Fix attestation compatibility issue in distributed validator cluster

packages/cli/src/cmds/validator/handler.ts

@@ -51,6 +51,7 @@ export async function validatorHandler(args: IValidatorCliArgs & GlobalArgs): Pr
 
   const {version, commit} = getVersionData();
   logger.info("Lodestar", {network, version, commit});
+  if (args.distributed) logger.info("Client is configured to run as part of a distributed validator cluster");
   logger.info("Connecting to LevelDB database", {path: validatorPaths.validatorsDbDir});
 
   const dbPath = validatorPaths.validatorsDbDir;
@@ -165,7 +166,9 @@ export async function validatorHandler(args: IValidatorCliArgs & GlobalArgs): Pr
       doppelgangerProtectionEnabled,
       afterBlockDelaySlotFraction: args.afterBlockDelaySlotFraction,
       scAfterBlockDelaySlotFraction: args.scAfterBlockDelaySlotFraction,
+      disableAttestationGrouping: args.disableAttestationGrouping,
       valProposerConfig,
+      distributed: args.distributed,
     },
     metrics
   );

packages/cli/src/cmds/validator/options.ts

@@ -36,6 +36,7 @@ export type IValidatorCliArgs = AccountValidatorArgs &
     graffiti: string;
     afterBlockDelaySlotFraction?: number;
     scAfterBlockDelaySlotFraction?: number;
+    disableAttestationGrouping?: boolean;
     suggestedFeeRecipient?: string;
     proposerSettingsFile?: string;
     strictFeeRecipientCheck?: boolean;
@@ -52,6 +53,8 @@ export type IValidatorCliArgs = AccountValidatorArgs &
     "externalSigner.pubkeys"?: string[];
     "externalSigner.fetch"?: boolean;
 
+    distributed?: boolean;
+
     interopIndexes?: string;
     fromMnemonic?: string;
     mnemonicIndexes?: string;
@@ -189,6 +192,13 @@ export const validatorOptions: CliCommandOptions<IValidatorCliArgs> = {
     type: "number",
   },
 
+  disableAttestationGrouping: {
+    hidden: true,
+    description:
+      "Disables attestation service grouping optimization, attestation tasks will be executed per committee instead of just once for all committees.",
+    type: "boolean",
+  },
+
   proposerSettingsFile: {
     description:
       "A yaml file to specify detailed default and per validator pubkey customized proposer configs. PS: This feature and its format is in alpha and subject to change",
@@ -277,6 +287,13 @@ export const validatorOptions: CliCommandOptions<IValidatorCliArgs> = {
     group: "externalSignerUrl",
   },
 
+  // Distributed validator
+
+  distributed: {
+    description: "Enables specific features required to run as part of a distributed validator cluster",
+    type: "boolean",
+  },
+
   // Metrics
 
   metrics: {

packages/validator/src/services/attestation.ts

@@ -12,8 +12,9 @@ import {groupAttDutiesByCommitteeIndex} from "./utils.js";
 import {ChainHeaderTracker} from "./chainHeaderTracker.js";
 import {ValidatorEventEmitter} from "./emitter.js";
 
-type AttestationServiceOpts = {
+export type AttestationServiceOpts = {
   afterBlockDelaySlotFraction?: number;
+  disableAttestationGrouping?: boolean;
 };
 
 /**
@@ -64,41 +65,86 @@ export class AttestationService {
     await Promise.race([sleep(this.clock.msToSlot(slot + 1 / 3), signal), this.emitter.waitForBlockSlot(slot)]);
     this.metrics?.attesterStepCallProduceAttestation.observe(this.clock.secFromSlot(slot + 1 / 3));
 
