blocksync

Documentation

Overview

Package blocksync implements two versions of a reactor Service that are responsible for block propagation and gossip between peers. This mechanism was formerly known as fast-sync.

In order for a full node to successfully participate in consensus, it must have the latest view of state. The blocksync protocol is a mechanism in which peers may exchange and gossip entire blocks with one another, in a request/response type model, until they've successfully synced to the latest head block. Once succussfully synced, the full node can switch to an active role in consensus and will no longer blocksync and thus no longer run the blocksync process.

Note, the blocksync reactor Service gossips entire block and relevant data such that each receiving peer may construct the entire view of the blocksync state.

There is currently only one version of the blocksync reactor Service that is battle-tested, but whose test coverage is lacking and is not formally verified.

The v0 blocksync reactor Service has one p2p channel, BlockchainChannel. This channel is responsible for handling messages that both request blocks and respond to block requests from peers. For every block request from a peer, the reactor will execute respondToPeer which will fetch the block from the node's state store and respond to the peer. For every block response, the node will add the block to its pool via AddBlock.

Internally, v0 runs a poolRoutine that constantly checks for what blocks it needs and requests them. The poolRoutine is also responsible for taking blocks from the pool, saving and executing each block.

Index

• Constants
• func GetChannelDescriptor() *p2p.ChannelDescriptor
• type BlockPool
  • func NewBlockPool(logger log.Logger, start int64, requestsCh chan<- BlockRequest, ...) *BlockPool
  • func (pool *BlockPool) AddBlock(peerID types.NodeID, block *types.Block, extCommit *types.ExtendedCommit, ...) error
  • func (pool *BlockPool) GetStatus() (height int64, numPending int32, lenRequesters int)
  • func (pool *BlockPool) IsCaughtUp() bool
  • func (pool *BlockPool) LastAdvance() time.Time
  • func (pool *BlockPool) MaxPeerHeight() int64
  • func (pool *BlockPool) OnStart(ctx context.Context) error
  • func (*BlockPool) OnStop()
  • func (pool *BlockPool) PeekTwoBlocks() (first, second *types.Block, firstExtCommit *types.ExtendedCommit)
  • func (pool *BlockPool) PopRequest()
  • func (pool *BlockPool) RedoRequest(height int64) types.NodeID
  • func (pool *BlockPool) RemovePeer(peerID types.NodeID)
  • func (pool *BlockPool) SetPeerRange(peerID types.NodeID, base int64, height int64)
• type BlockRequest
• type Reactor
  • func NewReactor(logger log.Logger, stateStore sm.Store, blockExec *sm.BlockExecutor, ...) *Reactor
  • func (r *Reactor) GetMaxPeerBlockHeight() int64
  • func (r *Reactor) GetRemainingSyncTime() time.Duration
  • func (r *Reactor) GetTotalSyncedTime() time.Duration
  • func (r *Reactor) OnStart(ctx context.Context) error
  • func (r *Reactor) OnStop()
  • func (r *Reactor) PublishStatus(event types.EventDataBlockSyncStatus) error
  • func (r *Reactor) SetChannel(ch *p2p.Channel)
  • func (r *Reactor) SwitchToBlockSync(ctx context.Context, state sm.State) error

Constants

const (
	// BlockSyncChannel is a channel for blocks and status updates
	BlockSyncChannel = p2p.ChannelID(0x40)
)

const (
	MaxMsgSize = types.MaxBlockSizeBytes +
		bcproto.BlockResponseMessagePrefixSize +
		bcproto.BlockResponseMessageFieldKeySize
)

Functions

func GetChannelDescriptor

func GetChannelDescriptor() *p2p.ChannelDescriptor

Types

type BlockPool

type BlockPool struct {
	service.BaseService
	// contains filtered or unexported fields
}

BlockPool keeps track of the block sync peers, block requests and block responses.

func NewBlockPool

func NewBlockPool(
	logger log.Logger,
	start int64,
	requestsCh chan<- BlockRequest,
	errorsCh chan<- peerError,
) *BlockPool

NewBlockPool returns a new BlockPool with the height equal to start. Block requests and errors will be sent to requestsCh and errorsCh accordingly.

func (*BlockPool) AddBlock

func (pool *BlockPool) AddBlock(peerID types.NodeID, block *types.Block, extCommit *types.ExtendedCommit, blockSize int) error

AddBlock validates that the block comes from the peer it was expected from and calls the requester to store it.

