Broadcast VC requests in parallel and fix subscription error

common/eth2/src/lib.rs

@@ -121,6 +121,7 @@ impl fmt::Display for Error {
 pub struct Timeouts {
     pub attestation: Duration,
     pub attester_duties: Duration,
+    pub attestation_subscriptions: Duration,
     pub liveness: Duration,
     pub proposal: Duration,
     pub proposer_duties: Duration,
@@ -137,6 +138,7 @@ impl Timeouts {
         Timeouts {
             attestation: timeout,
             attester_duties: timeout,
+            attestation_subscriptions: timeout,
             liveness: timeout,
             proposal: timeout,
             proposer_duties: timeout,
@@ -2515,7 +2517,12 @@ impl BeaconNodeHttpClient {
             .push("validator")
             .push("beacon_committee_subscriptions");
 
-        self.post(path, &subscriptions).await?;
+        self.post_with_timeout(
+            path,
+            &subscriptions,
+            self.timeouts.attestation_subscriptions,
+        )
+        .await?;
 
         Ok(())
     }

validator_client/src/beacon_node_fallback.rs

@@ -134,6 +134,12 @@ impl<T: Debug> fmt::Display for Errors<T> {
     }
 }
 
+impl<T> Errors<T> {
+    pub fn num_errors(&self) -> usize {
+        self.0.len()
+    }
+}
+
 /// Reasons why a candidate might not be ready.
 #[derive(Debug, Clone, Copy)]
 pub enum CandidateError {
@@ -599,46 +605,41 @@ impl<T: SlotClock, E: EthSpec> BeaconNodeFallback<T, E> {
         F: Fn(&'a BeaconNodeHttpClient) -> R,
         R: Future<Output = Result<O, Err>>,
     {
-        let mut results = vec![];
         let mut to_retry = vec![];
         let mut retry_unsynced = vec![];
 
         // Run `func` using a `candidate`, returning the value or capturing errors.
-        //
-        // We use a macro instead of a closure here since it is not trivial to move `func` into a
-        // closure.
-        macro_rules! try_func {
-            ($candidate: ident) => {{
-                inc_counter_vec(&ENDPOINT_REQUESTS, &[$candidate.beacon_node.as_ref()]);
+        let run_on_candidate = |candidate: &'a CandidateBeaconNode<E>| async {
+            inc_counter_vec(&ENDPOINT_REQUESTS, &[candidate.beacon_node.as_ref()]);
 
-                // There exists a race condition where `func` may be called when the candidate is
-                // actually not ready. We deem this an acceptable inefficiency.
-                match func(&$candidate.beacon_node).await {
-                    Ok(val) => results.push(Ok(val)),
-                    Err(e) => {
-                        // If we have an error on this function, make the client as not-ready.
-                        //
-                        // There exists a race condition where the candidate may have been marked
-                        // as ready between the `func` call and now. We deem this an acceptable
-                        // inefficiency.
-                        if matches!(offline_on_failure, OfflineOnFailure::Yes) {
-                            $candidate.set_offline().await;
-                        }
-                        results.push(Err((
-                            $candidate.beacon_node.to_string(),
-                            Error::RequestFailed(e),
-                        )));
-                        inc_counter_vec(&ENDPOINT_ERRORS, &[$candidate.beacon_node.as_ref()]);
+            // There exists a race condition where `func` may be called when the candidate is
+            // actually not ready. We deem this an acceptable inefficiency.
+            match func(&candidate.beacon_node).await {
+                Ok(val) => Ok(val),
+                Err(e) => {
+                    // If we have an error on this function, mark the client as not-ready.
+                    //
+                    // There exists a race condition where the candidate may have been marked
+                    // as ready between the `func` call and now. We deem this an acceptable
+                    // inefficiency.
+                    if matches!(offline_on_failure, OfflineOnFailure::Yes) {
+                        candidate.set_offline().await;
                     }
+                    inc_counter_vec(&ENDPOINT_ERRORS, &[candidate.beacon_node.as_ref()]);
+                    Err((candidate.beacon_node.to_string(), Error::RequestFailed(e)))
                 }
-            }};
-        }
+            }
+        };
 
