diff --git a/substrate/frame/staking-rewards/src/lib.rs b/substrate/frame/staking-rewards/src/lib.rs
index cffa6411b017bd1a075632166d91643d99e4c03b..4b282bc0205921dc98ec10d5e64c90a4d9b34d05 100644
--- a/substrate/frame/staking-rewards/src/lib.rs
+++ b/substrate/frame/staking-rewards/src/lib.rs
@@ -30,9 +30,16 @@
//! a new Freeze). Once staked, the staker begins accumulating the right to claim the 'reward asset'
//! each block, proportional to their share of the total staked tokens in the pool.
//!
-//! Reward assets pending distribution are held in an account derived from the Pallet's ID.
-//! This pool should be adequately funded to ensure there are enough funds to make good on staker
-//! claims.
+//! Reward assets pending distribution are held in an account derived from the pallet ID and a
+//! unique pool ID.
+//!
+//! Care should be taken to keep pool accounts adequately funded with the reward asset.
+//!
+//! ## Permissioning
+//!
+//! Currently, pool creation and management is permissioned and restricted to a configured Origin.
+//!
+//! Future iterations of this pallet may allow permissionless creation and management of pools.
//!
//! ## Implementation Notes
//!
@@ -61,10 +68,7 @@ use sp_core::Get;
use sp_runtime::{DispatchError, Saturating};
use sp_std::boxed::Box;
-/// Unique identifier for a staking pool. (staking_asset, reward_asset).
-pub type PoolId<AssetId> = (AssetId, AssetId);
-
-/// Information on a user currently staking in a pool.
+/// A pool staker.
#[derive(Decode, Encode, MaxEncodedLen, TypeInfo)]
pub struct PoolStakerInfo<Balance> {
amount: Balance,
@@ -72,19 +76,32 @@ pub struct PoolStakerInfo<Balance> {
reward_debt: Balance,
}
-/// Staking pool.
-#[derive(Decode, Encode, MaxEncodedLen, TypeInfo)]
-pub struct PoolInfo<Balance, BlockNumber> {
+/// A staking pool.
+// #[derive(Decode, Encode, MaxEncodedLen, TypeInfo)]
+#[derive(Decode, Encode, Default, PartialEq, Eq, MaxEncodedLen, TypeInfo)]
+pub struct PoolInfo<AssetId, Balance, BlockNumber> {
+ /// The asset that is staked in this pool.
+ staking_asset_id: AssetId,
+ /// The asset that is distributed as rewards in this pool.
+ reward_asset_id: AssetId,
+ /// The amount of tokens distributed per block.
reward_rate_per_block: Balance,
+ /// The total amount of tokens staked in this pool.
total_tokens_staked: Balance,
+ /// Total accumulated rewards per share. Used when calculating payouts.
accumulated_rewards_per_share: Balance,
+ /// Last block number the pool was updated. Used when calculating payouts.
last_rewarded_block: BlockNumber,
}
#[frame_support::pallet(dev_mode)]
pub mod pallet {
use super::*;
- use frame_support::pallet_prelude::*;
+ use codec::{EncodeLike, FullCodec};
+ use frame_support::{
+ pallet_prelude::*,
+ traits::{tokens::AssetId, Incrementable},
+ };
use frame_system::pallet_prelude::*;
use sp_runtime::traits::AccountIdConversion;
@@ -101,24 +118,38 @@ pub mod pallet {
type PalletId: Get<PalletId>;
/// Identifier for each type of asset.
- type AssetId: Member + Parameter + Clone + MaybeSerializeDeserialize + MaxEncodedLen;
+ type AssetId: AssetId + Member + Parameter;
/// The type in which the assets are measured.
type Balance: Balance + TypeInfo;
+ /// The origin with permission to create and manage pools.
