fix: Respect autostart in mono mode

cmd/sst/mosaic.go

@@ -430,8 +430,8 @@ func CmdMosaic(c *cli.Cli) error {
 			fnTitle = "Worker"
 			fnFilter = "worker"
 		}
-		mono.AddProcess("deploy", []string{currentExecutable, "ui", "--filter=sst"}, "", "SST")
-		mono.AddProcess("function", []string{currentExecutable, "ui", "--filter=" + fnFilter}, "", fnTitle)
+		mono.AddProcess("deploy", []string{currentExecutable, "ui", "--filter=sst"}, "", "SST", true)
+		mono.AddProcess("function", []string{currentExecutable, "ui", "--filter=" + fnFilter}, "", fnTitle, true)
 
 		wg.Go(func() error {
 			defer c.Cancel()
@@ -462,11 +462,12 @@ func CmdMosaic(c *cli.Cli) error {
 								append([]string{currentExecutable, "dev", "--"}, words...),
 								dir,
 								title,
+								d.Autostart,
 								"SST_CHILD="+d.Name,
 							)
 						}
 						for range evt.Tunnels {
-							mono.AddProcess("tunnel", []string{currentExecutable, "tunnel", "--stage", p.App().Stage}, "", "Tunnel")
+							mono.AddProcess("tunnel", []string{currentExecutable, "tunnel", "--stage", p.App().Stage}, "", "Tunnel", true)
 						}
 						break
 					}

cmd/sst/mosaic/monoplexer/monoplexer.go

@@ -22,18 +22,21 @@ type Line struct {
 }
 
 type Process struct {
-	name  string
-	title string
-	cmd   *exec.Cmd
-	dir   string
+	name    string
+	title   string
+	command []string
+	cmd     *exec.Cmd
+	dir     string
+	env     []string
+	started bool
 }
 
 func (p *Process) IsDifferent(title string, command []string, directory string) bool {
-	if len(command) != len(p.cmd.Args) {
+	if len(command) != len(p.command) {
 		return true
 	}
 	for i := range command {
-		if command[i] != p.cmd.Args[i] {
+		if command[i] != p.command[i] {
 			return true
 		}
 	}
@@ -49,53 +52,74 @@ func (p *Process) IsDifferent(title string, command []string, directory string)
 func New() *Monoplexer {
 	return &Monoplexer{
 		processes: map[string]*Process{},
-		lines:     make(chan Line),
+		lines:     make(chan Line, 32),
 	}
 }
 
-func (m *Monoplexer) AddProcess(name string, command []string, directory string, title string, env ...string) {
-	exists, ok := m.processes[name]
-	if ok {
-		if !exists.IsDifferent(title, command, directory) {
-			return
-		}
-		m.lines <- Line{
-			line:    "dev config changed, restarting...",
-			process: name,
-		}
-		process.Kill(exists.cmd.Process)
-		delete(m.processes, name)
-	}
-
+func (p *Process) start(lines chan Line) {
 	r, w := io.Pipe()
-	cmd := process.Command(command[0], command[1:]...)
+	cmd := process.Command(p.command[0], p.command[1:]...)
 	cmd.SysProcAttr = getProcAttr()
 	cmd.Stdout = w
 	cmd.Stderr = w
-	if directory != "" {
-		cmd.Dir = directory
+	if p.dir != "" {
+		cmd.Dir = p.dir
 	}
-	if len(env) > 0 {
-		cmd.Env = append(os.Environ(), env...)
+	if len(p.env) > 0 {
+		cmd.Env = append(os.Environ(), p.env...)
 	}
 	go func() {
 		// read r line by line
 		scanner := bufio.NewScanner(r)
 		for scanner.Scan() {
-			m.lines <- Line{
+			lines <- Line{
 				line:    scanner.Text(),
-				process: name,
+				process: p.name,
 			}
 		}
 	}()
 	cmd.Start()
-	m.processes[name] = &Process{
-		name:  name,
-		title: title,
-		cmd:   cmd,
-		dir:   directory,
+	p.cmd = cmd
+	p.started = true
+}
+
+func (m *Monoplexer) AddProcess(name string, command []string, directory string, title string, autostart bool, env ...string) {
+	exists, ok := m.processes[name]
+	if ok {
+		if !exists.IsDifferent(title, command, directory) {
+			if !exists.started && autostart {
+				exists.start(m.lines)
+			}
+			return
+		}
+		if exists.started {
+			m.lines <- Line{
+				line:    "dev config changed, restarting...",
+				process: name,
+			}
+			process.Kill(exists.cmd.Process)
+		}
+		delete(m.processes, name)
+	}
+
+	proc := &Process{
+		name:    name,
+		title:   title,
+		command: command,
+		dir:     directory,
+		env:     env,
+	}
+	m.processes[name] = proc
+	if autostart {
+		proc.start(m.lines)
+		return
+	}
+	m.lines <- Line{
+		line:    "auto-start disabled",
+		process: name,
 	}
 }
+
 func (m *Monoplexer) Start(ctx context.Context) error {
 	for {
 		select {

