ type (
 		ns            string
 		returnCh      chan client.EvalResult
 		done          chan struct{}
+		debug         bool
 	}
 
 	Opts struct {
 		InitNS        string
 		OutputHandler client.OutputHandler
 		ErrorHandler  client.ErrorHandler
 		ConnBuilder   client.ConnBuilder
+		Debug         bool
 	}
 )
 
+func (resp *Response) String() string {
+	bs, _ := edn.Marshal(resp)
+	return string(bs)
+}
+
 func NewClient(opts *Opts) (*Client, error) {
 	connBuilder := opts.ConnBuilder
 	socket, err := connBuilder.Connect()
@@ -59,6 +67,7 @@ func NewClient(opts *Opts) (*Client, error) {
 		errHandler:    opts.ErrorHandler,
 		ns:            initNS,
 		done:          make(chan struct{}),
+		debug:         opts.Debug,
 	}
 	if err := c.Send("(set! *print-namespace-maps* false)\n"); err != nil {
 		return nil, err
@@ -88,7 +97,11 @@ func (c *Client) Close() error {
 }
 
 func (c *Client) Send(code client.Request) error {
-	if _, err := c.writer.WriteString(code.(string)); err != nil {
+	msg := code.(string)
+	if c.debug {
+		c.outputHandler.Debug(fmt.Sprintf("[DEBUG:SEND] %q\n", strings.TrimSpace(msg)))
+	}
+	if _, err := c.writer.WriteString(msg); err != nil {
 		return err
 	}
 	return c.writer.Flush()
@@ -102,12 +115,14 @@ func (c *Client) Recv() (client.Response, error) {
 		}
 		return nil, err
 	}
+	if c.debug {
+		c.outputHandler.Debug(fmt.Sprintf("[DEBUG:RECV] %s\n", resp.String()))
+	}
 	return client.Response(&resp), nil
 }
 
 func (c *Client) HandleResp(response client.Response) {
 	resp := response.(*Response)
-	// fmt.Printf("resp: %v\n", resp)
 	switch resp.Tag.String() {
 	case ":ret":
 		c.handleResult(resp)

repl/repl.go

@@ -69,6 +69,10 @@ func (r *Repl) Err(s string) {
 	r.printer.With(color.FgRed).Fprint(r.err, s)
 }
 
+func (r *Repl) Debug(s string) {
+	r.printer.With(color.FgHiBlue).Fprint(r.err, s)
+}
+
 func (r *Repl) handleResults(ch <-chan client.EvalResult, hidesResult bool) {
 	for {
 		select {