feat(lk): use tmp directory while preparing files (#441)

cmd/lk/app.go

@@ -267,22 +267,32 @@ func setupTemplate(ctx context.Context, cmd *cli.Command) error {
 }
 
 func cloneTemplate(_ context.Context, cmd *cli.Command, url, appName string) error {
+	var out []byte
 	var cmdErr error
+
+	tempName, relocate, cleanup := useTempPath(appName)
+	defer cleanup()
+
 	if err := spinner.New().
 		Title("Cloning template from " + url).
 		Action(func() {
-			c := exec.Command("git", "clone", "--depth=1", url, appName)
-			var out []byte
-			if out, cmdErr = c.CombinedOutput(); len(out) > 0 && cmd.Bool("verbose") {
-				fmt.Println(string(out))
-			}
-			os.RemoveAll(path.Join(appName, ".git"))
+			c := exec.Command("git", "clone", "--depth=1", url, tempName)
+			out, cmdErr = c.CombinedOutput()
+			os.RemoveAll(path.Join(tempName, ".git"))
 		}).
 		Style(theme.Focused.Title).
 		Run(); err != nil {
 		return err
 	}
-	return cmdErr
+
+	if len(out) > 0 && (cmdErr != nil || cmd.Bool("verbose")) {
+		fmt.Println(string(out))
+	}
+
+	if cmdErr != nil {
+		return cmdErr
+	}
+	return relocate()
 }
 
 func instantiateEnv(ctx context.Context, cmd *cli.Command, rootPath string, addlEnv *map[string]string) error {

cmd/lk/utils.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"net/url"
 	"os"
+	"path"
 	"path/filepath"
 	"strings"
 
@@ -30,6 +31,7 @@ import (
 	"github.com/twitchtv/twirp"
 	"github.com/urfave/cli/v3"
 
+	"github.com/livekit/protocol/utils/guid"
 	"github.com/livekit/protocol/utils/interceptors"
 
 	"github.com/livekit/livekit-cli/pkg/config"
@@ -153,6 +155,20 @@ func wrapWith(wrap string) func(string) string {
 	}
 }
 
+// Provides a temporary path, a function to relocate it to a permanent path,
+// and a function to clean up the temporary path that should always be deferred
+// in the case of a failure to relocate.
+func useTempPath(permanentPath string) (string, func() error, func() error) {
+	tempPath := path.Join(os.TempDir(), guid.New("LK_"))
+	relocate := func() error {
+		return os.Rename(tempPath, permanentPath)
+	}
+	cleanup := func() error {
+		return os.RemoveAll(tempPath)
+	}
+	return tempPath, relocate, cleanup
+}
+
 func hashString(str string) (string, error) {
 	hash := sha256.New()
 	if _, err := hash.Write([]byte(str)); err != nil {