Add CloseDB() call

PENDING.md

@@ -146,6 +146,7 @@ FEATURES
   basis for the validator commission model.
   * [x/auth] Support account removal in the account mapper.
   * [client/keys] [\#2544](https://github.com/cosmos/cosmos-sdk/issues/2544) Add `GetReadOnlyKeyBase()` to acquire read-only LevelDB databases.
+  * [crypto/keys] [\#2544](https://github.com/cosmos/cosmos-sdk/issues/2544) Add `CloseDB()` to release locks and close the storage backend.
 
 * Tendermint
 

crypto/keys/keybase.go

@@ -426,6 +426,11 @@ func (kb dbKeybase) Update(name, oldpass string, getNewpass func() (string, erro
 	}
 }
 
+// CloseDB releases the lock and closes the storage backend.
+func (kb dbKeybase) CloseDB() {
+	kb.db.Close()
+}
+
 func (kb dbKeybase) writeLocalKey(priv tmcrypto.PrivKey, name, passphrase string) Info {
 	// encrypt private key using passphrase
 	privArmor := mintkey.EncryptArmorPrivKey(priv, passphrase)

crypto/keys/types.go

@@ -47,6 +47,9 @@ type Keybase interface {
 
 	// *only* works on locally-stored keys. Temporary method until we redo the exporting API
 	ExportPrivateKeyObject(name string, passphrase string) (crypto.PrivKey, error)
+
+	// Close the database
+	CloseDB()
 }
 
 // KeyType reflects a human-readable type for key listing.