Rpc for pending rewards (#11831)

* rpc pending rewards

* commit

* remove unused imports

* fix

* fix

* fmt

* fix

* fmt

* fix

* docs

* docs & formatting

* better formatting

* temporary fix

* error handling

* fix?

* fmt

* use to_string

* fmt

* fixed error handling

* fix

* rpc added to client

* Update Cargo.toml

* Update Cargo.toml

* fix wrong reward counter

* expose function

* move implementation

* docs

* docs

* docs

* Update lib.rs

* Update lib.rs

* unexpose functions

* unused dependency

* update Cargo.lock

* Update frame/nomination-pools/src/lib.rs

* Update lib.rs

* Update lib.rs

* Update frame/nomination-pools/rpc/runtime-api/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* remove rpc

* remove rpc directory

* final fix

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/Cargo.lock

@@ -4759,6 +4759,7 @@ dependencies = [
  "pallet-multisig",
  "pallet-nomination-pools",
  "pallet-nomination-pools-benchmarking",
+ "pallet-nomination-pools-runtime-api",
  "pallet-offences",
  "pallet-offences-benchmarking",
  "pallet-preimage",
@@ -5911,6 +5912,15 @@ dependencies = [
  "sp-std",
 ]
 
+[[package]]
+name = "pallet-nomination-pools-runtime-api"
+version = "1.0.0-dev"
+dependencies = [
+ "parity-scale-codec",
+ "sp-api",
+ "sp-std",
+]
+
 [[package]]
 name = "pallet-nomination-pools-test-staking"
 version = "1.0.0"

substrate/Cargo.toml

@@ -116,6 +116,7 @@ members = [
 	"frame/nomination-pools",
 	"frame/nomination-pools/benchmarking",
 	"frame/nomination-pools/test-staking",
+	"frame/nomination-pools/runtime-api",
 	"frame/randomness-collective-flip",
 	"frame/ranked-collective",
 	"frame/recovery",

substrate/bin/node/runtime/Cargo.toml

@@ -79,6 +79,7 @@ pallet-mmr = { version = "4.0.0-dev", default-features = false, path = "../../..
 pallet-multisig = { version = "4.0.0-dev", default-features = false, path = "../../../frame/multisig" }
 pallet-nomination-pools = { version = "1.0.0", default-features = false, path = "../../../frame/nomination-pools"}
 pallet-nomination-pools-benchmarking = { version = "1.0.0", default-features = false, optional = true, path = "../../../frame/nomination-pools/benchmarking" }
+pallet-nomination-pools-runtime-api = { version = "1.0.0-dev", default-features = false, path = "../../../frame/nomination-pools/runtime-api" }
 pallet-offences = { version = "4.0.0-dev", default-features = false, path = "../../../frame/offences" }
 pallet-offences-benchmarking = { version = "4.0.0-dev", path = "../../../frame/offences/benchmarking", default-features = false, optional = true }
 pallet-preimage = { version = "4.0.0-dev", default-features = false, path = "../../../frame/preimage" }
@@ -145,6 +146,7 @@ std = [
 	"pallet-mmr/std",
 	"pallet-multisig/std",
 	"pallet-nomination-pools/std",
+	"pallet-nomination-pools-runtime-api/std",
 	"pallet-identity/std",
 	"pallet-scheduler/std",
 	"node-primitives/std",

substrate/bin/node/runtime/src/lib.rs

@@ -1835,6 +1835,12 @@ impl_runtime_apis! {
 		}
 	}
 
+	impl pallet_nomination_pools_runtime_api::NominationPoolsApi<Block, AccountId, Balance> for Runtime {
+		fn pending_rewards(member_account: AccountId) -> Balance {
+			NominationPools::pending_rewards(member_account)
+		}
+	}
+
 	impl sp_consensus_babe::BabeApi<Block> for Runtime {
 		fn configuration() -> sp_consensus_babe::BabeGenesisConfiguration {
 			// The choice of `c` parameter (where `1 - c` represents the

substrate/frame/nomination-pools/runtime-api/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "pallet-nomination-pools-runtime-api"
+version = "1.0.0-dev"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2021"
+license = "Apache-2.0"
+homepage = "https://substrate.io"
+repository = "https://github.com/paritytech/substrate/"
+description = "Runtime API for nomination-pools FRAME pallet"
+readme = "README.md"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive"] }
+sp-api = { version = "4.0.0-dev", default-features = false, path = "../../../primitives/api" }
+sp-std = { version = "4.0.0-dev", default-features = false, path = "../../../primitives/std" }
+
+[features]
+default = ["std"]
+std = [
+	"codec/std",
+	"sp-api/std",
+	"sp-std/std",
+]

substrate/frame/nomination-pools/runtime-api/README.md

@@ -0,0 +1,3 @@
+Runtime API definition for nomination-pools pallet.
+
+License: Apache-2.0

substrate/frame/nomination-pools/runtime-api/src/lib.rs

@@ -0,0 +1,33 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2022 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Runtime API definition for nomination-pools pallet.
+//! Currently supports only one rpc endpoint.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use codec::Codec;
+
+sp_api::decl_runtime_apis! {
+	/// Runtime api for accessing information about nomination pools.
+	pub trait NominationPoolsApi<AccountId, Balance>
+		where AccountId: Codec, Balance: Codec
+	{
+		/// Returns the pending rewards for the member that the AccountId was given for.
+		fn pending_rewards(member: AccountId) -> Balance;
+	}
+}

substrate/frame/nomination-pools/src/lib.rs

@@ -939,7 +939,7 @@ pub struct RewardPool<T: Config> {
 
 impl<T: Config> RewardPool<T> {
 	/// Getter for [`RewardPool::last_recorded_reward_counter`].
-	fn last_recorded_reward_counter(&self) -> T::RewardCounter {
+	pub(crate) fn last_recorded_reward_counter(&self) -> T::RewardCounter {
 		self.last_recorded_reward_counter
 	}
 
@@ -2147,6 +2147,20 @@ pub mod pallet {
 }
 
 impl<T: Config> Pallet<T> {
+	/// Returns the pending rewards for the specified `member_account`.
+	///
+	/// In the case of error the function returns balance of zero.
+	pub fn pending_rewards(member_account: T::AccountId) -> BalanceOf<T> {
+		if let Some(pool_member) = PoolMembers::<T>::get(member_account) {
+			if let Some(reward_pool) = RewardPools::<T>::get(pool_member.pool_id) {
+				return pool_member
+					.pending_rewards(reward_pool.last_recorded_reward_counter())
+					.unwrap_or_default()
+			}
+		}
+		BalanceOf::<T>::default()
+	}
+
 	/// The amount of bond that MUST REMAIN IN BONDED in ALL POOLS.
 	///
 	/// It is the responsibility of the depositor to put these funds into the pool initially. Upon