L1-297: Add inflation api (#1831)

aleph-client/src/aleph_zero.rs

@@ -1173,6 +1173,42 @@ pub mod api {
                         ],
                     )
                 }
+                #[doc = " Returns inflation from now to now + 1 year. Capped at 100%"]
+                pub fn yearly_inflation(
+                    &self,
+                ) -> ::subxt::runtime_api::Payload<
+                    types::YearlyInflation,
+                    runtime_types::sp_arithmetic::per_things::Perbill,
+                > {
+                    ::subxt::runtime_api::Payload::new_static(
+                        "AlephSessionApi",
+                        "yearly_inflation",
+                        types::YearlyInflation {},
+                        [
+                            139u8, 25u8, 143u8, 190u8, 127u8, 191u8, 235u8, 69u8, 16u8, 116u8,
+                            112u8, 112u8, 54u8, 191u8, 49u8, 113u8, 139u8, 52u8, 66u8, 37u8, 43u8,
+                            81u8, 15u8, 144u8, 77u8, 17u8, 224u8, 107u8, 178u8, 227u8, 171u8, 52u8,
+                        ],
+                    )
+                }
+                #[doc = " Returns payout. First tuple item is a validators payout, 2nd is the rest."]
+                pub fn current_era_payout(
+                    &self,
+                ) -> ::subxt::runtime_api::Payload<
+                    types::CurrentEraPayout,
+                    (::core::primitive::u128, ::core::primitive::u128),
+                > {
+                    ::subxt::runtime_api::Payload::new_static(
+                        "AlephSessionApi",
+                        "current_era_payout",
+                        types::CurrentEraPayout {},
+                        [
+                            55u8, 146u8, 5u8, 196u8, 176u8, 34u8, 184u8, 92u8, 198u8, 150u8, 212u8,
+                            142u8, 203u8, 99u8, 146u8, 45u8, 21u8, 125u8, 209u8, 88u8, 98u8, 5u8,
+                            10u8, 63u8, 48u8, 176u8, 68u8, 234u8, 115u8, 19u8, 64u8, 10u8,
+                        ],
+                    )
+                }
             }
             pub mod types {
                 use super::runtime_types;
@@ -1334,6 +1370,34 @@ pub mod api {
                 pub struct KeyOwner {
                     pub key: runtime_types::primitives::app::Public,
                 }
+                #[derive(
+                    :: subxt :: ext :: codec :: Decode,
+                    :: subxt :: ext :: codec :: Encode,
+                    :: subxt :: ext :: scale_decode :: DecodeAsType,
+                    :: subxt :: ext :: scale_encode :: EncodeAsType,
+                    Clone,
+                    Debug,
+                    Eq,
+                    PartialEq,
+                )]
+                # [codec (crate = :: subxt :: ext :: codec)]
+                #[decode_as_type(crate_path = ":: subxt :: ext :: scale_decode")]
+                #[encode_as_type(crate_path = ":: subxt :: ext :: scale_encode")]
+                pub struct YearlyInflation {}
+                #[derive(
+                    :: subxt :: ext :: codec :: Decode,
+                    :: subxt :: ext :: codec :: Encode,
+                    :: subxt :: ext :: scale_decode :: DecodeAsType,
+                    :: subxt :: ext :: scale_encode :: EncodeAsType,
+                    Clone,
+                    Debug,
+                    Eq,
+                    PartialEq,
+                )]
+                # [codec (crate = :: subxt :: ext :: codec)]
+                #[decode_as_type(crate_path = ":: subxt :: ext :: scale_decode")]
+                #[encode_as_type(crate_path = ":: subxt :: ext :: scale_encode")]
+                pub struct CurrentEraPayout {}
             }
         }
         pub mod nomination_pools_api {

bin/fake-runtime-api/src/lib.rs

@@ -9,7 +9,7 @@ use pallet_transaction_payment::FeeDetails;
 use pallet_transaction_payment_rpc_runtime_api::RuntimeDispatchInfo;
 use primitives::{
     AccountId, ApiError as AlephApiError, AuraId, AuthorityId as AlephId, Balance, Block, Nonce,
-    SessionAuthorityData, SessionCommittee, SessionIndex, SessionValidatorError,
+    Perbill, SessionAuthorityData, SessionCommittee, SessionIndex, SessionValidatorError,
     Version as FinalityVersion,
 };
 use sp_consensus_aura::SlotDuration;
@@ -187,6 +187,14 @@ pub mod fake_runtime {
             fn key_owner(_key: AlephId) -> Option<AccountId> {
                 unimplemented!()
             }
+
+            fn yearly_inflation() -> Perbill {
+                unimplemented!()
+            }
+
+            fn current_era_payout() -> (Balance, Balance) {
+                unimplemented!()
+            }
         }
 
         /// There’s an important remark on how this fake runtime must be implemented - it does not need to

bin/runtime/src/lib.rs

@@ -452,6 +452,23 @@ parameter_types! {
 
 pub struct ExponentialEraPayout;
 
