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package consensus
import (
"bytes"
"fmt"
"hash/crc32"
"io"
"reflect"
//"strconv"
//"strings"
"time"
abci "github.com/tendermint/abci/types"
//auto "github.com/tendermint/tmlibs/autofile"
cmn "github.com/tendermint/tmlibs/common"
"github.com/tendermint/tmlibs/log"
"github.com/tendermint/tendermint/proxy"
sm "github.com/tendermint/tendermint/state"
"github.com/tendermint/tendermint/types"
"github.com/tendermint/tendermint/version"
)
var crc32c = crc32.MakeTable(crc32.Castagnoli)
// Functionality to replay blocks and messages on recovery from a crash.
// There are two general failure scenarios: failure during consensus, and failure while applying the block.
// The former is handled by the WAL, the latter by the proxyApp Handshake on restart,
// which ultimately hands off the work to the WAL.
//-----------------------------------------
// recover from failure during consensus
// by replaying messages from the WAL
// Unmarshal and apply a single message to the consensus state
// as if it were received in receiveRoutine
// Lines that start with "#" are ignored.
// NOTE: receiveRoutine should not be running
func (cs *ConsensusState) readReplayMessage(msg *TimedWALMessage, newStepCh chan interface{}) error {
// skip meta messages
if _, ok := msg.Msg.(EndHeightMessage); ok {
return nil
}
// for logging
switch m := msg.Msg.(type) {
case types.EventDataRoundState:
cs.Logger.Info("Replay: New Step", "height", m.Height, "round", m.Round, "step", m.Step)
// these are playback checks
ticker := time.After(time.Second * 2)
if newStepCh != nil {
select {
case mi := <-newStepCh:
m2 := mi.(types.EventDataRoundState)
if m.Height != m2.Height || m.Round != m2.Round || m.Step != m2.Step {
return fmt.Errorf("RoundState mismatch. Got %v; Expected %v", m2, m)
}
case <-ticker:
return fmt.Errorf("Failed to read off newStepCh")
}
}
case msgInfo:
peerKey := m.PeerKey
if peerKey == "" {
peerKey = "local"
}
switch msg := m.Msg.(type) {
case *ProposalMessage:
p := msg.Proposal
cs.Logger.Info("Replay: Proposal", "height", p.Height, "round", p.Round, "header",
p.BlockPartsHeader, "pol", p.POLRound, "peer", peerKey)
case *BlockPartMessage:
cs.Logger.Info("Replay: BlockPart", "height", msg.Height, "round", msg.Round, "peer", peerKey)
case *VoteMessage:
v := msg.Vote
cs.Logger.Info("Replay: Vote", "height", v.Height, "round", v.Round, "type", v.Type,
"blockID", v.BlockID, "peer", peerKey)
}
cs.handleMsg(m)
case timeoutInfo:
cs.Logger.Info("Replay: Timeout", "height", m.Height, "round", m.Round, "step", m.Step, "dur", m.Duration)
cs.handleTimeout(m, cs.RoundState)
default:
return fmt.Errorf("Replay: Unknown TimedWALMessage type: %v", reflect.TypeOf(msg.Msg))
}
return nil
}
// replay only those messages since the last block.
// timeoutRoutine should run concurrently to read off tickChan
func (cs *ConsensusState) catchupReplay(csHeight int64) error {
// set replayMode
cs.replayMode = true
defer func() { cs.replayMode = false }()
// Ensure that ENDHEIGHT for this height doesn't exist.
// NOTE: This is just a sanity check. As far as we know things work fine
// without it, and Handshake could reuse ConsensusState if it weren't for
// this check (since we can crash after writing ENDHEIGHT).
//
// Ignore data corruption errors since this is a sanity check.
