feat: add pseudo-ttys so piped output isn't buffered

Author: heldtogether

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/charmbracelet/x/ansi v0.9.2 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.13 // indirect
 	github.com/charmbracelet/x/term v0.2.1 // indirect
+	github.com/creack/pty v1.1.24 // indirect
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect

go.sum

@@ -16,6 +16,8 @@ github.com/charmbracelet/x/cellbuf v0.0.13 h1:/KBBKHuVRbq1lYx5BzEHBAFBP8VcQzJejZ
 github.com/charmbracelet/x/cellbuf v0.0.13/go.mod h1:xe0nKWGd3eJgtqZRaN9RjMtK7xUYchjzPr7q6kcvCCs=
 github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
 github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
+github.com/creack/pty v1.1.24 h1:bJrF4RRfyJnbTJqzRLHzcGaZK1NeM5kTC9jGgovnR1s=
+github.com/creack/pty v1.1.24/go.mod h1:08sCNb52WyoAwi2QDyzUCTgcvVFhUzewun7wtTfvcwE=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f h1:Y/CXytFA4m6baUTXGLOoWe4PQhGxaX0KpnayAqC48p4=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f/go.mod h1:vw97MGsxSvLiUE2X8qFplwetxpGLQrlU1Q9AUEIzCaM=
 github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=

internal/config.go

@@ -3,6 +3,8 @@ package internal
 import (
 	"log"
 	"os"
+	"os/exec"
+	"sync"
 
 	"gopkg.in/yaml.v3"
 )
@@ -27,6 +29,9 @@ type Command struct {
 
 	LogTail string
 	Status  CommandStatus
+
+	proc *exec.Cmd
+	mu   sync.Mutex
 }
 
 func LoadConfig(configPath string) []*Command {

internal/execer.go

@@ -7,18 +7,16 @@ import (
 	"log/slog"
 	"os/exec"
 	"strings"
-	"sync"
 	"syscall"
+
+	"github.com/creack/pty"
 )
 
 type ExecerCallback func(c *Command, line string, err error, done bool)
 
 type Execer struct {
 	Command  *Command
 	Callback ExecerCallback
-
-	mu   sync.Mutex
-	proc *exec.Cmd
 }
 
 func NewExecer(c *Command, cb ExecerCallback) *Execer {
@@ -34,64 +32,50 @@ func (e *Execer) Start() {
 	parts := strings.Fields(e.Command.Exec)
 	cmd := exec.Command(parts[0], parts[1:]...)
 	cmd.Dir = e.Command.Cwd
-	cmd.SysProcAttr = &syscall.SysProcAttr{
-		Setpgid: true,
-	}
-
-	stdout, err := cmd.StdoutPipe()
-	if err != nil {
-		e.Callback(e.Command, "", err, true)
-		return
-	}
 
-	stderr, err := cmd.StderrPipe()
+	ptmx, err := pty.Start(cmd)
 	if err != nil {
 		e.Callback(e.Command, "", err, true)
 		return
 	}
 
-	if err := cmd.Start(); err != nil {
-		e.Callback(e.Command, "", err, true)
-		return
-	}
-
 	slog.Info("Starting command", "cmd", strings.Join(cmd.Args, " "), "PID", cmd.Process.Pid)
 
-	e.mu.Lock()
-	e.proc = cmd
-	e.mu.Unlock()
+	e.Command.mu.Lock()
+	e.Command.proc = cmd
+	e.Command.mu.Unlock()
 
 	go func() {
-		r := io.MultiReader(stdout, stderr)
+		r := io.MultiReader(ptmx)
 		scanner := bufio.NewScanner(r)
 
 		for scanner.Scan() {
-			e.mu.Lock()
+			e.Command.mu.Lock()
 			e.Callback(e.Command, fmt.Sprintf("%s", scanner.Text()), nil, false)
-			e.mu.Unlock()
+			e.Command.mu.Unlock()
 		}
 	}()
 	err = cmd.Wait()
-	e.mu.Lock()
+	e.Command.mu.Lock()
 	e.Callback(e.Command, "", err, true)
-	e.mu.Unlock()
+	e.Command.mu.Unlock()
 }
 
 func (e *Execer) Stop() error {
-	e.mu.Lock()
-	defer e.mu.Unlock()
+	e.Command.mu.Lock()
+	defer e.Command.mu.Unlock()
 
-	if e.proc != nil && e.proc.Process != nil {
-		slog.Debug("killing proc", "PID", e.proc.Process.Pid)
-		pgid, err := syscall.Getpgid(e.proc.Process.Pid)
+	if e.Command.proc != nil && e.Command.proc.Process != nil {
+		slog.Debug("killing proc", "PID", e.Command.proc.Process.Pid)
+		pgid, err := syscall.Getpgid(e.Command.proc.Process.Pid)
 		if err == nil {
 			err = syscall.Kill(-pgid, syscall.SIGKILL)
-			slog.Debug("killed process group", "PID", e.proc.Process.Pid, "error", err)
+			slog.Debug("killed process group", "PID", e.Command.proc.Process.Pid, "error", err)
 		} else {
-			err = e.proc.Process.Kill()
-			slog.Debug("killed process", "PID", e.proc.Process.Pid, "error", err)
+			err = e.Command.proc.Process.Kill()
+			slog.Debug("killed process", "PID", e.Command.proc.Process.Pid, "error", err)
 		}
-		e.proc = nil
+		e.Command.proc = nil
 		return err
 	}
 

internal/execer_test.go

@@ -79,9 +79,9 @@ func TestExecerStopsOldProcessBeforeStart(t *testing.T) {
 	time.Sleep(100 * time.Millisecond)
 
 	// Check that the process is running
-	execer.mu.Lock()
-	firstProc := execer.proc
-	execer.mu.Unlock()
+	cmd.mu.Lock()
+	firstProc := cmd.proc
+	cmd.mu.Unlock()
 
 	if firstProc == nil || firstProc.Process == nil {
 		t.Fatal("expected first process to be started")
@@ -93,9 +93,9 @@ func TestExecerStopsOldProcessBeforeStart(t *testing.T) {
 	// Wait for the stop to take effect
 	time.Sleep(100 * time.Millisecond)
 
-	execer.mu.Lock()
-	secondProc := execer.proc
-	execer.mu.Unlock()
+	cmd.mu.Lock()
+	secondProc := cmd.proc
+	cmd.mu.Unlock()
 
 	if secondProc == nil || secondProc.Process == nil {
 		t.Fatal("expected second process to be started")