+impl ExponentialEraPayout {
+    fn era_payout(total_issuance: Balance, era_duration_millis: u64) -> (Balance, Balance) {
+        const VALIDATOR_REWARD: Perbill = Perbill::from_percent(90);
+
+        let azero_cap = pallet_aleph::AzeroCap::<Runtime>::get();
+        let horizon = pallet_aleph::ExponentialInflationHorizon::<Runtime>::get();
+
+        let total_payout: Balance =
+            exp_helper(Perbill::from_rational(era_duration_millis, horizon))
+                * (azero_cap.saturating_sub(total_issuance));
+        let validators_payout = VALIDATOR_REWARD * total_payout;
+        let rest = total_payout - validators_payout;
+
+        (validators_payout, rest)
+    }
+}
+
 /// Calculates 1 - exp(-x) for small positive x
 fn exp_helper(x: Perbill) -> Perbill {
     let x2 = x * x;
@@ -467,18 +484,7 @@ impl pallet_staking::EraPayout<Balance> for ExponentialEraPayout {
         total_issuance: Balance,
         era_duration_millis: u64,
     ) -> (Balance, Balance) {
-        const VALIDATOR_REWARD: Perbill = Perbill::from_percent(90);
-
-        let azero_cap = pallet_aleph::AzeroCap::<Runtime>::get();
-        let horizon = pallet_aleph::ExponentialInflationHorizon::<Runtime>::get();
-
-        let total_payout: Balance =
-            exp_helper(Perbill::from_rational(era_duration_millis, horizon))
-                * (azero_cap.saturating_sub(total_issuance));
-        let validators_payout = VALIDATOR_REWARD * total_payout;
-        let rest = total_payout - validators_payout;
-
-        (validators_payout, rest)
+        ExponentialEraPayout::era_payout(total_issuance, era_duration_millis)
     }
 }
 
@@ -1214,6 +1220,24 @@ impl_runtime_apis! {
         fn key_owner(key: AlephId) -> Option<AccountId> {
             Session::key_owner(primitives::KEY_TYPE, key.as_ref())
         }
+
+        fn yearly_inflation() -> Perbill {
+            // Milliseconds per year for the Julian year (365.25 days).
+            const MILLISECONDS_PER_YEAR: u64 = 1000 * 3600 * 24 * 36525 / 100;
+            let total_issuance = pallet_balances::Pallet::<Runtime>::total_issuance();
+
+            let (validator_payout, rest)
+                = ExponentialEraPayout::era_payout(total_issuance, MILLISECONDS_PER_YEAR);
+
+            Perbill::from_rational(validator_payout + rest, total_issuance)
+        }
+
+        fn current_era_payout() -> (Balance, Balance) {
+            const MILLISECONDS_PER_ERA: u64 = MILLISECS_PER_BLOCK * (DEFAULT_SESSION_PERIOD * DEFAULT_SESSIONS_PER_ERA) as u64;
+            let total_issuance = pallet_balances::Pallet::<Runtime>::total_issuance();
+
+            ExponentialEraPayout::era_payout(total_issuance, MILLISECONDS_PER_ERA)
+        }
     }
 
     impl pallet_nomination_pools_runtime_api::NominationPoolsApi<Block, AccountId, Balance> for Runtime {
@@ -1371,7 +1395,6 @@ impl_runtime_apis! {
 #[cfg(test)]
 mod tests {
     use frame_support::traits::Get;
-    use pallet_staking::EraPayout;
     use primitives::HEAP_PAGES;
     use smallvec::Array;
 
@@ -1600,8 +1623,6 @@ mod tests {
         assert!(lhs < rhs);
     }
 
-    /// `EraPayout::era_payout` ignores the first argument, we set it to zero.
-    const DUMMY_TOTAL_STAKED: Balance = 0;
     const MILLISECS_PER_DAY: u64 = 24 * 60 * 60 * 1000;
 
     struct EraPayoutInputs {
@@ -1623,7 +1644,6 @@ mod tests {
             pallet_aleph::ExponentialInflationHorizon::<Runtime>::put(inputs.horizon);
             let (validators_payout, rest) =
                 <Runtime as pallet_staking::Config>::EraPayout::era_payout(
-                    DUMMY_TOTAL_STAKED,
                     inputs.total_issuance,
                     inputs.era_duration_millis,
                 );
@@ -1645,7 +1665,6 @@ mod tests {
                 pallet_aleph::ExponentialInflationHorizon::<Runtime>::put(inputs.horizon);
                 let (validators_payout, rest) =
                     <Runtime as pallet_staking::Config>::EraPayout::era_payout(
-                        DUMMY_TOTAL_STAKED,
                         total_issuance,
                         inputs.era_duration_millis,
                     );

pallets/aleph-runtime-api/src/lib.rs

@@ -2,8 +2,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use primitives::{
-    AccountId, ApiError, AuthorityId, SessionAuthorityData, SessionCommittee, SessionIndex,
-    SessionValidatorError, Version,
+    AccountId, ApiError, AuthorityId, Balance, Perbill, SessionAuthorityData, SessionCommittee,
+    SessionIndex, SessionValidatorError, Version,
 };
 pub use sp_consensus_aura::sr25519::AuthorityId as AuraId;
 use sp_std::vec::Vec;
@@ -33,5 +33,9 @@ sp_api::decl_runtime_apis! {
         /// also as `aleph_key` - consensus engine's part of session keys) in the current session
         /// of AlephBFT (finalisation committee).
         fn key_owner(key: AuthorityId) -> Option<AccountId>;
+        /// Returns inflation from now to now + 1 year. Capped at 100%
+        fn yearly_inflation() -> Perbill;
+        /// Returns payout. First tuple item is a validators payout, 2nd is the rest.
+        fn current_era_payout() -> (Balance, Balance);
     }
 }