-    // Beacon node's endpoint produceAttestationData return data is not dependant on committeeIndex.
+    if (this.opts?.disableAttestationGrouping) {
+      // Attestation service grouping optimization must be disabled in a distributed validator cluster as
+      // middleware clients such as Charon (https://github.com/ObolNetwork/charon) expect the actual committee index
+      // to be sent to produceAttestationData endpoint. This is required because the middleware client itself
+      // calls produceAttestationData on the beacon node for each validator and there is a slight chance that
+      // the `beacon_block_root` (LMD GHOST vote) changes between calls which would cause a conflict between
+      // attestations submitted by Lodestar and other VCs in the cluster, resulting in aggregation failure.
+      // See https://github.com/ChainSafe/lodestar/issues/5103 for further details and references.
+      const dutiesByCommitteeIndex = groupAttDutiesByCommitteeIndex(duties);
+      await Promise.all(
+        Array.from(dutiesByCommitteeIndex.entries()).map(([index, duties]) =>
+          this.runAttestationTasksPerCommittee(duties, slot, index, signal).catch((e) => {
+            this.logger.error("Error on attestation routine", {slot, index}, e);
+          })
+        )
+      );
+    } else {
+      // Beacon node's endpoint produceAttestationData return data is not dependant on committeeIndex.
+      // Produce a single attestation for all committees and submit unaggregated attestations in one go.
+      await this.runAttestationTasksGrouped(duties, slot, signal);
+    }
+  };
+
+  private async runAttestationTasksPerCommittee(
+    dutiesSameCommittee: AttDutyAndProof[],
+    slot: Slot,
+    index: number,
+    signal: AbortSignal
+  ): Promise<void> {
+    // Produce attestation with actual committee index
+    const attestation = await this.produceAttestation(index, slot);
+
+    // Step 1. Sign `Attestation` for each validator. Then publish all `Attestations` in one go
+    await this.signAndPublishAttestations(slot, attestation, dutiesSameCommittee);
+
+    // Step 2. after all attestations are submitted, make an aggregate.
+    // First, wait until the `aggregation_production_instant` (2/3rds of the way through the slot)
+    await sleep(this.clock.msToSlot(slot + 2 / 3), signal);
+    this.metrics?.attesterStepCallProduceAggregate.observe(this.clock.secFromSlot(slot + 2 / 3));
+
+    // Then download, sign and publish a `SignedAggregateAndProof` for each
+    // validator that is elected to aggregate for this `slot` and `committeeIndex`.
+    await this.produceAndPublishAggregates(attestation, dutiesSameCommittee);
+  }
+
+  private async runAttestationTasksGrouped(
+    dutiesAll: AttDutyAndProof[],
+    slot: Slot,
+    signal: AbortSignal
+  ): Promise<void> {
     // Produce a single attestation for all committees, and clone mutate before signing
-    // Downstream tooling may require that produceAttestation is called with a 'real' committee index
-    // So we pick the first duty's committee index - see https://github.com/ChainSafe/lodestar/issues/4687
-    const attestationNoCommittee = await this.produceAttestation(duties[0].duty.committeeIndex, slot);
+    const attestationNoCommittee = await this.produceAttestation(0, slot);
 
     // Step 1. Mutate, and sign `Attestation` for each validator. Then publish all `Attestations` in one go
-    await this.signAndPublishAttestations(slot, attestationNoCommittee, duties);
+    await this.signAndPublishAttestations(slot, attestationNoCommittee, dutiesAll);
 
     // Step 2. after all attestations are submitted, make an aggregate.
-    // First, wait until the `aggregation_production_instant` (2/3rds of the way though the slot)
+    // First, wait until the `aggregation_production_instant` (2/3rds of the way through the slot)
     await sleep(this.clock.msToSlot(slot + 2 / 3), signal);
     this.metrics?.attesterStepCallProduceAggregate.observe(this.clock.secFromSlot(slot + 2 / 3));
 
-    const dutiesByCommitteeIndex = groupAttDutiesByCommitteeIndex(this.dutiesService.getDutiesAtSlot(slot));
+    const dutiesByCommitteeIndex = groupAttDutiesByCommitteeIndex(dutiesAll);
 
     // Then download, sign and publish a `SignedAggregateAndProof` for each
-    // validator that is elected to aggregate for this `slot` and
-    // `committeeIndex`.
+    // validator that is elected to aggregate for this `slot` and `committeeIndex`.
     await Promise.all(
-      Array.from(dutiesByCommitteeIndex.entries()).map(([index, duties]) => {
+      Array.from(dutiesByCommitteeIndex.entries()).map(([index, dutiesSameCommittee]) => {
         const attestationData: phase0.AttestationData = {...attestationNoCommittee, index};
-        return this.produceAndPublishAggregates(attestationData, duties);
+        return this.produceAndPublishAggregates(attestationData, dutiesSameCommittee);
       })
     );
-  };
+  }
 
