Merge pull request #3596 from ethereum-optimism/jg/channel_in_reader

op-node: Switch channel bank and channel in reader to a pull based stage

op-node/rollup/derive/attributes_queue.go

@@ -22,58 +22,60 @@ import (
 // This stage can be reset by clearing it's batch buffer.
 // This stage does not need to retain any references to L1 blocks.
 
-type AttributesQueueOutput interface {
-	AddSafeAttributes(attributes *eth.PayloadAttributes)
-	SafeL2Head() eth.L2BlockRef
-	StageProgress
-}
-
 type AttributesQueue struct {
-	log      log.Logger
-	config   *rollup.Config
-	dl       L1ReceiptsFetcher
-	next     AttributesQueueOutput
-	progress Progress
-	batches  []*BatchData
+	log    log.Logger
+	config *rollup.Config
+	dl     L1ReceiptsFetcher
+	prev   *BatchQueue
+	batch  *BatchData
 }
 
-func NewAttributesQueue(log log.Logger, cfg *rollup.Config, l1Fetcher L1ReceiptsFetcher, next AttributesQueueOutput) *AttributesQueue {
+func NewAttributesQueue(log log.Logger, cfg *rollup.Config, l1Fetcher L1ReceiptsFetcher, prev *BatchQueue) *AttributesQueue {
 	return &AttributesQueue{
 		log:    log,
 		config: cfg,
 		dl:     l1Fetcher,
-		next:   next,
+		prev:   prev,
 	}
 }
 
-func (aq *AttributesQueue) AddBatch(batch *BatchData) {
-	aq.log.Debug("Received next batch", "batch_epoch", batch.EpochNum, "batch_timestamp", batch.Timestamp, "tx_count", len(batch.Transactions))
-	aq.batches = append(aq.batches, batch)
+func (aq *AttributesQueue) Origin() eth.L1BlockRef {
+	return aq.prev.Origin()
 }
 
-func (aq *AttributesQueue) Progress() Progress {
-	return aq.progress
-}
-
-func (aq *AttributesQueue) Step(ctx context.Context, outer Progress) error {
-	if changed, err := aq.progress.Update(outer); err != nil || changed {
-		return err
+func (aq *AttributesQueue) NextAttributes(ctx context.Context, l2SafeHead eth.L2BlockRef) (*eth.PayloadAttributes, error) {
+	// Get a batch if we need it
+	if aq.batch == nil {
+		batch, err := aq.prev.NextBatch(ctx, l2SafeHead)
+		if err != nil {
+			return nil, err
+		}
+		aq.batch = batch
 	}
-	if len(aq.batches) == 0 {
-		return io.EOF
+
+	// Actually generate the next attributes
+	if attrs, err := aq.createNextAttributes(ctx, aq.batch, l2SafeHead); err != nil {
+		return nil, err
+	} else {
+		// Clear out the local state once we will succeed
+		aq.batch = nil
+		return attrs, nil
 	}
-	batch := aq.batches[0]
 
-	safeL2Head := aq.next.SafeL2Head()
+}
+
+// createNextAttributes transforms a batch into a payload attributes. This sets `NoTxPool` and appends the batched transactions
+// to the attributes transaction list
+func (aq *AttributesQueue) createNextAttributes(ctx context.Context, batch *BatchData, l2SafeHead eth.L2BlockRef) (*eth.PayloadAttributes, error) {
 	// sanity check parent hash
-	if batch.ParentHash != safeL2Head.Hash {
-		return NewCriticalError(fmt.Errorf("valid batch has bad parent hash %s, expected %s", batch.ParentHash, safeL2Head.Hash))
+	if batch.ParentHash != l2SafeHead.Hash {
+		return nil, NewResetError(fmt.Errorf("valid batch has bad parent hash %s, expected %s", batch.ParentHash, l2SafeHead.Hash))
 	}
 	fetchCtx, cancel := context.WithTimeout(ctx, 20*time.Second)
 	defer cancel()
-	attrs, err := PreparePayloadAttributes(fetchCtx, aq.config, aq.dl, safeL2Head, batch.Timestamp, batch.Epoch())
+	attrs, err := PreparePayloadAttributes(fetchCtx, aq.config, aq.dl, l2SafeHead, batch.Timestamp, batch.Epoch())
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	// we are verifying, not sequencing, we've got all transactions and do not pull from the tx-pool
@@ -83,19 +85,9 @@ func (aq *AttributesQueue) Step(ctx context.Context, outer Progress) error {
 
 	aq.log.Info("generated attributes in payload queue", "txs", len(attrs.Transactions), "timestamp", batch.Timestamp)
 
-	// Slice off the batch once we are guaranteed to succeed
-	aq.batches = aq.batches[1:]
-
-	aq.next.AddSafeAttributes(attrs)
-	return nil
+	return attrs, nil
 }
 
-func (aq *AttributesQueue) ResetStep(ctx context.Context, l1Fetcher L1Fetcher) error {
-	aq.batches = aq.batches[:0]
-	aq.progress = aq.next.Progress()
+func (aq *AttributesQueue) Reset(ctx context.Context, _ eth.L1BlockRef) error {
 	return io.EOF
 }
-
-func (aq *AttributesQueue) SafeL2Head() eth.L2BlockRef {
-	return aq.next.SafeL2Head()
-}

op-node/rollup/derive/attributes_queue_test.go

@@ -2,7 +2,6 @@ package derive
 
 import (
 	"context"
-	"io"
 	"math/big"
 	"math/rand"
 	"testing"
@@ -17,29 +16,10 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 )
 
