validator_discovery: simplification (#3009)

* validator_discovery: simplification

* compilation fixes

* compilation fixes II

* compilation fixes III

* compilation fixes IV

polkadot/node/network/gossip-support/src/lib.rs

@@ -18,22 +18,19 @@
 //! and issuing a connection request to the validators relevant to
 //! the gossiping subsystems on every new session.
 
-use futures::{channel::mpsc, FutureExt as _};
+use futures::{channel::oneshot, FutureExt as _};
 use polkadot_node_subsystem::{
 	messages::{
-		GossipSupportMessage,
+		AllMessages, GossipSupportMessage, NetworkBridgeMessage,
 	},
 	ActiveLeavesUpdate, FromOverseer, OverseerSignal,
 	Subsystem, SpawnedSubsystem, SubsystemContext,
 };
-use polkadot_node_subsystem_util::{
-	validator_discovery,
-	self as util,
-};
+use polkadot_node_subsystem_util as util;
 use polkadot_primitives::v1::{
 	Hash, SessionIndex, AuthorityDiscoveryId,
 };
-use polkadot_node_network_protocol::{peer_set::PeerSet, PeerId};
+use polkadot_node_network_protocol::peer_set::PeerSet;
 use sp_keystore::{CryptoStore, SyncCryptoStorePtr};
 use sp_application_crypto::{Public, AppKey};
 
@@ -48,7 +45,7 @@ pub struct GossipSupport {
 struct State {
 	last_session_index: Option<SessionIndex>,
 	/// when we overwrite this, it automatically drops the previous request
-	_last_connection_request: Option<mpsc::Receiver<(AuthorityDiscoveryId, PeerId)>>,
+	_last_connection_request: Option<oneshot::Sender<()>>,
 }
 
 impl GossipSupport {
@@ -123,6 +120,24 @@ async fn ensure_i_am_an_authority(
 	Err(util::Error::NotAValidator)
 }
 
+/// A helper function for making a `ConnectToValidators` request.
+pub async fn connect_to_authorities(
+	ctx: &mut impl SubsystemContext,
+	validator_ids: Vec<AuthorityDiscoveryId>,
+	peer_set: PeerSet,
+) -> oneshot::Sender<()> {
+	let (keep_alive_handle, keep_alive) = oneshot::channel();
+
+	ctx.send_message(AllMessages::NetworkBridge(
+		NetworkBridgeMessage::ConnectToValidators {
+			validator_ids,
+			peer_set,
+			keep_alive,
+		}
+	)).await;
+
+	keep_alive_handle
+}
 
 impl State {
 	/// 1. Determine if the current session index has changed.
@@ -147,14 +162,14 @@ impl State {
 				ensure_i_am_an_authority(keystore, &authorities).await?;
 				tracing::debug!(target: LOG_TARGET, num = ?authorities.len(), "Issuing a connection request");
 
-				let request = validator_discovery::connect_to_authorities(
+				let keep_alive_handle = connect_to_authorities(
 					ctx,
 					authorities,
 					PeerSet::Validation,
 				).await;
 
 				self.last_session_index = Some(new_session);
-				self._last_connection_request = Some(request);
+				self._last_connection_request = Some(keep_alive_handle);
 			}
 		}