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refactor: make chain iterator updates synchronous #602

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Merged
merged 1 commit into from
Apr 6, 2025
Merged

refactor: make chain iterator updates synchronous #602

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121 changes: 103 additions & 18 deletions chain/chain.go
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,9 @@ type Chain struct {
lastDbBlockIndex uint64
blocks []database.Block
headers []ledger.BlockHeader
waitingChan chan struct{}
waitingChanMutex sync.Mutex
iterators []*ChainIterator
}

func NewChain(
Expand Down Expand Up @@ -196,17 +199,24 @@ func (c *Chain) AddBlock(block ledger.Block, blockNonce []byte, txn *database.Tx
BlockNumber: block.BlockNumber(),
}
c.tipBlockIndex = newBlockIndex
// Notify waiting iterators
if c.waitingChan != nil {
close(c.waitingChan)
c.waitingChan = nil
}
// Generate event
c.eventBus.Publish(
ChainUpdateEventType,
event.NewEvent(
if c.eventBus != nil {
c.eventBus.Publish(
ChainUpdateEventType,
ChainBlockEvent{
Point: tmpPoint,
Block: tmpBlock,
},
),
)
event.NewEvent(
ChainUpdateEventType,
ChainBlockEvent{
Point: tmpPoint,
Block: tmpBlock,
},
),
)
}
return nil
}

Expand Down Expand Up @@ -277,16 +287,29 @@ func (c *Chain) Rollback(point ocommon.Point) error {
BlockNumber: tmpBlock.Number,
}
c.tipBlockIndex = rollbackBlockIndex
// Update iterators for rollback
for _, iter := range c.iterators {
if iter.lastPoint.Slot > point.Slot {
// Don't update rollback point if the iterator already has an older one pending
if iter.needsRollback && point.Slot > iter.rollbackPoint.Slot {
continue
}
iter.rollbackPoint = point
iter.needsRollback = true
}
}
// Generate event
c.eventBus.Publish(
ChainUpdateEventType,
event.NewEvent(
if c.eventBus != nil {
c.eventBus.Publish(
ChainUpdateEventType,
ChainRollbackEvent{
Point: point,
},
),
)
event.NewEvent(
ChainUpdateEventType,
ChainRollbackEvent{
Point: point,
},
),
)
}
return nil
}

Expand Down Expand Up @@ -319,11 +342,18 @@ func (c *Chain) HeaderRange(count int) (ocommon.Point, ocommon.Point) {
// FromPoint returns a ChainIterator starting at the specified point. If inclusive is true, the iterator
// will start at the specified point. Otherwise it will start at the point following the specified point
func (c *Chain) FromPoint(point ocommon.Point, inclusive bool) (*ChainIterator, error) {
return newChainIterator(
c.mutex.Lock()
defer c.mutex.Unlock()
iter, err := newChainIterator(
c,
point,
inclusive,
)
if err != nil {
return nil, err
}
c.iterators = append(c.iterators, iter)
return iter, nil
}

func (c *Chain) BlockByPoint(point ocommon.Point, txn *database.Txn) (database.Block, error) {
Expand Down Expand Up @@ -370,3 +400,58 @@ func (c *Chain) blockByIndex(blockIndex uint64, txn *database.Txn) (database.Blo
}
return c.blocks[memBlockIndex], nil
}

