feat(rpc): Add RPC call to query inflation and ROI

Cargo.toml

@@ -231,6 +231,8 @@ pallet-gear-rpc = { path = "pallets/gear/rpc" }
 pallet-gear-rpc-runtime-api = { path = "pallets/gear/rpc/runtime-api", default-features = false }
 pallet-gear-scheduler = { path = "pallets/gear-scheduler", default-features = false }
 pallet-gear-staking-rewards = { path = "pallets/staking-rewards", default-features = false }
+pallet-gear-staking-rewards-rpc = { path = "pallets/staking-rewards/rpc" }
+pallet-gear-staking-rewards-rpc-runtime-api = { path = "pallets/staking-rewards/rpc/runtime-api", default-features = false }
 pallet-gear-voucher = { path = "pallets/gear-voucher", default-features = false }
 pallet-gear-bank = { path = "pallets/gear-bank", default-features = false }
 runtime-common = { package = "gear-runtime-common", path = "runtime/common", default-features = false }

node/service/Cargo.toml

@@ -22,6 +22,8 @@ serde = { workspace = true, features = ["derive"] }
 # Gear
 pallet-gear-rpc.workspace = true
 pallet-gear-rpc-runtime-api = { workspace = true, features = ["std"] }
+pallet-gear-staking-rewards-rpc.workspace = true
+pallet-gear-staking-rewards-rpc-runtime-api = { workspace = true, features = ["std"] }
 runtime-primitives = { workspace = true, features = ["std"] }
 gear-runtime-interface = { workspace = true, features = ["std"] }
 authorship.workspace = true

node/service/src/client.rs

@@ -119,6 +119,7 @@ pub trait RuntimeApiCollection:
     + sp_offchain::OffchainWorkerApi<Block>
     + sp_session::SessionKeys<Block>
     + pallet_gear_rpc_runtime_api::GearApi<Block>
+    + pallet_gear_staking_rewards_rpc_runtime_api::GearStakingRewardsApi<Block>
 where
     <Self as sp_api::ApiExt<Block>>::StateBackend: sp_api::StateBackend<BlakeTwo256>,
 {
@@ -136,7 +137,8 @@ where
         + sp_api::Metadata<Block>
         + sp_offchain::OffchainWorkerApi<Block>
         + sp_session::SessionKeys<Block>
-        + pallet_gear_rpc_runtime_api::GearApi<Block>,
+        + pallet_gear_rpc_runtime_api::GearApi<Block>
+        + pallet_gear_staking_rewards_rpc_runtime_api::GearStakingRewardsApi<Block>,
     <Self as sp_api::ApiExt<Block>>::StateBackend: sp_api::StateBackend<BlakeTwo256>,
 {
 }

node/service/src/rpc/mod.rs

@@ -101,6 +101,7 @@ where
         + 'static,
     C::Api: substrate_frame_rpc_system::AccountNonceApi<Block, AccountId, Index>,
     C::Api: pallet_gear_rpc::GearRuntimeApi<Block>,
+    C::Api: pallet_gear_staking_rewards_rpc::GearStakingRewardsRuntimeApi<Block>,
     C::Api: pallet_transaction_payment_rpc::TransactionPaymentRuntimeApi<Block, Balance>,
     C::Api: BabeApi<Block>,
     C::Api: BlockBuilder<Block>,
@@ -110,6 +111,7 @@ where
     B::State: sc_client_api::backend::StateBackend<sp_runtime::traits::HashFor<Block>>,
 {
     use pallet_gear_rpc::{Gear, GearApiServer};
+    use pallet_gear_staking_rewards_rpc::{GearStakingRewards, GearStakingRewardsApiServer};
     use pallet_transaction_payment_rpc::{TransactionPayment, TransactionPaymentApiServer};
     use runtime_info::{RuntimeInfoApi, RuntimeInfoServer};
     use sc_consensus_babe_rpc::{Babe, BabeApiServer};
@@ -192,7 +194,9 @@ where
 
     io.merge(Gear::new(client.clone()).into_rpc())?;
 
-    io.merge(RuntimeInfoApi::<C, Block, B>::new(client).into_rpc())?;
+    io.merge(RuntimeInfoApi::<C, Block, B>::new(client.clone()).into_rpc())?;
+
+    io.merge(GearStakingRewards::new(client).into_rpc())?;
 