   /**
    * Performs the first step of the attesting process: downloading one `Attestation` object.
    * Beacon node's endpoint produceAttestationData return data is not dependant on committeeIndex.
    * For a validator client with many validators this allows to do a single call for all committees
    * in a slot, saving resources in both the vc and beacon node
    *
-   * A committee index is still passed in for the benefit of downstream tooling -
-   * see https://github.com/ChainSafe/lodestar/issues/4687
+   * Note: the actual committeeIndex must be passed in if attestation grouping is disabled
    */
   private async produceAttestation(committeeIndex: number, slot: Slot): Promise<phase0.AttestationData> {
     // Produce one attestation data per slot and committeeIndex

packages/validator/src/validator.ts

@@ -33,9 +33,11 @@ export type ValidatorOptions = {
   abortController: AbortController;
   afterBlockDelaySlotFraction?: number;
   scAfterBlockDelaySlotFraction?: number;
+  disableAttestationGrouping?: boolean;
   doppelgangerProtectionEnabled?: boolean;
   closed?: boolean;
   valProposerConfig?: ValidatorProposerConfig;
+  distributed?: boolean;
 };
 
 // TODO: Extend the timeout, and let it be customizable
@@ -123,7 +125,10 @@ export class Validator {
       emitter,
       chainHeaderTracker,
       metrics,
-      {afterBlockDelaySlotFraction: opts.afterBlockDelaySlotFraction}
+      {
+        afterBlockDelaySlotFraction: opts.afterBlockDelaySlotFraction,
+        disableAttestationGrouping: opts.disableAttestationGrouping || opts.distributed,
+      }
     );
 
     this.syncCommitteeService = new SyncCommitteeService(

packages/validator/test/unit/services/attestation.test.ts

@@ -4,7 +4,7 @@ import bls from "@chainsafe/bls";
 import {toHexString} from "@chainsafe/ssz";
 import {ssz} from "@lodestar/types";
 import {HttpStatusCode} from "@lodestar/api";
-import {AttestationService} from "../../../src/services/attestation.js";
+import {AttestationService, AttestationServiceOpts} from "../../../src/services/attestation.js";
 import {AttDutyAndProof} from "../../../src/services/attestationDuties.js";
 import {ValidatorStore} from "../../../src/services/validatorStore.js";
 import {getApiClientStub} from "../../utils/apiStub.js";
@@ -37,9 +37,28 @@ describe("AttestationService", function () {
 
   let controller: AbortController; // To stop clock
   beforeEach(() => (controller = new AbortController()));
-  afterEach(() => controller.abort());
+  afterEach(() => {
+    controller.abort();
+    sandbox.resetHistory();
+  });
+
+  context("With attestation grouping enabled", () => {
+    const opts: AttestationServiceOpts = {disableAttestationGrouping: false};
+
+    it("Should produce, sign, and publish an attestation + aggregate", async () => {
+      await testAttestationTasks(opts);
+    });
+  });
 
-  it("Should produce, sign, and publish an attestation + aggregate", async () => {
+  context("With attestation grouping disabled", () => {
+    const opts: AttestationServiceOpts = {disableAttestationGrouping: true};
+
+    it("Should produce, sign, and publish an attestation + aggregate", async () => {
+      await testAttestationTasks(opts);
+    });
+  });
+
+  async function testAttestationTasks(opts?: AttestationServiceOpts): Promise<void> {
     const clock = new ClockMock();
     const attestationService = new AttestationService(
       loggerVc,
@@ -48,7 +67,8 @@ describe("AttestationService", function () {
       validatorStore,
       emitter,
       chainHeadTracker,
-      null
+      null,
+      opts
     );
 
     const attestation = ssz.phase0.Attestation.defaultValue();
@@ -121,5 +141,5 @@ describe("AttestationService", function () {
       [[aggregate]], // 1 arg, = aggregate[]
       "wrong publishAggregateAndProofs() args"
     );
-  });
+  }
 });