cmd/combine: ensure output dir exists (#2537)

Ensures the output folder exists before writing combined keys to it.

category: bug
ticket: #2536

cmd/combine/combine.go

@@ -129,6 +129,10 @@ func Combine(ctx context.Context, inputDir, outputDir string, force, noverify bo
 		combinedKeys = append(combinedKeys, secret)
 	}
 
+	if err := os.MkdirAll(outputDir, 0o755); err != nil {
+		return errors.Wrap(err, "ensure output directory exists", z.Str("output_dir", outputDir))
+	}
+
 	ksPath := filepath.Join(outputDir, "keystore-0.json")
 	_, err = os.Stat(ksPath)
 	if err == nil && !force {

cmd/combine/combine_test.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"path"
 	"path/filepath"
 	"testing"
 
@@ -249,7 +250,7 @@ func combineTest(
 	}
 
 	dir := t.TempDir()
-	od := t.TempDir()
+	od := path.Join(dir, "validator_keys")
 
 	// flatten secrets, each validator slice is unpacked in a flat structure
 	var rawSecrets []tbls.PrivateKey

eth2util/keystore/keystore.go

@@ -52,11 +52,17 @@ func StoreKeysInsecure(secrets []tbls.PrivateKey, dir string, _ confirmInsecure)
 
 // StoreKeys stores the secrets in dir/keystore-%d.json EIP 2335 Keystore files
 // with new random passwords stored in dir/Keystore-%d.txt.
+//
+// Note it doesn't ensure the folder dir exists.
 func StoreKeys(secrets []tbls.PrivateKey, dir string) error {
 	return storeKeysInternal(secrets, dir, "keystore-%d.json")
 }
 
 func storeKeysInternal(secrets []tbls.PrivateKey, dir string, filenameFmt string, opts ...keystorev4.Option) error {
+	if err := checkDir(dir); err != nil {
+		return err
+	}
+
 	type data struct {
 		index  int
 		secret tbls.PrivateKey
@@ -206,3 +212,16 @@ func randomHex32() (string, error) {
 
 	return hex.EncodeToString(b), nil
 }
+
+// checkDir checks if dir exists and is a directory.
+func checkDir(dir string) error {
+	if info, err := os.Stat(dir); os.IsNotExist(err) {
+		return errors.Wrap(err, "keystore dir does not exist", z.Str("dir", dir))
+	} else if err != nil {
+		return errors.Wrap(err, "check keystore dir", z.Str("dir", dir))
+	} else if !info.IsDir() {
+		return errors.New("keystore dir is not a directory", z.Str("dir", dir))
+	}
+
+	return nil
+}

eth2util/keystore/keystore_test.go

@@ -296,3 +296,11 @@ func storeNewKeyForT(t *testing.T, target string) tbls.PrivateKey {
 
 	return secret
 }
+
+func TestCheckDir(t *testing.T) {
+	err := keystore.StoreKeys(nil, "foo")
+	require.ErrorContains(t, err, "not exist")
+
+	err = keystore.StoreKeys(nil, "testdata/keystore-scrypt.json")
+	require.ErrorContains(t, err, "not a directory")
+}