     Ok(io)
 }

pallets/staking-rewards/rpc/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "pallet-gear-staking-rewards-rpc"
+version = "1.0.0"
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+homepage = "https://gear-tech.io"
+repository = "https://github.com/gear-tech/gear"
+
+[dependencies]
+jsonrpsee = { workspace = true, features = ["server", "macros"] }
+
+# Substrate packages
+sp-api.workspace = true
+sp-blockchain.workspace = true
+sp-runtime.workspace = true
+
+# Local packages
+pallet-gear-staking-rewards-rpc-runtime-api.workspace = true

pallets/staking-rewards/rpc/runtime-api/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "pallet-gear-staking-rewards-rpc-runtime-api"
+version = "1.0.0"
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+homepage = "https://gear-tech.io"
+repository = "https://github.com/gear-tech/gear"
+
+[dependencies]
+sp-api.workspace = true
+pallet-gear-staking-rewards.workspace = true
+
+[features]
+default = ["std"]
+std = [
+    "sp-api/std",
+    "pallet-gear-staking-rewards/std",
+]

pallets/staking-rewards/rpc/runtime-api/src/lib.rs

@@ -0,0 +1,28 @@
+// This file is part of Gear.
+
+// Copyright (C) 2021-2023 Gear Technologies Inc.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub use pallet_gear_staking_rewards::InflationInfo;
+
+sp_api::decl_runtime_apis! {
+    pub trait GearStakingRewardsApi {
+        /// Calculate token economics related data.
+        fn inflation_info() -> InflationInfo;
+    }
+}

pallets/staking-rewards/rpc/src/lib.rs

@@ -0,0 +1,96 @@
+// This file is part of Gear.
+
+// Copyright (C) 2021-2023 Gear Technologies Inc.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! RPC interface for the gear module.
+
+use jsonrpsee::{
+    core::{Error as JsonRpseeError, RpcResult},
+    proc_macros::rpc,
+    types::error::{CallError, ErrorObject},
+};
+pub use pallet_gear_staking_rewards_rpc_runtime_api::GearStakingRewardsApi as GearStakingRewardsRuntimeApi;
+use pallet_gear_staking_rewards_rpc_runtime_api::InflationInfo;
+use sp_api::ProvideRuntimeApi;
+use sp_blockchain::HeaderBackend;
+use sp_runtime::traits::Block as BlockT;
+use std::sync::Arc;
+
+#[rpc(server)]
+pub trait GearStakingRewardsApi<BlockHash, ResponseType> {
+    #[method(name = "stakingRewards_inflationInfo")]
+    fn query_inflation_info(&self, at: Option<BlockHash>) -> RpcResult<ResponseType>;
+}
+
+/// Provides RPC methods to query token economics related data.
+pub struct GearStakingRewards<C, P> {
+    /// Shared reference to the client.
+    client: Arc<C>,
+    _marker: std::marker::PhantomData<P>,
+}
+
+impl<C, P> GearStakingRewards<C, P> {
+    /// Creates a new instance of the GearStakingRewards Rpc helper.
+    pub fn new(client: Arc<C>) -> Self {
+        Self {
+            client,
+            _marker: Default::default(),
+        }
+    }
+}
+
+/// Error type of this RPC api.
+pub enum Error {
+    /// The transaction was not decodable.
+    DecodeError,
+    /// The call to runtime failed.
+    RuntimeError,
+}
+
+impl From<Error> for i32 {
+    fn from(e: Error) -> i32 {
+        match e {
+            Error::RuntimeError => 1,
+            Error::DecodeError => 2,
+        }
+    }
+}
+
+impl<C, Block> GearStakingRewardsApiServer<<Block as BlockT>::Hash, InflationInfo>
+    for GearStakingRewards<C, Block>
+where
+    Block: BlockT,
+    C: 'static + ProvideRuntimeApi<Block> + HeaderBackend<Block>,
+    C::Api: GearStakingRewardsRuntimeApi<Block>,
+{
+    fn query_inflation_info(&self, at: Option<Block::Hash>) -> RpcResult<InflationInfo> {
+        let api = self.client.runtime_api();
+        let at_hash = at.unwrap_or_else(|| self.client.info().best_hash);
+
+        fn map_err(err: impl std::fmt::Debug, desc: &'static str) -> JsonRpseeError {
+            CallError::Custom(ErrorObject::owned(
+                Error::RuntimeError.into(),
+                desc,
+                Some(format!("{err:?}")),
+            ))
+            .into()
+        }
+
+        api.inflation_info(at_hash)
+            .map_err(|e| map_err(e, "Unable to query inflation info"))
+    }
+}

pallets/staking-rewards/src/lib.rs

@@ -59,6 +59,8 @@ use frame_support::{
     PalletId,
 };
 use pallet_staking::EraPayout;
+use parity_scale_codec::{Decode, Encode};
+pub use scale_info::TypeInfo;
 use sp_runtime::{
     traits::{AccountIdConversion, Saturating, StaticLookup},
     PerThing, Perquintill,
@@ -79,6 +81,16 @@ pub type NegativeImbalanceOf<T> = <<T as pallet_staking::Config>::Currency as Cu
 >>::NegativeImbalance;
 type AccountIdLookupOf<T> = <<T as frame_system::Config>::Lookup as StaticLookup>::Source;
 
