image-builder-maintenance: implement graceful shutdown on signal

graceful shutdown on SIGTERM and SIGINT even when currently
executing SQL statements

cmd/image-builder-maintenance/main.go

@@ -3,6 +3,9 @@ package main
 import (
 	"context"
 	"fmt"
+	"os"
+	"os/signal"
+	"syscall"
 	"time"
 
 	"github.com/ilyakaznacheev/cleanenv"
@@ -11,8 +14,28 @@ import (
 )
 
 func main() {
-	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Hour)
-	defer cancel()
+	ctx, applicationCancel := context.WithCancel(context.Background())
+	defer applicationCancel()
+
+	terminationSignal := make(chan os.Signal, 1)
+	signal.Notify(terminationSignal, syscall.SIGTERM, syscall.SIGINT)
+	defer signal.Stop(terminationSignal)
+
+	// Channel to track graceful application shutdown
+	shutdownSignal := make(chan struct{})
+
+	go func() {
+		select {
+		case <-terminationSignal:
+			fmt.Println("Received termination signal, cancelling context...")
+			applicationCancel()
+		case <-shutdownSignal:
+			// Normal application shutdown, no logging
+		}
+	}()
+
+	ctx, cancelTimeout := context.WithTimeout(ctx, 2*time.Hour)
+	defer cancelTimeout()
 
 	logrus.SetReportCaller(true)
 
@@ -44,4 +67,5 @@ func main() {
 		logrus.Fatalf("Error during DBCleanup: %v", err)
 	}
 	logrus.Info("🦀🦀🦀 dbqueue cleanup done 🦀🦀🦀")
+	close(shutdownSignal)
 }