Method ActivePartitionForKey

ring/partition_ring.go:137–158

ActivePartitionForKey returns partition for the given key. Only active partitions are considered. Only one partition is returned: in other terms, the replication factor is always 1.

(key uint32)

// ActivePartitionForKey returns partition for the given key. Only active partitions are considered.
// Only one partition is returned: in other terms, the replication factor is always 1.
func (r *PartitionRing) ActivePartitionForKey(key uint32) (int32, error) {
	var (
		start       = searchToken(r.ringTokens, key)
		iterations  = 0
		tokensCount = len(r.ringTokens)
	)

	for i := start; iterations < tokensCount; i++ {
		iterations++

		if i >= tokensCount {
			i %= tokensCount
		}

		// If the partition is not active we'll keep walking the ring.
		if r.ringPartitionActive[i] {
			return r.ringPartitionIDs[i], nil
		}
	}

	return 0, ErrNoActivePartitionFound
}

// ShuffleShardSize returns number of partitions that would be in the result of ShuffleShard call with the same size.
func (r *PartitionRing) ShuffleShardSize(size int) int {