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package state
import (
"errors"
"fmt"
fail "github.com/ebuchman/fail-test"
abci "github.com/tendermint/abci/types"
crypto "github.com/tendermint/go-crypto"
"github.com/tendermint/tendermint/proxy"
"github.com/tendermint/tendermint/types"
dbm "github.com/tendermint/tmlibs/db"
"github.com/tendermint/tmlibs/log"
)
//-----------------------------------------------------------------------------
// BlockExecutor handles block execution and state updates.
// It exposes ApplyBlock(), which validates & executes the block, updates state w/ ABCI responses,
// then commits and updates the mempool atomically, then saves state.
// BlockExecutor provides the context and accessories for properly executing a block.
type BlockExecutor struct {
// save state, validators, consensus params, abci responses here
db dbm.DB
// execute the app against this
proxyApp proxy.AppConnConsensus
// events
eventBus types.BlockEventPublisher
// update these with block results after commit
mempool types.Mempool
evpool types.EvidencePool
logger log.Logger
}
// NewBlockExecutor returns a new BlockExecutor with a NopEventBus.
// Call SetEventBus to provide one.
func NewBlockExecutor(db dbm.DB, logger log.Logger, proxyApp proxy.AppConnConsensus,
mempool types.Mempool, evpool types.EvidencePool) *BlockExecutor {
return &BlockExecutor{
db: db,
proxyApp: proxyApp,
eventBus: types.NopEventBus{},
mempool: mempool,
evpool: evpool,
logger: logger,
}
}
// SetEventBus - sets the event bus for publishing block related events.
// If not called, it defaults to types.NopEventBus.
func (blockExec *BlockExecutor) SetEventBus(eventBus types.BlockEventPublisher) {
blockExec.eventBus = eventBus
}
// ValidateBlock validates the given block against the given state.
// If the block is invalid, it returns an error.
// Validation does not mutate state, but does require historical information from the stateDB,
// ie. to verify evidence from a validator at an old height.
func (blockExec *BlockExecutor) ValidateBlock(s State, block *types.Block) error {
return validateBlock(blockExec.db, s, block)
}
// ApplyBlock validates the block against the state, executes it against the app,
// fires the relevant events, commits the app, and saves the new state and responses.
// It's the only function that needs to be called
// from outside this package to process and commit an entire block.
// It takes a blockID to avoid recomputing the parts hash.
func (blockExec *BlockExecutor) ApplyBlock(s State, blockID types.BlockID, block *types.Block) (State, error) {
if err := blockExec.ValidateBlock(s, block); err != nil {
return s, ErrInvalidBlock(err)
}
abciResponses, err := execBlockOnProxyApp(blockExec.logger, blockExec.proxyApp, block)
if err != nil {
return s, ErrProxyAppConn(err)
}
fail.Fail() // XXX
// save the results before we commit
saveABCIResponses(blockExec.db, block.Height, abciResponses)
fail.Fail() // XXX
// update the state with the block and responses
s, err = updateState(s, blockID, block.Header, abciResponses)
if err != nil {
return s, fmt.Errorf("Commit failed for application: %v", err)
}
// lock mempool, commit state, update mempoool
appHash, err := blockExec.Commit(block)
if err != nil {
return s, fmt.Errorf("Commit failed for application: %v", err)
}
fail.Fail() // XXX
// update the app hash and save the state
s.AppHash = appHash
SaveState(blockExec.db, s)
fail.Fail() // XXX
// Update evpool now that state is saved
// TODO: handle the crash/recover scenario
// ie. (may need to call Update for last block)
blockExec.evpool.Update(block)
// events are fired after everything else
// NOTE: if we crash between Commit and Save, events wont be fired during replay
fireEvents(blockExec.logger, blockExec.eventBus, block, abciResponses)
return s, nil
}
// Commit locks the mempool, runs the ABCI Commit message, and updates the mempool.
// It returns the result of calling abci.Commit (the AppHash), and an error.
// The Mempool must be locked during commit and update because state is typically reset on Commit and old txs must be replayed
// against committed state before new txs are run in the mempool, lest they be invalid.
func (blockExec *BlockExecutor) Commit(block *types.Block) ([]byte, error) {
blockExec.mempool.Lock()
defer blockExec.mempool.Unlock()
// Commit block, get hash back
res, err := blockExec.proxyApp.CommitSync()
if err != nil {
blockExec.logger.Error("Client error during proxyAppConn.CommitSync", "err", err)
return nil, err
}
if res.IsErr() {
blockExec.logger.Error("Error in proxyAppConn.CommitSync", "err", res)
return nil, res
}
if res.Log != "" {
blockExec.logger.Debug("Commit.Log: " + res.Log)
}
blockExec.logger.Info("Committed state", "height", block.Height, "txs", block.NumTxs, "appHash", res.Data)
// Update mempool.
if err := blockExec.mempool.Update(block.Height, block.Txs); err != nil {
return nil, err
}
return res.Data, nil
}
//---------------------------------------------------------
// Helper functions for executing blocks and updating state
// Executes block's transactions on proxyAppConn.
