fix: only poll for deployment changes when needed

backend/controller/controller.go

@@ -1552,6 +1552,8 @@ func (s *Service) watchModuleChanges(ctx context.Context, sendChange func(respon
 	s.dal.DeploymentChanges.Subscribe(deploymentChanges)
 	defer s.dal.DeploymentChanges.Unsubscribe(deploymentChanges)
 
+	go s.dal.PollDeployments(ctx)
+
 	for {
 		select {
 		case <-ctx.Done():

backend/controller/dal/dal.go

@@ -214,13 +214,13 @@ func WithReservation(ctx context.Context, reservation Reservation, fn func() err
 func New(ctx context.Context, pool *pgxpool.Pool) (*DAL, error) {
 	_, err := pool.Acquire(ctx)
 	if err != nil {
-		return nil, fmt.Errorf("failed to acquire PG PubSub connection: %w", err)
+		return nil, fmt.Errorf("could not acquire connection: %w", err)
 	}
 	dal := &DAL{
 		db:                sql.NewDB(pool),
 		DeploymentChanges: pubsub.New[DeploymentNotification](),
 	}
-	go dal.pollDeployments(ctx)
+
 	return dal, nil
 }
 
@@ -233,7 +233,6 @@ type DAL struct {
 
 	// DeploymentChanges is a Topic that receives changes to the deployments table.
 	DeploymentChanges *pubsub.Topic[DeploymentNotification]
-	// RouteChanges is a Topic that receives changes to the routing table.
 }
 
 // Tx is DAL within a transaction.

backend/controller/dal/notify.go

@@ -72,7 +72,7 @@ func deploymentStateFromDeployment(deployment Deployment) (deploymentState, erro
 	}, nil
 }
 
-func (d *DAL) pollDeployments(ctx context.Context) {
+func (d *DAL) PollDeployments(ctx context.Context) {
 	logger := log.FromContext(ctx)
 	retry := backoff.Backoff{}