+ type PoolAdminOrigin: EnsureOrigin<Self::RuntimeOrigin>;
+
/// Registry of assets that can be configured to either stake for rewards, or be offered as
/// rewards for staking.
type Assets: Inspect<Self::AccountId, AssetId = Self::AssetId, Balance = Self::Balance>
+ Mutate<Self::AccountId>
+ Balanced<Self::AccountId>;
+
+ /// The type of the unique id for each pool.
+ type PoolId: PartialOrd
+ + Incrementable
+ + From<u32>
+ + FullCodec
+ + Clone
+ + Eq
+ + PartialEq
+ + sp_std::fmt::Debug
+ + scale_info::TypeInfo;
}
- /// State of stakers in each pool.
+ /// State of pool stakers.
#[pallet::storage]
pub type PoolStakers<T: Config> = StorageDoubleMap<
_,
Blake2_128Concat,
- PoolId<T::AssetId>,
+ T::PoolId,
Blake2_128Concat,
T::AccountId,
PoolStakerInfo<T::Balance>,
@@ -129,65 +160,73 @@ pub mod pallet {
pub type Pools<T: Config> = StorageMap<
_,
Blake2_128Concat,
- PoolId<T::AssetId>,
- PoolInfo<T::Balance, BlockNumberFor<T>>,
+ T::PoolId,
+ PoolInfo<T::AssetId, T::Balance, BlockNumberFor<T>>,
>;
+ /// Stores the [`PoolId`] to use for the next pool.
+ ///
+ /// Incremented when a new pool is created.
+ #[pallet::storage]
+ pub type NextPoolId<T: Config> = StorageValue<_, T::PoolId>;
+
#[pallet::event]
#[pallet::generate_deposit(pub(super) fn deposit_event)]
pub enum Event<T: Config> {
/// An account staked some tokens in a pool.
Staked {
- /// The account.
- who: T::AccountId,
+ /// The account that staked assets.
+ staker: T::AccountId,
/// The pool.
- pool_id: PoolId<T::AssetId>,
- /// The amount.
+ pool_id: T::PoolId,
+ /// The staked asset amount.
amount: T::Balance,
},
/// An account unstaked some tokens from a pool.
Unstaked {
- /// The account.
- who: T::AccountId,
+ /// The account that unstaked assets.
+ staker: T::AccountId,
/// The pool.
- pool_id: PoolId<T::AssetId>,
- /// The amount.
+ pool_id: T::PoolId,
+ /// The unstaked asset amount.
amount: T::Balance,
},
/// An account harvested some rewards.
RewardsHarvested {
- /// The account.
- who: T::AccountId,
+ /// The staker whos rewards were harvested.
+ staker: T::AccountId,
/// The pool.
- pool_id: PoolId<T::AssetId>,
- /// The rewarded tokens.
+ pool_id: T::PoolId,
+ /// The amount of harvested tokens.
amount: T::Balance,
},
/// A new reward pool was created.
PoolCreated {
- /// The pool.
- pool_id: PoolId<T::AssetId>,
+ /// Unique ID for the new pool.
+ pool_id: T::PoolId,
+ /// The staking asset.
+ staking_asset_id: T::AssetId,
+ /// The reward asset.
+ reward_asset_id: T::AssetId,
/// The initial reward rate per block.
reward_rate_per_block: T::Balance,
},
/// A reward pool was deleted.
PoolDeleted {
- /// The pool.
- pool_id: PoolId<T::AssetId>,
+ /// The deleted pool id.
+ pool_id: T::PoolId,
},
- /// A pool reward rate was been changed.
- PoolRewardRateChanged {
- /// The pool with the changed reward rate.
- pool_id: PoolId<T::AssetId>,
- /// The new reward rate of the reward rate per block distributed to stakers.
- reward_rate_per_block: T::Balance,
+ /// A pool was modified.
+ PoolModifed {
+ /// The modified pool.
+ pool_id: T::PoolId,
+ /// The new reward rate.
