prysm-pulse/beacon-chain/blockchain/process_block.go
2020-07-01 10:04:06 -07:00

292 lines
11 KiB
Go

package blockchain
import (
"context"
"encoding/hex"
"fmt"
"github.com/pkg/errors"
ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
"github.com/prysmaticlabs/prysm/shared/attestationutil"
"github.com/prysmaticlabs/prysm/shared/bytesutil"
"github.com/prysmaticlabs/prysm/shared/featureconfig"
"github.com/prysmaticlabs/prysm/shared/params"
"github.com/sirupsen/logrus"
"go.opencensus.io/trace"
)
// This defines size of the upper bound for initial sync block cache.
var initialSyncBlockCacheSize = 2 * params.BeaconConfig().SlotsPerEpoch
// onBlock is called when a gossip block is received. It runs regular state transition on the block.
// The block's signing root should be computed before calling this method to avoid redundant
// computation in this method and methods it calls into.
//
// Spec pseudocode definition:
// def on_block(store: Store, block: BeaconBlock) -> None:
// # Make a copy of the state to avoid mutability issues
// assert block.parent_root in store.block_states
// pre_state = store.block_states[block.parent_root].copy()
// # Blocks cannot be in the future. If they are, their consideration must be delayed until the are in the past.
// assert store.time >= pre_state.genesis_time + block.slot * SECONDS_PER_SLOT
// # Add new block to the store
// store.blocks[signing_root(block)] = block
// # Check block is a descendant of the finalized block
// assert (
// get_ancestor(store, signing_root(block), store.blocks[store.finalized_checkpoint.root].slot) ==
// store.finalized_checkpoint.root
// )
// # Check that block is later than the finalized epoch slot
// assert block.slot > compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
// # Check the block is valid and compute the post-state
// state = state_transition(pre_state, block)
// # Add new state for this block to the store
// store.block_states[signing_root(block)] = state
//
// # Update justified checkpoint
// if state.current_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
// if state.current_justified_checkpoint.epoch > store.best_justified_checkpoint.epoch:
// store.best_justified_checkpoint = state.current_justified_checkpoint
//
// # Update finalized checkpoint
// if state.finalized_checkpoint.epoch > store.finalized_checkpoint.epoch:
// store.finalized_checkpoint = state.finalized_checkpoint
func (s *Service) onBlock(ctx context.Context, signed *ethpb.SignedBeaconBlock, blockRoot [32]byte) (*stateTrie.BeaconState, error) {
ctx, span := trace.StartSpan(ctx, "blockchain.onBlock")
defer span.End()
if signed == nil || signed.Block == nil {
return nil, errors.New("nil block")
}
b := signed.Block
// Retrieve incoming block's pre state.
preState, err := s.getBlockPreState(ctx, b)
if err != nil {
return nil, err
}
log.WithFields(logrus.Fields{
"slot": b.Slot,
"root": fmt.Sprintf("0x%s...", hex.EncodeToString(blockRoot[:])[:8]),
}).Debug("Executing state transition on block")
postState, err := state.ExecuteStateTransition(ctx, preState, signed)
if err != nil {
return nil, errors.Wrap(err, "could not execute state transition")
}
if err := s.beaconDB.SaveBlock(ctx, signed); err != nil {
return nil, errors.Wrapf(err, "could not save block from slot %d", b.Slot)
}
if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, postState); err != nil {
return nil, errors.Wrapf(err, "could not insert block %d to fork choice store", b.Slot)
}
if err := s.stateGen.SaveState(ctx, blockRoot, postState); err != nil {
return nil, errors.Wrap(err, "could not save state")
}
// Update justified check point.
if postState.CurrentJustifiedCheckpoint().Epoch > s.justifiedCheckpt.Epoch {
if err := s.updateJustified(ctx, postState); err != nil {
return nil, err
}
}
// Update finalized check point. Prune the block cache and helper caches on every new finalized epoch.
if postState.FinalizedCheckpointEpoch() > s.finalizedCheckpt.Epoch {
if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
return nil, err
}
s.clearInitSyncBlocks()
if err := s.beaconDB.SaveFinalizedCheckpoint(ctx, postState.FinalizedCheckpoint()); err != nil {
return nil, errors.Wrap(err, "could not save finalized checkpoint")
}
fRoot := bytesutil.ToBytes32(postState.FinalizedCheckpoint().Root)
// Prune proto array fork choice nodes, all nodes before finalized check point will
// be pruned.
if err := s.forkChoiceStore.Prune(ctx, fRoot); err != nil {
return nil, errors.Wrap(err, "could not prune proto array fork choice nodes")
}
s.prevFinalizedCheckpt = s.finalizedCheckpt
s.finalizedCheckpt = postState.FinalizedCheckpoint()
if err := s.finalizedImpliesNewJustified(ctx, postState); err != nil {
return nil, errors.Wrap(err, "could not save new justified")
}
fBlock, err := s.beaconDB.Block(ctx, fRoot)
if err != nil {
return nil, errors.Wrap(err, "could not get finalized block to migrate")
}
if err := s.stateGen.MigrateToCold(ctx, fBlock.Block.Slot, fRoot); err != nil {
return nil, errors.Wrap(err, "could not migrate to cold")
}
}
// Epoch boundary bookkeeping such as logging epoch summaries.
if postState.Slot() >= s.nextEpochBoundarySlot {
logEpochData(postState)
reportEpochMetrics(postState)
// Update committees cache at epoch boundary slot.
