Add /eth/v1/beacon/deposit_snapshot endpoint (#13514)

* Add endpoint

* Uncomment in InitializeRoutes

* Add test

* Add 404

* Add more checks

* Test improvements

* Ssz

* Add ssz tags

* Add DepositSnapshot to bazel

* Fix tests

* Fix max size

* Resolve conflicts

* Revert untouched code

* Fix test + review

* Lint

* Oops

* Preston + Radek' review

* Only return 3 finalized roots

* Change to deposit contract depth

* Radek' review

* Gaz

---------

Co-authored-by: james-prysm <90280386+james-prysm@users.noreply.github.com>

api/server/structs/BUILD.bazel

@@ -1,4 +1,4 @@
-load("@prysm//tools/go:def.bzl", "go_library")
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
@@ -38,3 +38,13 @@ go_library(
         "@com_github_pkg_errors//:go_default_library",
     ],
 )
+
+go_test(
+    name = "go_default_test",
+    srcs = ["conversions_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//proto/prysm/v1alpha1:go_default_library",
+        "//testing/require:go_default_library",
+    ],
+)

api/server/structs/conversions.go

@@ -1074,3 +1074,17 @@ func sszBytesToUint256String(b []byte) (string, error) {
 	}
 	return bi.String(), nil
 }
+
+func DepositSnapshotFromConsensus(ds *eth.DepositSnapshot) *DepositSnapshot {
+	finalized := make([]string, 0, len(ds.Finalized))
+	for _, f := range ds.Finalized {
+		finalized = append(finalized, hexutil.Encode(f))
+	}
+	return &DepositSnapshot{
+		Finalized:            finalized,
+		DepositRoot:          hexutil.Encode(ds.DepositRoot),
+		DepositCount:         fmt.Sprintf("%d", ds.DepositCount),
+		ExecutionBlockHash:   hexutil.Encode(ds.ExecutionHash),
+		ExecutionBlockHeight: fmt.Sprintf("%d", ds.ExecutionDepth),
+	}
+}

api/server/structs/conversions_test.go

@@ -0,0 +1,26 @@
+package structs
+
+import (
+	"testing"
+
+	eth "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+)
+
+func TestDepositSnapshotFromConsensus(t *testing.T) {
+	ds := &eth.DepositSnapshot{
+		Finalized:      [][]byte{{0xde, 0xad, 0xbe, 0xef}, {0xca, 0xfe, 0xba, 0xbe}},
+		DepositRoot:    []byte{0xab, 0xcd},
+		DepositCount:   12345,
+		ExecutionHash:  []byte{0x12, 0x34},
+		ExecutionDepth: 67890,
+	}
+
+	res := DepositSnapshotFromConsensus(ds)
+	require.NotNil(t, res)
+	require.DeepEqual(t, []string{"0xdeadbeef", "0xcafebabe"}, res.Finalized)
+	require.Equal(t, "0xabcd", res.DepositRoot)
+	require.Equal(t, "12345", res.DepositCount)
+	require.Equal(t, "0x1234", res.ExecutionBlockHash)
+	require.Equal(t, "67890", res.ExecutionBlockHeight)
+}

api/server/structs/endpoints_beacon.go

@@ -184,3 +184,15 @@ type WeakSubjectivityData struct {
 	WsCheckpoint *Checkpoint `json:"ws_checkpoint"`
 	StateRoot    string      `json:"state_root"`
 }
+
+type GetDepositSnapshotResponse struct {
+	Data *DepositSnapshot `json:"data"`
+}
+
+type DepositSnapshot struct {
+	Finalized            []string `json:"finalized"`
+	DepositRoot          string   `json:"deposit_root"`
+	DepositCount         string   `json:"deposit_count"`
+	ExecutionBlockHash   string   `json:"execution_block_hash"`
+	ExecutionBlockHeight string   `json:"execution_block_height"`
+}

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

@@ -17,6 +17,7 @@ go_library(
         "//api/server:go_default_library",
         "//api/server/structs:go_default_library",
         "//beacon-chain/blockchain:go_default_library",
+        "//beacon-chain/cache/depositsnapshot:go_default_library",
         "//beacon-chain/core/altair:go_default_library",
         "//beacon-chain/core/blocks:go_default_library",
         "//beacon-chain/core/feed:go_default_library",
@@ -77,6 +78,7 @@ go_test(
         "//api/server:go_default_library",
         "//api/server/structs:go_default_library",
         "//beacon-chain/blockchain/testing:go_default_library",
+        "//beacon-chain/cache/depositsnapshot:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/core/time:go_default_library",
         "//beacon-chain/core/transition:go_default_library",