-type MockAttributesQueueOutput struct {
-	MockOriginStage
-}
-
-func (m *MockAttributesQueueOutput) AddSafeAttributes(attributes *eth.PayloadAttributes) {
-	m.Mock.MethodCalled("AddSafeAttributes", attributes)
-}
-
-func (m *MockAttributesQueueOutput) ExpectAddSafeAttributes(attributes *eth.PayloadAttributes) {
-	m.Mock.On("AddSafeAttributes", attributes).Once().Return()
-}
-
-func (m *MockAttributesQueueOutput) SafeL2Head() eth.L2BlockRef {
-	return m.Mock.MethodCalled("SafeL2Head").Get(0).(eth.L2BlockRef)
-}
-
-func (m *MockAttributesQueueOutput) ExpectSafeL2Head(head eth.L2BlockRef) {
-	m.Mock.On("SafeL2Head").Once().Return(head)
-}
-
-var _ AttributesQueueOutput = (*MockAttributesQueueOutput)(nil)
-
-func TestAttributesQueue_Step(t *testing.T) {
+// TestAttributesQueue checks that it properly uses the PreparePayloadAttributes function
+// (which is well tested) and that it properly sets NoTxPool and adds in the candidate
+// transactions.
+func TestAttributesQueue(t *testing.T) {
 	// test config, only init the necessary fields
 	cfg := &rollup.Config{
 		BlockTime:              2,
@@ -56,18 +36,9 @@ func TestAttributesQueue_Step(t *testing.T) {
 
 	l1Fetcher.ExpectInfoByHash(l1Info.InfoHash, l1Info, nil)
 
-	out := &MockAttributesQueueOutput{}
-	out.progress = Progress{
-		Origin: l1Info.BlockRef(),
-		Closed: false,
-	}
-	defer out.AssertExpectations(t)
-
 	safeHead := testutils.RandomL2BlockRef(rng)
 	safeHead.L1Origin = l1Info.ID()
 
-	out.ExpectSafeL2Head(safeHead)
-
 	batch := &BatchData{BatchV1{
 		ParentHash:   safeHead.Hash,
 		EpochNum:     rollup.Epoch(l1Info.InfoNum),
@@ -85,13 +56,11 @@ func TestAttributesQueue_Step(t *testing.T) {
 		Transactions:          []eth.Data{l1InfoTx, eth.Data("foobar"), eth.Data("example")},
 		NoTxPool:              true,
 	}
-	out.ExpectAddSafeAttributes(&attrs)
 
-	aq := NewAttributesQueue(testlog.Logger(t, log.LvlError), cfg, l1Fetcher, out)
-	require.NoError(t, RepeatResetStep(t, aq.ResetStep, l1Fetcher, 1))
+	aq := NewAttributesQueue(testlog.Logger(t, log.LvlError), cfg, l1Fetcher, nil)
 
-	aq.AddBatch(batch)
+	actual, err := aq.createNextAttributes(context.Background(), batch, safeHead)
 
-	require.NoError(t, aq.Step(context.Background(), out.progress), "adding batch to next stage, no EOF yet")
-	require.Equal(t, io.EOF, aq.Step(context.Background(), out.progress), "done with batches")
+	require.Nil(t, err)
+	require.Equal(t, attrs, *actual)
 }

op-node/rollup/derive/batch_queue.go

@@ -32,13 +32,18 @@ type BatchQueueOutput interface {
 	SafeL2Head() eth.L2BlockRef
 }
 
+type NextBatchProvider interface {
+	Origin() eth.L1BlockRef
+	NextBatch(ctx context.Context) (*BatchData, error)
+}
+
 // BatchQueue contains a set of batches for every L1 block.
 // L1 blocks are contiguous and this does not support reorgs.
 type BatchQueue struct {
-	log      log.Logger
-	config   *rollup.Config
-	next     BatchQueueOutput
-	progress Progress
+	log    log.Logger
+	config *rollup.Config
+	prev   NextBatchProvider
+	origin eth.L1BlockRef
 
 	l1Blocks []eth.L1BlockRef
 
@@ -47,62 +52,91 @@ type BatchQueue struct {
 }
 
 // NewBatchQueue creates a BatchQueue, which should be Reset(origin) before use.
-func NewBatchQueue(log log.Logger, cfg *rollup.Config, next BatchQueueOutput) *BatchQueue {
+func NewBatchQueue(log log.Logger, cfg *rollup.Config, prev NextBatchProvider) *BatchQueue {
 	return &BatchQueue{
 		log:    log,
 		config: cfg,
-		next:   next,
+		prev:   prev,
 	}
 }
 
-func (bq *BatchQueue) Progress() Progress {
-	return bq.progress
+func (bq *BatchQueue) Origin() eth.L1BlockRef {
+	return bq.prev.Origin()
 }
 