cmd/sst/mosaic/monoplexer/monoplexer_test.go

@@ -0,0 +1,98 @@
+package monoplexer
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/sst/sst/v3/pkg/process"
+)
+
+func TestAddProcessAutostartFalse(t *testing.T) {
+	m := New()
+	m.AddProcess("web", []string{"sh", "-c", "sleep 5"}, "", "Web", false)
+
+	proc := m.processes["web"]
+	if proc == nil {
+		t.Fatal("expected process to be registered")
+	}
+	if proc.started {
+		t.Fatal("expected process to remain stopped")
+	}
+
+	select {
+	case line := <-m.lines:
+		if line.process != "web" {
+			t.Fatalf("expected message for web, got %q", line.process)
+		}
+		if !strings.Contains(line.line, "auto-start disabled") {
+			t.Fatalf("expected disabled message, got %q", line.line)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("expected disabled message")
+	}
+}
+
+func TestAddProcessAutostartTrue(t *testing.T) {
+	m := New()
+	m.AddProcess("web", []string{"sh", "-c", "sleep 5"}, "", "Web", true)
+
+	proc := m.processes["web"]
+	if proc == nil {
+		t.Fatal("expected process to be registered")
+	}
+	if !proc.started {
+		t.Fatal("expected process to start")
+	}
+	if proc.cmd == nil || proc.cmd.Process == nil {
+		t.Fatal("expected child process to be running")
+	}
+
+	defer process.Kill(proc.cmd.Process)
+}
+
+func TestAddProcessStartsWhenAutostartEnabledLater(t *testing.T) {
+	m := New()
+	m.AddProcess("web", []string{"sh", "-c", "sleep 5"}, "", "Web", false)
+	<-m.lines
+
+	m.AddProcess("web", []string{"sh", "-c", "sleep 5"}, "", "Web", true)
+
+	proc := m.processes["web"]
+	if proc == nil {
+		t.Fatal("expected process to be registered")
+	}
+	if !proc.started {
+		t.Fatal("expected process to start when autostart becomes enabled")
+	}
+	if proc.cmd == nil || proc.cmd.Process == nil {
+		t.Fatal("expected child process to be running")
+	}
+
+	defer process.Kill(proc.cmd.Process)
+}
+
+func TestAddProcessConfigChangeKeepsProcessStopped(t *testing.T) {
+	m := New()
+	m.AddProcess("web", []string{"sh", "-c", "sleep 5"}, "", "Web", false)
+	<-m.lines
+
+	m.AddProcess("web", []string{"sh", "-c", "sleep 10"}, "", "Web", false)
+
+	proc := m.processes["web"]
+	if proc == nil {
+		t.Fatal("expected process to be registered")
+	}
+	if proc.started {
+		t.Fatal("expected process to remain stopped after config change")
+	}
+
+	select {
+	case line := <-m.lines:
+		if !strings.Contains(line.line, "auto-start disabled") {
+			t.Fatalf("expected disabled message, got %q", line.line)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("expected disabled message after config change")
+	}
+}