The very basic client app, not adapted for mobiles.

client/internal/application/application.go

@@ -0,0 +1,214 @@
+package application
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"os"
+	"strings"
+	"time"
+
+	"fyne.io/fyne/v2"
+)
+
+var (
+	errApplication  = errors.New("application")
+	errNoMainWindow = errors.New("no main window service registered")
+)
+
+// Application is a lifecycle controlling structure for application.
+type Application struct {
+	fyneApp  fyne.App
+	services []Service
+}
+
+// New creates new instance of lifecycle controlling structure.
+func New() *Application {
+	appl := &Application{}
+
+	appl.initialize()
+
+	return appl
+}
+
+func (a *Application) configure() error {
+	// First iteration - core services.
+	for _, service := range a.services {
+		if !strings.Contains(service.Name(), "core/") {
+			continue
+		}
+
+		slog.Debug("Launching configuration procedure for service", "service", service.Name())
+
+		if err := service.Configure(); err != nil {
+			return fmt.Errorf("configure service '%s': %w", service.Name(), err)
+		}
+	}
+
+	// Second iteration - rest of the services.
+	for _, service := range a.services {
+		if strings.Contains(service.Name(), "core/") {
+			continue
+		}
+
+		slog.Debug("Launching configuration procedure for service", "service", service.Name())
+
+		if err := service.Configure(); err != nil {
+			return fmt.Errorf("configure service '%s': %w", service.Name(), err)
+		}
+	}
+
+	return nil
+}
+
+func (a *Application) connectDependencies() error {
+	// First iteration - core services.
+	for _, service := range a.services {
+		if !strings.Contains(service.Name(), "core/") {
+			continue
+		}
+
+		slog.Debug("Connecting dependencies for service.", "service", service.Name())
+
+		if err := service.ConnectDependencies(); err != nil {
+			return fmt.Errorf("connect dependencies for service '%s': %w", service.Name(), err)
+		}
+	}
+
+	// Second iteration - rest of the services.
+	for _, service := range a.services {
+		if strings.Contains(service.Name(), "core/") {
+			continue
+		}
+
+		slog.Debug("Connecting dependencies for service.", "service", service.Name())
+
+		if err := service.ConnectDependencies(); err != nil {
+			return fmt.Errorf("connect dependencies for service '%s': %w", service.Name(), err)
+		}
+	}
+
+	return nil
+}
+
+// ContextWithTimeout returns context.Context with requested timeout.
+func (a *Application) ContextWithTimeout(timeout time.Duration) context.Context {
+	ctx, cancelFunc := context.WithTimeout(context.Background(), timeout)
+
+	// As we do not need to call cancelFunc - make linter happy.
+	// This probably will lead to context leak, so it should be investigated.
+	go func(_ context.CancelFunc) {}(cancelFunc)
+
+	return ctx
+}
+
+func (a *Application) initialize() {
+	a.services = make([]Service, 0)
+
+	a.initializeFyne()
+}
+
+func (a *Application) launchStartupTasks() error {
+	for _, service := range a.services {
+		if strings.Contains(service.Name(), "mainwindow") {
+			continue
+		}
+
+		if !strings.Contains(service.Name(), "core/") {
+			continue
+		}
+
+		slog.Debug("Launching startup tasks for service.", "service", service.Name())
+
+		if err := service.LaunchStartupTasks(); err != nil {
+			return fmt.Errorf("launch startup tasks for core/%s: %w", service.Name(), err)
+		}
+	}
+
+	for _, service := range a.services {
+		if strings.Contains(service.Name(), "core/") {
+			continue
+		}
+
+		slog.Debug("Launching startup tasks for service.", "service", service.Name())
+
+		if err := service.LaunchStartupTasks(); err != nil {
+			return fmt.Errorf("launch startup tasks for core/%s: %w", service.Name(), err)
+		}
+	}
+
+	var mainWindowService Service
+
+	for _, srv := range a.services {
+		if srv.Name() == "core/mainwindow" {
+			mainWindowService = srv
+
+			break
+		}
+	}
+
+	if mainWindowService == nil {
+		return fmt.Errorf("launch startup tasks: %w", errNoMainWindow)
+	}
+
+	if err := mainWindowService.LaunchStartupTasks(); err != nil {
+		return fmt.Errorf("launch startup tasks for %s: %w", mainWindowService.Name(), err)
+	}
+
+	return nil
+}
+
+// Shutdown stops application
+func (a *Application) Shutdown() error {
+	slog.Info("Stopping pztrn's Bunker...")
+
+	// Сначала тушим фичи.
+	for _, service := range a.services {
+		if !strings.Contains(service.Name(), "features/") {
+			continue
+		}
+
+		slog.Debug("Shutting down service.", "service", service.Name())
+
+		if err := service.Shutdown(); err != nil {
+			return fmt.Errorf("shutting down service '%s': %w", service.Name(), err)
+		}
+	}
+
+	// Потом тушим ядро.
+	for _, service := range a.services {
+		if !strings.Contains(service.Name(), "core/") {
+			continue
+		}
+
+		slog.Debug("Shutting down service.", "service", service.Name())
+
+		if err := service.Shutdown(); err != nil {
+			return fmt.Errorf("shutting down service '%s': %w", service.Name(), err)
+		}
+	}
+
+	os.Exit(0)
+
+	return nil
+}
+
+// Start запускает приложение.
+func (a *Application) Start() error {
+	if err := a.connectDependencies(); err != nil {
+		return fmt.Errorf("%w: %w", errApplication, err)
+	}
+
+	if err := a.configure(); err != nil {
+		return fmt.Errorf("%w: %w", errApplication, err)
+	}
+
+	if err := a.launchStartupTasks(); err != nil {
+		return fmt.Errorf("%w: %w", errApplication, err)
+	}
+
+	a.fyneApp.Run()
+
+	return nil
+}

