Ensure that io writers are properly closed. (#292)

Because the writers were being defered closed in New, this means that
some files could be closed before we had the opportunity to write to
them. This moves the close to their own func that can be ran in the
correct place.

Signed-off-by: Billy Lynch <billy@chainguard.dev>

internal/commands/root/root.go

@@ -65,6 +65,7 @@ func New(cfg *config.Config) *cobra.Command {
 		DisableAutoGenTag: true,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			s := io.New(o.Config.LogPath)
+			defer s.Close()
 			return s.Wrap(func() error {
 				switch {
 				case o.FlagVersion:

internal/io/streams.go

@@ -31,6 +31,8 @@ type Streams struct {
 
 	TTYIn  io.Reader
 	TTYOut io.Writer
+
+	close []func() error
 }
 
 func New(logPath string) *Streams {
@@ -46,7 +48,7 @@ func New(logPath string) *Streams {
 		// As a janky way to preserve error message, tee stderr to
 		// a temp file.
 		if f, err := os.Create(logPath); err == nil {
-			defer f.Close()
+			s.close = append(s.close, f.Close)
 			s.Err = io.MultiWriter(s.Err, f)
 		}
 	}
@@ -55,7 +57,7 @@ func New(logPath string) *Streams {
 	// set the input/output if we can actually open it.
 	tty, err := tty.Open()
 	if err == nil {
-		defer tty.Close()
+		s.close = append(s.close, tty.Close)
 		s.TTYIn = tty.Input()
 		s.TTYOut = tty.Output()
 	} else {
@@ -80,3 +82,12 @@ func (s *Streams) Wrap(fn func() error) error {
 	}
 	return nil
 }
+
+func (s *Streams) Close() error {
+	for _, fn := range s.close {
+		if err := fn(); err != nil {
+			return err
+		}
+	}
+	return nil
+}