-func (bq *BatchQueue) Step(ctx context.Context, outer Progress) error {
-	if changed, err := bq.progress.Update(outer); err != nil {
-		return err
-	} else if changed {
-		if !bq.progress.Closed { // init inputs if we moved to a new open origin
-			bq.l1Blocks = append(bq.l1Blocks, bq.progress.Origin)
+func (bq *BatchQueue) NextBatch(ctx context.Context, safeL2Head eth.L2BlockRef) (*BatchData, error) {
+	originBehind := bq.origin.Number < safeL2Head.L1Origin.Number
+
+	// Advance origin if needed
+	// Note: The entire pipeline has the same origin
+	// We just don't accept batches prior to the L1 origin of the L2 safe head
+	if bq.origin != bq.prev.Origin() {
+		bq.origin = bq.prev.Origin()
+		if !originBehind {
+			bq.l1Blocks = append(bq.l1Blocks, bq.origin)
+		} else {
+			// This is to handle the special case of startup. At startup we call Reset & include
+			// the L1 origin. That is the only time where immediately after `Reset` is called
+			// originBehind is false.
+			bq.l1Blocks = bq.l1Blocks[:0]
 		}
-		return nil
+		bq.log.Info("Advancing bq origin", "origin", bq.origin)
 	}
-	batch, err := bq.deriveNextBatch(ctx)
-	if err == io.EOF {
-		// very noisy, commented for now, or we should bump log level from trace to debug
-		// bq.log.Trace("need more L1 data before deriving next batch", "progress", bq.progress.Origin)
-		return io.EOF
+
+	// Load more data into the batch queue
+	outOfData := false
+	if batch, err := bq.prev.NextBatch(ctx); err == io.EOF {
+		outOfData = true
 	} else if err != nil {
-		return err
+		return nil, err
+	} else if !originBehind {
+		bq.AddBatch(batch, safeL2Head)
 	}
-	bq.next.AddBatch(batch)
-	return nil
+
+	// Skip adding data unless we are up to date with the origin, but do fully
+	// empty the previous stages
+	if originBehind {
+		if outOfData {
+			return nil, io.EOF
+		} else {
+			return nil, NotEnoughData
+		}
+	}
+
+	// Finally attempt to derive more batches
+	batch, err := bq.deriveNextBatch(ctx, outOfData, safeL2Head)
+	if err == io.EOF && outOfData {
+		return nil, io.EOF
+	} else if err == io.EOF {
+		return nil, NotEnoughData
+	} else if err != nil {
+		return nil, err
+	}
+	return batch, nil
 }
 
-func (bq *BatchQueue) ResetStep(ctx context.Context, l1Fetcher L1Fetcher) error {
+func (bq *BatchQueue) Reset(ctx context.Context, base eth.L1BlockRef) error {
 	// Copy over the Origin from the next stage
 	// It is set in the engine queue (two stages away) such that the L2 Safe Head origin is the progress
-	bq.progress = bq.next.Progress()
+	bq.origin = base
 	bq.batches = make(map[uint64][]*BatchWithL1InclusionBlock)
 	// Include the new origin as an origin to build on
+	// Note: This is only for the initialization case. During normal resets we will later
+	// throw out this block.
 	bq.l1Blocks = bq.l1Blocks[:0]
-	bq.l1Blocks = append(bq.l1Blocks, bq.progress.Origin)
+	bq.l1Blocks = append(bq.l1Blocks, base)
 	return io.EOF
 }
 
-func (bq *BatchQueue) AddBatch(batch *BatchData) {
-	if bq.progress.Closed {
-		panic("write batch while closed")
-	}
+func (bq *BatchQueue) AddBatch(batch *BatchData, l2SafeHead eth.L2BlockRef) {
 	if len(bq.l1Blocks) == 0 {
 		panic(fmt.Errorf("cannot add batch with timestamp %d, no origin was prepared", batch.Timestamp))
 	}
 	data := BatchWithL1InclusionBlock{
-		L1InclusionBlock: bq.progress.Origin,
+		L1InclusionBlock: bq.origin,
 		Batch:            batch,
 	}
-	validity := CheckBatch(bq.config, bq.log, bq.l1Blocks, bq.next.SafeL2Head(), &data)
+	validity := CheckBatch(bq.config, bq.log, bq.l1Blocks, l2SafeHead, &data)
 	if validity == BatchDrop {
 		return // if we do drop the batch, CheckBatch will log the drop reason with WARN level.
 	}
@@ -113,12 +147,11 @@ func (bq *BatchQueue) AddBatch(batch *BatchData) {
 // following the validity rules imposed on consecutive batches,
 // based on currently available buffered batch and L1 origin information.
 // If no batch can be derived yet, then (nil, io.EOF) is returned.
-func (bq *BatchQueue) deriveNextBatch(ctx context.Context) (*BatchData, error) {
+func (bq *BatchQueue) deriveNextBatch(ctx context.Context, outOfData bool, l2SafeHead eth.L2BlockRef) (*BatchData, error) {
 	if len(bq.l1Blocks) == 0 {
 		return nil, NewCriticalError(errors.New("cannot derive next batch, no origin was prepared"))
 	}
 	epoch := bq.l1Blocks[0]
-	l2SafeHead := bq.next.SafeL2Head()
 
 	if l2SafeHead.L1Origin != epoch.ID() {
 		return nil, NewResetError(fmt.Errorf("buffered L1 chain epoch %s in batch queue does not match safe head %s", epoch, l2SafeHead))
@@ -183,8 +216,8 @@ batchLoop:
 	// i.e. if the sequence window expired, we create empty batches
 	expiryEpoch := epoch.Number + bq.config.SeqWindowSize
 	forceNextEpoch :=
-		(expiryEpoch == bq.progress.Origin.Number && bq.progress.Closed) ||
-			expiryEpoch < bq.progress.Origin.Number
+		(expiryEpoch == bq.origin.Number && outOfData) ||
+			expiryEpoch < bq.origin.Number
 
 	if !forceNextEpoch {
 		// sequence window did not expire yet, still room to receive batches for the current epoch,

op-node/rollup/derive/channel_bank.go

@@ -2,7 +2,6 @@ package derive
 
 import (
 	"context"
-	"fmt"
 	"io"
 
 	"github.com/ethereum-optimism/optimism/op-node/eth"
@@ -11,6 +10,11 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 )
 
+type NextDataProvider interface {
+	NextData(ctx context.Context) ([]byte, error)
+	Origin() eth.L1BlockRef
+}
+
 // ChannelBank is a stateful stage that does the following:
 // 1. Unmarshalls frames from L1 transaction data
 // 2. Applies those frames to a channel
@@ -22,11 +26,6 @@ import (
 // Specifically, the channel bank is not allowed to become too large between successive calls
 // to `IngestData`. This means that we can do an ingest and then do a read while becoming too large.
 
