Add exportBlockProofBellatrix command to eth_data_exporter (#2093)

Add functionality to  export bellatrix block proofs from era files
to the eth_data_exporter tool.

fluffy/network/history/experimental/beacon_chain_block_proof.nim

@@ -87,12 +87,12 @@ type
 
   BeaconChainBlockProof* = object
     # Total size (8 + 1 + 3 + 1 + 14) * 32 bytes + 4 bytes = 868 bytes
-    beaconBlockBodyProof: BeaconBlockBodyProof
-    beaconBlockBodyRoot: Digest
-    beaconBlockHeaderProof: BeaconBlockHeaderProof
-    beaconBlockHeaderRoot: Digest
-    historicalRootsProof: HistoricalRootsProof
-    slot: Slot
+    beaconBlockBodyProof*: BeaconBlockBodyProof
+    beaconBlockBodyRoot*: Digest
+    beaconBlockHeaderProof*: BeaconBlockHeaderProof
+    beaconBlockHeaderRoot*: Digest
+    historicalRootsProof*: HistoricalRootsProof
+    slot*: Slot
 
 func getHistoricalRootsIndex*(slot: Slot): uint64 =
   slot div SLOTS_PER_HISTORICAL_ROOT
@@ -109,7 +109,7 @@ func getBlockRootsIndex*(blockHeader: BeaconBlockHeader): uint64 =
 # Builds proof to be able to verify that the EL block hash is part of
 # BeaconBlockBody for given root.
 func buildProof*(
-    blockBody: bellatrix.BeaconBlockBody
+    blockBody: bellatrix.TrustedBeaconBlockBody | bellatrix.BeaconBlockBody
 ): Result[BeaconBlockBodyProof, string] =
   # 16 as there are 10 fields
   # 9 as index (pos) of field = 9
@@ -152,7 +152,7 @@ func buildProof*(
 func buildProof*(
     batch: HistoricalBatch,
     blockHeader: BeaconBlockHeader,
-    blockBody: bellatrix.BeaconBlockBody,
+    blockBody: bellatrix.TrustedBeaconBlockBody | bellatrix.BeaconBlockBody,
 ): Result[BeaconChainBlockProof, string] =
   let
     blockRootIndex = getBlockRootsIndex(blockHeader)

fluffy/tools/eth_data_exporter.nim

@@ -692,3 +692,7 @@ when isMainModule:
       waitFor exportHistoricalRoots(
         config.restUrl, string config.dataDir, cfg, forkDigests
       )
+    of BeaconCmd.exportBlockProofBellatrix:
+      cmdExportBlockProofBellatrix(
+        string config.dataDir, string config.eraDir, config.slotNumber
+      )

fluffy/tools/eth_data_exporter/cl_data_exporter.nim

@@ -13,12 +13,19 @@ import
   chronos,
   stew/[byteutils, io2],
   eth/async_utils,
+  beacon_chain/era_db,
+  beacon_chain/spec/forks,
   beacon_chain/networking/network_metadata,
   beacon_chain/spec/eth2_apis/rest_beacon_client,
   beacon_chain/beacon_clock,
   ../../network/beacon/beacon_content,
+  ../../network/beacon/beacon_init_loader,
+  ../../network/history/experimental/beacon_chain_block_proof,
+  ../../network_metadata,
   ./exporter_common
 
+from beacon_chain/el/el_manager import toBeaconBlockHeader
+
 export beacon_clock
 
 const
@@ -296,3 +303,48 @@ proc exportHistoricalRoots*(
     quit 1
   else:
     notice "Succesfully wrote historical_roots to file", file
+
+proc cmdExportBlockProofBellatrix*(
+    dataDir: string, eraDir: string, slotNumber: uint64
+) =
+  let
+    networkData = loadNetworkData("mainnet")
+    db =
+      EraDB.new(networkData.metadata.cfg, eraDir, networkData.genesis_validators_root)
+    historical_roots = loadHistoricalRoots().asSeq()
+    slot = Slot(slotNumber)
+    era = era(slot)
+
+  # Note: Provide just empty historical_summaries here as this is only
+  # supposed to generate proofs for Bellatrix for now.
+  # For later proofs, it will be more difficult to use this call as we need
+  # to provide the (changing) historical summaries. Probably want to directly
+  # grab the right era file through different calls then.
+  var state: ForkedHashedBeaconState
+  db.getState(historical_roots, [], start_slot(era + 1), state).isOkOr:
+    error "Failed to load state", error = error
+    quit QuitFailure
+
+  let batch = HistoricalBatch(
+    block_roots: getStateField(state, block_roots).data,
+    state_roots: getStateField(state, state_roots).data,
+  )
+
+  let beaconBlock = db.getBlock(
+    historical_roots, [], slot, Opt.none(Eth2Digest), bellatrix.TrustedSignedBeaconBlock
+  ).valueOr:
+    error "Failed to load Bellatrix block", slot
+    quit QuitFailure
+
+  let beaconBlockHeader = beaconBlock.toBeaconBlockHeader()
+  let blockProof = buildProof(batch, beaconBlockHeader, beaconBlock.message.body).valueOr:
+    error "Failed to build proof for Bellatrix block", slot, error
+    quit QuitFailure
+
+  let file = dataDir / "block_proof_" & $slot & ".ssz"
+  let res = io2.writeFile(file, SSZ.encode(blockProof))
+  if res.isErr():
+    error "Failed writing block proof to file", file, error = ioErrorMsg(res.error)
+    quit 1
+  else:
+    notice "Succesfully wrote block proof to file", file

fluffy/tools/eth_data_exporter/exporter_conf.nim

@@ -70,6 +70,7 @@ type
     exportLCFinalityUpdate = "Export Light Client Finality Update"
     exportLCOptimisticUpdate = "Export Light Client Optimistic Update"
     exportHistoricalRoots = "Export historical roots from the beacon state (SSZ format)"
+    exportBlockProofBellatrix = "Export Bellatrix EL block proof from era files"
 
   ExporterConf* = object
     logLevel* {.
@@ -210,6 +211,11 @@ type
         discard
       of exportHistoricalRoots:
         discard
+      of exportBlockProofBellatrix:
+        slotNumber* {.
+          desc: "The slot for which to export the block proof", name: "slot"
+        .}: uint64
+        eraDir* {.desc: "Directory containing era files", name: "era-dir".}: InputDir
 
 proc parseCmdArg*(T: type Web3Url, p: string): T {.raises: [ValueError].} =
   let