Don't cache local keys by the cache keyring. (#190)

relayer/cmd/cli/keyring.go

@@ -238,6 +238,12 @@ func (ck *cacheKeyring) MigrateAll() ([]*keyring.Record, error) {
 }
 
 func (ck *cacheKeyring) cacheKey(keyInfo *keyring.Record) error {
+	// If the local is nil, the `ExportPrivKeyArmor` will return `keyring.ErrPrivKeyExtr`.
+	// Usually it happens to the imported keys with the public key only, that's why we don't cache such keys.
+	if keyInfo.GetLocal() == nil {
+		return nil
+	}
+
 	pass := uuid.NewString()
 	armor, err := ck.parentKeyring.ExportPrivKeyArmor(keyInfo.Name, pass)
 	if err != nil {