allow trusted node sync based on LC trusted block root

beacon_chain/conf.nim

@@ -779,15 +779,19 @@ type
 
       stateId* {.
         desc: "State id to sync to - this can be \"finalized\", a slot number or state hash or \"head\""
-        defaultValue: "finalized",
         name: "state-id"
-      .}: string
+      .}: Option[string]
 
       blockId* {.
         hidden
         desc: "Block id to sync to - this can be a block root, slot number, \"finalized\" or \"head\" (deprecated)"
       .}: Option[string]
 
+      lcTrustedBlockRoot* {.
+        hidden
+        desc: "Recent trusted finalized block root to initialize light client from"
+        name: "trusted-block-root" .}: Option[Eth2Digest]
+
       backfillBlocks* {.
         desc: "Backfill blocks directly from REST server instead of fetching via API"
         defaultValue: true

beacon_chain/nimbus_beacon_node.nim

@@ -1981,6 +1981,23 @@ proc handleStartUpCmd(config: var BeaconNodeConf) {.raises: [Defect, CatchableEr
     let
       network = loadEth2Network(config)
       cfg = network.cfg
+      syncTarget =
+        if config.stateId.isSome:
+          if config.lcTrustedBlockRoot.isSome:
+            warn "Ignoring `trustedBlockRoot`, `stateId` is set",
+              stateId = config.stateId,
+              trustedBlockRoot = config.lcTrustedBlockRoot
+          TrustedNodeSyncTarget(
+            kind: TrustedNodeSyncKind.StateId,
+            stateId: config.stateId.get)
+        elif config.lcTrustedBlockRoot.isSome:
+          TrustedNodeSyncTarget(
+            kind: TrustedNodeSyncKind.TrustedBlockRoot,
+            trustedBlockRoot: config.lcTrustedBlockRoot.get)
+        else:
+          TrustedNodeSyncTarget(
+            kind: TrustedNodeSyncKind.StateId,
+            stateId: "finalized")
       genesis =
         if network.genesisData.len > 0:
           newClone(readSszForkedHashedBeaconState(
@@ -1997,7 +2014,7 @@ proc handleStartUpCmd(config: var BeaconNodeConf) {.raises: [Defect, CatchableEr
       config.databaseDir,
       config.eraDir,
       config.trustedNodeUrl,
-      config.stateId,
+      syncTarget,
       config.backfillBlocks,
       config.reindex,
       config.downloadDepositSnapshot,

beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim

@@ -28,6 +28,20 @@ export
 from web3/ethtypes import BlockHash
 export ethtypes.BlockHash
 
+func decodeMediaType*(
+    contentType: Opt[ContentTypeData]): Result[MediaType, string] =
+  if contentType.isNone or isWildCard(contentType.get.mediaType):
+    return err("Missing or incorrect Content-Type")
+  ok contentType.get.mediaType
+
+func decodeEthConsensusVersion*(
+    value: string): Result[ConsensusFork, string] =
+  let normalizedValue = value.toLowerAscii()
+  for consensusFork in ConsensusFork:
+    if normalizedValue == ($consensusFork).toLowerAscii():
+      return ok consensusFork
+  err("Unsupported Eth-Consensus-Version: " & value)
+
 Json.createFlavor RestJson
 
 ## The RestJson format implements JSON serialization in the way specified
@@ -136,7 +150,9 @@ type
     Web3SignerSignatureResponse |
     Web3SignerStatusResponse |
     GetStateRootResponse |
-    GetBlockRootResponse
+    GetBlockRootResponse |
+    SomeForkedLightClientObject |
+    seq[SomeForkedLightClientObject]
 
   RestVersioned*[T] = object
     data*: T
@@ -1852,6 +1868,49 @@ proc writeValue*(writer: var JsonWriter[RestJson], value: ForkedHashedBeaconStat
     writer.writeField("data", value.denebData.data)
   writer.endRecord()
 