-type ChannelBankOutput interface {
-	StageProgress
-	WriteChannel(data []byte)
-}
-
 // ChannelBank buffers channel frames, and emits full channel data
 type ChannelBank struct {
 	log log.Logger
@@ -35,82 +34,78 @@ type ChannelBank struct {
 	channels     map[ChannelID]*Channel // channels by ID
 	channelQueue []ChannelID            // channels in FIFO order
 
-	progress Progress
-
-	next ChannelBankOutput
-	prev *L1Retrieval
+	prev    NextDataProvider
+	fetcher L1Fetcher
 }
 
-var _ Stage = (*ChannelBank)(nil)
+var _ PullStage = (*ChannelBank)(nil)
 
 // NewChannelBank creates a ChannelBank, which should be Reset(origin) before use.
-func NewChannelBank(log log.Logger, cfg *rollup.Config, next ChannelBankOutput, prev *L1Retrieval) *ChannelBank {
+func NewChannelBank(log log.Logger, cfg *rollup.Config, prev NextDataProvider, fetcher L1Fetcher) *ChannelBank {
 	return &ChannelBank{
 		log:          log,
 		cfg:          cfg,
 		channels:     make(map[ChannelID]*Channel),
 		channelQueue: make([]ChannelID, 0, 10),
-		next:         next,
 		prev:         prev,
+		fetcher:      fetcher,
 	}
 }
 
-func (ib *ChannelBank) Progress() Progress {
-	return ib.progress
+func (cb *ChannelBank) Origin() eth.L1BlockRef {
+	return cb.prev.Origin()
 }
 
-func (ib *ChannelBank) prune() {
+func (cb *ChannelBank) prune() {
 	// check total size
 	totalSize := uint64(0)
-	for _, ch := range ib.channels {
+	for _, ch := range cb.channels {
 		totalSize += ch.size
 	}
 	// prune until it is reasonable again. The high-priority channel failed to be read, so we start pruning there.
 	for totalSize > MaxChannelBankSize {
-		id := ib.channelQueue[0]
-		ch := ib.channels[id]
-		ib.channelQueue = ib.channelQueue[1:]
-		delete(ib.channels, id)
+		id := cb.channelQueue[0]
+		ch := cb.channels[id]
+		cb.channelQueue = cb.channelQueue[1:]
+		delete(cb.channels, id)
 		totalSize -= ch.size
 	}
 }
 
 // IngestData adds new L1 data to the channel bank.
 // Read() should be called repeatedly first, until everything has been read, before adding new data.\
-func (ib *ChannelBank) IngestData(data []byte) {
-	if ib.progress.Closed {
-		panic("write data to bank while closed")
-	}
-	ib.log.Debug("channel bank got new data", "origin", ib.progress.Origin, "data_len", len(data))
+func (cb *ChannelBank) IngestData(data []byte) {
+	origin := cb.Origin()
+	cb.log.Debug("channel bank got new data", "origin", origin, "data_len", len(data))
 
 	// TODO: Why is the prune here?
-	ib.prune()
+	cb.prune()
 
 	frames, err := ParseFrames(data)
 	if err != nil {
-		ib.log.Warn("malformed frame", "err", err)
+		cb.log.Warn("malformed frame", "err", err)
 		return
 	}
 
 	// Process each frame
 	for _, f := range frames {
-		currentCh, ok := ib.channels[f.ID]
+		currentCh, ok := cb.channels[f.ID]
 		if !ok {
 			// create new channel if it doesn't exist yet
-			currentCh = NewChannel(f.ID, ib.progress.Origin)
-			ib.channels[f.ID] = currentCh
-			ib.channelQueue = append(ib.channelQueue, f.ID)
+			currentCh = NewChannel(f.ID, origin)
+			cb.channels[f.ID] = currentCh
+			cb.channelQueue = append(cb.channelQueue, f.ID)
 		}
 
 		// check if the channel is not timed out
-		if currentCh.OpenBlockNumber()+ib.cfg.ChannelTimeout < ib.progress.Origin.Number {
-			ib.log.Warn("channel is timed out, ignore frame", "channel", f.ID, "frame", f.FrameNumber)
+		if currentCh.OpenBlockNumber()+cb.cfg.ChannelTimeout < origin.Number {
+			cb.log.Warn("channel is timed out, ignore frame", "channel", f.ID, "frame", f.FrameNumber)
 			continue
 		}
 
