feat: Add support for /eth/v1/beacon/deposit_snapshot

.golangci.yml

@@ -39,7 +39,6 @@ linters:
     - nolintlint
     - nakedret
     - prealloc
-    - revive
     - staticcheck
     - structcheck
     - stylecheck

go.mod

@@ -2,11 +2,13 @@ module github.com/ethpandaops/checkpointz
 
 go 1.17
 
+replace github.com/attestantio/go-eth2-client v0.15.7 => github.com/samcm/go-eth2-client v0.15.8
+
 require (
-	github.com/attestantio/go-eth2-client v0.15.2
+	github.com/attestantio/go-eth2-client v0.15.7
 	github.com/chuckpreslar/emission v0.0.0-20170206194824-a7ddd980baf9
 	github.com/creasty/defaults v1.6.0
-	github.com/ethpandaops/beacon v0.21.0
+	github.com/ethpandaops/beacon v0.24.0
 	github.com/go-co-op/gocron v1.18.0
 	github.com/julienschmidt/httprouter v1.3.0
 	github.com/pkg/errors v0.9.1

go.sum

@@ -38,10 +38,6 @@ github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuy
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
-github.com/attestantio/go-eth2-client v0.14.5 h1:pKOTcbv9KOiVixVKM5Cr8nJrjD1VOIWmrlNFO0YtF64=
-github.com/attestantio/go-eth2-client v0.14.5/go.mod h1:5kLLzdlyPGboWr8tAwnG/4Kpi43BHd/HWp++WmmP6Ws=
-github.com/attestantio/go-eth2-client v0.15.2 h1:4EYeA5IBSBypkUMhkkFALzMddaFDdb5PvCl7ORXEl6w=
-github.com/attestantio/go-eth2-client v0.15.2/go.mod h1:/Oh6YTuHmHhgLN/ZnQRKHGc7HdIzGlDkI2vjNZvOsvA=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
@@ -70,10 +66,8 @@ github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymF
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
-github.com/ethpandaops/beacon v0.20.0 h1:z389nMmzVYbPhP4+ahcaezqr9SivolWhnCYeWVeWFz8=
-github.com/ethpandaops/beacon v0.20.0/go.mod h1:fkS2U962xdB6+VwBn+J+DMK8cTgTtzVtjZWtvTKjbuE=
-github.com/ethpandaops/beacon v0.21.0 h1:s/088DT9oOYWt/mrDQ+mkhHiyK2wtMAOyE3Voar6nf0=
-github.com/ethpandaops/beacon v0.21.0/go.mod h1:fkS2U962xdB6+VwBn+J+DMK8cTgTtzVtjZWtvTKjbuE=
+github.com/ethpandaops/beacon v0.24.0 h1:WP0ySKmHgyJWTsVn47zOVEPzZ22FSa/fdkr/iIMmeLM=
+github.com/ethpandaops/beacon v0.24.0/go.mod h1:p+PMyAYXro2hgNEMNbCtzLOvzHund9Q9BTPATvf8/SA=
 github.com/ethpandaops/ethwallclock v0.2.0 h1:EeFKtZ7v6TAdn/oAh0xaPujD7N4amjBxrWIByraUfLM=
 github.com/ethpandaops/ethwallclock v0.2.0/go.mod h1:y0Cu+mhGLlem19vnAV2x0hpFS5KZ7oOi2SWYayv9l24=
 github.com/fatih/color v1.10.0/go.mod h1:ELkj/draVOlAH/xkhN6mQ50Qd0MPOk5AAr3maGEBuJM=
@@ -83,7 +77,6 @@ github.com/ferranbt/fastssz v0.1.2 h1:Dky6dXlngF6Qjc+EfDipAkE83N5I5DE68bY6O0VLNP
 github.com/ferranbt/fastssz v0.1.2/go.mod h1:X5UPrE2u1UJjxHA8X54u04SBwdAQjG2sFtWs39YxyWs=
 github.com/frankban/quicktest v1.14.3 h1:FJKSZTDHjyhriyC81FLQ0LY93eSai0ZyR/ZIkd3ZUKE=
 github.com/frankban/quicktest v1.14.3/go.mod h1:mgiwOwqx65TmIk1wJ6Q7wvnVMocbUorkibMOrVTHZps=
-github.com/go-co-op/gocron v1.16.2 h1:p9ghzsN5PqqPyWXYDO2JlvD1DOUNT8pPSyGYC62XBcY=
 github.com/go-co-op/gocron v1.16.2/go.mod h1:W/N9G7bntRo5fVQlmjncvqSt74jxCxHfjyHlgcB33T8=
 github.com/go-co-op/gocron v1.18.0 h1:SxTyJ5xnSN4byCq7b10LmmszFdxQlSQJod8s3gbnXxA=
 github.com/go-co-op/gocron v1.18.0/go.mod h1:sD/a0Aadtw5CpflUJ/lpP9Vfdk979Wl1Sg33HPHg0FY=
