VC: Add fallback mode for multiple beacon nodes.

beacon_chain/conf.nim

@@ -115,6 +115,10 @@ type
     Poll = "poll"
     Event = "event"
 
+  BeaconNodeMode* {.pure.} = enum
+    BestScore = "bestscore"
+    Fallback = "fallback"
+
   Web3SignerUrl* = object
     url*: Uri
     provenBlockProperties*: seq[string] # empty if this is not a verifying Web3Signer
@@ -1057,6 +1061,12 @@ type
       defaultValueDesc: $defaultBeaconNodeUri
       name: "beacon-node" .}: seq[Uri]
 
+    beaconNodeMode* {.
+      desc: "How validator client should operate multiple beacon nodes",
+      defaultValue: BeaconNodeMode.BestScore
+      defaultValueDesc: "Ask all beacon nodes and select the best response."
+      name: "beacon-node-mode" .}: BeaconNodeMode
+
     monitoringType* {.
       desc: "Enable block monitoring which are seen by beacon node (BETA)"
       defaultValue: BlockMonitoringType.Event

beacon_chain/validator_client/attestation_service.nim

@@ -76,7 +76,8 @@ proc serveAttestation(
       attestation = shortLog(atst)
     try:
       await vc.submitPoolAttestationsV2(
-        @[atst], consensusFork, ApiStrategyKind.First)
+        @[atst], consensusFork,
+        vc.getMode()[FnKind.submitPoolAttestations])
     except ValidatorApiError as exc:
       warn "Unable to publish attestation", reason = exc.getFailureReason()
       return false
@@ -155,7 +156,8 @@ proc serveAggregateAndProofV2*(
   let res =
     try:
       await vc.publishAggregateAndProofsV2(
-        @[signedProof], consensusFork, ApiStrategyKind.First)
+        @[signedProof], consensusFork,
+        vc.getMode()[FnKind.publishAggregateAndProofs])
     except ValidatorApiError as exc:
       warn "Unable to publish aggregated attestation",
             reason = exc.getFailureReason()
@@ -181,8 +183,10 @@ proc produceAndPublishAttestationsV2*(
   let
     vc = service.client
     fork = vc.forkAtEpoch(slot.epoch)
-    data = await vc.produceAttestationData(slot, CommitteeIndex(0),
-                                           ApiStrategyKind.Best)
+    data = await vc.produceAttestationData(
+      slot,
+      CommitteeIndex(0),
+      vc.getMode()[FnKind.produceAttestationData])
     registeredRes =
       vc.attachedValidators[].slashingProtection.withContext:
         var tmp: seq[RegisteredAttestation]
@@ -316,9 +320,10 @@ proc produceAndPublishAggregatesV2(
     block:
       let attestation =
         try:
-          await vc.getAggregatedAttestationV2(slot, attestationRoot,
-                                              committee_index,
-                                              ApiStrategyKind.Best)
+          await vc.getAggregatedAttestationV2(
+            slot, attestationRoot,
+            committee_index,
+            vc.getMode()[FnKind.getAggregatedAttestation])
         except ValidatorApiError as exc:
           warn "Unable to get aggregated attestation data", slot = slot,
                attestation_root = shortLog(attestationRoot),

beacon_chain/validator_client/block_service.nim

@@ -127,9 +127,10 @@ proc publishBlockV3(
   let
     maybeBlock =
       try:
-        await vc.produceBlockV3(slot, randaoReveal, graffiti,
-                                vc.config.builderBoostFactor,
-                                ApiStrategyKind.Best)
+        await vc.produceBlockV3(
+          slot, randaoReveal, graffiti,
+          vc.config.builderBoostFactor,
+          vc.getMode()[FnKind.produceBlock])
       except ValidatorApiError as exc:
         warn "Unable to retrieve block data", reason = exc.getFailureReason()
         return
@@ -185,13 +186,9 @@ proc publishBlockV3(
         res =
           try:
             debug "Sending blinded block"
-            if vc.isPastElectraFork(slot.epoch()):
-              await vc.publishBlindedBlockV2(
-                signedBlock, BroadcastValidationType.Gossip,
-                ApiStrategyKind.First)
-            else:
-              await vc.publishBlindedBlock(
-                signedBlock, ApiStrategyKind.First)
+            await vc.publishBlindedBlockV2(
+              signedBlock, BroadcastValidationType.Gossip,
+              vc.getMode()[FnKind.publishBlindedBlock])
           except ValidatorApiError as exc:
             warn "Unable to publish blinded block",
                  reason = exc.getFailureReason()
@@ -267,7 +264,7 @@ proc publishBlockV3(
             debug "Sending block"
             await vc.publishBlockV2(
               signedBlockContents, BroadcastValidationType.Gossip,
-              ApiStrategyKind.First)
+              vc.getMode()[FnKind.publishBlock])
           except ValidatorApiError as exc:
             warn "Unable to publish block", reason = exc.getFailureReason()
             return

beacon_chain/validator_client/common.nim

@@ -176,6 +176,27 @@ type
     BrokenClock,        ## BN wall clock is broken or has significan offset.
     InternalError       ## BN reports internal error.
 