-		ib.log.Trace("ingesting frame", "channel", f.ID, "frame_number", f.FrameNumber, "length", len(f.Data))
-		if err := currentCh.AddFrame(f, ib.progress.Origin); err != nil {
-			ib.log.Warn("failed to ingest frame into channel", "channel", f.ID, "frame_number", f.FrameNumber, "err", err)
+		cb.log.Trace("ingesting frame", "channel", f.ID, "frame_number", f.FrameNumber, "length", len(f.Data))
+		if err := currentCh.AddFrame(f, origin); err != nil {
+			cb.log.Warn("failed to ingest frame into channel", "channel", f.ID, "frame_number", f.FrameNumber, "err", err)
 			continue
 		}
 	}
@@ -118,98 +113,62 @@ func (ib *ChannelBank) IngestData(data []byte) {
 
 // Read the raw data of the first channel, if it's timed-out or closed.
 // Read returns io.EOF if there is nothing new to read.
-func (ib *ChannelBank) Read() (data []byte, err error) {
-	if len(ib.channelQueue) == 0 {
+func (cb *ChannelBank) Read() (data []byte, err error) {
+	if len(cb.channelQueue) == 0 {
 		return nil, io.EOF
 	}
-	first := ib.channelQueue[0]
-	ch := ib.channels[first]
-	timedOut := ch.OpenBlockNumber()+ib.cfg.ChannelTimeout < ib.progress.Origin.Number
+	first := cb.channelQueue[0]
+	ch := cb.channels[first]
+	timedOut := ch.OpenBlockNumber()+cb.cfg.ChannelTimeout < cb.Origin().Number
 	if timedOut {
-		ib.log.Debug("channel timed out", "channel", first, "frames", len(ch.inputs))
-		delete(ib.channels, first)
-		ib.channelQueue = ib.channelQueue[1:]
+		cb.log.Debug("channel timed out", "channel", first, "frames", len(ch.inputs))
+		delete(cb.channels, first)
+		cb.channelQueue = cb.channelQueue[1:]
 		return nil, io.EOF
 	}
 	if !ch.IsReady() {
 		return nil, io.EOF
 	}
 
-	delete(ib.channels, first)
-	ib.channelQueue = ib.channelQueue[1:]
+	delete(cb.channels, first)
+	cb.channelQueue = cb.channelQueue[1:]
 	r := ch.Reader()
 	// Suprress error here. io.ReadAll does return nil instead of io.EOF though.
 	data, _ = io.ReadAll(r)
 	return data, nil
 }
 
-// Step does the advancement for the channel bank.
-// Channel bank as the first non-pull stage does it's own progress maintentance.
-// When closed, it checks against the previous origin to determine if to open itself
-func (ib *ChannelBank) Step(ctx context.Context, _ Progress) error {
-	// Open ourselves
-	// This is ok to do b/c we would not have yielded control to the lower stages
-	// of the pipeline without being completely done reading from L1.
-	if ib.progress.Closed {
-		if ib.progress.Origin != ib.prev.Origin() {
-			ib.progress.Closed = false
-			ib.progress.Origin = ib.prev.Origin()
-			return nil
-		}
-	}
-
-	skipIngest := ib.next.Progress().Origin.Number > ib.progress.Origin.Number
-	outOfData := false
-
-	if data, err := ib.prev.NextData(ctx); err == io.EOF {
-		outOfData = true
+// NextData pulls the next piece of data from the channel bank.
+// Note that it attempts to pull data out of the channel bank prior to
+// loading data in (unlike most other stages). This is to ensure maintain
+// consistency around channel bank pruning which depends upon the order
+// of operations.
+func (cb *ChannelBank) NextData(ctx context.Context) ([]byte, error) {
+
+	// Do the read from the channel bank first
+	data, err := cb.Read()
+	if err == io.EOF {
+		// continue - We will attempt to load data into the channel bank
 	} else if err != nil {
-		return err
+		return nil, err
 	} else {
-		ib.IngestData(data)
+		return data, nil
 	}
 
-	// otherwise, read the next channel data from the bank
-	data, err := ib.Read()
-	if err == io.EOF { // need new L1 data in the bank before we can read more channel data
-		if outOfData {
-			if !ib.progress.Closed {
-				ib.progress.Closed = true
-				return nil
-			}
-			return io.EOF
-		} else {
-			return nil
-		}
+	// Then load data into the channel bank
+	if data, err := cb.prev.NextData(ctx); err == io.EOF {
+		return nil, io.EOF
 	} else if err != nil {
-		return err
+		return nil, err
 	} else {
-		if !skipIngest {
-			ib.next.WriteChannel(data)
-			return nil
-		}
+		cb.IngestData(data)
+		return nil, NotEnoughData
 	}
-	return nil
 }
 
-// ResetStep walks back the L1 chain, starting at the origin of the next stage,
-// to find the origin that the channel bank should be reset to,
-// to get consistent reads starting at origin.
-// Any channel data before this origin will be timed out by the time the channel bank is synced up to the origin,
-// so it is not relevant to replay it into the bank.
-func (ib *ChannelBank) ResetStep(ctx context.Context, l1Fetcher L1Fetcher) error {
-	ib.progress = ib.next.Progress()
-	ib.log.Debug("walking back to find reset origin for channel bank", "origin", ib.progress.Origin)
-	// go back in history if we are not distant enough from the next stage
-	resetBlock := ib.progress.Origin.Number - ib.cfg.ChannelTimeout
-	if ib.progress.Origin.Number < ib.cfg.ChannelTimeout {
-		resetBlock = 0 // don't underflow
-	}
-	parent, err := l1Fetcher.L1BlockRefByNumber(ctx, resetBlock)
-	if err != nil {
-		return NewTemporaryError(fmt.Errorf("failed to find channel bank block, failed to retrieve L1 reference: %w", err))
-	}
-	ib.progress.Origin = parent
+func (cb *ChannelBank) Reset(ctx context.Context, base eth.L1BlockRef) error {
+	cb.channels = make(map[ChannelID]*Channel)
+	cb.channelQueue = make([]ChannelID, 0, 10)
 	return io.EOF
 }
 

op-node/rollup/derive/channel_in_reader.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"io"
 
+	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum/go-ethereum/log"
 )
 
@@ -13,41 +14,36 @@ import (
 // This is a pure function from the channel, but each channel (or channel fragment)
 // must be tagged with an L1 inclusion block to be passed to the the batch queue.
 
