Add --disable-attesting flag to validator client (#7046)

Cleaned up and isolated version of the `--disable-attesting` flag for the VC, from the `holesky-rescue` branch:

- https://github.com/sigp/lighthouse/pull/7041

I figured we don't need the `--disable-attesting` flag on the BN for now, and it was a much more invasive impl.

book/src/help_vc.md

@@ -175,6 +175,10 @@ Flags:
           If this flag is set, Lighthouse will query the Beacon Node for only
           block headers during proposals and will sign over headers. Useful for
           outsourcing execution payload construction during proposals.
+      --disable-attesting
+          Disable the performance of attestation duties (and sync committee
+          duties). This flag should only be used in emergencies to prioritise
+          block proposal duties.
       --disable-auto-discover
           If present, do not attempt to discover new validators in the
           validators-dir. Validators will need to be manually added to the

validator_client/src/cli.rs

@@ -97,6 +97,15 @@ pub struct ValidatorClient {
     )]
     pub disable_auto_discover: bool,
 
+    #[clap(
+        long,
+        help = "Disable the performance of attestation duties (and sync committee duties). This \
+                flag should only be used in emergencies to prioritise block proposal duties.",
+        display_order = 0,
+        help_heading = FLAG_HEADER
+    )]
+    pub disable_attesting: bool,
+
     #[clap(
         long,
         help = "If present, the validator client will use longer timeouts for requests \

validator_client/src/config.rs

@@ -85,6 +85,7 @@ pub struct Config {
     /// Configuration for the initialized validators
     #[serde(flatten)]
     pub initialized_validators: InitializedValidatorsConfig,
+    pub disable_attesting: bool,
 }
 
 impl Default for Config {
@@ -126,6 +127,7 @@ impl Default for Config {
             validator_registration_batch_size: 500,
             distributed: false,
             initialized_validators: <_>::default(),
+            disable_attesting: false,
         }
     }
 }
@@ -379,6 +381,8 @@ impl Config {
                 true
             };
 
+        config.disable_attesting = validator_client_config.disable_attesting;
+
         Ok(config)
     }
 }

validator_client/src/lib.rs

@@ -478,6 +478,7 @@ impl<E: EthSpec> ProductionValidatorClient<E> {
             context: duties_context,
             enable_high_validator_count_metrics: config.enable_high_validator_count_metrics,
             distributed: config.distributed,
+            disable_attesting: config.disable_attesting,
         });
 
         // Update the metrics server.
@@ -507,6 +508,7 @@ impl<E: EthSpec> ProductionValidatorClient<E> {
             .validator_store(validator_store.clone())
             .beacon_nodes(beacon_nodes.clone())
             .runtime_context(context.service_context("attestation".into()))
+            .disable(config.disable_attesting)
             .build()?;
 
         let preparation_service = PreparationServiceBuilder::new()

validator_client/validator_services/src/attestation_service.rs

@@ -21,6 +21,7 @@ pub struct AttestationServiceBuilder<T: SlotClock + 'static, E: EthSpec> {
     slot_clock: Option<T>,
     beacon_nodes: Option<Arc<BeaconNodeFallback<T, E>>>,
     context: Option<RuntimeContext<E>>,
+    disable: bool,
 }
 
 impl<T: SlotClock + 'static, E: EthSpec> AttestationServiceBuilder<T, E> {
@@ -31,6 +32,7 @@ impl<T: SlotClock + 'static, E: EthSpec> AttestationServiceBuilder<T, E> {
             slot_clock: None,
             beacon_nodes: None,
             context: None,
+            disable: false,
         }
     }
 
@@ -59,6 +61,11 @@ impl<T: SlotClock + 'static, E: EthSpec> AttestationServiceBuilder<T, E> {
         self
     }
 
+    pub fn disable(mut self, disable: bool) -> Self {
+        self.disable = disable;
+        self
+    }
+
     pub fn build(self) -> Result<AttestationService<T, E>, String> {
         Ok(AttestationService {
             inner: Arc::new(Inner {
@@ -77,6 +84,7 @@ impl<T: SlotClock + 'static, E: EthSpec> AttestationServiceBuilder<T, E> {
                 context: self
                     .context
                     .ok_or("Cannot build AttestationService without runtime_context")?,
+                disable: self.disable,
             }),
         })
     }
@@ -89,6 +97,7 @@ pub struct Inner<T, E: EthSpec> {
     slot_clock: T,
     beacon_nodes: Arc<BeaconNodeFallback<T, E>>,
     context: RuntimeContext<E>,
+    disable: bool,
 }
 
 /// Attempts to produce attestations for all known validators 1/3rd of the way through each slot.
@@ -120,6 +129,10 @@ impl<T: SlotClock + 'static, E: EthSpec> AttestationService<T, E> {
     /// Starts the service which periodically produces attestations.
     pub fn start_update_service(self, spec: &ChainSpec) -> Result<(), String> {
         let log = self.context.log().clone();
+        if self.disable {
+            info!(log, "Attestation service disabled");
+            return Ok(());
+        }
 
         let slot_duration = Duration::from_secs(spec.seconds_per_slot);
         let duration_to_next_slot = self

validator_client/validator_services/src/duties_service.rs

@@ -230,6 +230,7 @@ pub struct DutiesService<T, E: EthSpec> {
     pub enable_high_validator_count_metrics: bool,
     /// If this validator is running in distributed mode.
     pub distributed: bool,
+    pub disable_attesting: bool,
 }
 
 impl<T: SlotClock + 'static, E: EthSpec> DutiesService<T, E> {
@@ -403,6 +404,11 @@ pub fn start_update_service<T: SlotClock + 'static, E: EthSpec>(
         "duties_service_proposers",
     );
 
+    // Skip starting attestation duties or sync committee services.
+    if core_duties_service.disable_attesting {
+        return;
+    }
+
     /*
      * Spawn the task which keeps track of local attestation duties.
      */

validator_client/validator_services/src/sync_committee_service.rs

@@ -87,6 +87,11 @@ impl<T: SlotClock + 'static, E: EthSpec> SyncCommitteeService<T, E> {
 
     pub fn start_update_service(self, spec: &ChainSpec) -> Result<(), String> {
         let log = self.context.log().clone();
+        if self.duties_service.disable_attesting {
+            info!(log, "Sync committee service disabled");
+            return Ok(());
+        }
+
         let slot_duration = Duration::from_secs(spec.seconds_per_slot);
         let duration_to_next_slot = self
             .slot_clock