Exemple #1
0
func (c RedisCache) Decrement(key string, delta uint64) (newValue uint64, err error) {
	conn := c.pool.Get()
	defer conn.Close()
	// Check for existance *before* increment as per the cache contract.
	// redis will auto create the key, and we don't want that, hence the exists call
	existed, err := exists(conn, key)
	if err != nil {
		return 0, err
	} else if !existed {
		return 0, ErrCacheMiss
	}
	// Decrement contract says you can only go to 0
	// so we go fetch the value and if the delta is greater than the amount,
	// 0 out the value
	currentVal, err := redis.Int64(conn.Do("GET", key))
	if err != nil {
		return 0, err
	}
	if delta > uint64(currentVal) {
		tempint, err := redis.Int64(conn.Do("DECRBY", key, currentVal))
		return uint64(tempint), err
	}
	tempint, err := redis.Int64(conn.Do("DECRBY", key, delta))
	return uint64(tempint), err
}
Exemple #2
0
func (c RedisCache) Increment(key string, delta uint64) (uint64, error) {
	conn := c.pool.Get()
	defer conn.Close()
	// Check for existance *before* increment as per the cache contract.
	// redis will auto create the key, and we don't want that. Since we need to do increment
	// ourselves instead of natively via INCRBY (redis doesn't support wrapping), we get the value
	// and do the exists check this way to minimize calls to Redis
	val, err := conn.Do("GET", key)
	if err != nil {
		return 0, err
	} else if val == nil {
		return 0, ErrCacheMiss
	}
	currentVal, err := redis.Int64(val, nil)
	if err != nil {
		return 0, err
	}
	var sum int64 = currentVal + int64(delta)
	_, err = conn.Do("SET", key, sum)
	if err != nil {
		return 0, err
	}
	return uint64(sum), nil
}