gr, found, err := cs.wal.SearchForEndHeight(csHeight, &WALSearchOptions{IgnoreDataCorruptionErrors: true})
if err != nil {
return err
}
if gr != nil {
if err := gr.Close(); err != nil {
return err
}
}
if found {
return fmt.Errorf("WAL should not contain #ENDHEIGHT %d.", csHeight)
}
// Search for last height marker
//
// Ignore data corruption errors in previous heights because we only care about last height
gr, found, err = cs.wal.SearchForEndHeight(csHeight-1, &WALSearchOptions{IgnoreDataCorruptionErrors: true})
if err == io.EOF {
cs.Logger.Error("Replay: wal.group.Search returned EOF", "#ENDHEIGHT", csHeight-1)
} else if err != nil {
return err
}
if !found {
return fmt.Errorf("Cannot replay height %d. WAL does not contain #ENDHEIGHT for %d.", csHeight, csHeight-1)
}
defer gr.Close() // nolint: errcheck
cs.Logger.Info("Catchup by replaying consensus messages", "height", csHeight)
var msg *TimedWALMessage
dec := WALDecoder{gr}
for {
msg, err = dec.Decode()
if err == io.EOF {
break
} else if IsDataCorruptionError(err) {
cs.Logger.Debug("data has been corrupted in last height of consensus WAL", "err", err, "height", csHeight)
panic(fmt.Sprintf("data has been corrupted (%v) in last height %d of consensus WAL", err, csHeight))
} else if err != nil {
return err
}
// NOTE: since the priv key is set when the msgs are received
// it will attempt to eg double sign but we can just ignore it
// since the votes will be replayed and we'll get to the next step
if err := cs.readReplayMessage(msg, nil); err != nil {
return err
}
}
cs.Logger.Info("Replay: Done")
return nil
}
//--------------------------------------------------------------------------------
// Parses marker lines of the form:
// #ENDHEIGHT: 12345
/*
func makeHeightSearchFunc(height int64) auto.SearchFunc {
return func(line string) (int, error) {
line = strings.TrimRight(line, "\n")
parts := strings.Split(line, " ")
if len(parts) != 2 {
return -1, errors.New("Line did not have 2 parts")
}
i, err := strconv.Atoi(parts[1])
if err != nil {
return -1, errors.New("Failed to parse INFO: " + err.Error())
}
if height < i {
return 1, nil
} else if height == i {
return 0, nil
} else {
return -1, nil
}
}
}*/
//----------------------------------------------
// Recover from failure during block processing
// by handshaking with the app to figure out where
// we were last and using the WAL to recover there
type Handshaker struct {
state *sm.State
store types.BlockStore
logger log.Logger
nBlocks int // number of blocks applied to the state
}
func NewHandshaker(state *sm.State, store types.BlockStore) *Handshaker {
return &Handshaker{state, store, log.NewNopLogger(), 0}
}
func (h *Handshaker) SetLogger(l log.Logger) {
h.logger = l
}
func (h *Handshaker) NBlocks() int {
return h.nBlocks
}
// TODO: retry the handshake/replay if it fails ?
func (h *Handshaker) Handshake(proxyApp proxy.AppConns) error {
// handshake is done via info request on the query conn
res, err := proxyApp.Query().InfoSync(abci.RequestInfo{version.Version})
if err != nil {
return fmt.Errorf("Error calling Info: %v", err)
}
blockHeight := int64(res.LastBlockHeight)
if blockHeight < 0 {
return fmt.Errorf("Got a negative last block height (%d) from the app", blockHeight)
}
appHash := res.LastBlockAppHash
h.logger.Info("ABCI Handshake", "appHeight", blockHeight, "appHash", fmt.Sprintf("%X", appHash))
// TODO: check version
// replay blocks up to the latest in the blockstore
_, err = h.ReplayBlocks(appHash, blockHeight, proxyApp)
if err != nil {
return fmt.Errorf("Error on replay: %v", err)
}
h.logger.Info("Completed ABCI Handshake - Tendermint and App are synced", "appHeight", blockHeight, "appHash", fmt.Sprintf("%X", appHash))
// TODO: (on restart) replay mempool
return nil
}
// Replay all blocks since appBlockHeight and ensure the result matches the current state.
// Returns the final AppHash or an error
func (h *Handshaker) ReplayBlocks(appHash []byte, appBlockHeight int64, proxyApp proxy.AppConns) ([]byte, error) {
storeBlockHeight := h.store.Height()
stateBlockHeight := h.state.LastBlockHeight
h.logger.Info("ABCI Replay Blocks", "appHeight", appBlockHeight, "storeHeight", storeBlockHeight, "stateHeight", stateBlockHeight)
// If appBlockHeight == 0 it means that we are at genesis and hence should send InitChain
if appBlockHeight == 0 {
validators := types.TM2PB.Validators(h.state.Validators)
if _, err := proxyApp.Consensus().InitChainSync(abci.RequestInitChain{validators}); err != nil {
return nil, err
}
}
// First handle edge cases and constraints on the storeBlockHeight
if storeBlockHeight == 0 {
return appHash, h.checkAppHash(appHash)
} else if storeBlockHeight < appBlockHeight {
// the app should never be ahead of the store (but this is under app's control)
return appHash, sm.ErrAppBlockHeightTooHigh{storeBlockHeight, appBlockHeight}
} else if storeBlockHeight < stateBlockHeight {
// the state should never be ahead of the store (this is under tendermint's control)
cmn.PanicSanity(cmn.Fmt("StateBlockHeight (%d) > StoreBlockHeight (%d)", stateBlockHeight, storeBlockHeight))
} else if storeBlockHeight > stateBlockHeight+1 {
// store should be at most one ahead of the state (this is under tendermint's control)
cmn.PanicSanity(cmn.Fmt("StoreBlockHeight (%d) > StateBlockHeight + 1 (%d)", storeBlockHeight, stateBlockHeight+1))
}
// Now either store is equal to state, or one ahead.
// For each, consider all cases of where the app could be, given app <= store
if storeBlockHeight == stateBlockHeight {
// Tendermint ran Commit and saved the state.
