add basic scheduler

internal/app/app.go

@@ -2,6 +2,8 @@ package app
 
 import (
 	"log/slog"
+
+	"git.front.kjuulh.io/kjuulh/orbis/internal/scheduler"
 )
 
 type App struct {
@@ -17,3 +19,7 @@ func NewApp() *App {
 func (a *App) Logger() *slog.Logger {
 	return a.logger
 }
+
+func (a *App) Scheduler() *scheduler.Scheduler {
+	return scheduler.NewScheduler(a.logger)
+}

internal/app/logging.go

@@ -3,10 +3,26 @@ package app
 import (
 	"log/slog"
 	"os"
+	"strings"
 
 	"gitlab.com/greyxor/slogor"
 )
 
 func setupLogging() *slog.Logger {
-	return slog.New(slogor.NewHandler(os.Stderr))
+	logLevelRaw := os.Getenv("ORBIS_LOG_LEVEL")
+	var logLevel slog.Leveler
+	switch strings.ToLower(logLevelRaw) {
+	case "debug":
+		logLevel = slog.LevelDebug
+	case "info":
+		logLevel = slog.LevelInfo
+	case "warn":
+		logLevel = slog.LevelWarn
+	case "error":
+		logLevel = slog.LevelError
+	default:
+		logLevel = slog.LevelInfo
+	}
+
+	return slog.New(slogor.NewHandler(os.Stderr, slogor.SetLevel(logLevel)))
 }

internal/lifecycles/lifecycles.go

@@ -0,0 +1 @@
+package lifecycles

internal/scheduler/scheduler.go

@@ -0,0 +1,41 @@
+package scheduler
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"time"
+)
+
+type Scheduler struct {
+	logger *slog.Logger
+}
+
+func NewScheduler(logger *slog.Logger) *Scheduler {
+	return &Scheduler{
+		logger: logger,
+	}
+}
+
+func (s *Scheduler) Execute(ctx context.Context) error {
+	for {
+		select {
+		case <-ctx.Done():
+			s.logger.Info("gracefully shutting down scheduler")
+			return nil
+		default:
+			if err := s.process(ctx); err != nil {
+				return fmt.Errorf("scheduler failed: %w", err)
+			}
+		}
+	}
+}
+
+func (s *Scheduler) process(ctx context.Context) error {
+	s.logger.Debug("scheduler processing items")
+
+	// FIXME: simulate work
+	time.Sleep(time.Second * 5)
+
+	return nil
+}

internal/utilities/singleton.go

@@ -0,0 +1,25 @@
+package utilities
+
+import (
+	"fmt"
+	"sync"
+)
+
+func Singleton[T any](init func() (T, error)) func() T {
+	var (
+		once sync.Once
+		t    T
+	)
+
+	return func() T {
+		once.Do(func() {
+			var err error
+			t, err = init()
+			if err != nil {
+				panic(fmt.Sprintf("creating %T failed: %s", t, err))
+			}
+		})
+
+		return t
+	}
+}