install go2rtc on bob

installs_on_host/go2rtc/pkg/shell/command.go

@@ -0,0 +1,59 @@
+package shell
+
+import (
+	"context"
+	"os/exec"
+)
+
+// Command like exec.Cmd, but with support:
+// - io.Closer interface
+// - Wait from multiple places
+// - Done channel
+type Command struct {
+	*exec.Cmd
+	ctx    context.Context
+	cancel context.CancelFunc
+	err    error
+}
+
+func NewCommand(s string) *Command {
+	ctx, cancel := context.WithCancel(context.Background())
+	args := QuoteSplit(s)
+	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
+	cmd.SysProcAttr = procAttr
+	return &Command{cmd, ctx, cancel, nil}
+}
+
+func (c *Command) Start() error {
+	if err := c.Cmd.Start(); err != nil {
+		return err
+	}
+
+	go func() {
+		c.err = c.Cmd.Wait()
+		c.cancel() // release context resources
+	}()
+
+	return nil
+}
+
+func (c *Command) Wait() error {
+	<-c.ctx.Done()
+	return c.err
+}
+
+func (c *Command) Run() error {
+	if err := c.Start(); err != nil {
+		return err
+	}
+	return c.Wait()
+}
+
+func (c *Command) Done() <-chan struct{} {
+	return c.ctx.Done()
+}
+
+func (c *Command) Close() error {
+	c.cancel()
+	return nil
+}

installs_on_host/go2rtc/pkg/shell/procattr.go

@@ -0,0 +1,7 @@
+//go:build !linux
+
+package shell
+
+import "syscall"
+
+var procAttr *syscall.SysProcAttr

installs_on_host/go2rtc/pkg/shell/procattr_linux.go

@@ -0,0 +1,6 @@
+package shell
+
+import "syscall"
+
+// will stop child if parent died (even with SIGKILL)
+var procAttr = &syscall.SysProcAttr{Pdeathsig: syscall.SIGTERM}

installs_on_host/go2rtc/pkg/shell/shell.go

@@ -0,0 +1,43 @@
+package shell
+
+import (
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+)
+
+func QuoteSplit(s string) []string {
+	var a []string
+
+	for len(s) > 0 {
+		switch c := s[0]; c {
+		case '\t', '\n', '\r', ' ': // unicode.IsSpace
+			s = s[1:]
+		case '"', '\'': // quote chars
+			if i := strings.IndexByte(s[1:], c); i > 0 {
+				a = append(a, s[1:i+1])
+				s = s[i+2:]
+			} else {
+				return nil // error
+			}
+		default:
+			i := strings.IndexAny(s, "\t\n\r ")
+			if i > 0 {
+				a = append(a, s[:i])
+				s = s[i:]
+			} else {
+				a = append(a, s)
+				s = ""
+			}
+		}
+	}
+
+	return a
+}
+
+func RunUntilSignal() {
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+	println("exit with signal:", (<-sigs).String())
+}

installs_on_host/go2rtc/pkg/shell/shell_test.go

@@ -0,0 +1,18 @@
+package shell
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestQuoteSplit(t *testing.T) {
+	s := `
+python "-c" 'import time
+print("time", time.time())'
+`
+	require.Equal(t, []string{"python", "-c", "import time\nprint(\"time\", time.time())"}, QuoteSplit(s))
+
+	s = `ffmpeg -i "video=FaceTime HD Camera" -i "DeckLink SDI (2)"`
+	require.Equal(t, []string{"ffmpeg", "-i", `video=FaceTime HD Camera`, "-i", "DeckLink SDI (2)"}, QuoteSplit(s))
+}