cmd/tailscale: allow serve|funnel off to delete an entire port

This PR allows you to do "tailscale serve -bg -https:4545 off" and it
will delete all handlers under it. It will also prompt you for a y/n in case
you wanted to delete a single port.

Updates #8489

Signed-off-by: Marwan Sulaiman <marwan@tailscale.com>

cmd/tailscale/cli/serve_legacy.go

@@ -164,6 +164,7 @@ type serveEnv struct {
 	tcp              string    // TCP port
 	tlsTerminatedTCP string    // a TLS terminated TCP port
 	subcmd           serveMode // subcommand
+	yes              bool      // update without prompt
 
 	lc localServeClient // localClient interface, specific to serve
 

cmd/tailscale/cli/serve_v2.go

@@ -128,7 +128,7 @@ func newServeV2Command(e *serveEnv, subcmd serveMode) *ffcli.Command {
 			fs.StringVar(&e.http, "http", "", "Expose an HTTP server at the specified port")
 			fs.StringVar(&e.tcp, "tcp", "", "Expose a TCP forwarder to forward raw TCP packets at the specified port")
 			fs.StringVar(&e.tlsTerminatedTCP, "tls-terminated-tcp", "", "Expose a TCP forwarder to forward TLS-terminated TCP packets at the specified port")
-
+			fs.BoolVar(&e.yes, "yes", false, "Update without interactive prompts")
 		}),
 		UsageFunc: usageFunc,
 		Subcommands: []*ffcli.Command{
@@ -679,13 +679,40 @@ func (e *serveEnv) removeWebServe(sc *ipn.ServeConfig, dnsName string, srvPort u
 		return errors.New("cannot remove web handler; currently serving TCP")
 	}
 
-	hp := ipn.HostPort(net.JoinHostPort(dnsName, strconv.Itoa(int(srvPort))))
-	if !sc.WebHandlerExists(hp, mount) {
+	portStr := strconv.Itoa(int(srvPort))
+	hp := ipn.HostPort(net.JoinHostPort(dnsName, portStr))
+
+	var targetExists bool
+	var mounts []string
+	// mount is deduced from e.setPath but it is ambiguous as
+	// to whether the user explicitly passed "/" or it was defaulted to.
+	if e.setPath == "" {
+		targetExists = sc.Web[hp] != nil && len(sc.Web[hp].Handlers) > 0
+		if targetExists {
+			for mount := range sc.Web[hp].Handlers {
+				mounts = append(mounts, mount)
+			}
+		}
+	} else {
+		targetExists = sc.WebHandlerExists(hp, mount)
+		mounts = []string{mount}
+	}
+
+	if !targetExists {
 		return errors.New("error: handler does not exist")
 	}
 
+	if len(mounts) > 1 {
+		msg := fmt.Sprintf("Are you sure you want to delete %d handlers under port %s?", len(mounts), portStr)
+		if !e.yes && !promptYesNo(msg) {
+			return nil
+		}
+	}
+
 	// delete existing handler, then cascade delete if empty
-	delete(sc.Web[hp].Handlers, mount)
+	for _, m := range mounts {
+		delete(sc.Web[hp].Handlers, m)
+	}
 	if len(sc.Web[hp].Handlers) == 0 {
 		delete(sc.Web, hp)
 		delete(sc.TCP, srvPort)

cmd/tailscale/cli/serve_v2_test.go

@@ -725,6 +725,40 @@ func TestServeDevConfigMutations(t *testing.T) {
 		wantErr: anyErr(),
 	})
 
+	add(step{
+		command: cmd("serve reset"),
+		want:    &ipn.ServeConfig{},
+	})
+
+	// start two handlers and turn them off in one command
+	add(step{
+		command: cmd("serve --https=4545 --set-path=/foo --bg localhost:3000"),
+		want: &ipn.ServeConfig{
+			TCP: map[uint16]*ipn.TCPPortHandler{4545: {HTTPS: true}},
+			Web: map[ipn.HostPort]*ipn.WebServerConfig{
+				"foo.test.ts.net:4545": {Handlers: map[string]*ipn.HTTPHandler{
+					"/foo": {Proxy: "http://127.0.0.1:3000"},
+				}},
+			},
+		},
+	})
+	add(step{
+		command: cmd("serve --https=4545 --set-path=/bar --bg localhost:3000"),
+		want: &ipn.ServeConfig{
+			TCP: map[uint16]*ipn.TCPPortHandler{4545: {HTTPS: true}},
+			Web: map[ipn.HostPort]*ipn.WebServerConfig{
+				"foo.test.ts.net:4545": {Handlers: map[string]*ipn.HTTPHandler{
+					"/foo": {Proxy: "http://127.0.0.1:3000"},
+					"/bar": {Proxy: "http://127.0.0.1:3000"},
+				}},
+			},
+		},
+	})
+	add(step{
+		command: cmd("serve --https=4545 --bg --yes localhost:3000 off"),
+		want:    &ipn.ServeConfig{},
+	})
+
 	lc := &fakeLocalServeClient{}
 	// And now run the steps above.
 	for i, st := range steps {

cmd/tailscale/cli/update.go

@@ -82,7 +82,14 @@ func confirmUpdate(ver string) bool {
 		return false
 	}
 
-	fmt.Printf("This will update Tailscale from %v to %v. Continue? [y/n] ", version.Short(), ver)
+	msg := fmt.Sprintf("This will update Tailscale from %v to %v. Continue?", version.Short(), ver)
+	return promptYesNo(msg)
+}
+
+// PromptYesNo takes a question and prompts the user to answer the
+// question with a yes or no. It appends a [y/n] to the message.
+func promptYesNo(msg string) bool {
+	fmt.Print(msg + " [y/n] ")
 	var resp string
 	fmt.Scanln(&resp)
 	resp = strings.ToLower(resp)