Implement NewDiskClient.

disk.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strconv"
 	"sync"
 	"time"
 
@@ -24,6 +25,24 @@ type diskClient struct {
 	closed bool
 }
 
+var idCounter struct {
+	mu      sync.Mutex
+	counter int
+}
+
+func newId() string {
+	idCounter.mu.Lock()
+	defer idCounter.mu.Unlock()
+
+	s := strconv.FormatInt(int64(idCounter.counter), 16)
+	idCounter.counter++
+	return s
+}
+
+func NewDiskClient(g *group) *diskClient {
+	return &diskClient{group: g, id: newId()}
+}
+
 func (client *diskClient) Group() *group {
 	return client.group
 }

webclient.go

@@ -1078,10 +1078,7 @@ func handleClientMessage(c *webClient, m clientMessage) error {
 					return c.error(userError("already recording"))
 				}
 			}
-			disk := &diskClient{
+			disk := NewDiskClient(c.group)
-				group: c.group,
-				id:    "recording",
-			}
 			_, err := addClient(c.group.name, disk)
 			if err != nil {
 				disk.Close()