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fix(dot/state/epoch, lib/babe): enable block production through epoch…
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…s without rely on finalization (#2593)

* fix: block production to be independant of finalized blocks

Co-authored-by: Timothy Wu <timwu20@gmail.com>
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@EclesioMeloJunior @timwu20
EclesioMeloJunior and timwu20 committed Jul 6, 2022
1 parent 3d920cf commit a0a1804
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Showing 9 changed files with 164 additions and 341 deletions.
186 changes: 77 additions & 109 deletions dot/state/epoch.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,14 +12,16 @@ import (

"github.com/ChainSafe/chaindb"
"github.com/ChainSafe/gossamer/dot/types"
"github.com/ChainSafe/gossamer/lib/blocktree"
"github.com/ChainSafe/gossamer/lib/common"
"github.com/ChainSafe/gossamer/pkg/scale"
)

var (
ErrConfigNotFound = errors.New("config data not found")
ErrEpochNotInMemory = errors.New("epoch not found in memory map")
errHashNotInMemory = errors.New("hash not found in memory map")
errEpochDataNotFound = errors.New("epoch data not found in the database")
errEpochNotInDatabase = errors.New("epoch data not found in the database")
errHashNotPersisted = errors.New("hash with next epoch not found in database")
errNoPreRuntimeDigest = errors.New("header does not contain pre-runtime digest")
)
Expand Down Expand Up @@ -58,11 +60,11 @@ type EpochState struct {

nextEpochDataLock sync.RWMutex
// nextEpochData follows the format map[epoch]map[block hash]next epoch data
nextEpochData map[uint64]map[common.Hash]types.NextEpochData
nextEpochData nextEpochMap[types.NextEpochData]

nextConfigDataLock sync.RWMutex
// nextConfigData follows the format map[epoch]map[block hash]next config data
nextConfigData map[uint64]map[common.Hash]types.NextConfigData
nextConfigData nextEpochMap[types.NextConfigData]
}

// NewEpochStateFromGenesis returns a new EpochState given information for the first epoch, fetched from the runtime
Expand Down Expand Up @@ -90,8 +92,8 @@ func NewEpochStateFromGenesis(db chaindb.Database, blockState *BlockState,
blockState: blockState,
db: epochDB,
epochLength: genesisConfig.EpochLength,
nextEpochData: make(map[uint64]map[common.Hash]types.NextEpochData),
nextConfigData: make(map[uint64]map[common.Hash]types.NextConfigData),
nextEpochData: make(nextEpochMap[types.NextEpochData]),
nextConfigData: make(nextEpochMap[types.NextConfigData]),
}

auths, err := types.BABEAuthorityRawToAuthority(genesisConfig.GenesisAuthorities)
Expand Down Expand Up @@ -151,8 +153,8 @@ func NewEpochState(db chaindb.Database, blockState *BlockState) (*EpochState, er
db: chaindb.NewTable(db, epochPrefix),
epochLength: epochLength,
skipToEpoch: skipToEpoch,
nextEpochData: make(map[uint64]map[common.Hash]types.NextEpochData),
nextConfigData: make(map[uint64]map[common.Hash]types.NextConfigData),
nextEpochData: make(nextEpochMap[types.NextEpochData]),
nextConfigData: make(nextEpochMap[types.NextConfigData]),
}, nil
}

Expand Down Expand Up @@ -247,25 +249,29 @@ func (s *EpochState) SetEpochData(epoch uint64, info *types.EpochData) error {
// if the header params is nil then it will search only in database
func (s *EpochState) GetEpochData(epoch uint64, header *types.Header) (*types.EpochData, error) {
epochData, err := s.getEpochDataFromDatabase(epoch)
if err == nil && epochData != nil {
if err != nil && !errors.Is(err, chaindb.ErrKeyNotFound) {
return nil, fmt.Errorf("failed to retrieve epoch data from database: %w", err)
}

if epochData != nil {
return epochData, nil
}

if err != nil && !errors.Is(err, chaindb.ErrKeyNotFound) {
return nil, fmt.Errorf("failed to get epoch data from database: %w", err)
if header == nil {
return nil, errEpochNotInDatabase
}