         // First pass: try `func` on all synced and ready candidates.
         //
         // This ensures that we always choose a synced node if it is available.
+        let mut first_batch_futures = vec![];
         for candidate in &self.candidates {
             match candidate.status(RequireSynced::Yes).await {
+                Ok(_) => {
+                    first_batch_futures.push(run_on_candidate(candidate));
+                }
                 Err(CandidateError::NotSynced) if require_synced == false => {
                     // This client is unsynced we will try it after trying all synced clients
                     retry_unsynced.push(candidate);
@@ -647,22 +648,24 @@ impl<T: SlotClock, E: EthSpec> BeaconNodeFallback<T, E> {
                     // This client was not ready on the first pass, we might try it again later.
                     to_retry.push(candidate);
                 }
-                Ok(_) => try_func!(candidate),
             }
         }
+        let first_batch_results = futures::future::join_all(first_batch_futures).await;
 
         // Second pass: try `func` on ready unsynced candidates. This only runs if we permit
         // unsynced candidates.
         //
         // Due to async race-conditions, it is possible that we will send a request to a candidate
         // that has been set to an offline/unready status. This is acceptable.
-        if require_synced == false {
-            for candidate in retry_unsynced {
-                try_func!(candidate);
-            }
-        }
+        let second_batch_results = if require_synced == false {
+            futures::future::join_all(retry_unsynced.into_iter().map(run_on_candidate)).await
+        } else {
+            vec![]
+        };
 
         // Third pass: try again, attempting to make non-ready clients become ready.
+        let mut third_batch_futures = vec![];
+        let mut third_batch_results = vec![];
         for candidate in to_retry {
             // If the candidate hasn't luckily transferred into the correct state in the meantime,
             // force an update of the state.
@@ -676,16 +679,21 @@ impl<T: SlotClock, E: EthSpec> BeaconNodeFallback<T, E> {
             };
 
             match new_status {
-                Ok(()) => try_func!(candidate),
-                Err(CandidateError::NotSynced) if require_synced == false => try_func!(candidate),
-                Err(e) => {
-                    results.push(Err((
-                        candidate.beacon_node.to_string(),
-                        Error::Unavailable(e),
-                    )));
+                Ok(()) => third_batch_futures.push(run_on_candidate(candidate)),
+                Err(CandidateError::NotSynced) if require_synced == false => {
+                    third_batch_futures.push(run_on_candidate(candidate))
                 }
+                Err(e) => third_batch_results.push(Err((
+                    candidate.beacon_node.to_string(),
+                    Error::Unavailable(e),
+                ))),
             }
         }
+        third_batch_results.extend(futures::future::join_all(third_batch_futures).await);
+
+        let mut results = first_batch_results;
+        results.extend(second_batch_results);
+        results.extend(third_batch_results);
 
         let errors: Vec<_> = results.into_iter().filter_map(|res| res.err()).collect();
 

validator_client/src/duties_service.rs

@@ -86,7 +86,8 @@ const _: () = assert!({
 /// This number is based upon `MIN_PEER_DISCOVERY_SLOT_LOOK_AHEAD` value in the
 /// `beacon_node::network::attestation_service` crate. It is not imported directly to avoid
 /// bringing in the entire crate.
-const _: () = assert!(ATTESTATION_SUBSCRIPTION_OFFSETS[0] > 2);
+const MIN_ATTESTATION_SUBSCRIPTION_LOOKAHEAD: u64 = 2;
+const _: () = assert!(ATTESTATION_SUBSCRIPTION_OFFSETS[0] > MIN_ATTESTATION_SUBSCRIPTION_LOOKAHEAD);
 
 // The info in the enum variants is displayed in logging, clippy thinks it's dead code.
 #[derive(Debug)]
@@ -121,6 +122,8 @@ pub struct DutyAndProof {
 pub struct SubscriptionSlots {
     /// Pairs of `(slot, already_sent)` in slot-descending order.
     slots: Vec<(Slot, AtomicBool)>,
+    /// The slot of the duty itself.
+    duty_slot: Slot,
 }
 
 /// Create a selection proof for `duty`.
@@ -172,18 +175,20 @@ impl SubscriptionSlots {
             .filter(|scheduled_slot| *scheduled_slot > current_slot)
             .map(|scheduled_slot| (scheduled_slot, AtomicBool::new(false)))
             .collect();
-        Arc::new(Self { slots })
+        Arc::new(Self { slots, duty_slot })
     }
 
