Add light client mode to fluffy (#1396)

fluffy/conf.nim

@@ -12,6 +12,8 @@ import
   uri, confutils, confutils/std/net, chronicles,
   eth/keys, eth/net/nat, eth/p2p/discoveryv5/[enr, node],
   json_rpc/rpcproxy,
+  nimcrypto/hash,
+  stew/byteutils,
   ./network/wire/portal_protocol_config
 
 proc defaultDataDir*(): string =
@@ -40,6 +42,8 @@ const
   defaultStorageSizeDesc* = $defaultStorageSize
 
 type
+  TrustedDigest* = MDigest[32 * 8]
+
   PortalCmd* = enum
     noCommand
 
@@ -208,12 +212,25 @@ type
       defaultValueDesc: $defaultStorageSizeDesc
       name: "storage-size" .}: uint32
 
+    trustedBlockRoot* {.
+      desc: "Recent trusted finalized block root to initialize the consensus light client from. " &
+            "If not provided by the user, portal light client will be disabled."
+      defaultValue: none(TrustedDigest)
+      name: "trusted-block-root" .}: Option[TrustedDigest]
+
     case cmd* {.
       command
       defaultValue: noCommand .}: PortalCmd
     of noCommand:
       discard
 
+func parseCmdArg*(T: type TrustedDigest, input: string): T
+                 {.raises: [ValueError, Defect].} =
+  TrustedDigest.fromHex(input)
+
+func completeCmdArg*(T: type TrustedDigest, input: string): seq[string] =
+  return @[]
+
 proc parseCmdArg*(T: type enr.Record, p: TaintedString): T
     {.raises: [Defect, ConfigurationError].} =
   if not fromURI(result, p):

fluffy/fluffy.nim

@@ -14,11 +14,22 @@ import
   json_rpc/rpcproxy, stew/[byteutils, io2],
   eth/keys, eth/net/nat,
   eth/p2p/discoveryv5/protocol as discv5_protocol,
+  beacon_chain/beacon_clock,
+  beacon_chain/spec/forks,
+  beacon_chain/spec/datatypes/altair,
+  beacon_chain/gossip_processing/light_client_processor,
   ./conf, ./network_metadata, ./common/common_utils,
   ./rpc/[rpc_eth_api, bridge_client, rpc_discovery_api, rpc_portal_api,
     rpc_portal_debug_api],
   ./network/state/[state_network, state_content],
   ./network/history/[history_network, history_content],
+  ./network/beacon_light_client/[
+    light_client_init_loader,
+    light_client_content,
+    beacon_light_client,
+    light_client_db,
+    light_client_network
+  ],
   ./network/wire/[portal_stream, portal_protocol_config],
   ./data/[history_data_seeding, history_data_parser],
   ./content_db
@@ -163,6 +174,78 @@ proc run(config: PortalConf) {.raises: [CatchableError, Defect].} =
   let bridgeClient = initializeBridgeClient(config.bridgeUri)
 
   d.start()
+
+  # TODO: Currently disabled by default as it is not stable/polished enough,
+  # ultimatetely this should probably be always on.
+  if config.trustedBlockRoot.isSome():
+    # fluffy light client works only over mainnet data
+    let
+      networkData = loadNetworkData("mainnet")
+
+      db = LightClientDb.new(config.dataDir / "lightClientDb")
+
+      lightClientNetwork = LightClientNetwork.new(
+        d,
+        db,
+        streamManager,
+        networkData.forks,
+        bootstrapRecords = bootstrapRecords)
+
+      getBeaconTime = networkData.clock.getBeaconTimeFn()
+
+      refDigests = newClone networkData.forks
+
+      lc = LightClient.new(
+        lightClientNetwork,
+        rng,
+        networkData.metadata.cfg,
+        refDigests,
+        getBeaconTime,
+        networkData.genesis_validators_root,
+        LightClientFinalizationMode.Optimistic
+      )
+
+    # TODO: For now just log headers. Ultimately we should also use callbacks for each
+    # lc object to save them to db and offer them to the network.
+    proc onFinalizedHeader(
+        lightClient: LightClient, finalizedHeader: BeaconBlockHeader) =
+      info "New LC finalized header",
+        finalized_header = shortLog(finalizedHeader)
+
+    proc onOptimisticHeader(
+        lightClient: LightClient, optimisticHeader: BeaconBlockHeader) =
+      info "New LC optimistic header",
+        optimistic_header = shortLog(optimisticHeader)
+
+    lc.onFinalizedHeader = onFinalizedHeader
+    lc.onOptimisticHeader = onOptimisticHeader
+    lc.trustedBlockRoot = config.trustedBlockRoot
+
+    proc onSecond(time: Moment) =
+      let wallSlot = getBeaconTime().slotOrZero()
+      # TODO this is a place to enable/disable gossip based on the current status
+      # of light client
+      # lc.updateGossipStatus(wallSlot + 1)
+
+    proc runOnSecondLoop() {.async.} =
+      let sleepTime = chronos.seconds(1)
+      while true:
+        let start = chronos.now(chronos.Moment)
+        await chronos.sleepAsync(sleepTime)
+        let afterSleep = chronos.now(chronos.Moment)
+        let sleepTime = afterSleep - start
+        onSecond(start)
+        let finished = chronos.now(chronos.Moment)
+        let processingTime = finished - afterSleep
+        trace "onSecond task completed", sleepTime, processingTime
+
+    onSecond(Moment.now())
+
+    lightClientNetwork.start()
+    lc.start()
+
+    asyncSpawn runOnSecondLoop()
+
   historyNetwork.start()
   stateNetwork.start()
 