-type BatchQueueStage interface {
-	StageProgress
-	AddBatch(batch *BatchData)
-}
-
 type ChannelInReader struct {
 	log log.Logger
 
 	nextBatchFn func() (BatchWithL1InclusionBlock, error)
 
-	progress Progress
-
-	next BatchQueueStage
+	prev *ChannelBank
 }
 
-var _ ChannelBankOutput = (*ChannelInReader)(nil)
+var _ PullStage = (*ChannelInReader)(nil)
 
 // NewChannelInReader creates a ChannelInReader, which should be Reset(origin) before use.
-func NewChannelInReader(log log.Logger, next BatchQueueStage) *ChannelInReader {
-	return &ChannelInReader{log: log, next: next}
+func NewChannelInReader(log log.Logger, prev *ChannelBank) *ChannelInReader {
+	return &ChannelInReader{
+		log:  log,
+		prev: prev,
+	}
 }
 
-func (cr *ChannelInReader) Progress() Progress {
-	return cr.progress
+func (cr *ChannelInReader) Origin() eth.L1BlockRef {
+	return cr.prev.Origin()
 }
 
 // TODO: Take full channel for better logging
-func (cr *ChannelInReader) WriteChannel(data []byte) {
-	if cr.progress.Closed {
-		panic("write channel while closed")
-	}
-	if f, err := BatchReader(bytes.NewBuffer(data), cr.progress.Origin); err == nil {
+func (cr *ChannelInReader) WriteChannel(data []byte) error {
+	if f, err := BatchReader(bytes.NewBuffer(data), cr.Origin()); err == nil {
 		cr.nextBatchFn = f
+		return nil
 	} else {
 		cr.log.Error("Error creating batch reader from channel data", "err", err)
+		return err
 	}
 }
 
@@ -57,32 +53,37 @@ func (cr *ChannelInReader) NextChannel() {
 	cr.nextBatchFn = nil
 }
 
-func (cr *ChannelInReader) Step(ctx context.Context, outer Progress) error {
-	if changed, err := cr.progress.Update(outer); err != nil || changed {
-		return err
-	}
-
+// NextBatch pulls out the next batch from the channel if it has it.
+// It returns io.EOF when it cannot make any more progress.
+// It will return a temporary error if it needs to be called again to advance some internal state.
+func (cr *ChannelInReader) NextBatch(ctx context.Context) (*BatchData, error) {
 	if cr.nextBatchFn == nil {
-		return io.EOF
+		if data, err := cr.prev.NextData(ctx); err == io.EOF {
+			return nil, io.EOF
+		} else if err != nil {
+			return nil, err
+		} else {
+			if err := cr.WriteChannel(data); err != nil {
+				return nil, NewTemporaryError(err)
+			}
+		}
 	}
 
 	// TODO: can batch be non nil while err == io.EOF
 	// This depends on the behavior of rlp.Stream
 	batch, err := cr.nextBatchFn()
-
 	if err == io.EOF {
-		return io.EOF
+		cr.NextChannel()
+		return nil, NotEnoughData
 	} else if err != nil {
 		cr.log.Warn("failed to read batch from channel reader, skipping to next channel now", "err", err)
 		cr.NextChannel()
-		return nil
+		return nil, NotEnoughData
 	}
-	cr.next.AddBatch(batch.Batch)
-	return nil
+	return batch.Batch, nil
 }
 
-func (cr *ChannelInReader) ResetStep(ctx context.Context, l1Fetcher L1Fetcher) error {
+func (cr *ChannelInReader) Reset(ctx context.Context, _ eth.L1BlockRef) error {
 	cr.nextBatchFn = nil
-	cr.progress = cr.next.Progress()
 	return io.EOF
 }

op-node/rollup/derive/engine_queue.go

@@ -17,6 +17,11 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 )
 
+type NextAttributesProvider interface {
+	Origin() eth.L1BlockRef
+	NextAttributes(context.Context, eth.L2BlockRef) (*eth.PayloadAttributes, error)
+}
+
 type Engine interface {
 	GetPayload(ctx context.Context, payloadId eth.PayloadID) (*eth.ExecutionPayload, error)
 	ForkchoiceUpdate(ctx context.Context, state *eth.ForkchoiceState, attr *eth.PayloadAttributes) (*eth.ForkchoiceUpdatedResult, error)
@@ -64,8 +69,6 @@ type EngineQueue struct {
 
 	finalizedL1 eth.BlockID
 
-	progress Progress
-
 	safeAttributes []*eth.PayloadAttributes
 	unsafePayloads PayloadsQueue // queue of unsafe payloads, ordered by ascending block number, may have gaps
 
