mirror of
https://gitlab.com/pulsechaincom/prysm-pulse.git
synced 2024-12-25 04:47:18 +00:00
142 lines
4.3 KiB
Go
142 lines
4.3 KiB
Go
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package cache
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import (
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"errors"
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"strconv"
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"sync"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promauto"
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"github.com/prysmaticlabs/prysm/shared/params"
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"github.com/prysmaticlabs/prysm/shared/sliceutil"
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"k8s.io/client-go/tools/cache"
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)
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var (
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// ErrNotCommittee will be returned when a cache object is not a pointer to
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// a Committee struct.
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ErrNotCommittee = errors.New("object is not a committee struct")
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// maxShuffledIndicesSize defines the max number of shuffled indices list can cache.
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// 2 for current epoch and next epoch.
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maxShuffledIndicesSize = 2
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// CommitteeCacheMiss tracks the number of committee requests that aren't present in the cache.
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CommitteeCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
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Name: "committee_cache_miss",
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Help: "The number of committee requests that aren't present in the cache.",
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})
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// CommitteeCacheHit tracks the number of committee requests that are in the cache.
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CommitteeCacheHit = promauto.NewCounter(prometheus.CounterOpts{
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Name: "committee_cache_hit",
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Help: "The number of committee requests that are present in the cache.",
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})
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)
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// Committee defines the committee per epoch and shard.
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type Committee struct {
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StartShard uint64
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CommitteeCount uint64
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Epoch uint64
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Committee []uint64
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}
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// CommitteeCache is a struct with 1 queue for looking up shuffled indices list by epoch and shard.
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type CommitteeCache struct {
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CommitteeCache *cache.FIFO
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lock sync.RWMutex
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}
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// committeeKeyFn takes the epoch as the key to retrieve shuffled indices of a committee in a given epoch.
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func committeeKeyFn(obj interface{}) (string, error) {
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info, ok := obj.(*Committee)
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if !ok {
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return "", ErrNotCommittee
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}
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return strconv.Itoa(int(info.Epoch)), nil
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}
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// NewCommitteeCache creates a new committee cache for storing/accessing shuffled indices of a committee.
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func NewCommitteeCache() *CommitteeCache {
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return &CommitteeCache{
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CommitteeCache: cache.NewFIFO(committeeKeyFn),
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}
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}
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// ShuffledIndices fetches the shuffled indices by epoch and shard. Every list of indices
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// represent one committee. Returns true if the list exists with epoch and shard. Otherwise returns false, nil.
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func (c *CommitteeCache) ShuffledIndices(epoch uint64, shard uint64) ([]uint64, error) {
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c.lock.RLock()
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defer c.lock.RUnlock()
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obj, exists, err := c.CommitteeCache.GetByKey(strconv.Itoa(int(epoch)))
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if err != nil {
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return nil, err
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}
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if exists {
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CommitteeCacheHit.Inc()
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} else {
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CommitteeCacheMiss.Inc()
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return nil, nil
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}
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item, ok := obj.(*Committee)
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if !ok {
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return nil, ErrNotCommittee
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}
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start, end := startEndIndices(item, shard)
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return item.Committee[start:end], nil
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}
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// AddCommitteeShuffledList adds Committee shuffled list object to the cache. T
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// his method also trims the least recently list if the cache size has ready the max cache size limit.
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func (c *CommitteeCache) AddCommitteeShuffledList(committee *Committee) error {
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c.lock.Lock()
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defer c.lock.Unlock()
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if err := c.CommitteeCache.AddIfNotPresent(committee); err != nil {
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return err
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}
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trim(c.CommitteeCache, maxShuffledIndicesSize)
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return nil
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}
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// Epochs returns the epochs stored in the committee cache. These are the keys to the cache.
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func (c *CommitteeCache) Epochs() ([]uint64, error) {
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epochs := make([]uint64, len(c.CommitteeCache.ListKeys()))
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for i, s := range c.CommitteeCache.ListKeys() {
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epoch, err := strconv.Atoi(s)
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if err != nil {
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return nil, err
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}
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epochs[i] = uint64(epoch)
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}
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return epochs, nil
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}
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// EpochInCache returns true if an input epoch is part of keys in cache.
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func (c *CommitteeCache) EpochInCache(wantedEpoch uint64) (bool, error) {
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for _, s := range c.CommitteeCache.ListKeys() {
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epoch, err := strconv.Atoi(s)
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if err != nil {
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return false, err
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}
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if wantedEpoch == uint64(epoch) {
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return true, nil
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}
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}
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return false, nil
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}
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func startEndIndices(c *Committee, wantedShard uint64) (uint64, uint64) {
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shardCount := params.BeaconConfig().ShardCount
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currentShard := (wantedShard + shardCount - c.StartShard) % shardCount
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validatorCount := uint64(len(c.Committee))
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start := sliceutil.SplitOffset(validatorCount, c.CommitteeCount, currentShard)
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end := sliceutil.SplitOffset(validatorCount, c.CommitteeCount, currentShard+1)
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return start, end
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}
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