@@ -172,8 +165,6 @@ github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5m
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
-github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
-github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/inconshreveable/mousetrap v1.0.1 h1:U3uMjPSQEBMNp1lFxmllqCPM6P5u/Xq7Pgzkat/bFNc=
 github.com/inconshreveable/mousetrap v1.0.1/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
@@ -238,14 +229,12 @@ github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5Fsn
 github.com/prometheus/client_golang v1.7.1/go.mod h1:PY5Wy2awLA44sXw4AOSfFBetzPP4j5+D6mVACh+pe2M=
 github.com/prometheus/client_golang v1.11.0/go.mod h1:Z6t4BnS23TR94PD6BsDNk8yVqroYurpAkEiz0P2BEV0=
 github.com/prometheus/client_golang v1.12.1/go.mod h1:3Z9XVyYiZYEO+YQWt3RD2R3jrbd179Rt297l4aS6nDY=
-github.com/prometheus/client_golang v1.13.0 h1:b71QUfeo5M8gq2+evJdTPfZhYMAU0uKPkyPJ7TPsloU=
 github.com/prometheus/client_golang v1.13.0/go.mod h1:vTeo+zgvILHsnnj/39Ou/1fPN5nJFOEMgftOUOmlvYQ=
 github.com/prometheus/client_golang v1.14.0 h1:nJdhIvne2eSX/XRAFV9PcvFFRbrjbcTUj0VP62TMhnw=
 github.com/prometheus/client_golang v1.14.0/go.mod h1:8vpkKitgIVNcqrRBWh1C4TIUQgYNtG/XQE4E/Zae36Y=
 github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
 github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
-github.com/prometheus/client_model v0.2.0 h1:uq5h0d+GuxiXLJLNABMgp2qUWDPiLvgCzz2dUR+/W/M=
 github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/client_model v0.3.0 h1:UBgGFHqYdG/TPFD1B1ogZywDqEkwp3fBMvqdiQ7Xew4=
 github.com/prometheus/client_model v0.3.0/go.mod h1:LDGWKZIo7rky3hgvBe+caln+Dr3dPggB5dvjtD7w9+w=
@@ -279,29 +268,31 @@ github.com/rs/zerolog v1.26.1/go.mod h1:/wSSJWX7lVrsOwlbyTRSOJvqRlc+WjWlfes+CiJ+
 github.com/rs/zerolog v1.27.0 h1:1T7qCieN22GVc8S4Q2yuexzBb1EqjbgjSH9RohbMjKs=
 github.com/rs/zerolog v1.27.0/go.mod h1:7frBqO0oezxmnO7GF86FY++uy8I0Tk/If5ni1G9Qc0U=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/samcm/go-eth2-client v0.15.8 h1:V2gwKrnxImQE/Fmy9a2rzNRj0GQqnhP74Rgfm067HTA=
+github.com/samcm/go-eth2-client v0.15.8/go.mod h1:PLRKnILnr63V3yl2VagBqnhVRFBWc0V+JhQSsXQaSwQ=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
 github.com/sirupsen/logrus v1.9.0 h1:trlNQbNUG3OdDrDil03MCb1H2o9nJ1x4/5LYw7byDE0=
 github.com/sirupsen/logrus v1.9.0/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
 github.com/spf13/cast v1.5.0 h1:rj3WzYc11XZaIZMPKmwP96zkFEnnAmV8s6XbB2aY32w=
 github.com/spf13/cast v1.5.0/go.mod h1:SpXXQ5YoyJw6s3/6cMTQuxvgRl3PCJiyaX9p6b155UU=
-github.com/spf13/cobra v1.5.0 h1:X+jTBEBqF0bHN+9cSMgmfuvv2VHJ9ezmFNf9Y/XstYU=
-github.com/spf13/cobra v1.5.0/go.mod h1:dWXEIy2H428czQCjInthrTRUg7yKbok+2Qi/yBIJoUM=
 github.com/spf13/cobra v1.6.1 h1:o94oiPyS4KD1mPy2fmcYYHHfCxLqYjJOhGsCHFZtEzA=
 github.com/spf13/cobra v1.6.1/go.mod h1:IOw/AERYS7UzyrGinqmz6HLUo219MORXGxhbaJUqzrY=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/yuin/goldmark v1.1.25/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.1.32/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=

