Resolves #393

When new changes are introduced, re-build the debug binary and restart
the Delve Debugger client. It also adds a verbose mode for dlv command
which notifies the user if enabled.

cmd/commands/dlv/dlv.go

@@ -1 +1,16 @@
+// Copyright 2017 bee authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+// Package dlv ...
 package dlv

cmd/commands/dlv/dlv_amd64.go

@@ -23,6 +23,8 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"strings"
+	"time"
 
 	"github.com/beego/bee/cmd/commands"
 	"github.com/beego/bee/cmd/commands/version"
@@ -32,11 +34,12 @@ import (
 	"github.com/derekparker/delve/service/rpc2"
 	"github.com/derekparker/delve/service/rpccommon"
 	"github.com/derekparker/delve/terminal"
+	"github.com/fsnotify/fsnotify"
 )
 
 var cmdDlv = &commands.Command{
 	CustomFlags: true,
-	UsageLine:   "dlv [-package=\"\"] [-port=8181]",
+	UsageLine:   "dlv [-package=\"\"] [-port=8181] [-verbose=false]",
 	Short:       "Start a debugging session using Delve",
 	Long: `dlv command start a debugging session using debugging tool Delve.
 
@@ -50,43 +53,89 @@ var cmdDlv = &commands.Command{
 
 var (
 	packageName string
+	verbose     bool
 	port        int
 )
 
 func init() {
 	fs := flag.NewFlagSet("dlv", flag.ContinueOnError)
-	fs.IntVar(&port, "port", 8181, "Port to listen to for clients")
 	fs.StringVar(&packageName, "package", "", "The package to debug (Must have a main package)")
+	fs.BoolVar(&verbose, "verbose", false, "Enable verbose mode")
+	fs.IntVar(&port, "port", 8181, "Port to listen to for clients")
 	cmdDlv.Flag = *fs
 	commands.AvailableCommands = append(commands.AvailableCommands, cmdDlv)
 }
 
 func runDlv(cmd *commands.Command, args []string) int {
 	if err := cmd.Flag.Parse(args); err != nil {
-		beeLogger.Log.Fatalf("Error parsing flags: %v", err.Error())
+		beeLogger.Log.Fatalf("Error while parsing flags: %v", err.Error())
 	}
 
-	debugname := "debug"
-	addr := fmt.Sprintf("127.0.0.1:%d", port)
-	return runDelve(addr, debugname)
+	var (
+		addr       = fmt.Sprintf("127.0.0.1:%d", port)
+		paths      = make([]string, 0)
+		notifyChan = make(chan int)
+	)
+
+	if err := loadPathsToWatch(&paths); err != nil {
+		beeLogger.Log.Fatalf("Error while loading paths to watch: %v", err.Error())
+	}
+	go startWatcher(paths, notifyChan)
+	return startDelveDebugger(addr, notifyChan)
 }
 
-// runDelve runs the Delve debugger server
-func runDelve(addr, debugname string) int {
-	beeLogger.Log.Info("Starting Delve Debugger...")
-
-	err := gobuild(debugname, packageName)
-	if err != nil {
-		beeLogger.Log.Fatalf("%v", err)
+// buildDebug builds a debug binary in the current working directory
+func buildDebug() (string, error) {
+	args := []string{"-gcflags", "-N -l", "-o", "debug"}
+	args = append(args, utils.SplitQuotedFields("-ldflags='-linkmode internal'")...)
+	args = append(args, packageName)
+	if err := utils.GoCommand("build", args...); err != nil {
+		return "", err
 	}
 
-	fp, err := filepath.Abs("./" + debugname)
+	fp, err := filepath.Abs("./debug")
 	if err != nil {
-		beeLogger.Log.Fatalf("%v", err)
+		return "", err
+	}
+	return fp, nil
+}
+
+// loadPathsToWatch loads the paths that needs to be watched for changes
+func loadPathsToWatch(paths *[]string) error {
+	directory, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	filepath.Walk(directory, func(path string, info os.FileInfo, _ error) error {
+		if strings.HasSuffix(info.Name(), "docs") {
+			return filepath.SkipDir
+		}
+		if strings.HasSuffix(info.Name(), "swagger") {
+			return filepath.SkipDir
+		}
+		if strings.HasSuffix(info.Name(), "vendor") {
+			return filepath.SkipDir
+		}
+
+		if filepath.Ext(info.Name()) == ".go" {
+			*paths = append(*paths, path)
+		}
+		return nil
+	})
+	return nil
+}
+
+// startDelveDebugger starts the Delve debugger server
+func startDelveDebugger(addr string, ch chan int) int {
+	beeLogger.Log.Info("Starting Delve Debugger...")
+
+	fp, err := buildDebug()
+	if err != nil {
+		beeLogger.Log.Fatalf("Error while building debug binary: %v", err)
 	}
 	defer os.Remove(fp)
 