// Either the app is asking for replay, or we're all synced up.
if appBlockHeight < storeBlockHeight {
// the app is behind, so replay blocks, but no need to go through WAL (state is already synced to store)
return h.replayBlocks(proxyApp, appBlockHeight, storeBlockHeight, false)
} else if appBlockHeight == storeBlockHeight {
// We're good!
return appHash, h.checkAppHash(appHash)
}
} else if storeBlockHeight == stateBlockHeight+1 {
// We saved the block in the store but haven't updated the state,
// so we'll need to replay a block using the WAL.
if appBlockHeight < stateBlockHeight {
// the app is further behind than it should be, so replay blocks
// but leave the last block to go through the WAL
return h.replayBlocks(proxyApp, appBlockHeight, storeBlockHeight, true)
} else if appBlockHeight == stateBlockHeight {
// We haven't run Commit (both the state and app are one block behind),
// so replayBlock with the real app.
// NOTE: We could instead use the cs.WAL on cs.Start,
// but we'd have to allow the WAL to replay a block that wrote it's ENDHEIGHT
h.logger.Info("Replay last block using real app")
return h.replayBlock(storeBlockHeight, proxyApp.Consensus())
} else if appBlockHeight == storeBlockHeight {
// We ran Commit, but didn't save the state, so replayBlock with mock app
abciResponses, err := h.state.LoadABCIResponses(storeBlockHeight)
if err != nil {
return nil, err
}
mockApp := newMockProxyApp(appHash, abciResponses)
h.logger.Info("Replay last block using mock app")
return h.replayBlock(storeBlockHeight, mockApp)
}
}
cmn.PanicSanity("Should never happen")
return nil, nil
}
func (h *Handshaker) replayBlocks(proxyApp proxy.AppConns, appBlockHeight, storeBlockHeight int64, mutateState bool) ([]byte, error) {
// App is further behind than it should be, so we need to replay blocks.
// We replay all blocks from appBlockHeight+1.
//
// Note that we don't have an old version of the state,
// so we by-pass state validation/mutation using sm.ExecCommitBlock.
// This also means we won't be saving validator sets if they change during this period.
// TODO: Load the historical information to fix this and just use state.ApplyBlock
//
// If mutateState == true, the final block is replayed with h.replayBlock()
var appHash []byte
var err error
finalBlock := storeBlockHeight
if mutateState {
finalBlock -= 1
}
for i := appBlockHeight + 1; i <= finalBlock; i++ {
h.logger.Info("Applying block", "height", i)
block := h.store.LoadBlock(i)
appHash, err = sm.ExecCommitBlock(proxyApp.Consensus(), block, h.logger, h.state.LastValidators)
if err != nil {
return nil, err
}
h.nBlocks += 1
}
if mutateState {
// sync the final block
return h.replayBlock(storeBlockHeight, proxyApp.Consensus())
}
return appHash, h.checkAppHash(appHash)
}
// ApplyBlock on the proxyApp with the last block.
func (h *Handshaker) replayBlock(height int64, proxyApp proxy.AppConnConsensus) ([]byte, error) {
mempool := types.MockMempool{}
evpool := types.MockEvidencePool{}
block := h.store.LoadBlock(height)
meta := h.store.LoadBlockMeta(height)
if err := h.state.ApplyBlock(types.NopEventBus{}, proxyApp,
block, meta.BlockID.PartsHeader, mempool, evpool); err != nil {
return nil, err
}
h.nBlocks += 1
return h.state.AppHash, nil
}
func (h *Handshaker) checkAppHash(appHash []byte) error {
if !bytes.Equal(h.state.AppHash, appHash) {
panic(fmt.Errorf("Tendermint state.AppHash does not match AppHash after replay. Got %X, expected %X", appHash, h.state.AppHash).Error())
}
return nil
}
//--------------------------------------------------------------------------------
// mockProxyApp uses ABCIResponses to give the right results
// Useful because we don't want to call Commit() twice for the same block on the real app.
func newMockProxyApp(appHash []byte, abciResponses *sm.ABCIResponses) proxy.AppConnConsensus {
clientCreator := proxy.NewLocalClientCreator(&mockProxyApp{
appHash: appHash,
abciResponses: abciResponses,
})
cli, _ := clientCreator.NewABCIClient()
err := cli.Start()
if err != nil {
panic(err)
}
return proxy.NewAppConnConsensus(cli)
}
type mockProxyApp struct {
abci.BaseApplication
appHash []byte
txCount int
abciResponses *sm.ABCIResponses
}
func (mock *mockProxyApp) DeliverTx(tx []byte) abci.ResponseDeliverTx {
r := mock.abciResponses.DeliverTx[mock.txCount]
mock.txCount += 1
return *r
}
func (mock *mockProxyApp) EndBlock(req abci.RequestEndBlock) abci.ResponseEndBlock {
mock.txCount = 0
return *mock.abciResponses.EndBlock
}
func (mock *mockProxyApp) Commit() abci.ResponseCommit {
return abci.ResponseCommit{Code: abci.CodeTypeOK, Data: mock.appHash}
}