pkg/api/handler.go

@@ -50,6 +50,7 @@ func (h *Handler) Register(ctx context.Context, router *httprouter.Router) error
 	router.GET("/eth/v1/beacon/genesis", h.wrappedHandler(h.handleEthV1BeaconGenesis))
 	router.GET("/eth/v1/beacon/blocks/:block_id/root", h.wrappedHandler(h.handleEthV1BeaconBlocksRoot))
 	router.GET("/eth/v1/beacon/states/:state_id/finality_checkpoints", h.wrappedHandler(h.handleEthV1BeaconStatesFinalityCheckpoints))
+	router.GET("/eth/v1/beacon/deposit_snapshot", h.wrappedHandler(h.handleEthV1BeaconDepositSnapshot))
 
 	router.GET("/eth/v1/config/spec", h.wrappedHandler(h.handleEthV1ConfigSpec))
 	router.GET("/eth/v1/config/deposit_contract", h.wrappedHandler(h.handleEthV1ConfigDepositContract))
@@ -564,3 +565,20 @@ func (h *Handler) handleEthV1BeaconBlocksRoot(ctx context.Context, r *http.Reque
 		},
 	}), nil
 }
+
+func (h *Handler) handleEthV1BeaconDepositSnapshot(ctx context.Context, r *http.Request, p httprouter.Params, contentType ContentType) (*HTTPResponse, error) {
+	if err := ValidateContentType(contentType, []ContentType{ContentTypeJSON}); err != nil {
+		return NewUnsupportedMediaTypeResponse(nil), err
+	}
+
+	snapshot, err := h.eth.DepositSnapshot(ctx)
+	if err != nil {
+		return NewInternalServerErrorResponse(nil), err
+	}
+
+	return NewSuccessResponse(ContentTypeResolvers{
+		ContentTypeJSON: func() ([]byte, error) {
+			return json.Marshal(snapshot)
+		},
+	}), nil
+}

pkg/beacon/config.go

@@ -27,6 +27,8 @@ type CacheConfig struct {
 	Blocks store.Config `yaml:"blocks" default:"{\"MaxItems\": 200}"`
 	// States holds the state cache configuration.
 	States store.Config `yaml:"states" default:"{\"MaxItems\": 5}"`
+	// DepositSnapshots holds the deposit snapshot cache configuration.
+	DepositSnapshots store.Config `yaml:"deposit_snapshots" default:"{\"MaxItems\": 50}"`
 }
 
 type FrontendConfig struct {

pkg/beacon/default.go

@@ -31,8 +31,9 @@ type Default struct {
 	head          *v1.Finality
 	servingBundle *v1.Finality
 
