update

pkg/inventory/redis_service.go

@@ -2,6 +2,7 @@ package inventory
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"strconv"
@@ -80,6 +81,32 @@ func (s *RedisInventoryService) UpdateInventory(ctx context.Context, rdb redis.P
 	return cmd.Err()
 }
 
+func (s *RedisInventoryService) IncrementInventory(ctx context.Context, rdb redis.Pipeliner, sku SKU, locationID LocationID, quantity int64) error {
+	key := getInventoryKey(sku, locationID)
+	cmd := rdb.IncrBy(ctx, key, quantity)
+	return cmd.Err()
+}
+
+func (s *RedisInventoryService) SendInventoryChanged(ctx context.Context, sku SKU, locationID LocationID) error {
+	key := getInventoryKey(sku, locationID)
+	currentValCmd := s.client.Get(ctx, key)
+	if err := currentValCmd.Err(); err != nil {
+		return err
+	}
+	currentVal, err := currentValCmd.Int64()
+	if err != nil {
+		return err
+	}
+	payloadMap := map[string]int64{key: currentVal}
+	payloadBytes, err := json.Marshal(payloadMap)
+	if err != nil {
+		return err
+	}
+	payload := string(payloadBytes)
+	cmd := s.client.Publish(ctx, "inventory_changed", payload)
+	return cmd.Err()
+}
+
 var (
 	ErrInsufficientInventory = errors.New("insufficient inventory")
 	ErrInvalidQuantity       = errors.New("invalid quantity")