if err := helpers.UpdateCommitteeCache(postState, helpers.CurrentEpoch(postState)); err != nil {
return nil, err
}
if err := helpers.UpdateProposerIndicesInCache(postState, helpers.CurrentEpoch(postState)); err != nil {
return nil, err
}
s.nextEpochBoundarySlot = helpers.StartSlot(helpers.NextEpoch(postState))
}
// Delete the processed block attestations from attestation pool.
if err := s.deletePoolAtts(b.Body.Attestations); err != nil {
return nil, err
}
// Delete the processed block attester slashings from slashings pool.
for i := 0; i < len(b.Body.AttesterSlashings); i++ {
s.slashingPool.MarkIncludedAttesterSlashing(b.Body.AttesterSlashings[i])
}
defer reportAttestationInclusion(b)
return postState, nil
}
// onBlockInitialSyncStateTransition is called when an initial sync block is received.
// It runs state transition on the block and without any BLS verification. The excluded BLS verification
// includes attestation's aggregated signature. It also does not save attestations.
// The block's signing root should be computed before calling this method to avoid redundant
// computation in this method and methods it calls into.
func (s *Service) onBlockInitialSyncStateTransition(ctx context.Context, signed *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
ctx, span := trace.StartSpan(ctx, "blockchain.onBlock")
defer span.End()
if signed == nil || signed.Block == nil {
return errors.New("nil block")
}
b := signed.Block
// Retrieve incoming block's pre state.
preState, err := s.verifyBlkPreState(ctx, b)
if err != nil {
return err
}
// To invalidate cache for parent root because pre state will get mutated.
s.stateGen.DeleteHotStateInCache(bytesutil.ToBytes32(b.ParentRoot))
// Exit early if the pre state slot is higher than incoming block's slot.
if preState.Slot() >= signed.Block.Slot {
return nil
}
var postState *stateTrie.BeaconState
if featureconfig.Get().InitSyncNoVerify {
postState, err = state.ExecuteStateTransitionNoVerifyAttSigs(ctx, preState, signed)
} else {
postState, err = state.ExecuteStateTransition(ctx, preState, signed)
}
if err != nil {
return errors.Wrap(err, "could not execute state transition")
}
s.saveInitSyncBlock(blockRoot, signed)
if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, postState); err != nil {
return errors.Wrapf(err, "could not insert block %d to fork choice store", b.Slot)
}
if err := s.stateGen.SaveState(ctx, blockRoot, postState); err != nil {
return errors.Wrap(err, "could not save state")
}
// Rate limit how many blocks (2 epochs worth of blocks) a node keeps in the memory.
if uint64(len(s.getInitSyncBlocks())) > initialSyncBlockCacheSize {
if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
return err
}
s.clearInitSyncBlocks()
}
// Update finalized check point. Prune the block cache and helper caches on every new finalized epoch.
if postState.FinalizedCheckpointEpoch() > s.finalizedCheckpt.Epoch {
if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
return err
}
s.clearInitSyncBlocks()
if err := s.beaconDB.SaveFinalizedCheckpoint(ctx, postState.FinalizedCheckpoint()); err != nil {
return errors.Wrap(err, "could not save finalized checkpoint")
}
s.prevFinalizedCheckpt = s.finalizedCheckpt
s.finalizedCheckpt = postState.FinalizedCheckpoint()
fRoot := bytesutil.ToBytes32(postState.FinalizedCheckpoint().Root)
fBlock, err := s.beaconDB.Block(ctx, fRoot)
if err != nil {
return errors.Wrap(err, "could not get finalized block to migrate")
}
if err := s.stateGen.MigrateToCold(ctx, fBlock.Block.Slot, fRoot); err != nil {
return errors.Wrap(err, "could not migrate to cold")
}
}
// Epoch boundary bookkeeping such as logging epoch summaries.
if postState.Slot() >= s.nextEpochBoundarySlot {
reportEpochMetrics(postState)
s.nextEpochBoundarySlot = helpers.StartSlot(helpers.NextEpoch(postState))
// Update committees cache at epoch boundary slot.
if err := helpers.UpdateCommitteeCache(postState, helpers.CurrentEpoch(postState)); err != nil {
return err
}
if err := helpers.UpdateProposerIndicesInCache(postState, helpers.CurrentEpoch(postState)); err != nil {
return err
}
}
return nil
}
// This feeds in the block and block's attestations to fork choice store. It's allows fork choice store
// to gain information on the most current chain.
func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk *ethpb.BeaconBlock, root [32]byte, state *stateTrie.BeaconState) error {
if err := s.fillInForkChoiceMissingBlocks(ctx, blk, state); err != nil {
return err
}
// Feed in block to fork choice store.
if err := s.forkChoiceStore.ProcessBlock(ctx,
blk.Slot, root, bytesutil.ToBytes32(blk.ParentRoot), bytesutil.ToBytes32(blk.Body.Graffiti),
state.CurrentJustifiedCheckpoint().Epoch,
state.FinalizedCheckpointEpoch()); err != nil {
return errors.Wrap(err, "could not process block for proto array fork choice")
}
// Feed in block's attestations to fork choice store.
for _, a := range blk.Body.Attestations {
committee, err := helpers.BeaconCommitteeFromState(state, a.Data.Slot, a.Data.CommitteeIndex)
if err != nil {
return err
}
indices := attestationutil.AttestingIndices(a.AggregationBits, committee)
s.forkChoiceStore.ProcessAttestation(ctx, indices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)
}
return nil
}