// Returns a list of transaction results and updates to the validator set
func execBlockOnProxyApp(logger log.Logger, proxyAppConn proxy.AppConnConsensus, block *types.Block) (*ABCIResponses, error) {
var validTxs, invalidTxs = 0, 0
txIndex := 0
abciResponses := NewABCIResponses(block)
// Execute transactions and get hash
proxyCb := func(req *abci.Request, res *abci.Response) {
switch r := res.Value.(type) {
case *abci.Response_DeliverTx:
// TODO: make use of res.Log
// TODO: make use of this info
// Blocks may include invalid txs.
txRes := r.DeliverTx
if txRes.Code == abci.CodeTypeOK {
validTxs++
} else {
logger.Debug("Invalid tx", "code", txRes.Code, "log", txRes.Log)
invalidTxs++
}
abciResponses.DeliverTx[txIndex] = txRes
txIndex++
}
}
proxyAppConn.SetResponseCallback(proxyCb)
// determine which validators did not sign last block
absentVals := make([]int32, 0)
for valI, vote := range block.LastCommit.Precommits {
if vote == nil {
absentVals = append(absentVals, int32(valI))
}
}
// TODO: determine which validators were byzantine
// Begin block
_, err := proxyAppConn.BeginBlockSync(abci.RequestBeginBlock{
Hash: block.Hash(),
Header: types.TM2PB.Header(block.Header),
AbsentValidators: absentVals,
ByzantineValidators: nil,
})
if err != nil {
logger.Error("Error in proxyAppConn.BeginBlock", "err", err)
return nil, err
}
// Run txs of block
for _, tx := range block.Txs {
proxyAppConn.DeliverTxAsync(tx)
if err := proxyAppConn.Error(); err != nil {
return nil, err
}
}
// End block
abciResponses.EndBlock, err = proxyAppConn.EndBlockSync(abci.RequestEndBlock{block.Height})
if err != nil {
logger.Error("Error in proxyAppConn.EndBlock", "err", err)
return nil, err
}
logger.Info("Executed block", "height", block.Height, "validTxs", validTxs, "invalidTxs", invalidTxs)
valUpdates := abciResponses.EndBlock.ValidatorUpdates
if len(valUpdates) > 0 {
logger.Info("Updates to validators", "updates", abci.ValidatorsString(valUpdates))
}
return abciResponses, nil
}
func updateValidators(currentSet *types.ValidatorSet, updates []*abci.Validator) error {
// If more or equal than 1/3 of total voting power changed in one block, then
// a light client could never prove the transition externally. See
// ./lite/doc.go for details on how a light client tracks validators.
vp23, err := changeInVotingPowerMoreOrEqualToOneThird(currentSet, updates)
if err != nil {
return err
}
if vp23 {
return errors.New("the change in voting power must be strictly less than 1/3")
}
for _, v := range updates {
pubkey, err := crypto.PubKeyFromBytes(v.PubKey) // NOTE: expects go-wire encoded pubkey
if err != nil {
return err
}
address := pubkey.Address()
power := int64(v.Power)
// mind the overflow from int64
if power < 0 {
return fmt.Errorf("Power (%d) overflows int64", v.Power)
}
_, val := currentSet.GetByAddress(address)
if val == nil {
// add val
added := currentSet.Add(types.NewValidator(pubkey, power))
if !added {
return fmt.Errorf("Failed to add new validator %X with voting power %d", address, power)
}
} else if v.Power == 0 {
// remove val
_, removed := currentSet.Remove(address)
if !removed {
return fmt.Errorf("Failed to remove validator %X", address)
}
} else {
// update val
val.VotingPower = power
updated := currentSet.Update(val)
if !updated {
return fmt.Errorf("Failed to update validator %X with voting power %d", address, power)
}
}
}
return nil
}
func changeInVotingPowerMoreOrEqualToOneThird(currentSet *types.ValidatorSet, updates []*abci.Validator) (bool, error) {
threshold := currentSet.TotalVotingPower() * 1 / 3
acc := int64(0)
for _, v := range updates {
pubkey, err := crypto.PubKeyFromBytes(v.PubKey) // NOTE: expects go-wire encoded pubkey
if err != nil {
return false, err
}
address := pubkey.Address()
power := int64(v.Power)
// mind the overflow from int64
if power < 0 {
return false, fmt.Errorf("Power (%d) overflows int64", v.Power)
}
_, val := currentSet.GetByAddress(address)
if val == nil {
acc += power
} else {
np := val.VotingPower - power
if np < 0 {
np = -np
}
acc += np
}
if acc >= threshold {
return true, nil
}
}
return false, nil
}
// updateState returns a new State updated according to the header and responses.