This requires an extended commit at the same height as the supplied block - the block contains the last commit, but we need the latest commit in case we need to switch over from block sync to consensus at this height. If the height of the extended commit and the height of the block do not match, we do not add the block and return an error. TODO: ensure that blocks come in order for each peer.

func (*BlockPool) GetStatus

func (pool *BlockPool) GetStatus() (height int64, numPending int32, lenRequesters int)

GetStatus returns pool's height, numPending requests and the number of requesters.

func (*BlockPool) IsCaughtUp

func (pool *BlockPool) IsCaughtUp() bool

IsCaughtUp returns true if this node is caught up, false - otherwise.

func (*BlockPool) LastAdvance

func (pool *BlockPool) LastAdvance() time.Time

LastAdvance returns the time when the last block was processed (or start time if no blocks were processed).

func (*BlockPool) MaxPeerHeight

func (pool *BlockPool) MaxPeerHeight() int64

MaxPeerHeight returns the highest reported height.

func (*BlockPool) OnStart

func (pool *BlockPool) OnStart(ctx context.Context) error

OnStart implements service.Service by spawning requesters routine and recording pool's start time.

func (*BlockPool) OnStop

func (*BlockPool) OnStop()

func (*BlockPool) PeekTwoBlocks

func (pool *BlockPool) PeekTwoBlocks() (first, second *types.Block, firstExtCommit *types.ExtendedCommit)

PeekTwoBlocks returns blocks at pool.height and pool.height+1. We need to see the second block's Commit to validate the first block. So we peek two blocks at a time. We return an extended commit, containing vote extensions and their associated signatures, as this is critical to consensus in ABCI++ as we switch from block sync to consensus mode.

The caller will verify the commit.

func (*BlockPool) PopRequest

func (pool *BlockPool) PopRequest()

PopRequest pops the first block at pool.height. It must have been validated by the second Commit from PeekTwoBlocks. TODO(thane): (?) and its corresponding ExtendedCommit.

func (*BlockPool) RedoRequest

func (pool *BlockPool) RedoRequest(height int64) types.NodeID

RedoRequest invalidates the block at pool.height, Remove the peer and redo request from others. Returns the ID of the removed peer.

func (*BlockPool) RemovePeer

func (pool *BlockPool) RemovePeer(peerID types.NodeID)

RemovePeer removes the peer with peerID from the pool. If there's no peer with peerID, function is a no-op.

func (*BlockPool) SetPeerRange

func (pool *BlockPool) SetPeerRange(peerID types.NodeID, base int64, height int64)

SetPeerRange sets the peer's alleged blockchain base and height.

type BlockRequest

type BlockRequest struct {
	Height int64
	PeerID types.NodeID
}

BlockRequest stores a block request identified by the block Height and the PeerID responsible for delivering the block.

type Reactor

type Reactor struct {
	service.BaseService
	// contains filtered or unexported fields
}

Reactor handles long-term catchup syncing.

func NewReactor

func NewReactor(
	logger log.Logger,
	stateStore sm.Store,
	blockExec *sm.BlockExecutor,
	store *store.BlockStore,
	consReactor consensusReactor,
	peerEvents p2p.PeerEventSubscriber,
	blockSync bool,
	metrics *consensus.Metrics,
	eventBus *eventbus.EventBus,
	restartCh chan struct{},
	selfRemediationConfig *config.SelfRemediationConfig,
) *Reactor

NewReactor returns new reactor instance.

func (*Reactor) GetMaxPeerBlockHeight

func (r *Reactor) GetMaxPeerBlockHeight() int64

func (*Reactor) GetRemainingSyncTime

func (r *Reactor) GetRemainingSyncTime() time.Duration

func (*Reactor) GetTotalSyncedTime

func (r *Reactor) GetTotalSyncedTime() time.Duration

func (*Reactor) OnStart

func (r *Reactor) OnStart(ctx context.Context) error

OnStart starts separate go routines for each p2p Channel and listens for envelopes on each. In addition, it also listens for peer updates and handles messages on that p2p channel accordingly. The caller must be sure to execute OnStop to ensure the outbound p2p Channels are closed.

If blockSync is enabled, we also start the pool and the pool processing goroutine. If the pool fails to start, an error is returned.

func (*Reactor) OnStop

func (r *Reactor) OnStop()

OnStop stops the reactor by signaling to all spawned goroutines to exit and blocking until they all exit.

func (*Reactor) PublishStatus

func (r *Reactor) PublishStatus(event types.EventDataBlockSyncStatus) error

func (*Reactor) SetChannel

func (r *Reactor) SetChannel(ch *p2p.Channel)

func (*Reactor) SwitchToBlockSync

func (r *Reactor) SwitchToBlockSync(ctx context.Context, state sm.State) error

SwitchToBlockSync is called by the state sync reactor when switching to fast sync.