Publish ITWorx Pulse source

internal/notification/dispatcher.go

@@ -0,0 +1,67 @@
+package notification
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+)
+
+type Dispatcher struct {
+	Store    Store
+	Channels map[string]ChannelSender
+	Limiter  *RateLimiter
+}
+
+func (dispatcher Dispatcher) DispatchDue(ctx context.Context, now time.Time, limit int) (int, error) {
+	if dispatcher.Store == nil {
+		return 0, ErrUnavailable
+	}
+	items, err := dispatcher.Store.ClaimDue(ctx, now.UTC(), limit)
+	if err != nil {
+		return 0, err
+	}
+	delivered := 0
+	for _, item := range items {
+		sender, ok := dispatcher.Channels[item.ChannelID]
+		if !ok || sender == nil {
+			_, completeErr := dispatcher.Store.Complete(ctx, item.ID, item.Attempts, false, errors.New("notification channel sender unavailable"), now)
+			if completeErr != nil {
+				return delivered, completeErr
+			}
+			continue
+		}
+		delivery := Delivery{ID: item.ID, EventType: item.EventType, Subject: item.Subject, Body: item.Body, IdempotencyKey: item.IdempotencyKey, Attempt: item.Attempts}
+		sendErr := sender.Send(ctx, delivery)
+		if _, completeErr := dispatcher.Store.Complete(ctx, item.ID, item.Attempts, sendErr == nil, sendErr, now); completeErr != nil {
+			return delivered, completeErr
+		}
+		if sendErr == nil {
+			delivered++
+		}
+	}
+	return delivered, nil
+}
+
+// Test sends a bounded, in-memory test delivery. It deliberately does not
+// enqueue or mutate an outbox record, and it uses the actor/channel pair as a
+// rate-limit key so test actions cannot become a delivery amplification path.
+func (dispatcher Dispatcher) Test(ctx context.Context, actor, channelID string, delivery Delivery, now time.Time) error {
+	if actor == "" || len(actor) > 160 || channelID == "" {
+		return fmt.Errorf("%w: test identity is invalid", ErrInvalid)
+	}
+	if dispatcher.Limiter == nil {
+		return ErrUnavailable
+	}
+	if !dispatcher.Limiter.Allow(actor+":"+channelID, now.UTC()) {
+		return fmt.Errorf("%w: notification test rate limit exceeded", ErrConflict)
+	}
+	sender, ok := dispatcher.Channels[channelID]
+	if !ok || sender == nil {
+		return ErrNotFound
+	}
+	if err := delivery.Validate(); err != nil {
+		return err
+	}
+	return sender.Send(ctx, delivery)
+}