Add block_gossip Beacon API events (#5864)

* Add bls event

* Update events and types

* Add bls in event

* Event bls

* tests..rs

* change order

* another tests.rs

* Signed BLS

* Revert "another tests.rs"

This reverts commit 7f54e9c1ce.

* Revert "Signed BLS"

This reverts commit 1146bc734b.

* withdrawal_keyparis

* Fix genesis

* block gossip

* Add definition for BlockGossip

* Fix block gossip

* Tests.rs

* Update block and events

* Add bls event

* Event bls

* tests..rs

* change order

* another tests.rs

* Signed BLS

* Revert "another tests.rs"

This reverts commit 7f54e9c1ce.

* Revert "Signed BLS"

This reverts commit 1146bc734b.

* block gossip

* Add definition for BlockGossip

* Fix block gossip

* Tests.rs

* Update block and events

* Merge branch 'BeaconAPI-events-block-gossip' of https://github.com/chong-he/lighthouse into BeaconAPI-events-block-gossip

* Remove tests

* Tests.rs

* Tests.rs

* Tests.rs

* Tests similar to block event

* Update common/eth2/src/types.rs

Co-authored-by: Michael Sproul <micsproul@gmail.com>

* Merge remote-tracking branch 'origin/unstable' into BeaconAPI-events-block-gossip

* Fix tests

beacon_node/beacon_chain/src/block_verification.rs

@@ -67,7 +67,7 @@ use crate::{
     metrics, BeaconChain, BeaconChainError, BeaconChainTypes,
 };
 use derivative::Derivative;
-use eth2::types::{EventKind, PublishBlockRequest};
+use eth2::types::{BlockGossip, EventKind, PublishBlockRequest};
 use execution_layer::PayloadStatus;
 pub use fork_choice::{AttestationFromBlock, PayloadVerificationStatus};
 use parking_lot::RwLockReadGuard;
@@ -974,6 +974,16 @@ impl<T: BeaconChainTypes> GossipVerifiedBlock<T> {
         // Validate the block's execution_payload (if any).
         validate_execution_payload_for_gossip(&parent_block, block.message(), chain)?;
 
+        // Beacon API block_gossip events
+        if let Some(event_handler) = chain.event_handler.as_ref() {
+            if event_handler.has_block_gossip_subscribers() {
+                event_handler.register(EventKind::BlockGossip(Box::new(BlockGossip {
+                    slot: block.slot(),
+                    block: block_root,
+                })));
+            }
+        }
+
         // Having checked the proposer index and the block root we can cache them.
         let consensus_context = ConsensusContext::new(block.slot())
             .set_current_block_root(block_root)

beacon_node/beacon_chain/src/events.rs

@@ -23,6 +23,7 @@ pub struct ServerSentEventHandler<E: EthSpec> {
     proposer_slashing_tx: Sender<EventKind<E>>,
     attester_slashing_tx: Sender<EventKind<E>>,
     bls_to_execution_change_tx: Sender<EventKind<E>>,
+    block_gossip_tx: Sender<EventKind<E>>,
     log: Logger,
 }
 
@@ -51,6 +52,7 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
         let (proposer_slashing_tx, _) = broadcast::channel(capacity);
         let (attester_slashing_tx, _) = broadcast::channel(capacity);
         let (bls_to_execution_change_tx, _) = broadcast::channel(capacity);
+        let (block_gossip_tx, _) = broadcast::channel(capacity);
 
         Self {
             attestation_tx,
@@ -69,6 +71,7 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
             proposer_slashing_tx,
             attester_slashing_tx,
             bls_to_execution_change_tx,
+            block_gossip_tx,
             log,
         }
     }
@@ -147,6 +150,10 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
                 .bls_to_execution_change_tx
                 .send(kind)
                 .map(|count| log_count("bls to execution change", count)),
+            EventKind::BlockGossip(_) => self
+                .block_gossip_tx
+                .send(kind)
+                .map(|count| log_count("block gossip", count)),
         };
         if let Err(SendError(event)) = result {
             trace!(self.log, "No receivers registered to listen for event"; "event" => ?event);
@@ -217,6 +224,10 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
         self.bls_to_execution_change_tx.subscribe()
     }
 
+    pub fn subscribe_block_gossip(&self) -> Receiver<EventKind<E>> {
+        self.block_gossip_tx.subscribe()
+    }
+
     pub fn has_attestation_subscribers(&self) -> bool {
         self.attestation_tx.receiver_count() > 0
     }
@@ -272,4 +283,8 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
     pub fn has_bls_to_execution_change_subscribers(&self) -> bool {
         self.bls_to_execution_change_tx.receiver_count() > 0
     }
+
+    pub fn has_block_gossip_subscribers(&self) -> bool {
+        self.block_gossip_tx.receiver_count() > 0
+    }
 }