func (c *Chain) iterNext(iter *ChainIterator, blocking bool) (*ChainIteratorResult, error) {
c.mutex.RLock()
// Check for pending rollback
if iter.needsRollback {
ret := &ChainIteratorResult{}
ret.Point = iter.rollbackPoint
ret.Rollback = true
iter.lastPoint = iter.rollbackPoint
iter.needsRollback = false
if iter.rollbackPoint.Slot > 0 {
// Lookup block index for rollback point
tmpBlock, err := c.BlockByPoint(iter.rollbackPoint, nil)
if err != nil {
c.mutex.RUnlock()
return nil, err
}
iter.nextBlockIndex = tmpBlock.ID + 1
}
c.mutex.RUnlock()
return ret, nil
}
ret := &ChainIteratorResult{}
// Lookup next block in metadata DB
tmpBlock, err := c.blockByIndex(iter.nextBlockIndex, nil)
// Return immedidately if a block is found
if err == nil {
ret.Point = ocommon.NewPoint(tmpBlock.Slot, tmpBlock.Hash)
ret.Block = tmpBlock
iter.nextBlockIndex++
iter.lastPoint = ret.Point
c.mutex.RUnlock()
return ret, nil
}
// Return any actual error
if !errors.Is(err, ErrBlockNotFound) {
c.mutex.RUnlock()
return ret, err
}
// Return immediately if we're not blocking
if !blocking {
c.mutex.RUnlock()
return nil, ErrIteratorChainTip
}
c.mutex.RUnlock()
// Wait for chain update
c.waitingChanMutex.Lock()
if c.waitingChan == nil {
c.waitingChan = make(chan struct{})
}
c.waitingChanMutex.Unlock()
<-c.waitingChan
// Call ourselves again now that we should have new data
return c.iterNext(iter, blocking)
}
36 changes: 13 additions & 23 deletions chain/chain_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -18,10 +18,8 @@ import (
"encoding/hex"
"errors"
"testing"
"time"

"github.com/blinklabs-io/dingo/chain"
"github.com/blinklabs-io/dingo/event"
"github.com/blinklabs-io/gouroboros/ledger"
"github.com/blinklabs-io/gouroboros/ledger/common"
ocommon "github.com/blinklabs-io/gouroboros/protocol/common"
Expand Down Expand Up @@ -105,10 +103,9 @@ var (
)

func TestChainBasic(t *testing.T) {
eventBus := event.NewEventBus(nil)
c, err := chain.NewChain(
nil, // db
eventBus,
nil, // db
nil, // eventBus,
false, // persistent
)
if err != nil {
Expand Down Expand Up @@ -176,10 +173,9 @@ func TestChainBasic(t *testing.T) {
}

func TestChainRollback(t *testing.T) {
eventBus := event.NewEventBus(nil)
c, err := chain.NewChain(
nil, // db
eventBus,
nil, // db
nil, // eventBus,
false, // persistent
)
if err != nil {
Expand All @@ -194,7 +190,7 @@ func TestChainRollback(t *testing.T) {
if err != nil {
t.Fatalf("unexpected error creating chain iterator: %s", err)
}
// Iterate until hitting chain tip, and make sure we get blocks in the correct order with
// Iterate until hitting chain tip, and make sure we get blocks in the correct order
testBlockIdx := 0
for {
next, err := iter.Next(false)
Expand Down Expand Up @@ -243,8 +239,6 @@ func TestChainRollback(t *testing.T) {
testRollbackPoint.Hash,
)
}
// XXX: how fast does this propagate to iterators?
time.Sleep(1000 * time.Millisecond)
// The chain iterator should give us a rollback
next, err := iter.Next(false)
if err != nil {
Expand All @@ -267,10 +261,9 @@ func TestChainRollback(t *testing.T) {

func TestChainHeaderRange(t *testing.T) {
testBlockCount := 3
eventBus := event.NewEventBus(nil)
c, err := chain.NewChain(
nil, // db
eventBus,
nil, // db
nil, // eventBus,
false, // persistent
)
if err != nil {
Expand Down Expand Up @@ -316,10 +309,9 @@ func TestChainHeaderRange(t *testing.T) {

func TestChainHeaderBlock(t *testing.T) {
testBlockCount := 3
eventBus := event.NewEventBus(nil)
c, err := chain.NewChain(
nil, // db
eventBus,
nil, // db
nil, // eventBus,
false, // persistent
)
if err != nil {
Expand Down Expand Up @@ -347,10 +339,9 @@ func TestChainHeaderBlock(t *testing.T) {

func TestChainHeaderWrongBlock(t *testing.T) {
testBlockCount := 3
eventBus := event.NewEventBus(nil)
c, err := chain.NewChain(
nil, // db
eventBus,
nil, // db
nil, // eventBus,
false, // persistent
)
if err != nil {
Expand Down Expand Up @@ -386,10 +377,9 @@ func TestChainHeaderWrongBlock(t *testing.T) {

func TestChainHeaderRollback(t *testing.T) {
testBlockCount := 3
eventBus := event.NewEventBus(nil)
c, err := chain.NewChain(
nil, // db
eventBus,
nil, // db
nil, // eventBus,
false, // persistent
)
if err != nil {
Expand Down
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