+  FnKind* {.pure.} = enum
+    getProposerDuties
+    getAttesterDuties
+    getSyncCommitteeDuties
+    getHeadBlockRoot
+    getValidators
+    produceAttestationData
+    submitPoolAttestations
+    getAggregatedAttestation
+    publishAggregateAndProofs
+    produceBlock
+    publishBlock
+    publishBlindedBlock
+    produceSyncCommitteeContribution
+    submitPoolSyncCommitteeSignature
+    publishContributionAndProofs
+    submitBeaconCommitteeSelections
+    submitSyncCommitteeSelections
+
+  VCBeaconNodeMode* = array[int(high(FnKind)) + 1, ApiStrategyKind]
+
   BeaconNodesCounters* = object
     data*: array[int(high(RestBeaconNodeStatus)) + 1, int]
 
@@ -312,6 +333,49 @@ const
     RestBeaconNodeStatus.InternalError
   }
 
+  BestScoreMode* = VCBeaconNodeMode([
+    ApiStrategyKind.First,     # getProposerDuties
+    ApiStrategyKind.First,     # getAttesterDuties
+    ApiStrategyKind.First,     # getSyncCommitteeDuties
+    ApiStrategyKind.Best,      # getHeadBlockRoot
+    ApiStrategyKind.First,     # getValidators
+    ApiStrategyKind.Best,      # produceAttestationData
+    ApiStrategyKind.First,     # submitPoolAttestations
+    ApiStrategyKind.Best,      # getAggregatedAttestation
+    ApiStrategyKind.First,     # publishAggregateAndProofs
+    ApiStrategyKind.Best,      # produceBlock
+    ApiStrategyKind.First,     # publishBlock
+    ApiStrategyKind.First,     # publishBlindedBlock
+    ApiStrategyKind.Best,      # produceSyncCommitteeContribution
+    ApiStrategyKind.First,     # submitPoolSyncCommitteeSignature
+    ApiStrategyKind.First,     # publishContributionAndProofs
+    ApiStrategyKind.Best,      # submitBeaconCommitteeSelections
+    ApiStrategyKind.Best       # submitSyncCommitteeSelections
+  ])
+
+  FallbackMode* = VCBeaconNodeMode([
+    ApiStrategyKind.Priority,  # getProposerDuties
+    ApiStrategyKind.Priority,  # getAttesterDuties
+    ApiStrategyKind.Priority,  # getSyncCommitteeDuties
+    ApiStrategyKind.Priority,  # getHeadBlockRoot
+    ApiStrategyKind.Priority,  # getValidators
+    ApiStrategyKind.Priority,  # produceAttestationData
+    ApiStrategyKind.Priority,  # submitPoolAttestations
+    ApiStrategyKind.Priority,  # getAggregatedAttestation
+    ApiStrategyKind.Priority,  # publishAggregateAndProofs
+    ApiStrategyKind.Priority,  # produceBlock
+    ApiStrategyKind.Priority,  # publishBlock
+    ApiStrategyKind.Priority,  # publishBlindedBlock
+    ApiStrategyKind.Priority,  # produceSyncCommitteeContribution
+    ApiStrategyKind.Priority,  # submitPoolSyncCommitteeSignature
+    ApiStrategyKind.Priority,  # publishContributionAndProofs
+    ApiStrategyKind.Priority,  # submitBeaconCommitteeSelections
+    ApiStrategyKind.Priority   # submitSyncCommitteeSelections
+  ])
+
+template `[]`*(vcs: VCBeaconNodeMode, index: FnKind): ApiStrategyKind =
+  vcs[int(index)]
+
 func SlotDuration*(vc: ValidatorClientRef): Duration =
   vc.timeParams.SLOT_DURATION
 
@@ -1670,6 +1734,13 @@ func finish_slot*(epoch: Epoch): Slot =
   ## Return the last slot of ``epoch``.
   (epoch + 1).start_slot() - 1
 
+func getMode*(vc: ValidatorClientRef): VCBeaconNodeMode =
+  case vc.config.beaconNodeMode
+  of BeaconNodeMode.BestScore:
+    BestScoreMode
+  of BeaconNodeMode.Fallback:
+    FallbackMode
+
 proc getGraffitiBytes*(vc: ValidatorClientRef,
                        validator: AttachedValidator): GraffitiBytes =
   getGraffiti(vc.config.validatorsDir, vc.config.defaultGraffitiBytes(),