func updateState(s State, blockID types.BlockID, header *types.Header,
abciResponses *ABCIResponses) (State, error) {
// copy the valset so we can apply changes from EndBlock
// and update s.LastValidators and s.Validators
prevValSet := s.Validators.Copy()
nextValSet := prevValSet.Copy()
// update the validator set with the latest abciResponses
lastHeightValsChanged := s.LastHeightValidatorsChanged
if len(abciResponses.EndBlock.ValidatorUpdates) > 0 {
err := updateValidators(nextValSet, abciResponses.EndBlock.ValidatorUpdates)
if err != nil {
return s, fmt.Errorf("Error changing validator set: %v", err)
}
// change results from this height but only applies to the next height
lastHeightValsChanged = header.Height + 1
}
// Update validator accums and set state variables
nextValSet.IncrementAccum(1)
// update the params with the latest abciResponses
nextParams := s.ConsensusParams
lastHeightParamsChanged := s.LastHeightConsensusParamsChanged
if abciResponses.EndBlock.ConsensusParamUpdates != nil {
// NOTE: must not mutate s.ConsensusParams
nextParams = s.ConsensusParams.Update(abciResponses.EndBlock.ConsensusParamUpdates)
err := nextParams.Validate()
if err != nil {
return s, fmt.Errorf("Error updating consensus params: %v", err)
}
// change results from this height but only applies to the next height
lastHeightParamsChanged = header.Height + 1
}
// NOTE: the AppHash has not been populated.
// It will be filled on state.Save.
return State{
ChainID: s.ChainID,
LastBlockHeight: header.Height,
LastBlockTotalTx: s.LastBlockTotalTx + header.NumTxs,
LastBlockID: blockID,
LastBlockTime: header.Time,
Validators: nextValSet,
LastValidators: s.Validators.Copy(),
LastHeightValidatorsChanged: lastHeightValsChanged,
ConsensusParams: nextParams,
LastHeightConsensusParamsChanged: lastHeightParamsChanged,
LastResultsHash: abciResponses.ResultsHash(),
AppHash: nil,
}, nil
}
// Fire NewBlock, NewBlockHeader.
// Fire TxEvent for every tx.
// NOTE: if Tendermint crashes before commit, some or all of these events may be published again.
func fireEvents(logger log.Logger, eventBus types.BlockEventPublisher, block *types.Block, abciResponses *ABCIResponses) {
// NOTE: do we still need this buffer ?
txEventBuffer := types.NewTxEventBuffer(eventBus, int(block.NumTxs))
for i, tx := range block.Data.Txs {
txEventBuffer.PublishEventTx(types.EventDataTx{types.TxResult{
Height: block.Height,
Index: uint32(i),
Tx: tx,
Result: *(abciResponses.DeliverTx[i]),
}})
}
eventBus.PublishEventNewBlock(types.EventDataNewBlock{block})
eventBus.PublishEventNewBlockHeader(types.EventDataNewBlockHeader{block.Header})
err := txEventBuffer.Flush()
if err != nil {
logger.Error("Failed to flush event buffer", "err", err)
}
}
//----------------------------------------------------------------------------------------------------
// Execute block without state. TODO: eliminate
// ExecCommitBlock executes and commits a block on the proxyApp without validating or mutating the state.
// It returns the application root hash (result of abci.Commit).
func ExecCommitBlock(appConnConsensus proxy.AppConnConsensus, block *types.Block, logger log.Logger) ([]byte, error) {
_, err := execBlockOnProxyApp(logger, appConnConsensus, block)
if err != nil {
logger.Error("Error executing block on proxy app", "height", block.Height, "err", err)
return nil, err
}
// Commit block, get hash back
res, err := appConnConsensus.CommitSync()
if err != nil {
logger.Error("Client error during proxyAppConn.CommitSync", "err", res)
return nil, err
}
if res.IsErr() {
logger.Error("Error in proxyAppConn.CommitSync", "err", res)
return nil, res
}
if res.Log != "" {
logger.Info("Commit.Log: " + res.Log)
}
return res.Data, nil
}