     /// Return `true` if we should send a subscription at `slot`.
     fn should_send_subscription_at(&self, slot: Slot) -> bool {
         // Iterate slots from smallest to largest looking for one that hasn't been completed yet.
-        self.slots
-            .iter()
-            .rev()
-            .any(|(scheduled_slot, already_sent)| {
-                slot >= *scheduled_slot && !already_sent.load(Ordering::Relaxed)
-            })
+        slot + MIN_ATTESTATION_SUBSCRIPTION_LOOKAHEAD <= self.duty_slot
+            && self
+                .slots
+                .iter()
+                .rev()
+                .any(|(scheduled_slot, already_sent)| {
+                    slot >= *scheduled_slot && !already_sent.load(Ordering::Relaxed)
+                })
     }
 
     /// Update our record of subscribed slots to account for successful subscription at `slot`.
@@ -737,7 +742,7 @@ async fn poll_beacon_attesters<T: SlotClock + 'static, E: EthSpec>(
     // If there are any subscriptions, push them out to beacon nodes
     if !subscriptions.is_empty() {
         let subscriptions_ref = &subscriptions;
-        if let Err(e) = duties_service
+        let subscription_result = duties_service
             .beacon_nodes
             .request(
                 RequireSynced::No,
@@ -753,15 +758,8 @@ async fn poll_beacon_attesters<T: SlotClock + 'static, E: EthSpec>(
                         .await
                 },
             )
-            .await
-        {
-            error!(
-                log,
-                "Failed to subscribe validators";
-                "error" => %e
-            )
-        } else {
-            // Record that subscriptions were successfully sent.
+            .await;
+        if subscription_result.as_ref().is_ok() {
             debug!(
                 log,
                 "Broadcast attestation subscriptions";
@@ -770,6 +768,25 @@ async fn poll_beacon_attesters<T: SlotClock + 'static, E: EthSpec>(
             for subscription_slots in subscription_slots_to_confirm {
                 subscription_slots.record_successful_subscription_at(current_slot);
             }
+        } else if let Err(e) = subscription_result {
+            if e.num_errors() < duties_service.beacon_nodes.num_total() {
+                warn!(
+                    log,
+                    "Some subscriptions failed";
+                    "error" => %e,
+                );
+                // If subscriptions were sent to at least one node, regard that as a success.
+                // There is some redundancy built into the subscription schedule to handle failures.
+                for subscription_slots in subscription_slots_to_confirm {
+                    subscription_slots.record_successful_subscription_at(current_slot);
+                }
+            } else {
+                error!(
+                    log,
+                    "All subscriptions failed";
+                    "error" => %e
+                );
+            }
         }
     }
 

validator_client/src/lib.rs

@@ -75,6 +75,7 @@ const WAITING_FOR_GENESIS_POLL_TIME: Duration = Duration::from_secs(12);
 /// This can help ensure that proper endpoint fallback occurs.
 const HTTP_ATTESTATION_TIMEOUT_QUOTIENT: u32 = 4;
 const HTTP_ATTESTER_DUTIES_TIMEOUT_QUOTIENT: u32 = 4;
+const HTTP_ATTESTATION_SUBSCRIPTIONS_TIMEOUT_QUOTIENT: u32 = 24;
 const HTTP_LIVENESS_TIMEOUT_QUOTIENT: u32 = 4;
 const HTTP_PROPOSAL_TIMEOUT_QUOTIENT: u32 = 2;
 const HTTP_PROPOSER_DUTIES_TIMEOUT_QUOTIENT: u32 = 4;
@@ -323,6 +324,8 @@ impl<E: EthSpec> ProductionValidatorClient<E> {
                 Timeouts {
                     attestation: slot_duration / HTTP_ATTESTATION_TIMEOUT_QUOTIENT,
                     attester_duties: slot_duration / HTTP_ATTESTER_DUTIES_TIMEOUT_QUOTIENT,
+                    attestation_subscriptions: slot_duration
+                        / HTTP_ATTESTATION_SUBSCRIPTIONS_TIMEOUT_QUOTIENT,
                     liveness: slot_duration / HTTP_LIVENESS_TIMEOUT_QUOTIENT,
                     proposal: slot_duration / HTTP_PROPOSAL_TIMEOUT_QUOTIENT,
                     proposer_duties: slot_duration / HTTP_PROPOSER_DUTIES_TIMEOUT_QUOTIENT,