feat(sequencers/based): add based batch time (#2911)

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## Overview

ref: #2906

Add based block time based on epoch da time.

DO NOT MERGE YET, based on #2908
to avoid conflicts later.

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Author: julienrbrt

block/internal/da/client_test.go

@@ -523,3 +523,226 @@ func TestClient_Retrieve_Timeout(t *testing.T) {
 		assert.Assert(t, result.Message != "")
 	})
 }
+
+func TestClient_RetrieveHeaders(t *testing.T) {
+	logger := zerolog.Nop()
+	dataLayerHeight := uint64(100)
+	mockIDs := [][]byte{[]byte("id1")}
+	mockBlobs := [][]byte{[]byte("header-blob")}
+	mockTimestamp := time.Now()
+
+	mockDAInstance := &mockDA{
+		getIDsFunc: func(ctx context.Context, height uint64, namespace []byte) (*coreda.GetIDsResult, error) {
+			return &coreda.GetIDsResult{
+				IDs:       mockIDs,
+				Timestamp: mockTimestamp,
+			}, nil
+		},
+		getFunc: func(ctx context.Context, ids []coreda.ID, namespace []byte) ([]coreda.Blob, error) {
+			return mockBlobs, nil
+		},
+	}
+
+	client := NewClient(Config{
+		DA:            mockDAInstance,
+		Logger:        logger,
+		Namespace:     "test-header-ns",
+		DataNamespace: "test-data-ns",
+	})
+
+	result := client.RetrieveHeaders(context.Background(), dataLayerHeight)
+
+	assert.Equal(t, coreda.StatusSuccess, result.Code)
+	assert.Equal(t, dataLayerHeight, result.Height)
+	assert.Equal(t, len(mockBlobs), len(result.Data))
+}
+
+func TestClient_RetrieveData(t *testing.T) {
+	logger := zerolog.Nop()
+	dataLayerHeight := uint64(200)
+	mockIDs := [][]byte{[]byte("id1"), []byte("id2")}
+	mockBlobs := [][]byte{[]byte("data-blob-1"), []byte("data-blob-2")}
+	mockTimestamp := time.Now()
+
+	mockDAInstance := &mockDA{
+		getIDsFunc: func(ctx context.Context, height uint64, namespace []byte) (*coreda.GetIDsResult, error) {
+			return &coreda.GetIDsResult{
+				IDs:       mockIDs,
+				Timestamp: mockTimestamp,
+			}, nil
+		},
+		getFunc: func(ctx context.Context, ids []coreda.ID, namespace []byte) ([]coreda.Blob, error) {
+			return mockBlobs, nil
+		},
+	}
+
+	client := NewClient(Config{
+		DA:            mockDAInstance,
+		Logger:        logger,
+		Namespace:     "test-header-ns",
+		DataNamespace: "test-data-ns",
+	})
+
+	result := client.RetrieveData(context.Background(), dataLayerHeight)
+
+	assert.Equal(t, coreda.StatusSuccess, result.Code)
+	assert.Equal(t, dataLayerHeight, result.Height)
+	assert.Equal(t, len(mockBlobs), len(result.Data))
+}
+
+func TestClient_RetrieveBatched(t *testing.T) {
+	logger := zerolog.Nop()
+	dataLayerHeight := uint64(100)
+
+	// Create 200 IDs to exceed default batch size
+	numIDs := 200
+	mockIDs := make([][]byte, numIDs)
+	for i := range numIDs {
+		mockIDs[i] = []byte{byte(i)}
+	}
+
+	// Track which batches were requested
+	batchCalls := []int{}
+
+	mockDAInstance := &mockDA{
+		getIDsFunc: func(ctx context.Context, height uint64, namespace []byte) (*coreda.GetIDsResult, error) {
+			return &coreda.GetIDsResult{
+				IDs:       mockIDs,
+				Timestamp: time.Now(),
+			}, nil
+		},
+		getFunc: func(ctx context.Context, ids []coreda.ID, namespace []byte) ([]coreda.Blob, error) {
+			batchCalls = append(batchCalls, len(ids))
+			// Return a blob for each ID in the batch
+			blobs := make([][]byte, len(ids))
+			for i := range ids {
+				blobs[i] = []byte("blob")
+			}
+			return blobs, nil
+		},
+	}
+
+	client := NewClient(Config{
+		DA:                mockDAInstance,
+		Logger:            logger,
+		Namespace:         "test-ns",
+		DataNamespace:     "test-data-ns",
+		RetrieveBatchSize: 50, // Set smaller batch size for testing
+	})
+
+	encodedNamespace := coreda.NamespaceFromString("test-ns")
+	result := client.Retrieve(context.Background(), dataLayerHeight, encodedNamespace.Bytes())
+
+	assert.Equal(t, coreda.StatusSuccess, result.Code)
+	assert.Equal(t, numIDs, len(result.Data))
+
+	// Should have made 4 batches: 50 + 50 + 50 + 50 = 200
+	assert.Equal(t, 4, len(batchCalls))
+	assert.Equal(t, 50, batchCalls[0])
+	assert.Equal(t, 50, batchCalls[1])
+	assert.Equal(t, 50, batchCalls[2])
+	assert.Equal(t, 50, batchCalls[3])
+}
+
+func TestClient_RetrieveBatched_PartialBatch(t *testing.T) {
+	logger := zerolog.Nop()
+	dataLayerHeight := uint64(100)
+
+	// Create 175 IDs to test partial batch at the end
+	numIDs := 175
+	mockIDs := make([][]byte, numIDs)
+	for i := range numIDs {
+		mockIDs[i] = []byte{byte(i)}
+	}
+
+	batchCalls := []int{}
+
+	mockDAInstance := &mockDA{
+		getIDsFunc: func(ctx context.Context, height uint64, namespace []byte) (*coreda.GetIDsResult, error) {
+			return &coreda.GetIDsResult{
+				IDs:       mockIDs,
+				Timestamp: time.Now(),
+			}, nil
+		},
+		getFunc: func(ctx context.Context, ids []coreda.ID, namespace []byte) ([]coreda.Blob, error) {
+			batchCalls = append(batchCalls, len(ids))
+			blobs := make([][]byte, len(ids))
+			for i := range ids {
+				blobs[i] = []byte("blob")
+			}
+			return blobs, nil
+		},
+	}
+
+	client := NewClient(Config{
+		DA:                mockDAInstance,
+		Logger:            logger,
+		Namespace:         "test-ns",
+		DataNamespace:     "test-data-ns",
+		RetrieveBatchSize: 50,
+	})
+
+	encodedNamespace := coreda.NamespaceFromString("test-ns")
+	result := client.Retrieve(context.Background(), dataLayerHeight, encodedNamespace.Bytes())
+
+	assert.Equal(t, coreda.StatusSuccess, result.Code)
+	assert.Equal(t, numIDs, len(result.Data))
+
+	// Should have made 4 batches: 50 + 50 + 50 + 25 = 175
+	assert.Equal(t, 4, len(batchCalls))
+	assert.Equal(t, 50, batchCalls[0])
+	assert.Equal(t, 50, batchCalls[1])
+	assert.Equal(t, 50, batchCalls[2])
+	assert.Equal(t, 25, batchCalls[3]) // Partial batch
+}
+
+func TestClient_RetrieveBatched_ErrorInSecondBatch(t *testing.T) {
+	logger := zerolog.Nop()
+	dataLayerHeight := uint64(100)
+
+	// Create 200 IDs to require multiple batches
+	numIDs := 200
+	mockIDs := make([][]byte, numIDs)
+	for i := range numIDs {
+		mockIDs[i] = []byte{byte(i)}
+	}
+
+	batchCallCount := 0
+
+	mockDAInstance := &mockDA{
+		getIDsFunc: func(ctx context.Context, height uint64, namespace []byte) (*coreda.GetIDsResult, error) {
+			return &coreda.GetIDsResult{
+				IDs:       mockIDs,
+				Timestamp: time.Now(),
+			}, nil
+		},
+		getFunc: func(ctx context.Context, ids []coreda.ID, namespace []byte) ([]coreda.Blob, error) {
+			batchCallCount++
+			// Fail on second batch
+			if batchCallCount == 2 {
+				return nil, errors.New("network error in batch 2")
+			}
+			blobs := make([][]byte, len(ids))
+			for i := range ids {
+				blobs[i] = []byte("blob")
+			}
+			return blobs, nil
+		},
+	}
+
+	client := NewClient(Config{
+		DA:                mockDAInstance,
+		Logger:            logger,
+		Namespace:         "test-ns",
+		DataNamespace:     "test-data-ns",
+		RetrieveBatchSize: 50,
+	})
+
+	encodedNamespace := coreda.NamespaceFromString("test-ns")
+	result := client.Retrieve(context.Background(), dataLayerHeight, encodedNamespace.Bytes())
+
+	assert.Equal(t, coreda.StatusError, result.Code)
+	assert.Assert(t, result.Message != "")
+	// Error message should mention the batch range
+	assert.Assert(t, len(result.Message) > 0)
+}

block/internal/da/forced_inclusion_retriever.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"time"
 
 	"github.com/rs/zerolog"
 
@@ -25,6 +26,7 @@ type ForcedInclusionRetriever struct {
 
 // ForcedInclusionEvent contains forced inclusion transactions retrieved from DA.
 type ForcedInclusionEvent struct {
+	Timestamp     time.Time
 	StartDaHeight uint64
 	EndDaHeight   uint64
 	Txs           [][]byte
@@ -158,6 +160,10 @@ func (r *ForcedInclusionRetriever) processForcedInclusionBlobs(
 		}
 	}
 
+	if result.Timestamp.After(event.Timestamp) {
+		event.Timestamp = result.Timestamp
+	}
+
 	r.logger.Debug().
 		Uint64("height", height).
 		Int("blob_count", len(result.Data)).

block/internal/da/forced_inclusion_retriever_test.go

@@ -244,6 +244,7 @@ func TestForcedInclusionRetriever_RetrieveForcedIncludedTxs_MultiHeightEpoch(t *
 	assert.Assert(t, event != nil)
 	assert.Equal(t, event.StartDaHeight, uint64(100))
 	assert.Equal(t, event.EndDaHeight, uint64(102))
+	assert.Assert(t, event.Timestamp.After(time.Time{}))
 
 	// Should have collected all txs from all heights
 	expectedTxCount := len(testBlobsByHeight[100]) + len(testBlobsByHeight[101]) + len(testBlobsByHeight[102])
@@ -334,6 +335,7 @@ func TestForcedInclusionRetriever_processForcedInclusionBlobs(t *testing.T) {
 			} else {
 				assert.NilError(t, err)
 				assert.Equal(t, len(event.Txs), tt.expectedTxCount)
+				assert.Equal(t, event.Timestamp, time.Time{})
 			}
 		})
 	}

sequencers/based/sequencer.go

@@ -37,6 +37,8 @@ type BasedSequencer struct {
 
 	// Cached transactions from the current DA block being processed
 	currentBatchTxs [][]byte
+	// DA epoch end time for timestamp calculation
+	currentDAEndTime time.Time
 }
 
 // NewBasedSequencer creates a new based sequencer instance
@@ -97,13 +99,15 @@ func (s *BasedSequencer) GetNextBatch(ctx context.Context, req coresequencer.Get
 	// If we have no cached transactions or we've consumed all from the current DA block,
 	// fetch the next DA epoch
 	daHeight := s.GetDAHeight()
+
 	if len(s.currentBatchTxs) == 0 || s.checkpoint.TxIndex >= uint64(len(s.currentBatchTxs)) {
-		daEndHeight, err := s.fetchNextDAEpoch(ctx, req.MaxBytes)
+		daEndTime, daEndHeight, err := s.fetchNextDAEpoch(ctx, req.MaxBytes)
 		if err != nil {
 			return nil, err
 		}
 
 		daHeight = daEndHeight
+		s.currentDAEndTime = daEndTime
 	}
 
 	// Create batch from current position up to MaxBytes
@@ -129,15 +133,21 @@ func (s *BasedSequencer) GetNextBatch(ctx context.Context, req coresequencer.Get
 		}
 	}
 
+	// Calculate timestamp based on remaining transactions after this batch
+	// timestamp correspond to the last block time of a DA epoch, based on the remaining transactions to be executed
+	// this is done in order to handle the case where a DA epoch must fit in multiple blocks
+	remainingTxs := uint64(len(s.currentBatchTxs)) - s.checkpoint.TxIndex
+	timestamp := s.currentDAEndTime.Add(-time.Duration(remainingTxs) * time.Millisecond)
+
 	return &coresequencer.GetNextBatchResponse{
 		Batch:     batch,
-		Timestamp: time.Time{}, // TODO(@julienrbrt): we need to use DA block timestamp for determinism
+		Timestamp: timestamp,
 		BatchData: req.LastBatchData,
 	}, nil
 }
 
 // fetchNextDAEpoch fetches transactions from the next DA epoch
-func (s *BasedSequencer) fetchNextDAEpoch(ctx context.Context, maxBytes uint64) (uint64, error) {
+func (s *BasedSequencer) fetchNextDAEpoch(ctx context.Context, maxBytes uint64) (time.Time, uint64, error) {
 	currentDAHeight := s.checkpoint.DAHeight
 
 	s.logger.Debug().
@@ -149,16 +159,16 @@ func (s *BasedSequencer) fetchNextDAEpoch(ctx context.Context, maxBytes uint64)
 	if err != nil {
 		// Check if forced inclusion is not configured
 		if errors.Is(err, block.ErrForceInclusionNotConfigured) {
-			return 0, block.ErrForceInclusionNotConfigured
+			return time.Time{}, 0, block.ErrForceInclusionNotConfigured
 		} else if errors.Is(err, coreda.ErrHeightFromFuture) {
 			// If we get a height from future error, stay at current position
 			// We'll retry the same height on the next call until DA produces that block
 			s.logger.Debug().
 				Uint64("da_height", currentDAHeight).
 				Msg("DA height from future, waiting for DA to produce block")
-			return 0, nil
+			return time.Time{}, 0, nil
 		}
-		return 0, fmt.Errorf("failed to retrieve forced inclusion transactions: %w", err)
+		return time.Time{}, 0, fmt.Errorf("failed to retrieve forced inclusion transactions: %w", err)
 	}
 
 	// Validate and filter transactions
@@ -188,7 +198,7 @@ func (s *BasedSequencer) fetchNextDAEpoch(ctx context.Context, maxBytes uint64)
 	// Cache the transactions for this DA epoch
 	s.currentBatchTxs = validTxs
 
-	return forcedTxsEvent.EndDaHeight, nil
+	return forcedTxsEvent.Timestamp.UTC(), forcedTxsEvent.EndDaHeight, nil
 }
 
 // createBatchFromCheckpoint creates a batch from the current checkpoint position respecting MaxBytes