// lookup in-memory only if header is given
if header != nil && errors.Is(err, chaindb.ErrKeyNotFound) {
epochData, err = s.getEpochDataFromMemory(epoch, header)
if err != nil {
return nil, fmt.Errorf("failed to get epoch data from memory: %w", err)
}
s.nextEpochDataLock.RLock()
defer s.nextEpochDataLock.RUnlock()

inMemoryEpochData, err := s.nextEpochData.Retrieve(s.blockState, epoch, header)
if err != nil {
return nil, fmt.Errorf("failed to get epoch data from memory: %w", err)
}

if epochData == nil {
return nil, fmt.Errorf("%w: for epoch %d and header with hash %s",
errEpochDataNotFound, epoch, header.Hash())
epochData, err = inMemoryEpochData.ToEpochData()
if err != nil {
return nil, fmt.Errorf("cannot transform into epoch data: %w", err)
}

return epochData, nil
Expand All @@ -287,32 +293,6 @@ func (s *EpochState) getEpochDataFromDatabase(epoch uint64) (*types.EpochData, e
return raw.ToEpochData()
}

// getEpochDataFromMemory retrieves the right epoch data that belongs to the header parameter
func (s *EpochState) getEpochDataFromMemory(epoch uint64, header *types.Header) (*types.EpochData, error) {
s.nextEpochDataLock.RLock()
defer s.nextEpochDataLock.RUnlock()

atEpoch, has := s.nextEpochData[epoch]
if !has {
return nil, fmt.Errorf("%w: %d", ErrEpochNotInMemory, epoch)
}

headerHash := header.Hash()

for hash, value := range atEpoch {
isDescendant, err := s.blockState.IsDescendantOf(hash, headerHash)
if err != nil {
return nil, fmt.Errorf("cannot verify the ancestry: %w", err)
}

if isDescendant {
return value.ToEpochData()
}
}

return nil, fmt.Errorf("%w: %s", errHashNotInMemory, headerHash)
}

// GetLatestEpochData returns the EpochData for the current epoch
func (s *EpochState) GetLatestEpochData() (*types.EpochData, error) {
curr, err := s.GetCurrentEpoch()
Expand All @@ -323,26 +303,6 @@ func (s *EpochState) GetLatestEpochData() (*types.EpochData, error) {
return s.GetEpochData(curr, nil)
}

// HasEpochData returns whether epoch data exists for a given epoch
func (s *EpochState) HasEpochData(epoch uint64) (bool, error) {
has, err := s.db.Has(epochDataKey(epoch))
if err == nil && has {
return has, nil
}

// we can have `has == false` and `err == nil`
// so ensure the error is not nil in the condition below.
if err != nil && !errors.Is(chaindb.ErrKeyNotFound, err) {
return false, fmt.Errorf("cannot check database for epoch key %d: %w", epoch, err)
}

s.nextEpochDataLock.Lock()
defer s.nextEpochDataLock.Unlock()

_, has = s.nextEpochData[epoch]
return has, nil
}

// SetConfigData sets the BABE config data for a given epoch
func (s *EpochState) SetConfigData(epoch uint64, info *types.ConfigData) error {
enc, err := scale.Marshal(*info)
Expand All @@ -364,28 +324,44 @@ func (s *EpochState) setLatestConfigData(epoch uint64) error {
return s.db.Put(latestConfigDataKey, buf)
}

// GetConfigData returns the config data for a given epoch persisted in database
// otherwise tries to get the data from the in-memory map using the header.
// If the header params is nil then it will search only in the database
func (s *EpochState) GetConfigData(epoch uint64, header *types.Header) (*types.ConfigData, error) {
configData, err := s.getConfigDataFromDatabase(epoch)
if err == nil && configData != nil {
return configData, nil
}
// GetConfigData returns the newest config data for a given epoch persisted in database
// otherwise tries to get the data from the in-memory map using the header. If we don't
// find any config data for the current epoch we lookup in the previous epochs, as the spec says:
// - The supplied configuration data are intended to be used from the next epoch onwards.
// If the header params is nil then it will search only in the database.
func (s *EpochState) GetConfigData(epoch uint64, header *types.Header) (configData *types.ConfigData, err error) {
for tryEpoch := int(epoch); tryEpoch >= 0; tryEpoch-- {
configData, err = s.getConfigDataFromDatabase(uint64(tryEpoch))
if err != nil && !errors.Is(err, chaindb.ErrKeyNotFound) {
return nil, fmt.Errorf("failed to retrieve config epoch from database: %w", err)
}

if err != nil && !errors.Is(err, chaindb.ErrKeyNotFound) {
return nil, fmt.Errorf("failed to get config data from database: %w", err)
} else if header == nil {
// if no header is given then skip the lookup in-memory
return configData, nil
}
if configData != nil {
return configData, nil
}

configData, err = s.getConfigDataFromMemory(epoch, header)
if err != nil {
return nil, fmt.Errorf("failed to get config data from memory: %w", err)
// there is no config data for the `tryEpoch` on database and we don't have a
// header to lookup in the memory map, so let's go retrieve the previous epoch
if header == nil {
continue
}