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

@@ -15,6 +15,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/api"
 	"github.com/prysmaticlabs/prysm/v4/api/server/structs"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache/depositsnapshot"
 	corehelpers "github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db/filters"
@@ -2071,3 +2072,48 @@ func (s *Server) GetGenesis(w http.ResponseWriter, r *http.Request) {
 	}
 	httputil.WriteJson(w, resp)
 }
+
+// GetDepositSnapshot retrieves the EIP-4881 Deposit Tree Snapshot. Either a JSON or,
+// if the Accept header was added, bytes serialized by SSZ will be returned.
+func (s *Server) GetDepositSnapshot(w http.ResponseWriter, r *http.Request) {
+	ctx, span := trace.StartSpan(r.Context(), "beacon.GetDepositSnapshot")
+	defer span.End()
+
+	if s.BeaconDB == nil {
+		httputil.HandleError(w, "Could not retrieve beaconDB", http.StatusInternalServerError)
+		return
+	}
+	eth1data, err := s.BeaconDB.ExecutionChainData(ctx)
+	if err != nil {
+		httputil.HandleError(w, "Could not retrieve execution chain data: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if eth1data == nil {
+		httputil.HandleError(w, "Could not retrieve execution chain data: empty Eth1Data", http.StatusInternalServerError)
+		return
+	}
+	snapshot := eth1data.DepositSnapshot
+	if snapshot == nil || len(snapshot.Finalized) == 0 {
+		httputil.HandleError(w, "No Finalized Snapshot Available", http.StatusNotFound)
+		return
+	}
+	if len(snapshot.Finalized) > depositsnapshot.DepositContractDepth {
+		httputil.HandleError(w, "Retrieved invalid deposit snapshot", http.StatusInternalServerError)
+		return
+	}
+	if httputil.RespondWithSsz(r) {
+		sszData, err := snapshot.MarshalSSZ()
+		if err != nil {
+			httputil.HandleError(w, "Could not marshal deposit snapshot into SSZ: "+err.Error(), http.StatusInternalServerError)
+			return
+		}
+		httputil.WriteSsz(w, sszData, "deposit_snapshot.ssz")
+		return
+	}
+	httputil.WriteJson(
+		w,
+		&structs.GetDepositSnapshotResponse{
+			Data: structs.DepositSnapshotFromConsensus(snapshot),
+		},
+	)
+}

