add orbis demo

README.md

@@ -0,0 +1,3 @@
+# Orbis
+
+!(orbis demo)[assets/demo.gif]

cmd/orbis/main.go

@@ -1,8 +1,12 @@
 package main
 
 import (
+	"context"
 	"fmt"
 	"os"
+	"os/signal"
+	"syscall"
+	"time"
 
 	"git.front.kjuulh.io/kjuulh/orbis/internal/app"
 	"github.com/joho/godotenv"
@@ -17,7 +21,23 @@ func main() {
 
 	app := app.NewApp()
 
-	if err := newRoot(app).Execute(); err != nil {
+	ctx, cancel := context.WithCancel(context.Background())
+	stop := make(chan os.Signal, 1)
+	signal.Notify(stop, os.Interrupt, syscall.SIGTERM)
+
+	go func() {
+		<-stop
+
+		app.Logger().Info("stop signal received: shutting down orbis")
+		cancel()
+
+		// Start timer for hard stop
+		time.Sleep(time.Second * 10)
+		fmt.Println("orbis failed to stop in time, forced to hard cancel")
+		os.Exit(1)
+	}()
+
+	if err := newRoot(app).ExecuteContext(ctx); err != nil {
 		fmt.Printf("%s\n", err)
 		os.Exit(1)
 	}

internal/scheduler/scheduler.go

@@ -18,10 +18,20 @@ func NewScheduler(logger *slog.Logger) *Scheduler {
 }
 
 func (s *Scheduler) Execute(ctx context.Context) error {
+	acquiredLeader, err := s.acquireLeader(ctx)
+	if err != nil {
+		return err
+	}
+
+	if !acquiredLeader {
+		s.logger.Info("gracefully shutting down non-elected scheduler")
+		return nil
+	}
+
 	for {
 		select {
 		case <-ctx.Done():
-			s.logger.Info("gracefully shutting down scheduler")
+			s.logger.Info("gracefully shutting down elected scheduler")
 			return nil
 		default:
 			if err := s.process(ctx); err != nil {
@@ -31,11 +41,26 @@ func (s *Scheduler) Execute(ctx context.Context) error {
 	}
 }
 
+func (s *Scheduler) acquireLeader(ctx context.Context) (bool, error) {
+	for {
+		select {
+		case <-ctx.Done():
+			return false, nil
+
+		default:
+			// Attempt to acquire leader
+			//
+			return true, nil
+
+		}
+	}
+}
+
 func (s *Scheduler) process(ctx context.Context) error {
 	s.logger.Debug("scheduler processing items")
 
 	// FIXME: simulate work
-	time.Sleep(time.Second * 5)
+	time.Sleep(time.Second * 2)
 
 	return nil
 }