client/internal/application/fyne.go

@@ -0,0 +1,17 @@
+package application
+
+import (
+	"bunker/commons"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/app"
+)
+
+// Fyne возвращает экземпляр Fyne для взаимодействия с ним.
+func (a *Application) Fyne() fyne.App {
+	return a.fyneApp
+}
+
+func (a *Application) initializeFyne() {
+	a.fyneApp = app.NewWithID(commons.ClientAppID)
+}

client/internal/application/service.go

@@ -0,0 +1,80 @@
+package application
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	// ErrServiceAlreadyRegistered returns if trying to register a service with name already taken by other service.
+	ErrServiceAlreadyRegistered = errors.New("service with such name already registered")
+	// ErrServiceNotFound returns if trying to gather service with unknown name.
+	ErrServiceNotFound = errors.New("service with such name wasn't found")
+)
+
+// Service is an interface every service should conform to. Specific services will have own interface for
+// cross-service interation.
+type Service interface {
+	// Configure configures service. Called after ConnectDependencies and before LaunchStartupTasks.
+	Configure() error
+	// ConnectDependencies gets neccessary dependencies.
+	ConnectDependencies() error
+	// Initialize initializes service's internal state. Called while registering service with Application
+	// lifecycle controller.
+	Initialize() error
+	// Name returns service name.
+	Name() string
+	// LaunchStartupTasks launches tasks on application start. Called after ConnectDependencies and Configure.
+	LaunchStartupTasks() error
+	// Shutdown stops service.
+	Shutdown() error
+}
+
+// RegisterService registering service with lifecycle controller for later use in any other service.
+func (a *Application) RegisterService(srv Service) error {
+	var found bool
+
+	for _, knownService := range a.services {
+		if srv.Name() == knownService.Name() {
+			found = true
+
+			break
+		}
+	}
+
+	if found {
+		return fmt.Errorf(
+			"%w: RegisterService: check for service '%s' registration: %w",
+			errApplication,
+			srv.Name(),
+			ErrServiceAlreadyRegistered,
+		)
+	}
+
+	if err := srv.Initialize(); err != nil {
+		return fmt.Errorf("%w: RegisterService: initialize service '%s': %w", errApplication, srv.Name(), err)
+	}
+
+	a.services = append(a.services, srv)
+
+	return nil
+}
+
+// Service returns requested service.
+func (a *Application) Service(name string) Service {
+	var srv Service
+
+	for _, knownService := range a.services {
+		if knownService.Name() == name {
+			srv = knownService
+
+			break
+		}
+	}
+
+	if srv == nil {
+		return nil
+	}
+
+	return srv
+}