@@ -73,14 +76,15 @@ type EngineQueue struct {
 	finalityData []FinalityData
 
 	engine Engine
+	prev   NextAttributesProvider
+
+	progress Progress // only used for pipeline resets
 
 	metrics Metrics
 }
 
-var _ AttributesQueueOutput = (*EngineQueue)(nil)
-
 // NewEngineQueue creates a new EngineQueue, which should be Reset(origin) before use.
-func NewEngineQueue(log log.Logger, cfg *rollup.Config, engine Engine, metrics Metrics) *EngineQueue {
+func NewEngineQueue(log log.Logger, cfg *rollup.Config, engine Engine, metrics Metrics, prev NextAttributesProvider) *EngineQueue {
 	return &EngineQueue{
 		log:          log,
 		cfg:          cfg,
@@ -91,6 +95,7 @@ func NewEngineQueue(log log.Logger, cfg *rollup.Config, engine Engine, metrics M
 			MaxSize: maxUnsafePayloadsMemory,
 			SizeFn:  payloadMemSize,
 		},
+		prev: prev,
 	}
 }
 
@@ -146,17 +151,30 @@ func (eq *EngineQueue) LastL2Time() uint64 {
 	return uint64(eq.safeAttributes[len(eq.safeAttributes)-1].Timestamp)
 }
 
-func (eq *EngineQueue) Step(ctx context.Context, outer Progress) error {
-	if changed, err := eq.progress.Update(outer); err != nil || changed {
-		return err
-	}
+func (eq *EngineQueue) Step(ctx context.Context, _ Progress) error {
 	if len(eq.safeAttributes) > 0 {
 		return eq.tryNextSafeAttributes(ctx)
 	}
+	outOfData := false
+	if len(eq.safeAttributes) == 0 {
+		if next, err := eq.prev.NextAttributes(ctx, eq.safeHead); err == io.EOF {
+			outOfData = true
+		} else if err != nil {
+			return err
+		} else {
+			eq.safeAttributes = append(eq.safeAttributes, next)
+			return NotEnoughData
+		}
+	}
 	if eq.unsafePayloads.Len() > 0 {
 		return eq.tryNextUnsafePayload(ctx)
 	}
-	return io.EOF
+
+	if outOfData {
+		return io.EOF
+	} else {
+		return nil
+	}
 }
 
 // tryFinalizeL2 traverses the past L1 blocks, checks if any has been finalized,
@@ -186,11 +204,11 @@ func (eq *EngineQueue) postProcessSafeL2() {
 		eq.finalityData = append(eq.finalityData[:0], eq.finalityData[1:finalityLookback]...)
 	}
 	// remember the last L2 block that we fully derived from the given finality data
-	if len(eq.finalityData) == 0 || eq.finalityData[len(eq.finalityData)-1].L1Block.Number < eq.progress.Origin.Number {
+	if len(eq.finalityData) == 0 || eq.finalityData[len(eq.finalityData)-1].L1Block.Number < eq.prev.Origin().Number {
 		// append entry for new L1 block
 		eq.finalityData = append(eq.finalityData, FinalityData{
 			L2Block: eq.safeHead,
-			L1Block: eq.progress.Origin.ID(),
+			L1Block: eq.prev.Origin().ID(),
 		})
 	} else {
 		// if it's a now L2 block that was derived from the same latest L1 block, then just update the entry
@@ -205,7 +223,7 @@ func (eq *EngineQueue) logSyncProgress(reason string) {
 		"l2_safe", eq.safeHead,
 		"l2_unsafe", eq.unsafeHead,
 		"l2_time", eq.unsafeHead.Time,
-		"l1_derived", eq.progress.Origin,
+		"l1_derived", eq.prev.Origin(),
 	)
 }
 
@@ -398,6 +416,15 @@ func (eq *EngineQueue) ResetStep(ctx context.Context, l1Fetcher L1Fetcher) error
 		return NewResetError(fmt.Errorf("cannot reset block derivation to start at L2 block %s with time %d older than its L1 origin %s with time %d, time invariant is broken",
 			safe, safe.Time, l1Origin, l1Origin.Time))
 	}
+
+	pipelineNumber := l1Origin.Number - eq.cfg.ChannelTimeout
+	if l1Origin.Number < eq.cfg.ChannelTimeout {
+		pipelineNumber = 0
+	}
+	pipelineOrigin, err := l1Fetcher.L1BlockRefByNumber(ctx, pipelineNumber)
+	if err != nil {
+		return NewTemporaryError(fmt.Errorf("failed to fetch the new L1 progress: origin: %v; err: %w", pipelineNumber, err))
+	}
 	eq.log.Debug("Reset engine queue", "safeHead", safe, "unsafe", unsafe, "safe_timestamp", safe.Time, "unsafe_timestamp", unsafe.Time, "l1Origin", l1Origin)
 	eq.unsafeHead = unsafe
 	eq.safeHead = safe
@@ -405,8 +432,7 @@ func (eq *EngineQueue) ResetStep(ctx context.Context, l1Fetcher L1Fetcher) error
 	eq.finalityData = eq.finalityData[:0]
 	// note: we do not clear the unsafe payloadds queue; if the payloads are not applicable anymore the parent hash checks will clear out the old payloads.
 	eq.progress = Progress{
-		Origin: l1Origin,
-		Closed: false,
+		Origin: pipelineOrigin,
 	}
 	eq.metrics.RecordL2Ref("l2_finalized", finalized)
 	eq.metrics.RecordL2Ref("l2_safe", safe)

op-node/rollup/derive/engine_queue_test.go

 package derive
 
 import (
+	"context"
+	"io"
 	"math/rand"
 	"testing"
 
@@ -14,6 +16,20 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 )
 
