LC Updates by Range to read from DB

CHANGELOG.md

@@ -22,6 +22,7 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 - Fix `engine_exchangeCapabilities` implementation.
 - Updated the default `scrape-interval` in `Client-stats` to 2 minutes to accommodate Beaconcha.in API rate limits.
 - Switch to compounding when consolidating with source==target.
+- Changed `GetLightClientUpdatesByRange` API to read from the DB instead of computing.
 
 ### Deprecated
 

api/server/structs/BUILD.bazel

@@ -39,6 +39,7 @@ go_library(
         "//proto/eth/v2:go_default_library",
         "//proto/migration:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//runtime/version:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",

api/server/structs/conversions_lightclient.go

@@ -10,8 +10,21 @@ import (
 	v1 "github.com/prysmaticlabs/prysm/v5/proto/eth/v1"
 	v2 "github.com/prysmaticlabs/prysm/v5/proto/eth/v2"
 	"github.com/prysmaticlabs/prysm/v5/proto/migration"
+	"github.com/prysmaticlabs/prysm/v5/runtime/version"
 )
 
+func LightClientUpdateResponseFromConsensus(update *v2.LightClientUpdateWithVersion) (*LightClientUpdateResponse, error) {
+	data, err := LightClientUpdateFromConsensus(update.Data)
+	if err != nil {
+		return nil, err
+	}
+
+	return &LightClientUpdateResponse{
+		Version: version.String(int(update.Version)),
+		Data:    data,
+	}, nil
+}
+
 func LightClientUpdateFromConsensus(update *v2.LightClientUpdate) (*LightClientUpdate, error) {
 	attestedHeader, err := lightClientHeaderContainerToJSON(update.AttestedHeader)
 	if err != nil {

beacon-chain/rpc/eth/light-client/BUILD.bazel

@@ -21,7 +21,6 @@ go_library(
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/interfaces:go_default_library",
-        "//consensus-types/primitives:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
         "//network/httputil:go_default_library",
         "//proto/eth/v2:go_default_library",
@@ -46,16 +45,19 @@ go_test(
         "//beacon-chain/blockchain/testing:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/core/light-client:go_default_library",
+        "//beacon-chain/db/kv:go_default_library",
         "//beacon-chain/rpc/testutil:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
+        "//proto/engine/v1:go_default_library",
         "//proto/eth/v1:go_default_library",
         "//proto/eth/v2:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
+        "//runtime/version:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",

beacon-chain/rpc/eth/light-client/handlers.go

@@ -11,10 +11,8 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/api"
 	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/rpc/eth/shared"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing/trace"
 	"github.com/prysmaticlabs/prysm/v5/network/httputil"
 	"github.com/prysmaticlabs/prysm/v5/runtime/version"
@@ -117,108 +115,29 @@ func (s *Server) GetLightClientUpdatesByRange(w http.ResponseWriter, req *http.R
 		endPeriod = maxSlot / slotsPerPeriod
 	}
 
-	// Populate updates
-	var updates []*structs.LightClientUpdateResponse
-	for period := startPeriod; period <= endPeriod; period++ {
-		// Get the last known state of the period,
-		//    1. We wish the block has a parent in the same period if possible
-		//	  2. We wish the block has a state in the same period
-		lastSlotInPeriod := period*slotsPerPeriod + slotsPerPeriod - 1
-		if lastSlotInPeriod > maxSlot {
-			lastSlotInPeriod = maxSlot
-		}
-		firstSlotInPeriod := period * slotsPerPeriod
-
-		// Let's not use the first slot in the period, otherwise the attested header will be in previous period
-		firstSlotInPeriod++
-
-		var state state.BeaconState
-		var block interfaces.ReadOnlySignedBeaconBlock
-		for slot := lastSlotInPeriod; slot >= firstSlotInPeriod; slot-- {
-			state, err = s.Stater.StateBySlot(ctx, types.Slot(slot))
-			if err != nil {
-				continue
-			}
-
-			// Get the block
-			latestBlockHeader := state.LatestBlockHeader()
-			latestStateRoot, err := state.HashTreeRoot(ctx)
-			if err != nil {
-				continue
-			}
-			latestBlockHeader.StateRoot = latestStateRoot[:]
-			blockRoot, err := latestBlockHeader.HashTreeRoot()
-			if err != nil {
-				continue
-			}
-
-			block, err = s.Blocker.Block(ctx, blockRoot[:])
-			if err != nil || block == nil {
-				continue
-			}
-
-			syncAggregate, err := block.Block().Body().SyncAggregate()
-			if err != nil || syncAggregate == nil {
-				continue
-			}
-
-			if syncAggregate.SyncCommitteeBits.Count()*3 < config.SyncCommitteeSize*2 {
-				// Not enough votes
-				continue
-			}
-
-			break
-		}
+	// get updates
+	updatesMap, err := s.BeaconDB.LightClientUpdates(ctx, startPeriod, endPeriod)
+	if err != nil {
+		httputil.HandleError(w, "Could not get light client updates from DB: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
 
-		if block == nil {
-			// No valid block found for the period
-			continue
-		}
+	updates := make([]*structs.LightClientUpdateResponse, 0, len(updatesMap))
 
-		// Get attested state
-		attestedRoot := block.Block().ParentRoot()
-		attestedBlock, err := s.Blocker.Block(ctx, attestedRoot[:])
-		if err != nil || attestedBlock == nil {
-			continue
+	for i := startPeriod; i <= endPeriod; i++ {
+		update, ok := updatesMap[i]
+		if !ok {
+			// Only return the first contiguous range of updates
+			break
 		}
 
-		attestedSlot := attestedBlock.Block().Slot()
-		attestedState, err := s.Stater.StateBySlot(ctx, attestedSlot)
+		updateResponse, err := structs.LightClientUpdateResponseFromConsensus(update)
 		if err != nil {
-			continue
-		}
-
-		// Get finalized block
-		var finalizedBlock interfaces.ReadOnlySignedBeaconBlock
-		finalizedCheckPoint := attestedState.FinalizedCheckpoint()
-		if finalizedCheckPoint != nil {
-			finalizedRoot := bytesutil.ToBytes32(finalizedCheckPoint.Root)
-			finalizedBlock, err = s.Blocker.Block(ctx, finalizedRoot[:])
-			if err != nil {
-				finalizedBlock = nil
-			}
+			httputil.HandleError(w, "Could not convert light client update: "+err.Error(), http.StatusInternalServerError)
+			return
 		}
 
-		update, err := newLightClientUpdateFromBeaconState(
-			ctx,
-			state,
-			block,
-			attestedState,
-			attestedBlock,
-			finalizedBlock,
-		)
-
-		if err == nil {
-			updates = append(updates, &structs.LightClientUpdateResponse{
-				Version: version.String(attestedState.Version()),
-				Data:    update,
-			})
-		}
-	}
-
-	if len(updates) == 0 {
-		httputil.HandleError(w, "no updates found", http.StatusNotFound)
-		return
+		updates = append(updates, updateResponse)
 	}
 
 	httputil.WriteJson(w, updates)