+/// Token economics related details.
+#[derive(Clone, Decode, Encode, Eq, PartialEq, TypeInfo)]
+#[cfg_attr(feature = "std", derive(Debug, serde::Deserialize, serde::Serialize))]
+pub struct InflationInfo {
+    /// Inflation
+    pub inflation: Perquintill,
+    /// ROI
+    pub roi: Perquintill,
+}
+
 #[frame_support::pallet]
 pub mod pallet {
     use super::*;
@@ -333,11 +345,39 @@ pub mod pallet {
                 .saturating_sub(T::Currency::minimum_balance())
         }
 
+        /// Return the current total stakeable tokens amount.
+        ///
+        /// This value is not calculated but rather updated manually in line with tokenomics model.
         pub fn total_stakeable_tokens() -> BalanceOf<T> {
             // Should never be 0 but in theory could
             (Self::non_stakeable_share().left_from_one() * T::Currency::total_issuance())
                 .saturating_sub(Self::pool())
         }
+
+        /// Calculate actual infaltion and ROI parameters.
+        pub fn inflation_info() -> InflationInfo {
+            let total_staked = pallet_staking::Pallet::<T>::eras_total_stake(
+                pallet_staking::Pallet::<T>::current_era().unwrap_or(0),
+            );
+            let total_issuance = T::Currency::total_issuance();
+
+            let (payout, _) = inflation::compute_total_payout(
+                total_staked,
+                Self::total_stakeable_tokens(),
+                total_issuance,
+                Self::ideal_staking_ratio(),
+                T::MinInflation::get(),
+                Self::target_inflation(),
+                T::Falloff::get(),
+                T::MaxROI::get(),
+                Perquintill::one(),
+            );
+
+            let inflation = Perquintill::from_rational(payout, total_issuance);
+            let roi = Perquintill::from_rational(payout, total_staked);
+
+            InflationInfo { inflation, roi }
+        }
     }
 }
 

runtime/gear/Cargo.toml

@@ -70,6 +70,8 @@ pallet-gear-payment.workspace = true
 pallet-gear-voucher.workspace = true
 pallet-gear-rpc-runtime-api.workspace = true
 runtime-primitives.workspace = true
+pallet-gear-staking-rewards.workspace = true
+pallet-gear-staking-rewards-rpc-runtime-api.workspace = true
 
 [build-dependencies]
 substrate-build-script-utils.workspace = true
@@ -126,6 +128,8 @@ std = [
 	"sp-transaction-pool/std",
 	"sp-version/std",
 	"substrate-wasm-builder",
+	"pallet-gear-staking-rewards-rpc-runtime-api/std",
+	"pallet-gear-staking-rewards/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking/runtime-benchmarks",

runtime/gear/src/lib.rs

@@ -806,4 +806,10 @@ impl_runtime_apis_plus_common! {
             Executive::try_execute_block(block, state_root_check, signature_check, select).unwrap()
         }
     }
+
+    impl pallet_gear_staking_rewards_rpc_runtime_api::GearStakingRewardsApi<Block> for Runtime {
+        fn inflation_info() -> pallet_gear_staking_rewards::InflationInfo {
+            unimplemented!();
+        }
+    }
 }

runtime/vara/Cargo.toml

@@ -97,6 +97,7 @@ pallet-gear-payment.workspace = true
 pallet-gear-staking-rewards.workspace = true
 pallet-gear-voucher.workspace = true
 pallet-gear-rpc-runtime-api.workspace = true
+pallet-gear-staking-rewards-rpc-runtime-api.workspace = true
 runtime-primitives.workspace = true
 
 [dev-dependencies]
@@ -143,6 +144,7 @@ std = [
 	"pallet-gear-program/std",
 	"pallet-gear-staking-rewards/std",
 	"pallet-gear-rpc-runtime-api/std",
+	"pallet-gear-staking-rewards-rpc-runtime-api/std",
 	"pallet-grandpa/std",
 	"pallet-identity/std",
 	"pallet-im-online/std",