rpc: support personal apis with different keyring backends (#591)

* UPDATE Unlock keyring on start

* ADD comment

* ADD validation

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

server/start.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/cosmos/cosmos-sdk/codec"
+	"github.com/cosmos/cosmos-sdk/crypto/keyring"
 
 	"github.com/spf13/cobra"
 
@@ -101,6 +102,17 @@ which accepts a path for the resulting pprof file.
 				return startStandAlone(serverCtx, appCreator)
 			}
 
+			serverCtx.Logger.Info("Unlocking keyring")
+
+			// fire unlock precess for keyring
+			keyringBackend, _ := cmd.Flags().GetString(flags.FlagKeyringBackend)
+			if keyringBackend == keyring.BackendFile {
+				_, err = clientCtx.Keyring.List()
+				if err != nil {
+					return err
+				}
+			}
+
 			serverCtx.Logger.Info("starting ABCI with Tendermint")
 
 			// amino is needed here for backwards compatibility of REST routes