Kusama coretime revenue integration (#384)

Based on #381 

CC @ggwpez

relay/kusama/Cargo.toml

@@ -317,7 +317,7 @@ metadata-hash = ["substrate-wasm-builder?/metadata-hash"]
 on-chain-release-build = ["sp-api/disable-logging", "metadata-hash"]
 
 # Set timing constants (e.g. session period) to faster versions to speed up testing.
-fast-runtime = []
+fast-runtime = ["kusama-runtime-constants/fast-runtime"]
 
 runtime-metrics = ["runtime-parachains/runtime-metrics", "sp-io/with-tracing"]
 

relay/kusama/constants/Cargo.toml

@@ -29,3 +29,4 @@ std = [
 	"sp-weights/std",
 	"xcm-builder/std",
 ]
+fast-runtime = []

relay/kusama/constants/src/lib.rs

@@ -126,7 +126,7 @@ pub mod system_parachain {
 		/// WARNING: This constant is used accross chains, so additional care should be taken
 		/// when changing it.
 		#[cfg(feature = "fast-runtime")]
-		pub const TIMESLICE_PERIOD: u32 = 10;
+		pub const TIMESLICE_PERIOD: u32 = 20;
 		#[cfg(not(feature = "fast-runtime"))]
 		pub const TIMESLICE_PERIOD: u32 = 80;
 	}

system-parachains/coretime/coretime-kusama/Cargo.toml

@@ -204,7 +204,7 @@ try-runtime = [
 	"sp-runtime/try-runtime",
 ]
 
-fast-runtime = []
+fast-runtime = ["kusama-runtime-constants/fast-runtime"]
 
 # Enable metadata hash generation at compile time for the `CheckMetadataHash` extension.
 metadata-hash = ["substrate-wasm-builder?/metadata-hash"]

system-parachains/coretime/coretime-kusama/src/coretime.rs

@@ -21,14 +21,18 @@ use cumulus_primitives_core::relay_chain;
 use frame_support::{
 	parameter_types,
 	traits::{
-		fungible::{Balanced, Credit},
-		OnUnbalanced,
+		fungible::{Balanced, Credit, Inspect},
+		tokens::{Fortitude, Preservation},
+		DefensiveResult, OnUnbalanced,
 	},
 };
+use frame_system::Pallet as System;
 use kusama_runtime_constants::system_parachain::coretime;
 use pallet_broker::{CoreAssignment, CoreIndex, CoretimeInterface, PartsOf57600, RCBlockNumberOf};
+use parachains_common::{AccountId, Balance};
 use sp_runtime::traits::AccountIdConversion;
 use xcm::latest::prelude::*;
+use xcm_executor::traits::TransactAsset;
 
 /// A type containing the encoding of the coretime pallet in the Relay chain runtime. Used to
 /// construct any remote calls. The codec index must correspond to the index of `Coretime` in the
@@ -65,13 +69,52 @@ parameter_types! {
 
 /// Burn revenue from coretime sales. See
 /// [RFC-010](https://polkadot-fellows.github.io/RFCs/approved/0010-burn-coretime-revenue.html).
-pub struct BurnRevenue;
-impl OnUnbalanced<Credit<AccountId, Balances>> for BurnRevenue {
-	fn on_nonzero_unbalanced(credit: Credit<AccountId, Balances>) {
-		let _ = <Balances as Balanced<_>>::resolve(&CoretimeBurnAccount::get(), credit);
+pub struct BurnCoretimeRevenue;
+impl OnUnbalanced<Credit<AccountId, Balances>> for BurnCoretimeRevenue {
+	fn on_nonzero_unbalanced(amount: Credit<AccountId, Balances>) {
+		let acc = CoretimeBurnAccount::get();
+		if !System::<Runtime>::account_exists(&acc) {
+			System::<Runtime>::inc_providers(&acc);
+		}
+		Balances::resolve(&acc, amount).defensive_ok();
 	}
 }
 
+type AssetTransactor = <xcm_config::XcmConfig as xcm_executor::Config>::AssetTransactor;
+
+fn burn_at_relay(stash: &AccountId, value: Balance) -> Result<(), XcmError> {
+	let dest = Location::parent();
+	let stash_location =
+		Junction::AccountId32 { network: None, id: stash.clone().into() }.into_location();
+	let asset = Asset { id: AssetId(Location::parent()), fun: Fungible(value) };
+	let dummy_xcm_context = XcmContext { origin: None, message_id: [0; 32], topic: None };
+
+	let withdrawn = AssetTransactor::withdraw_asset(&asset, &stash_location, None)?;
+
+	AssetTransactor::can_check_out(&dest, &asset, &dummy_xcm_context)?;
+
+	let parent_assets = Into::<Assets>::into(withdrawn)
+		.reanchored(&dest, &Here.into())
+		.defensive_map_err(|_| XcmError::ReanchorFailed)?;
+
+	PolkadotXcm::send_xcm(
+		Here,
+		Location::parent(),
+		Xcm(vec![
+			Instruction::UnpaidExecution {
+				weight_limit: WeightLimit::Unlimited,
+				check_origin: None,
+			},
+			ReceiveTeleportedAsset(parent_assets.clone()),
+			BurnAsset(parent_assets),
+		]),
+	)?;
+
+	AssetTransactor::check_out(&dest, &asset, &dummy_xcm_context);
+
+	Ok(())
+}
+
 parameter_types! {
 	/// The revenue from on-demand coretime sales. This is distributed amonst those who contributed
 	/// regions to the pool.
@@ -184,9 +227,27 @@ impl CoretimeInterface for CoretimeAllocator {
 		}
 	}
 
-	#[cfg(feature = "runtime-benchmarks")]
-	fn ensure_notify_revenue_info(when: RCBlockNumberOf<Self>, revenue: Self::Balance) {
-		CoretimeRevenue::set(&Some((when, revenue)));
+	fn on_new_timeslice(t: pallet_broker::Timeslice) {
+		// Burn roughly once per day. Unchecked math: RHS hardcoded as non-zero.
+		if t % 180 != 0 {
+			return
+		}
+
+		let stash = CoretimeBurnAccount::get();
+		let value =
+			Balances::reducible_balance(&stash, Preservation::Expendable, Fortitude::Polite);
+
+		if value > 0 {
+			log::debug!(target: "runtime::coretime", "Going to burn {value} stashed tokens at RC");
+			match burn_at_relay(&stash, value) {
+				Ok(()) => {
+					log::debug!(target: "runtime::coretime", "Succesfully burnt {value} tokens");
+				},
+				Err(err) => {
+					log::error!(target: "runtime::coretime", "burn_at_relay failed: {err:?}");
+				},
+			}
+		}
 	}
 }
 
@@ -197,7 +258,7 @@ parameter_types! {
 impl pallet_broker::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Currency = Balances;
-	type OnRevenue = BurnRevenue;
+	type OnRevenue = BurnCoretimeRevenue;
 	type TimeslicePeriod = ConstU32<{ coretime::TIMESLICE_PERIOD }>;
 	type MaxLeasedCores = ConstU32<50>;
 	type MaxReservedCores = ConstU32<10>;

system-parachains/coretime/coretime-kusama/src/lib.rs

@@ -115,6 +115,7 @@ pub type Migrations = (
 	cumulus_pallet_xcmp_queue::migration::v5::MigrateV4ToV5<Runtime>,
 	pallet_broker::migration::MigrateV0ToV1<Runtime>,
 	pallet_broker::migration::MigrateV1ToV2<Runtime>,
+	pallet_broker::migration::MigrateV2ToV3<Runtime>,
 );
 
 /// Executive: handles dispatch to the various modules.