feat(app): add TaskPoller, wire DI, and add task integration tests

internal/app/task_poller.go

@@ -0,0 +1,61 @@
+package app
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+// TaskPollable defines the interface for refreshing stale task statuses.
+type TaskPollable interface {
+	RefreshStaleTasks(ctx context.Context) error
+}
+
+// TaskPoller periodically polls Slurm for task status updates via TaskPollable.
+type TaskPoller struct {
+	taskSvc  TaskPollable
+	interval time.Duration
+	cancel   context.CancelFunc
+	wg       sync.WaitGroup
+	logger   *zap.Logger
+}
+
+// NewTaskPoller creates a new TaskPoller with the given service, interval, and logger.
+func NewTaskPoller(taskSvc TaskPollable, interval time.Duration, logger *zap.Logger) *TaskPoller {
+	return &TaskPoller{
+		taskSvc:  taskSvc,
+		interval: interval,
+		logger:   logger,
+	}
+}
+
+// Start launches the background goroutine that periodically refreshes stale tasks.
+func (p *TaskPoller) Start(ctx context.Context) {
+	ctx, p.cancel = context.WithCancel(ctx)
+	p.wg.Add(1)
+	go func() {
+		defer p.wg.Done()
+		ticker := time.NewTicker(p.interval)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				if err := p.taskSvc.RefreshStaleTasks(ctx); err != nil {
+					p.logger.Error("failed to refresh stale tasks", zap.Error(err))
+				}
+			}
+		}
+	}()
+}
+
+// Stop cancels the background goroutine and waits for it to finish.
+func (p *TaskPoller) Stop() {
+	if p.cancel != nil {
+		p.cancel()
+	}
+	p.wg.Wait()
+}