-	blocks *store.Block
-	states *store.BeaconState
+	blocks           *store.Block
+	states           *store.BeaconState
+	depositSnapshots *store.DepositSnapshot
 
 	spec    *state.Spec
 	genesis *v1.Genesis
@@ -60,9 +61,10 @@ func NewDefaultProvider(namespace string, log logrus.FieldLogger, nodes []node.C
 
 		historicalSlotFailures: make(map[phase0.Slot]int),
 
-		broker: emission.NewEmitter(),
-		blocks: store.NewBlock(log, config.Caches.Blocks, namespace),
-		states: store.NewBeaconState(log, config.Caches.States, namespace),
+		broker:           emission.NewEmitter(),
+		blocks:           store.NewBlock(log, config.Caches.Blocks, namespace),
+		states:           store.NewBeaconState(log, config.Caches.States, namespace),
+		depositSnapshots: store.NewDepositSnapshot(log, config.Caches.DepositSnapshots, namespace),
 
 		metrics: NewMetrics(namespace + "_beacon"),
 	}
@@ -614,3 +616,7 @@ func (d *Default) GetSlotTime(ctx context.Context, slot phase0.Slot) (eth.SlotTi
 
 	return eth.CalculateSlotTime(slot, d.genesis.GenesisTime, d.spec.SecondsPerSlot.AsDuration()), nil
 }
+
+func (d *Default) GetDepositSnapshot(ctx context.Context, epoch phase0.Epoch) (*types.DepositSnapshot, error) {
+	return d.depositSnapshots.GetByEpoch(epoch)
+}

pkg/beacon/download.go

@@ -325,7 +325,48 @@ func (d *Default) fetchBundle(ctx context.Context, root phase0.Root, upstream *N
 		}
 	}
 
+	if slot != phase0.Slot(0) {
+		epoch := phase0.Epoch(slot / d.spec.SlotsPerEpoch)
+
+		// Download and store deposit snapshots
+		if err := d.downloadAndStoreDepositSnapshot(ctx, epoch, upstream); err != nil {
+			return nil, fmt.Errorf("failed to download and store deposit snapshot: %w", err)
+		}
+	}
+
 	d.log.Infof("Successfully fetched bundle from %s", upstream.Config.Name)
 
 	return block, nil
 }
+
+func (d *Default) downloadAndStoreDepositSnapshot(ctx context.Context, epoch phase0.Epoch, node *Node) error {
+	// Check if we already have the deposit snapshot.
+	if _, err := d.depositSnapshots.GetByEpoch(epoch); err == nil {
+		return nil
+	}
+
+	// Download the deposit snapshot from our upstream.
+	depositSnapshot, err := node.Beacon.FetchDepositSnapshot(ctx)
+	if err != nil {
+		return err
+	}
+
+	if depositSnapshot == nil {
+		return errors.New("invalid deposit snapshot")
+	}
+
+	// These are small so store them for a month. Max items will most likely purge it before then.
+	// Mostly just guarding against periods of non-finality; we won't have new items to purge the old ones which
+	// is a good thing here.
+	expiresAt := time.Now().Add(672 * time.Hour)
+
+	if err := d.depositSnapshots.Add(epoch, depositSnapshot, expiresAt); err != nil {
+		return fmt.Errorf("failed to store deposit snapshot: %w", err)
+	}
+
+	d.log.
+		WithFields(logrus.Fields{"epoch": epoch}).
+		Infof("Downloaded and stored deposit snapshot for epoch %d", epoch)
+
+	return nil
+}

