Rework priority groups, take 2 (#7700)

* Rework priority groups

* Broken tests fix

* Fix warning causing CI to fail

* [Hack] Try restore backwards-compatibility

* Fix peerset bug

* Doc fixes and clean up

* Error on state mismatch

* Try debug CI

* CI debugging

* [CI debug] Can I please see this line

* Revert "[CI debug] Can I please see this line"

This reverts commit 4b7cf7c1511f579cd818b21d46bd11642dfac5cb.

* Revert "CI debugging"

This reverts commit 9011f1f564b860386dc7dd6ffa9fc34ea7107623.

* Fix error! which isn't actually an error

* Fix Ok() returned when actually Err()

* Tweaks and fixes

* Fix build

* Peerset bugfix

* [Debug] Try outbound GrandPa slots

* Another bugfix

* Revert "[Debug] Try outbound GrandPa slots"

This reverts commit d175b9208c088faad77d9f0ce36ff6f48bd92dd3.

* [Debug] Try outbound GrandPa slots

* Apply suggestions from code review

Co-authored-by: Max Inden <mail@max-inden.de>

* Use consts for hardcoded peersets

* Revert "Try debug CI"

This reverts commit 62c4ad5e79c03d561c714a008022ecac463a597e.

* Renames

* Line widths

* Add doc

Co-authored-by: Max Inden <mail@max-inden.de>

substrate/client/network-gossip/src/bridge.rs

@@ -180,6 +180,12 @@ impl<B: BlockT> Future for GossipEngine<B> {
 				ForwardingState::Idle => {
 					match this.network_event_stream.poll_next_unpin(cx) {
 						Poll::Ready(Some(event)) => match event {
+							Event::SyncConnected { remote } => {
+								this.network.add_set_reserved(remote, this.protocol.clone());
+							}
+							Event::SyncDisconnected { remote } => {
+								this.network.remove_set_reserved(remote, this.protocol.clone());
+							}
 							Event::NotificationStreamOpened { remote, protocol, role } => {
 								if protocol != this.protocol {
 									continue;
@@ -325,10 +331,16 @@ mod tests {
 		fn report_peer(&self, _: PeerId, _: ReputationChange) {
 		}
 
-		fn disconnect_peer(&self, _: PeerId) {
+		fn disconnect_peer(&self, _: PeerId, _: Cow<'static, str>) {
 			unimplemented!();
 		}
 
+		fn add_set_reserved(&self, _: PeerId, _: Cow<'static, str>) {
+		}
+
+		fn remove_set_reserved(&self, _: PeerId, _: Cow<'static, str>) {
+		}
+
 		fn write_notification(&self, _: PeerId, _: Cow<'static, str>, _: Vec<u8>) {
 			unimplemented!();
 		}

substrate/client/network-gossip/src/lib.rs

@@ -40,6 +40,11 @@
 //! - Use the methods of the `GossipEngine` in order to send out messages and receive incoming
 //!   messages.
 //!
+//! The `GossipEngine` will automatically use `Network::add_set_reserved` and
+//! `Network::remove_set_reserved` to maintain a set of peers equal to the set of peers the
+//! node is syncing from. See the documentation of `sc-network` for more explanations about the
+//! concepts of peer sets.
+//!
 //! # What is a validator?
 //!
 //! The primary role of a `Validator` is to process incoming messages from peers, and decide
@@ -61,9 +66,9 @@ pub use self::state_machine::TopicNotification;
 pub use self::validator::{DiscardAll, MessageIntent, Validator, ValidatorContext, ValidationResult};
 
 use futures::prelude::*;
-use sc_network::{Event, ExHashT, NetworkService, PeerId, ReputationChange};
+use sc_network::{multiaddr, Event, ExHashT, NetworkService, PeerId, ReputationChange};
 use sp_runtime::{traits::Block as BlockT};
-use std::{borrow::Cow, pin::Pin, sync::Arc};
+use std::{borrow::Cow, iter, pin::Pin, sync::Arc};
 
 mod bridge;
 mod state_machine;
@@ -77,8 +82,14 @@ pub trait Network<B: BlockT> {
 	/// Adjust the reputation of a node.
 	fn report_peer(&self, peer_id: PeerId, reputation: ReputationChange);
 
+	/// Adds the peer to the set of peers to be connected to with this protocol.
+	fn add_set_reserved(&self, who: PeerId, protocol: Cow<'static, str>);
+
+	/// Removes the peer from the set of peers to be connected to with this protocol.
+	fn remove_set_reserved(&self, who: PeerId, protocol: Cow<'static, str>);
+
 	/// Force-disconnect a peer.
-	fn disconnect_peer(&self, who: PeerId);
+	fn disconnect_peer(&self, who: PeerId, protocol: Cow<'static, str>);
 
 	/// Send a notification to a peer.
 	fn write_notification(&self, who: PeerId, protocol: Cow<'static, str>, message: Vec<u8>);
@@ -99,8 +110,26 @@ impl<B: BlockT, H: ExHashT> Network<B> for Arc<NetworkService<B, H>> {
 		NetworkService::report_peer(self, peer_id, reputation);
 	}
 
-	fn disconnect_peer(&self, who: PeerId) {
-		NetworkService::disconnect_peer(self, who)
+	fn add_set_reserved(&self, who: PeerId, protocol: Cow<'static, str>) {
+		let addr = iter::once(multiaddr::Protocol::P2p(who.into()))
+			.collect::<multiaddr::Multiaddr>();
+		let result = NetworkService::add_to_peers_set(self, protocol, iter::once(addr).collect());
+		if let Err(err) = result {
+			log::error!(target: "gossip", "add_set_reserved failed: {}", err);
+		}
+	}
+
+	fn remove_set_reserved(&self, who: PeerId, protocol: Cow<'static, str>) {
+		let addr = iter::once(multiaddr::Protocol::P2p(who.into()))
+			.collect::<multiaddr::Multiaddr>();
+		let result = NetworkService::remove_from_peers_set(self, protocol, iter::once(addr).collect());
+		if let Err(err) = result {
+			log::error!(target: "gossip", "remove_set_reserved failed: {}", err);
+		}
+	}
+
+	fn disconnect_peer(&self, who: PeerId, protocol: Cow<'static, str>) {
+		NetworkService::disconnect_peer(self, who, protocol)
 	}
 
 	fn write_notification(&self, who: PeerId, protocol: Cow<'static, str>, message: Vec<u8>) {

substrate/client/network-gossip/src/state_machine.rs

@@ -495,10 +495,16 @@ mod tests {
 			self.inner.lock().unwrap().peer_reports.push((peer_id, reputation_change));
 		}
 
-		fn disconnect_peer(&self, _: PeerId) {
+		fn disconnect_peer(&self, _: PeerId, _: Cow<'static, str>) {
 			unimplemented!();
 		}
 
+		fn add_set_reserved(&self, _: PeerId, _: Cow<'static, str>) {
+		}
+
+		fn remove_set_reserved(&self, _: PeerId, _: Cow<'static, str>) {
+		}
+
 		fn write_notification(&self, _: PeerId, _: Cow<'static, str>, _: Vec<u8>) {
 			unimplemented!();
 		}