builder/qemu: allow to specify time.Duration in special <wait> command

Signed-off-by: Vasiliy Tolstov <v.tolstov@selfip.ru>

builder/qemu/step_type_boot_command.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"net"
+	"regexp"
 	"strings"
 	"time"
 	"unicode"
@@ -154,6 +155,19 @@ func vncSendString(c *vnc.ClientConn, original string) {
 			continue
 		}
 
+		if strings.HasPrefix(original, "<wait") && strings.HasSuffix(original, ">") {
+			re := regexp.MustCompile(`<wait([0-9hms]+)>$`)
+			dstr := re.FindStringSubmatch(original)
+			if len(dstr) > 1 {
+				log.Printf("Special code %s found, sleeping", dstr[0])
+				if dt, err := time.ParseDuration(dstr[1]); err == nil {
+					time.Sleep(dt)
+					original = original[len(dstr[0]):]
+					continue
+				}
+			}
+		}
+
 		for specialCode, specialValue := range special {
 			if strings.HasPrefix(original, specialCode) {
 				log.Printf("Special code '%s' found, replacing with: %d", specialCode, specialValue)

website/source/docs/builders/qemu.html.markdown

@@ -310,6 +310,9 @@ by the proper key:
     sending any additional keys. This is useful if you have to generally wait
     for the UI to update before typing more.
 
+-   `<waitXX> ` - Add user defined time.Duration pause before sending any
+    additional keys. For example `<wait10m>` or `<wait1m20s>`
+
 In addition to the special keys, each command to type is treated as a
 [configuration template](/docs/templates/configuration-templates.html). The
 available variables are: