Implement PeerDAS sync (#15564)

* PeerDAS: Implement sync

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix Satyajit's comment.

* Partially fix Potuz's comment.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Add tests for `sendDataColumnSidecarsRequest`.

* Fix Satyajit's comment.

* Implement `TestSendDataColumnSidecarsRequest`.

* Implement `TestFetchDataColumnSidecarsFromPeers`.

* Implement `TestUpdateResults`.

* Implement `TestSelectPeers`.

* Implement `TestCategorizeIndices`.

* Fix James' comment.

* Fix James's comment.

* Fix James' commit.

* Fix James' comment.

* Fix James' comment.

* Fix flakiness in `TestSelectPeers`.

* Update cmd/beacon-chain/flags/config.go

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

* Fix Preston's comment.

* Fix James's comment.

* Implement `TestFetchDataColumnSidecars`.

* Revert "Fix Potuz's comment."

This reverts commit c45230b455.

* Fix Potuz's comment.

* Revert "Fix James' comment."

This reverts commit a3f919205a.

* Fix James' comment.

* Fix Preston's comment.

* Fix James' comment.

* `selectPeers`: Avoid map with key but empty value.

* Fix typo.

* Fix Potuz's comment.

* Fix Potuz's comment.

* Fix James' comment.

* Add DataColumnStorage and SubscribeAllDataSubnets flag.

* Add extra flags

* Fix Potuz's and Preston's comment.

* Add rate limiter check.

---------

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>
Co-authored-by: Kasey Kirkham <kasey@users.noreply.github.com>

beacon-chain/sync/initial-sync/service_test.go

@@ -7,14 +7,17 @@ import (
 	"time"
 
 	"github.com/OffchainLabs/prysm/v6/async/abool"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	mock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/kv"
 	dbtest "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
-	p2pt "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
+	p2ptest "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
 	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -138,7 +141,7 @@ func TestService_InitStartStop(t *testing.T) {
 		},
 	}
 
-	p := p2pt.NewTestP2P(t)
+	p := p2ptest.NewTestP2P(t)
 	connectPeers(t, p, []*peerData{}, p.Peers())
 	for i, tt := range tests {
 		if i == 0 {
@@ -328,7 +331,7 @@ func TestService_markSynced(t *testing.T) {
 }
 
 func TestService_Resync(t *testing.T) {
-	p := p2pt.NewTestP2P(t)
+	p := p2ptest.NewTestP2P(t)
 	connectPeers(t, p, []*peerData{
 		{blocks: makeSequence(1, 160), finalizedEpoch: 5, headSlot: 160},
 	}, p.Peers())
@@ -511,5 +514,152 @@ func TestOriginOutsideRetention(t *testing.T) {
 	require.NoError(t, concreteDB.SaveOriginCheckpointBlockRoot(ctx, blk.Root()))
 	// This would break due to missing service dependencies, but will return nil fast due to being outside retention.
 	require.Equal(t, false, params.WithinDAPeriod(slots.ToEpoch(blk.Block().Slot()), slots.ToEpoch(clock.CurrentSlot())))
-	require.NoError(t, s.fetchOriginBlobs([]peer.ID{}))
+	require.NoError(t, s.fetchOriginSidecars([]peer.ID{}))
+}
+
+func TestFetchOriginSidecars(t *testing.T) {
+	ctx := t.Context()
+
+	beaconConfig := params.BeaconConfig()
+	genesisTime := time.Date(2025, time.August, 10, 0, 0, 0, 0, time.UTC)
+	secondsPerSlot := beaconConfig.SecondsPerSlot
+	slotsPerEpoch := beaconConfig.SlotsPerEpoch
+	secondsPerEpoch := uint64(slotsPerEpoch.Mul(secondsPerSlot))
+	retentionEpochs := beaconConfig.MinEpochsForDataColumnSidecarsRequest
+
+	genesisValidatorRoot := [fieldparams.RootLength]byte{}
+
+	t.Run("out of retention period", func(t *testing.T) {
+		// Create an origin block.
+		block := util.NewBeaconBlockFulu()
+		signedBlock, err := blocks.NewSignedBeaconBlock(block)
+		require.NoError(t, err)
+		roBlock, err := blocks.NewROBlock(signedBlock)
+		require.NoError(t, err)
+
+		// Save the block.
+		db := dbtest.SetupDB(t)
+		err = db.SaveOriginCheckpointBlockRoot(ctx, roBlock.Root())
+		require.NoError(t, err)
+		err = db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Define "now" to be one epoch after genesis time + retention period.
+		nowWrtGenesisSecs := retentionEpochs.Add(1).Mul(secondsPerEpoch)
+		now := genesisTime.Add(time.Duration(nowWrtGenesisSecs) * time.Second)
+		nower := func() time.Time { return now }
+		clock := startup.NewClock(genesisTime, genesisValidatorRoot, startup.WithNower(nower))
+
+		service := &Service{
+			cfg: &Config{
+				DB: db,
+			},
+			clock: clock,
+		}
+
+		err = service.fetchOriginSidecars(nil)
+		require.NoError(t, err)
+	})
+
+	t.Run("no commitments", func(t *testing.T) {
+		// Create an origin block.
+		block := util.NewBeaconBlockFulu()
+		signedBlock, err := blocks.NewSignedBeaconBlock(block)
+		require.NoError(t, err)
+		roBlock, err := blocks.NewROBlock(signedBlock)
+		require.NoError(t, err)
+
+		// Save the block.
+		db := dbtest.SetupDB(t)
+		err = db.SaveOriginCheckpointBlockRoot(ctx, roBlock.Root())
+		require.NoError(t, err)
+		err = db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Define "now" to be after genesis time + retention period.
+		nowWrtGenesisSecs := retentionEpochs.Mul(secondsPerEpoch)
+		now := genesisTime.Add(time.Duration(nowWrtGenesisSecs) * time.Second)
+		nower := func() time.Time { return now }
+		clock := startup.NewClock(genesisTime, genesisValidatorRoot, startup.WithNower(nower))
+
+		service := &Service{
+			cfg: &Config{
+				DB:  db,
+				P2P: p2ptest.NewTestP2P(t),
+			},
+			clock: clock,
+		}
+
+		err = service.fetchOriginSidecars(nil)
+		require.NoError(t, err)
+	})
+
+	t.Run("nominal", func(t *testing.T) {
+		samplesPerSlot := params.BeaconConfig().SamplesPerSlot
+
+		// Start the trusted setup.
+		err := kzg.Start()
+		require.NoError(t, err)
+
+		// Create block and sidecars.
+		const blobCount = 1
+		roBlock, _, verifiedRoSidecars := util.GenerateTestFuluBlockWithSidecars(t, blobCount)
+
+		// Save the block.
+		db := dbtest.SetupDB(t)
+		err = db.SaveOriginCheckpointBlockRoot(ctx, roBlock.Root())
+		require.NoError(t, err)
+
+		err = db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Create a data columns storage.
+		dir := t.TempDir()
+		dataColumnStorage, err := filesystem.NewDataColumnStorage(ctx, filesystem.WithDataColumnBasePath(dir))
+		require.NoError(t, err)
+
+		// Compute the columns to request.
+		p2p := p2ptest.NewTestP2P(t)
+		custodyGroupCount, err := p2p.CustodyGroupCount()
+		require.NoError(t, err)
+
+		samplingSize := max(custodyGroupCount, samplesPerSlot)
+		info, _, err := peerdas.Info(p2p.NodeID(), samplingSize)
+		require.NoError(t, err)
+
+		// Save all sidecars except what we need.
+		toSave := make([]blocks.VerifiedRODataColumn, 0, uint64(len(verifiedRoSidecars))-samplingSize)
+		for _, sidecar := range verifiedRoSidecars {
+			if !info.CustodyColumns[sidecar.Index] {
+				toSave = append(toSave, sidecar)
+			}
+		}
+
+		err = dataColumnStorage.Save(toSave)
+		require.NoError(t, err)
+
+		// Define "now" to be after genesis time + retention period.
+		nowWrtGenesisSecs := retentionEpochs.Mul(secondsPerEpoch)
+		now := genesisTime.Add(time.Duration(nowWrtGenesisSecs) * time.Second)
+		nower := func() time.Time { return now }
+		clock := startup.NewClock(genesisTime, genesisValidatorRoot, startup.WithNower(nower))
+
+		service := &Service{
+			cfg: &Config{
+				DB:                db,
+				P2P:               p2p,
+				DataColumnStorage: dataColumnStorage,
+			},
+			clock: clock,
+		}
+
+		err = service.fetchOriginSidecars(nil)
+		require.NoError(t, err)
+
+		// Check that needed sidecars are saved.
+		summary := dataColumnStorage.Summary(roBlock.Root())
+		for index := range info.CustodyColumns {
+			require.Equal(t, true, summary.HasIndex(index))
+		}
+	})
 }