+type fakeAttributesQueue struct {
+	origin eth.L1BlockRef
+}
+
+func (f *fakeAttributesQueue) Origin() eth.L1BlockRef {
+	return f.origin
+}
+
+func (f *fakeAttributesQueue) NextAttributes(_ context.Context, _ eth.L2BlockRef) (*eth.PayloadAttributes, error) {
+	return nil, io.EOF
+}
+
+var _ NextAttributesProvider = (*fakeAttributesQueue)(nil)
+
 func TestEngineQueue_Finalize(t *testing.T) {
 	logger := testlog.Logger(t, log.LvlInfo)
 
@@ -209,9 +225,12 @@ func TestEngineQueue_Finalize(t *testing.T) {
 
 	// and we fetch the L1 origin of that as starting point for engine queue
 	l1F.ExpectL1BlockRefByHash(refB.Hash, refB, nil)
+	l1F.ExpectL1BlockRefByNumber(refB.Number, refB, nil)
+
+	prev := &fakeAttributesQueue{}
 
-	eq := NewEngineQueue(logger, cfg, eng, metrics)
-	require.NoError(t, RepeatResetStep(t, eq.ResetStep, l1F, 20))
+	eq := NewEngineQueue(logger, cfg, eng, metrics, prev)
+	require.ErrorIs(t, eq.ResetStep(context.Background(), l1F), io.EOF)
 
 	require.Equal(t, refB1, eq.SafeL2Head(), "L2 reset should go back to sequence window ago: blocks with origin E and D are not safe until we reconcile, C is extra, and B1 is the end we look for")
 	require.Equal(t, refB, eq.Progress().Origin, "Expecting to be set back derivation L1 progress to B")
@@ -219,20 +238,19 @@ func TestEngineQueue_Finalize(t *testing.T) {
 
 	// now say C1 was included in D and became the new safe head
 	eq.progress.Origin = refD
+	prev.origin = refD
 	eq.safeHead = refC1
 	eq.postProcessSafeL2()
 
 	// now say D0 was included in E and became the new safe head
 	eq.progress.Origin = refE
+	prev.origin = refE
 	eq.safeHead = refD0
 	eq.postProcessSafeL2()
 
 	// let's finalize D (current L1), from which we fully derived C1 (it was safe head), but not D0 (included in E)
 	eq.Finalize(refD.ID())
 
-	// Now a few steps later, without consuming any additional L1 inputs,
-	// we should be able to resolve that B1 is now finalized, since it was included in finalized L1 block C
-	require.NoError(t, RepeatStep(t, eq.Step, eq.progress, 10))
 	require.Equal(t, refC1, eq.Finalized(), "C1 was included in finalized D, and should now be finalized")
 
 	l1F.AssertExpectations(t)

op-node/rollup/derive/error.go

 package derive
 
 import (
+	"errors"
 	"fmt"
 )
 
@@ -91,3 +92,7 @@ func NewCriticalError(err error) error {
 var ErrTemporary = NewTemporaryError(nil)
 var ErrReset = NewResetError(nil)
 var ErrCritical = NewCriticalError(nil)
+
+// NotEnoughData implies that the function currently does not have enough data to progress
+// but if it is retried enough times, it will eventually return a real value or io.EOF
+var NotEnoughData = errors.New("not enough data")

op-node/rollup/derive/pipeline.go

@@ -98,16 +98,16 @@ func NewDerivationPipeline(log log.Logger, cfg *rollup.Config, l1Fetcher L1Fetch
 	l1Traversal := NewL1Traversal(log, l1Fetcher)
 	dataSrc := NewDataSourceFactory(log, cfg, l1Fetcher) // auxiliary stage for L1Retrieval
 	l1Src := NewL1Retrieval(log, dataSrc, l1Traversal)
+	bank := NewChannelBank(log, cfg, l1Src, l1Fetcher)
+	chInReader := NewChannelInReader(log, bank)
+	batchQueue := NewBatchQueue(log, cfg, chInReader)
+	attributesQueue := NewAttributesQueue(log, cfg, l1Fetcher, batchQueue)
 
 	// Push stages (that act like pull stages b/c we push from the innermost stages prior to the outermost stages)
-	eng := NewEngineQueue(log, cfg, engine, metrics)
-	attributesQueue := NewAttributesQueue(log, cfg, l1Fetcher, eng)
-	batchQueue := NewBatchQueue(log, cfg, attributesQueue)
-	chInReader := NewChannelInReader(log, batchQueue)
-	bank := NewChannelBank(log, cfg, chInReader, l1Src)
-
-	stages := []Stage{eng, attributesQueue, batchQueue, chInReader, bank}
-	pullStages := []PullStage{l1Src, l1Traversal}
+	eng := NewEngineQueue(log, cfg, engine, metrics, attributesQueue)
+
+	stages := []Stage{eng}
+	pullStages := []PullStage{attributesQueue, batchQueue, chInReader, bank, l1Src, l1Traversal}
 
 	return &DerivationPipeline{
 		log:        log,

op-node/rollup/driver/state.go

@@ -440,6 +440,10 @@ func (s *state) eventLoop() {
 			} else if err != nil && errors.Is(err, derive.ErrCritical) {
 				s.log.Error("Derivation process critical error", "err", err)
 				return
+			} else if err != nil && errors.Is(err, derive.NotEnoughData) {
+				stepAttempts = 0 // don't do a backoff for this error
+				reqStep()
+				continue
 			} else if err != nil {
 				s.log.Error("Derivation process error", "attempts", stepAttempts, "err", err)
 				reqStep()