Uzum - 2

Актуальность: Q1 2026

Задача: Conduct a code review, then fix the code. go/basics

// Storage - persistent slow data store, methods can take >= 100ms
type storage interface {
  GetTasks() ([]Task, error)
  CompleteTasks(ctx context.Context, tasks []Task) error
  AddBarcode(ctx context.Context, id, name string) (string, error)
  UpdateProduct(id string, barcodeID string) error
}

type metrics interface {
  CountExecutionDuration(process string, execTime float64)
}

type productsNotifier interface {
  NotifyAboutChanges(productID string) error
}

type restClient interface {
  GetBarcode(productID string) (string, string, error)
}

type Task struct {
  ID        string
  ProductID string
  Status    string
}

type Transaction interface {
  Start()
  Finish() error
}

type Worker struct {
  storage    storage
  restClient restClient
  notify     productsNotifier
  metrics    metrics
}

// The code is syntactically correct
// We use Go 1.24
// The service runs in k8s on 3 pods
// Processing is triggered every 30 seconds after the previous one completes on the pod (cron/supervisor + delay)
// REST client for getting barcode information from the tax authority
// Single interface for working with the DB
// In our service, the only external dependencies are PostgreSQL and NATS
// Agreement with another team to notify about any changes to Products entities

func (w *Worker) process(ctx context.Context) error {
  defer w.metrics.CountExecutionDuration("barcode_tasks ", time.Since(time.Now()).Seconds())

  tasks, err := w.storage.GetTasks() // query: select * from tasks where status = 'todo ';
  if err != nil {
    return err
  }

  eg, gctx := errGroup.WithContext(ctx)

  for _, task := range tasks {
    eg.Go(func() error {
      return w.handleTask(ctx, task)
    })
  }

  return w.storage.CompleteTasks(gctx, tasks) // query: update tasks set status = 'done 'where id in (:ids);
}

func (w *Worker) handleTask(ctx context.Context, task Task) error {
  barcodeID, name, err := w.restClient.GetBarcode(task.ProductID)
  if err != nil {
    return err
  }

  id, err := w.storage.AddBarcode(ctx, barcodeID, name) // query: insert into barcodes(origin_id, name) values (:id, :name);
  if err != nil {
    return err
  }

  if err := w.storage.UpdateProduct(task.ProductID, id); err != nil { // query: update products set barcode_id = %s where id = %s;
    return err
  }

  w.notify.NotifyAboutChanges(task.ProductID)
  log.Info(fmt.Sprintf("barcode task for product id completed: %s ", task.ProductID))

  return nil
}