More persistance

beacon_chain/beacon_chain_db.nim

@@ -4,12 +4,12 @@ import
   spec/[datatypes, digest, crypto],
   eth_trie/db, ssz
 
+const STATE_STORAGE_PERIOD = 1000 # Save states once per this number of slots. TODO: Find a good number.
+
 type
   BeaconChainDB* = ref object
     backend: TrieDatabaseRef
 
-  BeaconStateRef* = ref BeaconState
-
   DbKey = object
     data: array[33, byte]
     dataEndPos: uint8
@@ -17,6 +17,9 @@ type
   DbKeyKind = enum
     kLastFinalizedState
     kHashToBlock
+    kSlotToBlockHash
+    kSlotToState
+    kHashToValidatorRegistryChangeLog
 
 
 template toOpenArray*(k: DbKey): openarray[byte] =
@@ -31,23 +34,67 @@ proc hashToBlockKey(h: Eth2Digest): DbKey =
   result.data[1 .. ^1] = h.data
   result.dataEndPos = 32
 
+proc slotToBlockHashKey(s: uint64): DbKey =
+  result.data[0] = byte ord(kSlotToBlockHash)
+  copyMem(addr result.data[1], unsafeAddr(s), sizeof(s))
+  result.dataEndPos = uint8 sizeof(s)
+
+proc slotToStateKey(s: uint64): DbKey =
+  result.data[0] = byte ord(kSlotToState)
+  copyMem(addr result.data[1], unsafeAddr(s), sizeof(s))
+  result.dataEndPos = uint8 sizeof(s)
+
+proc hashToValidatorRegistryChangeLogKey(deltaChainTip: Eth2Digest): DbKey =
+  result.data[0] = byte ord(kHashToValidatorRegistryChangeLog)
+  result.data[1 .. ^1] = deltaChainTip.data
+  result.dataEndPos = 32
+
 proc init*(T: type BeaconChainDB, backend: TrieDatabaseRef): BeaconChainDB =
   new result
   result.backend = backend
 
-proc lastFinalizedState*(db: BeaconChainDB): BeaconStateRef =
-  try:
-    let res = db.backend.get(lastFinalizedStateKey().toOpenArray)
-    if res.len != 0:
-      result.new
-      result[] = ssz.deserialize(res, BeaconState).get
-  except:
-    error "Failed to load the latest finalized state",
-          err = getCurrentExceptionMsg()
-    return nil
+proc lastFinalizedState*(db: BeaconChainDB): BeaconState =
+  let res = db.backend.get(lastFinalizedStateKey().toOpenArray)
+  if res.len == 0:
+    raise newException(Exception, "Internal error: Database has no finalized state")
+  ssz.deserialize(res, BeaconState).get
+
+proc isInitialized*(db: BeaconChainDB): bool =
+  db.backend.get(lastFinalizedStateKey().toOpenArray).len != 0
+
+proc persistState*(db: BeaconChainDB, s: BeaconState) =
+  if s.slot != GENESIS_SLOT:
+    # TODO: Verify incoming state slot is higher than lastFinalizedState one
+    discard
+  else:
+    # Make sure we have no states
+    assert(not db.isInitialized)
+
+  var prevState: BeaconState
+  if s.slot != GENESIS_SLOT:
+    prevState = db.lastFinalizedState()
+    if prevState.validator_registry_delta_chain_tip != s.validator_registry_delta_chain_tip:
+      # Validator registry has changed in the incoming state.
+      # TODO: Save the changelog.
+      discard
+
+  let serializedState = ssz.serialize(s)
+  db.backend.put(lastFinalizedStateKey().toOpenArray, serializedState)
+
+  if s.slot mod STATE_STORAGE_PERIOD == 0:
+    # Save slot to state mapping
+    db.backend.put(slotToStateKey(s.slot).toOpenArray, serializedState)
 
 proc persistBlock*(db: BeaconChainDB, s: BeaconState, b: BeaconBlock) =
-  db.backend.put(lastFinalizedStateKey().toOpenArray, ssz.serialize(s))
+  var prevState = db.lastFinalizedState()
+
+  db.persistState(s)
+
+  let blockHash = b.hash_tree_root_final
+  db.backend.put(hashToBlockKey(blockHash).toOpenArray, ssz.serialize(b))
+  db.backend.put(slotToBlockHashKey(b.slot).toOpenArray, blockHash.data)
+
+# proc getValidatorChangeLog*(deltaChainTip: Eth2Digest)
 
