chore: add Caddy gRPC service to retrieve Caddyfile config from machines

internal/machine/caddyconfig/server.go

@@ -0,0 +1,39 @@
+package caddyconfig
+
+import (
+	"context"
+	"os"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/emptypb"
+	"google.golang.org/protobuf/types/known/timestamppb"
+
+	"github.com/psviderski/uncloud/internal/machine/api/pb"
+)
+
+// Server implements the gRPC Caddy service.
+type Server struct {
+	pb.UnimplementedCaddyServer
+	service *Service
+}
+
+func NewServer(service *Service) *Server {
+	return &Server{service: service}
+}
+
+// GetConfig retrieves the current Caddy configuration from the machine.
+func (s *Server) GetConfig(ctx context.Context, _ *emptypb.Empty) (*pb.GetCaddyConfigResponse, error) {
+	caddyfile, modifiedAt, err := s.service.Caddyfile()
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, status.Errorf(codes.NotFound, err.Error())
+		}
+		return nil, status.Errorf(codes.Internal, err.Error())
+	}
+
+	return &pb.GetCaddyConfigResponse{
+		Caddyfile:  caddyfile,
+		ModifiedAt: timestamppb.New(modifiedAt),
+	}, nil
+}