beacon_chain/validator_client/duties_service.nim

@@ -68,7 +68,7 @@ proc pollForValidatorIndices*(
   for idents in chunks(validatorIdents, ClientMaximumValidatorIds):
     let res =
       try:
-        await vc.getValidators(idents, ApiStrategyKind.First)
+        await vc.getValidators(idents, vc.getMode()[FnKind.getValidators])
       except ValidatorApiError as exc:
         warn "Unable to get head state's validator information",
               reason = exc.getFailureReason()
@@ -123,8 +123,9 @@ proc pollForAttesterDuties*(
               for chunk in indices.chunks(DutiesMaximumValidatorIds):
                 let res =
                   try:
-                    await vc.getAttesterDuties(epoch, chunk,
-                                               ApiStrategyKind.First)
+                    await vc.getAttesterDuties(
+                      epoch, chunk,
+                      vc.getMode()[FnKind.getAttesterDuties])
                   except ValidatorApiError as exc:
                     warn "Unable to get attester duties", epoch = epoch,
                          reason = exc.getFailureReason()
@@ -225,8 +226,9 @@ proc pollForSyncCommitteeDuties*(
         for chunk in indices.chunks(DutiesMaximumValidatorIds):
           let res =
             try:
-              await vc.getSyncCommitteeDuties(epoch, chunk,
-                                              ApiStrategyKind.First)
+              await vc.getSyncCommitteeDuties(
+                epoch, chunk,
+                vc.getMode()[FnKind.getSyncCommitteeDuties])
             except ValidatorApiError as exc:
               warn "Unable to get sync committee duties",
                    period = period, epoch = epoch,
@@ -506,8 +508,8 @@ proc pollForBeaconProposers*(
 
   if vc.attachedValidators[].count() != 0:
     try:
-      let res = await vc.getProposerDuties(currentEpoch,
-                                           ApiStrategyKind.First)
+      let res = await vc.getProposerDuties(
+        currentEpoch, vc.getMode()[FnKind.getProposerDuties])
       let
         dependentRoot = res.dependent_root
         duties = res.data

beacon_chain/validator_client/selection_proofs.nim

@@ -1,5 +1,5 @@
 # beacon_chain
-# Copyright (c) 2023-2024 Status Research & Development GmbH
+# Copyright (c) 2023-2025 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).
@@ -173,8 +173,8 @@ proc fillAttestationSelectionProofs*(
       let sresponse =
         try:
           # Query middleware for aggregated signatures.
-          await vc.submitBeaconCommitteeSelections(selections,
-                                                   ApiStrategyKind.Best)
+          await vc.submitBeaconCommitteeSelections(
+            selections, vc.getMode()[FnKind.submitBeaconCommitteeSelections])
         except ValidatorApiError as exc:
           warn "Unable to submit beacon committee selections",
                reason = exc.getFailureReason()
@@ -455,8 +455,8 @@ proc fillSyncCommitteeSelectionProofs*(
       let sresponse =
         try:
           # Query middleware for aggregated signatures.
-          await vc.submitSyncCommitteeSelections(selections,
-                                                 ApiStrategyKind.Best)
+          await vc.submitSyncCommitteeSelections(
+            selections, vc.getMode()[FnKind.submitSyncCommitteeSelections])
         except ValidatorApiError as exc:
           warn "Unable to submit sync committee selections",
                reason = exc.getFailureReason()

beacon_chain/validator_client/sync_committee_service.nim

@@ -69,7 +69,8 @@ proc serveSyncCommitteeMessage*(
 
   let res =
     try:
-      await vc.submitPoolSyncCommitteeSignature(message, ApiStrategyKind.First)
+      await vc.submitPoolSyncCommitteeSignature(
+        message, vc.getMode()[FnKind.submitPoolSyncCommitteeSignature])
     except ValidatorApiError as exc:
       warn "Unable to publish sync committee message",
            reason = exc.getFailureReason()
@@ -190,8 +191,8 @@ proc serveContributionAndProof*(
 
   let res =
     try:
-      await vc.publishContributionAndProofs(@[restSignedProof],
-                                            ApiStrategyKind.First)
+      await vc.publishContributionAndProofs(
+        @[restSignedProof], vc.getMode()[FnKind.publishContributionAndProofs])
     except ValidatorApiError as exc:
       warn "Unable to publish sync contribution",
            reason = exc.getFailureReason()
@@ -252,7 +253,8 @@ proc produceAndPublishContributions(
             if isNil(resMap[subCommitteeIdx]):
               let future =
                 vc.produceSyncCommitteeContribution(
-                  slot, subCommitteeIdx, beaconBlockRoot, ApiStrategyKind.Best)
+                  slot, subCommitteeIdx, beaconBlockRoot,
+                  vc.getMode()[FnKind.produceSyncCommitteeContribution])
               resMap[int(subCommitteeIdx)] = future
               resFutures.add(FutureBase(future))
       (resItems, resFutures, resMap)
@@ -373,7 +375,8 @@ proc publishSyncMessagesAndContributions(
   let beaconBlockRoot =
     block:
       try:
-        let res = await vc.getHeadBlockRoot(ApiStrategyKind.Best)
+        let res = await vc.getHeadBlockRoot(
+          vc.getMode()[FnKind.getHeadBlockRoot])
         if res.execution_optimistic.isNone():
           ## The `execution_optimistic` is missing from the response, we assume
           ## that the BN is unaware optimistic sync, so we consider the BN