allow custom configs in Gnosis binary (#4134)

When running as Gnosis-chain binary the config was no longer adjustable.
Restores loading custom configs when running as Gnosis-chain binary,
as long as the following keys remain same:
- SLOTS_PER_EPOCH=16
- SECONDS_PER_SLOT=5
- BASE_REWARD_FACTOR=25
- EPOCHS_PER_SYNC_COMMITTEE_PERIOD=512

This allows running the Gnosis-chain binary on custom test networks.

beacon_chain/conf.nim

@@ -1223,21 +1223,27 @@ proc readValue*(r: var TomlReader, a: var Address)
 proc loadEth2Network*(
     eth2Network: Option[string]
 ): Eth2NetworkMetadata {.raises: [Defect, IOError].} =
-  network_name.set(2, labelValues = [eth2Network.get(otherwise = "mainnet")])
+  const defaultName =
-  when not defined(gnosisChainBinary):
+    when defined(gnosisChainBinary) and const_preset == "mainnet":
+      "gnosis"
+    elif const_preset == "mainnet":
+      "mainnet"
+    else:
+      "(unspecified)"
+  network_name.set(2, labelValues = [eth2Network.get(otherwise = defaultName)])
+
   if eth2Network.isSome:
     getMetadataForNetwork(eth2Network.get)
   else:
-      when const_preset == "mainnet":
+    when defined(gnosisChainBinary) and const_preset == "mainnet":
+      gnosisMetadata
+    elif const_preset == "mainnet":
       mainnetMetadata
     else:
       # Presumably other configurations can have other defaults, but for now
       # this simplifies the flow
-        echo "Must specify network on non-mainnet node"
+      fatal "Must specify network on non-mainnet node"
       quit 1
-  else:
-    checkNetworkParameterUse eth2Network
-    gnosisMetadata
 
 template loadEth2Network*(config: BeaconNodeConf): Eth2NetworkMetadata =
   loadEth2Network(config.eth2Network)

beacon_chain/networking/network_metadata.nim

@@ -200,19 +200,29 @@ template mergeTestnet(path: string, eth1Network: Eth1Network): Eth2NetworkMetada
   loadCompileTimeNetworkMetadata(mergeTestnetsDir & "/" & path,
                                  some eth1Network)
 
-when not defined(gnosisChainBinary):
+when defined(gnosisChainBinary) and const_preset == "mainnet":
-  when const_preset == "mainnet":
+  const
+    gnosisMetadata* = loadCompileTimeNetworkMetadata(
+      currentSourcePath.parentDir.replace('\\', '/') &
+      "/../../media/gnosis")
+  static:
+    for network in [gnosisMetadata]:
+      checkForkConsistency(network.cfg)
+
+elif const_preset == "mainnet":
   const
     mainnetMetadata* = eth2Network("shared/mainnet", mainnet)
     praterMetadata* = eth2Network("shared/prater", goerli)
     ropstenMetadata* = mergeTestnet("ropsten-beacon-chain", ropsten)
     sepoliaMetadata* = mergeTestnet("sepolia", sepolia)
   static:
-      for network in [mainnetMetadata, praterMetadata, ropstenMetadata, sepoliaMetadata]:
+    for network in [
+        mainnetMetadata, praterMetadata, ropstenMetadata, sepoliaMetadata]:
       checkForkConsistency(network.cfg)
 
-  proc getMetadataForNetwork*(networkName: string): Eth2NetworkMetadata {.raises: [Defect, IOError].} =
+proc getMetadataForNetwork*(
-    template loadRuntimeMetadata: auto =
+    networkName: string): Eth2NetworkMetadata {.raises: [Defect, IOError].} =
+  template loadRuntimeMetadata(): auto =
     if fileExists(networkName / "config.yaml"):
       try:
         loadEth2NetworkMetadata(networkName)
@@ -223,8 +233,19 @@ when not defined(gnosisChainBinary):
       fatal "config.yaml not found for network", networkName
       quit 1
 
-    var
+  let metadata =
-      metadata = when const_preset == "mainnet":
+    when defined(gnosisChainBinary) and const_preset == "mainnet":
+      case toLowerAscii(networkName)
+      of "gnosis":
+        gnosisMetadata
+      of "gnosis-chain":
+        warn "`--network:gnosis-chain` is deprecated, " &
+          "use `--network:gnosis` instead"
+        gnosisMetadata
+      else:
+        loadRuntimeMetadata()
+
+    elif const_preset == "mainnet":
       case toLowerAscii(networkName)
       of "mainnet":
         mainnetMetadata
@@ -236,6 +257,7 @@ when not defined(gnosisChainBinary):
         sepoliaMetadata
       else:
         loadRuntimeMetadata()
+
     else:
       loadRuntimeMetadata()
 
@@ -243,34 +265,15 @@ when not defined(gnosisChainBinary):
     fatal "The selected network is not compatible with the current build",
             reason = metadata.incompatibilityDesc
     quit 1
+
   metadata
 
-  proc getRuntimeConfig*(
+proc getRuntimeConfig*(
     eth2Network: Option[string]): RuntimeConfig {.raises: [Defect, IOError].} =
   if eth2Network.isSome:
     return getMetadataForNetwork(eth2Network.get).cfg
   defaultRuntimeConfig
 
-else:
-  const
-    gnosisMetadata* = loadCompileTimeNetworkMetadata(
-      currentSourcePath.parentDir.replace('\\', '/') & "/../../media/gnosis")
-
-  static: checkForkConsistency(gnosisMetadata.cfg)
-
-  proc checkNetworkParameterUse*(eth2Network: Option[string]) =
-    # Support `gnosis-chain` as network name which was used in v22.3
-    if eth2Network.isSome and eth2Network.get notin ["gnosis", "gnosis-chain"]:
-      fatal "The only supported value for the --network parameter is 'gnosis'"
-      quit 1
-
-    if eth2Network.isSome and eth2Network.get == "gnosis-chain":
-      warn "`--network:gnosis-chain` is deprecated, use `--network:gnosis` instead"
-
-  proc getRuntimeConfig*(eth2Network: Option[string]): RuntimeConfig {.raises: [Defect, IOError].} =
-    checkNetworkParameterUse eth2Network
-    gnosisMetadata.cfg
-
 proc extractGenesisValidatorRootFromSnapshot*(
     snapshot: string): Eth2Digest {.raises: [Defect, IOError, SszError].} =
   sszMount(snapshot, phase0.BeaconState).genesis_validators_root[]