// we will check in the memory map and if we don't find the data
// then we continue searching through the previous epoch
s.nextConfigDataLock.RLock()
inMemoryConfigData, err := s.nextConfigData.Retrieve(s.blockState, uint64(tryEpoch), header)
s.nextConfigDataLock.RUnlock()

if errors.Is(err, ErrEpochNotInMemory) {
continue
} else if err != nil {
return nil, fmt.Errorf("failed to get config data from memory: %w", err)
}

return inMemoryConfigData.ToConfigData(), err
}

return configData, nil
return nil, fmt.Errorf("%w: epoch %d", ErrConfigNotFound, epoch)
}

// getConfigDataFromDatabase returns the BABE config data for a given epoch persisted in database
Expand All @@ -404,26 +380,36 @@ func (s *EpochState) getConfigDataFromDatabase(epoch uint64) (*types.ConfigData,
return info, nil
}

// getConfigDataFromMemory retrieves the BABE config data for a given epoch that belongs to the header parameter
func (s *EpochState) getConfigDataFromMemory(epoch uint64, header *types.Header) (*types.ConfigData, error) {
s.nextConfigDataLock.RLock()
defer s.nextConfigDataLock.RUnlock()
type nextEpochMap[T types.NextEpochData | types.NextConfigData] map[uint64]map[common.Hash]T

atEpoch, has := s.nextConfigData[epoch]
func (nem nextEpochMap[T]) Retrieve(blockState *BlockState, epoch uint64, header *types.Header) (*T, error) {
atEpoch, has := nem[epoch]
if !has {
return nil, fmt.Errorf("%w: %d", ErrEpochNotInMemory, epoch)
}

headerHash := header.Hash()

for hash, value := range atEpoch {
isDescendant, err := s.blockState.IsDescendantOf(hash, headerHash)
isDescendant, err := blockState.IsDescendantOf(hash, headerHash)

// sometimes while moving to the next epoch is possible the header
// is not fully imported by the blocktree, in this case we will use
// its parent header which migth be already imported.
if errors.Is(err, blocktree.ErrEndNodeNotFound) {
parentHeader, err := blockState.GetHeader(header.ParentHash)
if err != nil {
return nil, fmt.Errorf("cannot get parent header: %w", err)
}

return nem.Retrieve(blockState, epoch, parentHeader)
}

if err != nil {
return nil, fmt.Errorf("cannot verify the ancestry: %w", err)
}

if isDescendant {
return value.ToConfigData(), nil
return &value, nil
}
}

Expand All @@ -441,24 +427,6 @@ func (s *EpochState) GetLatestConfigData() (*types.ConfigData, error) {
return s.GetConfigData(epoch, nil)
}

// HasConfigData returns whether config data exists for a given epoch
func (s *EpochState) HasConfigData(epoch uint64) (bool, error) {
has, err := s.db.Has(configDataKey(epoch))
if err == nil && has {
return has, nil
}

if err != nil && !errors.Is(chaindb.ErrKeyNotFound, err) {
return false, fmt.Errorf("cannot check database for epoch key %d: %w", epoch, err)
}

s.nextConfigDataLock.Lock()
defer s.nextConfigDataLock.Unlock()

_, has = s.nextConfigData[epoch]
return has, nil
}

// GetStartSlotForEpoch returns the first slot in the given epoch.
// If 0 is passed as the epoch, it returns the start slot for the current epoch.
func (s *EpochState) GetStartSlotForEpoch(epoch uint64) (uint64, error) {
Expand Down
3 changes: 0 additions & 3 deletions dot/state/epoch_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,9 +54,6 @@ func TestEpochState_CurrentEpoch(t *testing.T) {

func TestEpochState_EpochData(t *testing.T) {
s := newEpochStateFromGenesis(t)
has, err := s.HasEpochData(0)
require.NoError(t, err)
require.True(t, has)

keyring, err := keystore.NewSr25519Keyring()
require.NoError(t, err)
Expand Down
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