feat: rotate collator order each session

integration-tests/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "runtime-integration-tests"
-version = "1.0.5"
+version = "1.0.6"
 description = "Integration tests"
 authors = ["GalacticCouncil"]
 edition = "2021"

integration-tests/src/kusama_test_net.rs

@@ -307,6 +307,38 @@ pub mod basilisk {
 				get_account_id_from_seed::<sr25519::Public>("Bob"),
 				get_from_seed::<AuraId>("Bob"),
 			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Charlie"),
+				get_from_seed::<AuraId>("Charlie"),
+			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Collator4"),
+				get_from_seed::<AuraId>("Collator4"),
+			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Collator5"),
+				get_from_seed::<AuraId>("Collator5"),
+			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Collator6"),
+				get_from_seed::<AuraId>("Collator6"),
+			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Collator7"),
+				get_from_seed::<AuraId>("Collator7"),
+			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Collator8"),
+				get_from_seed::<AuraId>("Collator8"),
+			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Collator9"),
+				get_from_seed::<AuraId>("Collator9"),
+			),
+			(
+				get_account_id_from_seed::<sr25519::Public>("Collator10"),
+				get_from_seed::<AuraId>("Collator10"),
+			),
 		]
 	}
 

integration-tests/src/lib.rs

@@ -10,6 +10,7 @@ mod nft_marketplace;
 mod non_native_fee;
 mod oracle;
 mod router;
+mod sessions;
 mod transact_call_filter;
 mod vesting;
 mod xyk;

integration-tests/src/sessions.rs

@@ -0,0 +1,95 @@
+#![cfg(test)]
+use crate::kusama_test_net::*;
+use basilisk_runtime::CollatorRewards;
+use basilisk_runtime::Runtime;
+use frame_support::traits::Contains;
+use pallet_session::SessionManager;
+use polkadot_xcm::v3::prelude::*;
+use polkadot_xcm::VersionedXcm;
+use pretty_assertions::assert_eq;
+use xcm_emulator::TestExt;
+#[test]
+fn new_session_should_rotate_collators_list() {
+	TestNet::reset();
+
+	Basilisk::execute_with(|| {
+		let collator1 = basilisk::invulnerables()[0].0.clone(); //d435...
+		let collator2 = basilisk::invulnerables()[1].0.clone(); //8eaf...
+		let collator3 = basilisk::invulnerables()[2].0.clone(); //90b5...
+		let collator4 = basilisk::invulnerables()[3].0.clone(); //6ebe...
+		let collator5 = basilisk::invulnerables()[4].0.clone(); //ec5e...
+		let collator6 = basilisk::invulnerables()[5].0.clone(); //9c78...
+		let collator7 = basilisk::invulnerables()[6].0.clone(); //a678...
+		let collator8 = basilisk::invulnerables()[7].0.clone(); //2433...
+		let collator9 = basilisk::invulnerables()[8].0.clone(); //ee28...
+		let collator10 = basilisk::invulnerables()[9].0.clone(); //da53...
+
+		let collators = CollatorRewards::new_session(0).unwrap();
+		assert_eq!(
+			collators,
+			vec![
+				collator8.clone(),
+				collator4.clone(),
+				collator2.clone(),
+				collator3.clone(),
+				collator6.clone(),
+				collator7.clone(),
+				collator1.clone(),
+				collator10.clone(),
+				collator5.clone(),
+				collator9.clone()
+			]
+		);
+
+		let collators = CollatorRewards::new_session(1).unwrap();
+		assert_eq!(
+			collators,
+			vec![
+				collator4.clone(),
+				collator2.clone(),
+				collator3.clone(),
+				collator6.clone(),
+				collator7.clone(),
+				collator1.clone(),
+				collator10.clone(),
+				collator5.clone(),
+				collator9.clone(),
+				collator8.clone(),
+			]
+		);
+
+		let collators = CollatorRewards::new_session(2).unwrap();
+		assert_eq!(
+			collators,
+			vec![
+				collator2.clone(),
+				collator3.clone(),
+				collator6.clone(),
+				collator7.clone(),
+				collator1.clone(),
+				collator10.clone(),
+				collator5.clone(),
+				collator9.clone(),
+				collator8.clone(),
+				collator4.clone(),
+			]
+		);
+
+		let collators = CollatorRewards::new_session(3).unwrap();
+		assert_eq!(
+			collators,
+			vec![
+				collator3.clone(),
+				collator6.clone(),
+				collator7.clone(),
+				collator1.clone(),
+				collator10.clone(),
+				collator5.clone(),
+				collator9.clone(),
+				collator8.clone(),
+				collator4.clone(),
+				collator2.clone(),
+			]
+		);
+	});
+}

runtime/basilisk/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "basilisk-runtime"
-version = "122.0.0"
+version = "123.0.0"
 authors = ["GalacticCouncil"]
 edition = "2021"
 homepage = "https://github.com/galacticcouncil/Basilisk-node"

runtime/basilisk/src/lib.rs

@@ -101,7 +101,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("basilisk"),
 	impl_name: create_runtime_str!("basilisk"),
 	authoring_version: 1,
-	spec_version: 122,
+	spec_version: 123,
 	impl_version: 0,
 	apis: apis::RUNTIME_API_VERSIONS,
 	transaction_version: 1,

runtime/basilisk/src/system.rs

@@ -540,12 +540,34 @@ impl pallet_collator_rewards::Config for Runtime {
 	type RewardPerCollator = RewardPerCollator;
 	type RewardCurrencyId = NativeAssetId;
 	type ExcludedCollators = ExcludedCollators;
-	// We wrap the ` SessionManager` implementation of `CollatorSelection` to get the collatrs that
-	// we hand out rewards to.
-	type SessionManager = CollatorSelection;
+	type SessionManager = RotatingCollatorManager;
 	type MaxCandidates = MaxInvulnerables;
 }
 
+pub struct RotatingCollatorManager;
+impl SessionManager<AccountId> for RotatingCollatorManager {
+	fn new_session(new_index: SessionIndex) -> Option<Vec<AccountId>> {
+		// We wrap the ` SessionManager` implementation of `CollatorSelection` to get the collators that
+		// we hand out rewards to,
+		// then we rotate the collators to have a regular distribution for block production
+		let mut collators = CollatorSelection::new_session(new_index)?;
+
+		if let Some(rotation_amount) = (new_index as usize).checked_rem(collators.len()) {
+			collators.rotate_left(rotation_amount);
+		}
+
+		Some(collators)
+	}
+
+	fn end_session(end_index: SessionIndex) {
+		CollatorSelection::end_session(end_index)
+	}
+
+	fn start_session(start_index: SessionIndex) {
+		CollatorSelection::start_session(start_index)
+	}
+}
+
 parameter_types! {
 	pub const BasicDeposit: Balance = 5 * DOLLARS;
 	pub const ByteDeposit: Balance = DOLLARS / 10;
@@ -614,6 +636,8 @@ use frame_system::EnsureSigned;
 
 #[cfg(not(feature = "runtime-benchmarks"))]
 use frame_system::EnsureSignedBy;
+use pallet_session::SessionManager;
+use sp_staking::SessionIndex;
 
 impl pallet_state_trie_migration::Config for Runtime {
 	type ControlOrigin = EnsureRoot<Self::AccountId>;