pkg/beacon/finality_provider.go

@@ -55,4 +55,6 @@ type FinalityProvider interface {
 	OperatingMode() OperatingMode
 	// GetSlotTime returns the wall clock for the given slot.
 	GetSlotTime(ctx context.Context, slot phase0.Slot) (eth.SlotTime, error)
+	// GetDepositSnapshot returns the deposit snapshot at the given epoch.
+	GetDepositSnapshot(ctx context.Context, epoch phase0.Epoch) (*types.DepositSnapshot, error)
 }

pkg/beacon/store/deposit_snapshot.go

@@ -0,0 +1,63 @@
+package store
+
+import (
+	"errors"
+	"time"
+
+	"github.com/attestantio/go-eth2-client/spec/phase0"
+	"github.com/ethpandaops/beacon/pkg/beacon/api/types"
+	"github.com/ethpandaops/checkpointz/pkg/cache"
+	"github.com/ethpandaops/checkpointz/pkg/eth"
+	"github.com/sirupsen/logrus"
+)
+
+type DepositSnapshot struct {
+	store *cache.TTLMap
+	log   logrus.FieldLogger
+}
+
+func NewDepositSnapshot(log logrus.FieldLogger, config Config, namespace string) *DepositSnapshot {
+	d := &DepositSnapshot{
+		log:   log.WithField("component", "beacon/store/deposit_snapshot"),
+		store: cache.NewTTLMap(config.MaxItems, "deposit_snapshot", namespace),
+	}
+
+	d.store.OnItemDeleted(func(key string, value interface{}, expiredAt time.Time) {
+		d.log.WithField("key", key).WithField("expired_at", expiredAt.String()).Debug("Deposit snapshot was deleted from the cache")
+	})
+
+	d.store.EnableMetrics(namespace)
+
+	return d
+}
+
+func (d *DepositSnapshot) Add(epoch phase0.Epoch, snapshot *types.DepositSnapshot, expiresAt time.Time) error {
+	d.store.Add(eth.EpochAsString(epoch), snapshot, expiresAt)
+
+	d.log.WithFields(
+		logrus.Fields{
+			"epoch":      eth.EpochAsString(epoch),
+			"expires_at": expiresAt.String(),
+		},
+	).Debug("Added deposit snapshot")
+
+	return nil
+}
+
+func (d *DepositSnapshot) GetByEpoch(epoch phase0.Epoch) (*types.DepositSnapshot, error) {
+	data, _, err := d.store.Get(eth.EpochAsString(epoch))
+	if err != nil {
+		return nil, err
+	}
+
+	return d.parseSnapshot(data)
+}
+
+func (d *DepositSnapshot) parseSnapshot(data interface{}) (*types.DepositSnapshot, error) {
+	snapshot, ok := data.(*types.DepositSnapshot)
+	if !ok {
+		return nil, errors.New("invalid deposit snapshot type")
+	}
+
+	return snapshot, nil
+}

pkg/service/eth/eth.go

@@ -166,6 +166,33 @@ func (h *Handler) DepositContract(ctx context.Context) (*DepositContract, error)
 	}, nil
 }
 
+// DepositContract gets the deposit snapshot at the finalized checkpoint.
+func (h *Handler) DepositSnapshot(ctx context.Context) (*types.DepositSnapshot, error) {
+	var err error
+
+	const call = "beacon_deposit_snapshot"
+
+	h.metrics.ObserveCall(call, "")
+
+	defer func() {
+		if err != nil {
+			h.metrics.ObserveErrorCall(call, "")
+		}
+	}()
+
+	finality, err := h.provider.Finalized(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	snapshot, err := h.provider.GetDepositSnapshot(ctx, finality.Finalized.Epoch)
+	if err != nil {
+		return nil, err
+	}
+
+	return snapshot, nil
+}
+
 // NodeSyncing returns the sync state of the beacon node.
 func (h *Handler) NodeSyncing(ctx context.Context) (*v1.SyncState, error) {
 	var err error