+ new_reward_rate_per_block: T::Balance,
},
- /// Funds were withdrawn from the Reward Pool.
+ /// Reward assets were withdrawn from a pool.
RewardPoolWithdrawal {
- /// The asset withdrawn.
- reward_asset_id: T::AssetId,
- /// The caller.
- caller: T::AccountId,
+ /// The affected pool.
+ pool_id: T::PoolId,
/// The acount of reward asset withdrawn.
amount: T::Balance,
},
@@ -195,8 +234,8 @@ pub mod pallet {
#[pallet::error]
pub enum Error<T> {
- /// TODO
- TODO,
+ /// An operation was attempted on a non-existent pool.
+ NonExistentPool,
}
#[pallet::hooks]
@@ -220,20 +259,15 @@ pub mod pallet {
/// Removes an existing reward pool.
///
- /// TODO decide how to manage clean up of stakers from a removed pool
- pub fn remove_pool(
- _origin: OriginFor<T>,
- _staked_asset_id: Box<T::AssetId>,
- _reward_asset_id: Box<T::AssetId>,
- ) -> DispatchResult {
+ /// TODO decide how to manage clean up of stakers from a removed pool.
+ pub fn remove_pool(_origin: OriginFor<T>, _pool_id: T::PoolId) -> DispatchResult {
todo!()
}
/// Stake tokens in a pool.
pub fn stake(
_origin: OriginFor<T>,
- _staked_asset_id: Box<T::AssetId>,
- _reward_asset_id: Box<T::AssetId>,
+ _pool_id: T::PoolId,
_amount: T::Balance,
) -> DispatchResult {
todo!()
@@ -242,18 +276,17 @@ pub mod pallet {
/// Unstake tokens from a pool.
pub fn unstake(
_origin: OriginFor<T>,
- _staked_asset_id: Box<T::AssetId>,
- _reward_asset_id: Box<T::AssetId>,
+ _pool_id: T::PoolId,
_amount: T::Balance,
) -> DispatchResult {
todo!()
}
- /// Harvest unclaimed pool rewards.
+ /// Harvest unclaimed pool rewards for a staker.
pub fn harvest_rewards(
_origin: OriginFor<T>,
- _staked_asset_id: Box<T::AssetId>,
- _reward_asset_id: Box<T::AssetId>,
+ _staker: T::AccountId,
+ _pool_id: T::PoolId,
) -> DispatchResult {
todo!()
}
@@ -261,17 +294,34 @@ pub mod pallet {
/// Modify the reward rate of a pool.
pub fn modify_pool(
_origin: OriginFor<T>,
- _staked_asset_id: Box<T::AssetId>,
- _reward_asset_id: Box<T::AssetId>,
+ _pool_id: T::PoolId,
+ _new_reward_rate: T::Balance,
+ ) -> DispatchResult {
+ todo!()
+ }
+
+ /// Convinience method to deposit reward tokens into a pool.
+ ///
+ /// This method is not strictly necessary (tokens could be transferred directly to the
+ /// pool pot address), but is provided for convenience so manual derivation of the
+ /// account id is not required.
+ pub fn deposit_reward_tokens(
+ _origin: OriginFor<T>,
+ _pool_id: T::PoolId,
+ _amount: T::Balance,
) -> DispatchResult {
todo!()
}
}
impl<T: Config> Pallet<T> {
- /// The account ID of the reward pot.
- fn reward_pool_account_id() -> T::AccountId {
- T::PalletId::get().into_account_truncating()
+ /// Derive a pool account ID from the pallet's ID.
+ fn pool_account_id(id: &T::PoolId) -> Result<T::AccountId, DispatchError> {
+ if Pools::<T>::contains_key(id) {
+ Ok(T::PalletId::get().into_sub_account_truncating(id))
+ } else {
+ Err(Error::<T>::NonExistentPool.into())
+ }
}
/// Update pool state in preparation for reward harvesting.