privval: add grpc (#5725)

Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>

test/e2e/app/main.go

@@ -3,12 +3,14 @@ package main
 import (
 	"errors"
 	"fmt"
+	"net"
 	"os"
 	"path/filepath"
 	"strconv"
 	"time"
 
 	"github.com/spf13/viper"
+	"google.golang.org/grpc"
 
 	"github.com/tendermint/tendermint/abci/server"
 	"github.com/tendermint/tendermint/config"
@@ -19,6 +21,8 @@ import (
 	"github.com/tendermint/tendermint/node"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/privval"
+	grpcprivval "github.com/tendermint/tendermint/privval/grpc"
+	privvalproto "github.com/tendermint/tendermint/proto/tendermint/privval"
 	"github.com/tendermint/tendermint/proxy"
 	mcs "github.com/tendermint/tendermint/test/maverick/consensus"
 	maverick "github.com/tendermint/tendermint/test/maverick/node"
@@ -182,6 +186,24 @@ func startSigner(cfg *Config) error {
 		dialFn = privval.DialTCPFn(address, 3*time.Second, ed25519.GenPrivKey())
 	case "unix":
 		dialFn = privval.DialUnixFn(address)
+	case "grpc":
+		lis, err := net.Listen("tcp", address)
+		if err != nil {
+			return err
+		}
+		ss := grpcprivval.NewSignerServer(cfg.ChainID, filePV, logger)
+
+		s := grpc.NewServer()
+
+		privvalproto.RegisterPrivValidatorAPIServer(s, ss)
+
+		go func() { // no need to clean up since we remove docker containers
+			if err := s.Serve(lis); err != nil {
+				panic(err)
+			}
+		}()
+
+		return nil
 	default:
 		return fmt.Errorf("invalid privval protocol %q", protocol)
 	}
@@ -193,6 +215,7 @@ func startSigner(cfg *Config) error {
 	if err != nil {
 		return err
 	}
+
 	logger.Info(fmt.Sprintf("Remote signer connecting to %v", cfg.PrivValServer))
 	return nil
 }