 proc getBlock*(db: BeaconChainDB, hash: Eth2Digest, output: var BeaconBlock): bool =
   let res = db.backend.get(hashToBlockKey(hash).toOpenArray)

beacon_chain/beacon_node.nim

@@ -49,6 +49,12 @@ proc init*(T: type BeaconNode, conf: BeaconNodeConf): T =
 
   let trieDB = trieDB newChainDb(string conf.dataDir)
   result.db = BeaconChainDB.init(trieDB)
+
+  if not result.db.isInitialized:
+    # Use stateSnapshot as genesis
+    info "Initializing DB"
+    result.db.persistState(result.config.stateSnapshot.get)
+
   result.keys = ensureNetworkKeys(string conf.dataDir)
 
   var address: Address
@@ -81,14 +87,10 @@ proc connectToNetwork(node: BeaconNode) {.async.} =
 
 proc sync*(node: BeaconNode): Future[bool] {.async.} =
   let persistedState = node.db.lastFinalizedState()
-  if persistedState.isNil or
-     persistedState[].slotDistanceFromNow() > WEAK_SUBJECTVITY_PERIOD.int64:
-    if node.config.stateSnapshot.isSome:
-      node.beaconState = node.config.stateSnapshot.get
-    else:
-      node.beaconState = await obtainTrustedStateSnapshot(node.db)
+  if persistedState.slotDistanceFromNow() > WEAK_SUBJECTVITY_PERIOD.int64:
+    node.beaconState = await obtainTrustedStateSnapshot(node.db)
   else:
-    node.beaconState = persistedState[]
+    node.beaconState = persistedState
     var targetSlot = toSlot timeSinceGenesis(node.beaconState)
 
     let t = now()
@@ -354,6 +356,7 @@ proc processBlocks*(node: BeaconNode) =
     node.headBlock = newBlock
     node.headBlockRoot = newBlockRoot
     node.beaconState = state
+    node.db.persistBlock(node.beaconState, newBlock)
 
     # TODO:
     #

beacon_chain/randao.nim

@@ -13,7 +13,7 @@ proc initRandao*(bytes: openarray[byte]): Randao =
     raise newException(Exception, "Wrong randao size")
   var s: Eth2Digest
   s.data[0 .. ^1] = bytes
-  initRandao(bytes)
+  initRandao(s)
 
 proc initialCommitment*(r: Randao): Eth2Digest =
   repeatHash(r.seed, MaxRandaoLevels)

beacon_chain/sync_protocol.nim

@@ -16,7 +16,11 @@ type
 p2pProtocol BeaconSync(version = 1,
                        shortName = "bcs"):
   requestResponse:
-    proc getValidatorChangeLog(peer: Peer, changeLogHead: Eth2Digest)
+    proc getValidatorChangeLog(peer: Peer, changeLogHead: Eth2Digest) =
+      var bb: BeaconBlock
+      var bs: BeaconState
+      # TODO: get the changelog from the DB.
+      await peer.validatorChangeLog(reqId, bb, bs, [], [], @[])
 
     proc validatorChangeLog(peer: Peer,
                             signedBlock: BeaconBlock,
@@ -25,11 +29,6 @@ p2pProtocol BeaconSync(version = 1,
                             removed: openarray[uint32],
                             order: seq[byte])
 
-template `++`(x: var int): int =
-  let y = x
-  inc x
-  y
-
 type
   # A bit shorter names for convenience
   ChangeLog = BeaconSync.validatorChangeLog

beacon_chain/trusted_state_snapshots.nim

@@ -27,7 +27,7 @@ proc obtainTrustedStateSnapshot*(db: BeaconChainDB): Future[BeaconState] {.async
   #
   # 5. Check that the state snapshot hash is correct and save it in the DB.
 
-  discard
+  assert(false, "Not implemented")
 
 proc createStateSnapshot*(startup: ChainStartupData, outFile: string) =
   let initialState = get_initial_beacon_state(startup.validatorDeposits,