Internal cache first get

[derkan]

Hi,

You check redis cache first and fill it later.

// NOTE: This is an example. The cache has this functionality internally.
func (o *OrderAPI) OrderStatus(ctx context.Context, id string) (string, error) {
	cacheKey := "order-status-" + id
	fetchFn := func(ctx context.Context) (string, error) {
		// Check redis cache first.
		if orderStatus, ok := o.redisClient.Get(cacheKey); ok {
			return orderStatus, nil
		}

		// Fetch the order status from the underlying data source.
		var response OrderStatusResponse
		err := requests.URL(o.baseURL).
			Param("id", id).
			ToJSON(&response).
			Fetch(ctx)
		if err != nil {
			return "", err
		}

		// Add the order status to the redis cache.
		go func() { o.RedisClient.Set(cacheKey, response.OrderStatus, time.Hour) }()

		return response.OrderStatus, nil
	}

	return o.GetOrFetch(ctx, id, fetchFn)
}```

Why not make it always check from local? This will be much faster. Of cource this needs firing local cache update when distributedCache(redis) changes.

[viccon]

Hi and sorry for the late response. The fetchFn which you pass to GetOrFetch is only called if you receive a cache miss from the in-memory cache or if the data is old enough to warrant a refresh