welcome message for users now specific for windows and linux

monitoring of hold file changes and messaging to users to provide more
  interactivity

cmd/fsnotifytest/monitor.go

@@ -15,7 +15,7 @@ import (
 //     CHMOD
 // echo > .hold
 //
-// file name:    ./.hold on linux
+// file name:    ./.hold on linux and just .hold on windows
 
 func main() {
 	// Create a new watcher

cmd/wsproxy/wsproxy.go

@@ -48,6 +48,7 @@ func main() {
 		flag.PrintDefaults()
 	}
 	flag.Parse()
+	log.Println("Narg ", flag.NFlag())
 	if flag.NArg() != 1 {
 		flag.Usage()
 		os.Exit(1)

pkg/agent/help.txt

@@ -6,7 +6,11 @@ terminates.
 
 You can extend this time using
 
+  {{ if eq .os "windows" -}}
+  echo > %agentdir%\.hold
+  {{- else -}}
   touch $agentdir/.hold
+  {{- end }}
 
 The expiry time is equal to the modification time of the .hold
 file with the expiry duration added.

pkg/agent/session.go

@@ -1,13 +1,18 @@
 package agent
 
 import (
+	"bytes"
 	"fmt"
+	"github.com/fsnotify/fsnotify"
 	"github.com/gliderlabs/ssh"
 	"io"
 	"log"
 	"os"
+	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
+	"text/template"
 	"time"
 
 	_ "embed"
@@ -55,7 +60,8 @@ var state AgentState
 const holdFilename = ".hold"
 
 //go:embed help.txt
-var helpMessage string
+var helpMessageTemplate string
+var helpMessage = formatHelpMessage()
 
 func ConfigureAgent(advanceWarningTime, agentExpiryTime, tickerInterval time.Duration) {
 	if fileExists(holdFilename) {
@@ -81,6 +87,59 @@ func ConfigureAgent(advanceWarningTime, agentExpiryTime, tickerInterval time.Dur
 			check()
 		}
 	}()
+	go monitorHoldFile()
+}
+
+func monitorHoldFile() {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		log.Printf("Cannot watch old file %s, user notifications for change in expiry time will be unavailable: %v", holdFilename, err)
+	}
+	defer watcher.Close()
+	err = watcher.Add(".")
+	if err != nil {
+		log.Printf("Cannot watch old file %s, user notifications for change in expiry time will be unavailable: %v", holdFilename, err)
+	}
+	expiryTime := state.expiryTime(holdFilename)
+	for {
+		select {
+		case event, ok := <-watcher.Events:
+			if !ok {
+				return
+			}
+			base := filepath.Base(event.Name)
+			if base == holdFilename {
+				newExpiryTIme := state.expiryTime(holdFilename)
+				if newExpiryTIme != expiryTime {
+					message := fmt.Sprintf("Expiry time of session is now %s\n",
+						newExpiryTIme.Format(time.DateTime))
+					message += holdFileMessage()
+					messageUsers(message)
+					expiryTime = newExpiryTIme
+				}
+			}
+
+		case err, ok := <-watcher.Errors:
+			if !ok {
+				return
+			}
+			log.Println("Error:", err)
+		}
+	}
+}
+
+func holdFileMessage() string {
+	message := ""
+	if fileExists(holdFilename) {
+		message += fmt.Sprintf("When the last user exits, the session will timeout and not exit immediately.\n"+
+			"Remove the %s file if you want th session to terminate when the last user logs out",
+			holdFilename)
+	} else {
+		message += fmt.Sprintf("When the last user exits, the agent will return and the continuous\n" +
+			"integration job will continue.")
+
+	}
+	return message
 }
 
 func Login(sessionId int, sshSession ssh.Session) {
@@ -119,6 +178,22 @@ func PrintHelpMessage(sshSession ssh.Session) {
 		state.agentExpriryTime))
 }
 
+func formatHelpMessage() string {
+	templ, err := template.New("help").Parse(helpMessageTemplate)
+	if err != nil {
+		panic(err)
+	}
+	helpFormattedBuf := bytes.NewBuffer(make([]byte, 0))
+	log.Println("Runnning on ", runtime.GOOS)
+	data := map[string]string{"os": runtime.GOOS}
+	err = templ.Execute(helpFormattedBuf, data)
+	if err != nil {
+		panic(err)
+	}
+	helpFormatted := helpFormattedBuf.String()
+	return helpFormatted
+}
+
 func LogOut(sessionId int) {
 	log.Println("User logged out")
 	delete(state.sessions, sessionId)
@@ -127,7 +202,6 @@ func LogOut(sessionId int) {
 }
 
 func PrintMessage(sshSession ssh.Session, message string) {
-	io.WriteString(sshSession.Stderr(), "\n\r###\n\r")
 	for _, line := range strings.Split(message, "\n") {
 		io.WriteString(sshSession.Stderr(), "### "+line+"\n\r")
 	}