privval: add grpc (#5725)

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

test/e2e/pkg/manifest.go

@@ -78,8 +78,9 @@ type ManifestNode struct {
 	ABCIProtocol string `toml:"abci_protocol"`
 
 	// PrivvalProtocol specifies the protocol used to sign consensus messages:
-	// "file", "unix", or "tcp". Defaults to "file". For unix and tcp, the ABCI
+	// "file", "unix", "tcp", or "grpc". Defaults to "file". For tcp and unix, the ABCI
 	// application will launch a remote signer client in a separate goroutine.
+	// For grpc the ABCI application will launch a remote signer server.
 	// Only nodes with mode=validator will actually make use of this.
 	PrivvalProtocol string `toml:"privval_protocol"`
 

test/e2e/pkg/testnet.go

@@ -322,7 +322,7 @@ func (n Node) Validate(testnet Testnet) error {
 		return fmt.Errorf("invalid ABCI protocol setting %q", n.ABCIProtocol)
 	}
 	switch n.PrivvalProtocol {
-	case ProtocolFile, ProtocolUNIX, ProtocolTCP:
+	case ProtocolFile, ProtocolTCP, ProtocolGRPC, ProtocolUNIX:
 	default:
 		return fmt.Errorf("invalid privval protocol setting %q", n.PrivvalProtocol)
 	}