-	abs, err := filepath.Abs(debugname)
+	abs, err := filepath.Abs("./debug")
 	if err != nil {
 		beeLogger.Log.Fatalf("%v", err)
 	}
@@ -103,7 +152,7 @@ func runDelve(addr, debugname string) int {
 		AcceptMulti: true,
 		AttachPid:   0,
 		APIVersion:  2,
-		WorkingDir:  "./",
+		WorkingDir:  ".",
 		ProcessArgs: []string{abs},
 	}, false)
 	if err := server.Run(); err != nil {
@@ -112,26 +161,87 @@ func runDelve(addr, debugname string) int {
 
 	// Start the Delve client REPL
 	client := rpc2.NewClient(addr)
-	term := terminal.New(client, nil)
+	// Make sure the client is restarted when new changes are introduced
+	go func() {
+		for {
+			if val := <-ch; val == 0 {
+				if _, err := client.Restart(); err != nil {
+					utils.Notify("Error while restarting the client: "+err.Error(), "bee")
+				} else {
+					if verbose {
+						utils.Notify("Delve Debugger Restarted", "bee")
+					}
+				}
+			}
+		}
+	}()
 
+	// Create the terminal and connect it to the client debugger
+	term := terminal.New(client, nil)
 	status, err := term.Run()
 	if err != nil {
 		beeLogger.Log.Fatalf("Could not start Delve REPL: %v", err)
 	}
-	defer term.Close()
 
-	// Stop and kill the debugger server once
-	// user quits the REPL
+	// Stop and kill the debugger server once user quits the REPL
 	if err := server.Stop(true); err != nil {
 		beeLogger.Log.Fatalf("Could not stop Delve server: %v", err)
 	}
 	return status
 }
 
-// gobuild runs the "go build" command on the specified package
-func gobuild(debugname, pkg string) error {
-	args := []string{"-gcflags", "-N -l", "-o", debugname}
-	args = append(args, utils.SplitQuotedFields("-ldflags='-linkmode internal'")...)
-	args = append(args, pkg)
-	return utils.GoCommand("build", args...)
+var eventsModTime = make(map[string]int64)
+
+// startWatcher starts the fsnotify watcher on the passed paths
+func startWatcher(paths []string, ch chan int) {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		beeLogger.Log.Fatalf("Could not start the watcher: %v", err)
+	}
+	defer watcher.Close()
+
+	// Feed the paths to the watcher
+	for _, path := range paths {
+		if err := watcher.Add(path); err != nil {
+			beeLogger.Log.Fatalf("Could not set a watch on path: %v", err)
+		}
+	}
+
+	for {
+		select {
+		case evt := <-watcher.Events:
+			build := true
+			if filepath.Ext(evt.Name) != ".go" {
+				continue
+			}
+
+			mt := utils.GetFileModTime(evt.Name)
+			if t := eventsModTime[evt.Name]; mt == t {
+				build = false
+			}
+			eventsModTime[evt.Name] = mt
+
+			if build {
+				go func() {
+					if verbose {
+						utils.Notify("Rebuilding application with the new changes", "bee")
+					}
+
+					// Wait 1s before re-build until there is no file change
+					scheduleTime := time.Now().Add(1 * time.Second)
+					time.Sleep(scheduleTime.Sub(time.Now()))
+					_, err := buildDebug()
+					if err != nil {
+						utils.Notify("Build Failed: "+err.Error(), "bee")
+					} else {
+						ch <- 0 // Notify listeners
+					}
+				}()
+			}
+		case err := <-watcher.Errors:
+			if err != nil {
+				ch <- -1
+			}
+		}
+	}
 }