Other: Single instance

internal/focus/service.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 
+	"github.com/Masterminds/semver/v3"
 	"github.com/ProtonMail/proton-bridge/v2/internal/focus/proto"
 	"google.golang.org/grpc"
 	"google.golang.org/protobuf/types/known/emptypb"
@@ -24,11 +25,12 @@ type Service struct {
 	server   *grpc.Server
 	listener net.Listener
 	raiseCh  chan struct{}
+	version  *semver.Version
 }
 
 // NewService creates a new focus service.
 // It listens on the local host and port 1042 (by default).
-func NewService() (*Service, error) {
+func NewService(version *semver.Version) (*Service, error) {
 	listener, err := net.Listen("tcp", net.JoinHostPort(Host, fmt.Sprint(Port)))
 	if err != nil {
 		return nil, fmt.Errorf("failed to listen: %w", err)
@@ -38,6 +40,7 @@ func NewService() (*Service, error) {
 		server:   grpc.NewServer(),
 		listener: listener,
 		raiseCh:  make(chan struct{}, 1),
+		version:  version,
 	}
 
 	proto.RegisterFocusServer(service.server, service)
@@ -57,6 +60,13 @@ func (service *Service) Raise(context.Context, *emptypb.Empty) (*emptypb.Empty,
 	return &emptypb.Empty{}, nil
 }
 
+// Version implements the gRPC FocusService interface; it returns the version of the service.
+func (service *Service) Version(context.Context, *emptypb.Empty) (*proto.VersionResponse, error) {
+	return &proto.VersionResponse{
+		Version: service.version.Original(),
+	}, nil
+}
+
 // GetRaiseCh returns a channel on which events are sent when the application should be raised.
 func (service *Service) GetRaiseCh() <-chan struct{} {
 	return service.raiseCh