+## SomeForkedLightClientObject
+proc readValue*[T: SomeForkedLightClientObject](
+    reader: var JsonReader[RestJson], value: var T) {.
+    raises: [IOError, SerializationError, Defect].} =
+  var
+    version: Opt[ConsensusFork]
+    data: Opt[JsonString]
+
+  for fieldName in readObjectFields(reader):
+    case fieldName
+    of "version":
+      if version.isSome:
+        reader.raiseUnexpectedField("Multiple version fields found", T.name)
+      let consensusFork =
+        decodeEthConsensusVersion(reader.readValue(string)).valueOr:
+          reader.raiseUnexpectedValue("Incorrect version field value")
+      version.ok consensusFork
+    of "data":
+      if data.isSome:
+        reader.raiseUnexpectedField("Multiple data fields found", T.name)
+      data.ok reader.readValue(JsonString)
+    else:
+      unrecognizedFieldWarning()
+
+  if version.isNone:
+    reader.raiseUnexpectedValue("Field version is missing")
+  if data.isNone:
+    reader.raiseUnexpectedValue("Field data is missing")
+
+  withLcDataFork(lcDataForkAtConsensusFork(version.get)):
+    when lcDataFork > LightClientDataFork.None:
+      value = T(kind: lcDataFork)
+      try:
+        value.forky(lcDataFork) = RestJson.decode(
+          string(data.get()),
+          T.Forky(lcDataFork),
+          requireAllFields = true,
+          allowUnknownFields = true)
+      except SerializationError:
+        reader.raiseUnexpectedValue("Incorrect format (" & $lcDataFork & ")")
+    else:
+      reader.raiseUnexpectedValue("Unsupported fork " & $version.get)
+
 ## Web3SignerRequest
 proc writeValue*(writer: var JsonWriter[RestJson],
                  value: Web3SignerRequest) {.
@@ -2959,7 +3018,14 @@ proc decodeBytes*[T: DecodeTypes](
 proc encodeString*(value: string): RestResult[string] =
   ok(value)
 
-proc encodeString*(value: Epoch|Slot|CommitteeIndex|SyncSubcommitteeIndex): RestResult[string] =
+proc encodeString*(
+    value:
+      uint64 |
+      SyncCommitteePeriod |
+      Epoch |
+      Slot |
+      CommitteeIndex |
+      SyncSubcommitteeIndex): RestResult[string] =
   ok(Base10.toString(uint64(value)))
 
 proc encodeString*(value: ValidatorSig): RestResult[string] =

beacon_chain/spec/eth2_apis/rest_beacon_client.nim

@@ -10,12 +10,14 @@ import
   chronos, presto/client,
   "."/[
     rest_beacon_calls, rest_config_calls, rest_debug_calls,
-    rest_node_calls, rest_validator_calls, rest_keymanager_calls,
+    rest_keymanager_calls, rest_light_client_calls,
+    rest_node_calls, rest_validator_calls,
     rest_nimbus_calls, rest_common
   ]
 
 export
   chronos, client,
   rest_beacon_calls, rest_config_calls, rest_debug_calls,
-  rest_node_calls, rest_validator_calls, rest_keymanager_calls,
+  rest_keymanager_calls, rest_light_client_calls,
+  rest_node_calls, rest_validator_calls,
   rest_nimbus_calls, rest_common

beacon_chain/spec/eth2_apis/rest_common.nim

@@ -29,3 +29,26 @@ proc raiseUnknownStatusError*(resp: RestPlainResponse) {.
      noreturn, raises: [RestError, Defect].} =
   let msg = "Unknown response status error (" & $resp.status & ")"
   raise newException(RestError, msg)
+
+proc getBodyBytesWithCap*(
+    response: HttpClientResponseRef,
+    maxBytes: int): Future[Opt[seq[byte]]] {.async.} =
+  var reader = response.getBodyReader()
+  try:
+    let
+      data = await reader.read(maxBytes)
+      isComplete = reader.atEof()
+    await reader.closeWait()
+    reader = nil
+    await response.finish()
+    if not isComplete:
+      return err()
+    return ok data
+  except CancelledError as exc:
+    if not(isNil(reader)):
+      await reader.closeWait()
+    raise exc
+  except AsyncStreamError:
+    if not(isNil(reader)):
+      await reader.closeWait()
+    raise newHttpReadError("Could not read response")