beacon-chain/rpc/eth/beacon/handlers_test.go

@@ -20,6 +20,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/api"
 	"github.com/prysmaticlabs/prysm/v4/api/server/structs"
 	chainMock "github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain/testing"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache/depositsnapshot"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db"
 	dbTest "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
@@ -3617,3 +3618,64 @@ func TestGetGenesis(t *testing.T) {
 		assert.StringContains(t, "Chain genesis info is not yet known", e.Message)
 	})
 }
+
+func TestGetDepositSnapshot(t *testing.T) {
+	beaconDB := dbTest.SetupDB(t)
+	mockTrie := depositsnapshot.NewDepositTree()
+	deposits := [][32]byte{
+		bytesutil.ToBytes32([]byte{1}),
+		bytesutil.ToBytes32([]byte{2}),
+		bytesutil.ToBytes32([]byte{3}),
+	}
+	finalized := 2
+	for _, leaf := range deposits {
+		err := mockTrie.Insert(leaf[:], 0)
+		require.NoError(t, err)
+	}
+	err := mockTrie.Finalize(1, deposits[1], 1)
+	require.NoError(t, err)
+	err = mockTrie.Finalize(2, deposits[2], 2)
+	require.NoError(t, err)
+
+	snapshot, err := mockTrie.GetSnapshot()
+	require.NoError(t, err)
+	root, err := snapshot.CalculateRoot()
+	require.NoError(t, err)
+	chainData := &eth.ETH1ChainData{
+		DepositSnapshot: snapshot.ToProto(),
+	}
+	err = beaconDB.SaveExecutionChainData(context.Background(), chainData)
+	require.NoError(t, err)
+	s := Server{
+		BeaconDB: beaconDB,
+	}
+
+	request := httptest.NewRequest(http.MethodGet, "/eth/v1/beacon/deposit_snapshot", nil)
+	writer := httptest.NewRecorder()
+	t.Run("JSON response", func(t *testing.T) {
+		writer.Body = &bytes.Buffer{}
+		s.GetDepositSnapshot(writer, request)
+		assert.Equal(t, http.StatusOK, writer.Code)
+		resp := &structs.GetDepositSnapshotResponse{}
+		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
+		require.NotNil(t, resp.Data)
+
+		assert.Equal(t, hexutil.Encode(root[:]), resp.Data.DepositRoot)
+		assert.Equal(t, hexutil.Encode(deposits[2][:]), resp.Data.ExecutionBlockHash)
+		assert.Equal(t, strconv.Itoa(mockTrie.NumOfItems()), resp.Data.DepositCount)
+		assert.Equal(t, finalized, len(resp.Data.Finalized))
+	})
+	t.Run("SSZ response", func(t *testing.T) {
+		writer.Body = &bytes.Buffer{}
+		request.Header.Set("Accept", api.OctetStreamMediaType)
+		s.GetDepositSnapshot(writer, request)
+		assert.Equal(t, http.StatusOK, writer.Code)
+		resp := &eth.DepositSnapshot{}
+		require.NoError(t, resp.UnmarshalSSZ(writer.Body.Bytes()))
+
+		assert.Equal(t, hexutil.Encode(root[:]), hexutil.Encode(resp.DepositRoot))
+		assert.Equal(t, hexutil.Encode(deposits[2][:]), hexutil.Encode(resp.ExecutionHash))
+		assert.Equal(t, uint64(mockTrie.NumOfItems()), resp.DepositCount)
+		assert.Equal(t, finalized, len(resp.Finalized))
+	})
+}

beacon-chain/rpc/service.go

@@ -254,6 +254,7 @@ func (s *Service) initializeBeaconServerRoutes(beaconServer *beacon.Server) {
 	s.cfg.Router.HandleFunc("/eth/v1/beacon/blocks/{block_id}/attestations", beaconServer.GetBlockAttestations).Methods(http.MethodGet)
 	s.cfg.Router.HandleFunc("/eth/v1/beacon/blinded_blocks/{block_id}", beaconServer.GetBlindedBlock).Methods(http.MethodGet)
 	s.cfg.Router.HandleFunc("/eth/v1/beacon/blocks/{block_id}/root", beaconServer.GetBlockRoot).Methods(http.MethodGet)
+	s.cfg.Router.HandleFunc("/eth/v1/beacon/deposit_snapshot", beaconServer.GetDepositSnapshot).Methods(http.MethodGet)
 	s.cfg.Router.HandleFunc("/eth/v1/beacon/pool/attestations", beaconServer.ListAttestations).Methods(http.MethodGet)
 	s.cfg.Router.HandleFunc("/eth/v1/beacon/pool/attestations", beaconServer.SubmitAttestations).Methods(http.MethodPost)
 	s.cfg.Router.HandleFunc("/eth/v1/beacon/pool/voluntary_exits", beaconServer.ListVoluntaryExits).Methods(http.MethodGet)

beacon-chain/rpc/service_test.go

@@ -93,20 +93,20 @@ func TestServer_InitializeRoutes(t *testing.T) {
 		"/eth/v1/beacon/blocks/{block_id}/attestations":              {http.MethodGet},
 		"/eth/v1/beacon/blob_sidecars/{block_id}":                    {http.MethodGet},
 		"/eth/v1/beacon/rewards/sync_committee/{block_id}":           {http.MethodPost},
-		//"/eth/v1/beacon/deposit_snapshot": {http.MethodGet}, not implemented
-		"/eth/v1/beacon/rewards/blocks/{block_id}":           {http.MethodGet},
-		"/eth/v1/beacon/rewards/attestations/{epoch}":        {http.MethodPost},
-		"/eth/v1/beacon/blinded_blocks/{block_id}":           {http.MethodGet},
-		"/eth/v1/beacon/light_client/bootstrap/{block_root}": {http.MethodGet},
-		"/eth/v1/beacon/light_client/updates":                {http.MethodGet},
-		"/eth/v1/beacon/light_client/finality_update":        {http.MethodGet},
-		"/eth/v1/beacon/light_client/optimistic_update":      {http.MethodGet},
-		"/eth/v1/beacon/pool/attestations":                   {http.MethodGet, http.MethodPost},
-		"/eth/v1/beacon/pool/attester_slashings":             {http.MethodGet, http.MethodPost},
-		"/eth/v1/beacon/pool/proposer_slashings":             {http.MethodGet, http.MethodPost},
-		"/eth/v1/beacon/pool/sync_committees":                {http.MethodPost},
-		"/eth/v1/beacon/pool/voluntary_exits":                {http.MethodGet, http.MethodPost},
-		"/eth/v1/beacon/pool/bls_to_execution_changes":       {http.MethodGet, http.MethodPost},
+		"/eth/v1/beacon/deposit_snapshot":                            {http.MethodGet},
+		"/eth/v1/beacon/rewards/blocks/{block_id}":                   {http.MethodGet},
+		"/eth/v1/beacon/rewards/attestations/{epoch}":                {http.MethodPost},
+		"/eth/v1/beacon/blinded_blocks/{block_id}":                   {http.MethodGet},
+		"/eth/v1/beacon/light_client/bootstrap/{block_root}":         {http.MethodGet},
+		"/eth/v1/beacon/light_client/updates":                        {http.MethodGet},
+		"/eth/v1/beacon/light_client/finality_update":                {http.MethodGet},
+		"/eth/v1/beacon/light_client/optimistic_update":              {http.MethodGet},
+		"/eth/v1/beacon/pool/attestations":                           {http.MethodGet, http.MethodPost},
+		"/eth/v1/beacon/pool/attester_slashings":                     {http.MethodGet, http.MethodPost},
+		"/eth/v1/beacon/pool/proposer_slashings":                     {http.MethodGet, http.MethodPost},
+		"/eth/v1/beacon/pool/sync_committees":                        {http.MethodPost},
+		"/eth/v1/beacon/pool/voluntary_exits":                        {http.MethodGet, http.MethodPost},
+		"/eth/v1/beacon/pool/bls_to_execution_changes":               {http.MethodGet, http.MethodPost},
 	}
 
 	builderRoutes := map[string][]string{

proto/prysm/v1alpha1/BUILD.bazel

@@ -35,8 +35,8 @@ proto_library(
         "@com_google_protobuf//:any_proto",
         "@com_google_protobuf//:descriptor_proto",
         "@com_google_protobuf//:empty_proto",
-        "@com_google_protobuf//:wrappers_proto",
         "@com_google_protobuf//:timestamp_proto",
+        "@com_google_protobuf//:wrappers_proto",
         "@googleapis//google/api:annotations_proto",
     ],
 )
@@ -130,6 +130,7 @@ ssz_gen_marshal(
         "BlobSidecar",
         "BlobSidecars",
         "BlobIdentifier",
+        "DepositSnapshot",
     ],
 )
 
@@ -155,8 +156,8 @@ go_proto_library(
         "@org_golang_google_protobuf//runtime/protoimpl:go_default_library",
         "@org_golang_google_protobuf//types/descriptorpb:go_default_library",
         "@org_golang_google_protobuf//types/known/emptypb:go_default_library",
-        "@org_golang_google_protobuf//types/known/wrapperspb:go_default_library",
         "@org_golang_google_protobuf//types/known/timestamppb:go_default_library",
+        "@org_golang_google_protobuf//types/known/wrapperspb:go_default_library",
     ],
 )
 
@@ -176,8 +177,8 @@ go_proto_library(
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@googleapis//google/api:annotations_go_proto",
         "@io_bazel_rules_go//proto/wkt:descriptor_go_proto",
-        "@io_bazel_rules_go//proto/wkt:wrappers_go_proto",
         "@io_bazel_rules_go//proto/wkt:timestamp_go_proto",
+        "@io_bazel_rules_go//proto/wkt:wrappers_go_proto",
         "@org_golang_google_protobuf//types/descriptorpb:go_default_library",
         "@org_golang_google_protobuf//types/known/emptypb:go_default_library",
     ],