fluffy/network/beacon_light_client/beacon_light_client.nim

@@ -5,8 +5,11 @@
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
+when (NimMajor, NimMinor) < (1, 4):
+  {.push raises: [Defect].}
+else:
+  {.push raises: [].}
 
-{.push raises: [Defect].}
 
 import
   chronicles,

fluffy/network/beacon_light_client/light_client_init_loader.nim

@@ -0,0 +1,56 @@
+# Nimbus - Portal Network
+# Copyright (c) 2022 Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+when (NimMajor, NimMinor) < (1, 4):
+  {.push raises: [Defect].}
+else:
+  {.push raises: [].}
+
+import
+  beacon_chain/networking/network_metadata,
+  beacon_chain/spec/forks,
+  beacon_chain/spec/datatypes/altair,
+  beacon_chain/beacon_clock,
+  beacon_chain/nimbus_binary_common,
+  beacon_chain/conf
+
+type
+  NetworkInitData* = object
+    clock*: BeaconClock
+    metaData*: Eth2NetworkMetadata
+    forks*: ForkDigests
+    genesis_validators_root*: Eth2Digest
+
+proc loadNetworkData*(networkName: string): NetworkInitData {.raises: [CatchableError, Defect].}=
+  let
+    metadata =
+      try:
+        loadEth2Network(some("mainnet"))
+      except CatchableError as exc:
+        raiseAssert(exc.msg)
+
+    genesisState =
+      try:
+        template genesisData(): auto = metadata.genesisData
+        newClone(readSszForkedHashedBeaconState(
+          metadata.cfg, genesisData.toOpenArrayByte(genesisData.low, genesisData.high)))
+      except CatchableError as err:
+        raiseAssert "Invalid baked-in state: " & err.msg
+
+    beaconClock = BeaconClock.init(getStateField(genesisState[], genesis_time))
+
+    genesis_validators_root =
+      getStateField(genesisState[], genesis_validators_root)
+
+    forks = newClone ForkDigests.init(metadata.cfg, genesis_validators_root)
+
+  return NetworkInitData(
+    clock: beaconClock,
+    metaData: metaData,
+    forks: forks[],
+    genesis_validators_root: genesis_validators_root
+  )

fluffy/rpc/rpc_eth_api.nim

@@ -14,7 +14,11 @@ import
   eth/[common/eth_types, rlp],
   ../../nimbus/rpc/[rpc_types, hexstrings, filters],
   ../../nimbus/transaction,
-  ../../nimbus/common/chain_config,
+  # TODO: this is a bit weird but having this import makes beacon_light_client
+  # to fail compilation due throwing undeclared `CatchableError` in
+  # `vendor/nimbus-eth2/beacon_chain/spec/keystore.nim`. This is most probably
+  # caused by `readValue` clashing ?
+  # ../../nimbus/common/chain_config
   ../network/history/[history_network, history_content]
 
 # Subset of Eth JSON-RPC API: https://eth.wiki/json-rpc/API
@@ -190,8 +194,9 @@ proc installEthApiHandlers*(
   # Supported API through the Portal Network
 
   rpcServerWithProxy.rpc("eth_chainId") do() -> HexQuantityStr:
-    # The Portal Network can only support MainNet at the moment
-    return encodeQuantity(distinctBase(MainNet.ChainId))
+    # The Portal Network can only support MainNet at the moment, so always return
+    # 1
+    return encodeQuantity(uint64(1))
 
   rpcServerWithProxy.rpc("eth_getBlockByHash") do(
       data: EthHashStr, fullTransactions: bool) -> Option[BlockObject]: