refactor: Billing refactor (#992)

* Refactor billing logic for smart contracts to improve payment tracking, overdraft handling, and fund reservations.

* Redesign off-chain worker logic to enhance billing effectiveness and prevent failures.

* Improve management of contract payments, focusing on overdue payments and grace periods.

*Enhance logging and error management to reduce the risk of unstable contract states.

* Introduce new events for better visibility into billing processes.

* Adjust utilization revenue distribution.

* Address bugs to improve billing reliability.

* Update benchmarks and weights for all pallets, and adjust relevant tests.

---------

clients/tfchain-client-go/contract_events.go

@@ -242,3 +242,33 @@ type NodeExtraFeeSet struct {
 	ExtraFee types.U64 `json:"extra_fee"`
 	Topics   []types.Hash
 }
+
+type RentWaived struct {
+	Phase      types.Phase
+	ContractID types.U64 `json:"contract_id"`
+	Topics     []types.Hash
+}
+
+type ContractGracePeriodElapsed struct {
+	Phase       types.Phase
+	ContractID  types.U64 `json:"contract_id"`
+	GracePeriod types.U64 `json:"grace_period"`
+	Topics      []types.Hash
+}
+
+type ContractPaymentOverdrawn struct {
+	Phase                 types.Phase
+	ContractID            types.U64  `json:"contract_id"`
+	Timestamp             types.U64  `json:"timestamp"`
+	PartiallyBilledAmount types.U128 `json:"partially_billed_amount"`
+	Overdraft             types.U128 `json:"overdraft"`
+	Topics                []types.Hash
+}
+
+type RewardDistributed struct {
+	Phase             types.Phase
+	ContractID        types.U64  `json:"contract_id"`
+	StandardRewards   types.U128 `json:"standard_rewards"`
+	AdditionalRewards types.U128 `json:"additional_rewards"`
+	Topics            []types.Hash
+}

clients/tfchain-client-go/events.go

@@ -389,6 +389,10 @@ type EventRecords struct {
 	SmartContractModule_ServiceContractBilled        []ServiceContractBilled        //nolint:stylecheck,golint
 	SmartContractModule_BillingFrequencyChanged      []BillingFrequencyChanged      //nolint:stylecheck,golint
 	SmartContractModule_NodeExtraFeeSet              []NodeExtraFeeSet              //nolint:stylecheck,golint
+	SmartContractModule_RentWaived                   []RentWaived                   //nolint:stylecheck,golint
+	SmartContractModule_ContractGracePeriodElapsed   []ContractGracePeriodElapsed   //nolint:stylecheck,golint
+	SmartContractModule_ContractPaymentOverdrawn     []ContractPaymentOverdrawn     //nolint:stylecheck,golint
+	SmartContractModule_RewardDistributed            []RewardDistributed            //nolint:stylecheck,golint
 
 	// farm events
 	TfgridModule_FarmStored  []FarmStored  //nolint:stylecheck,golint

clients/tfchain-client-go/utils.go

@@ -127,6 +127,8 @@ var smartContractModuleErrors = []string{
 	"WrongAuthority",
 	"UnauthorizedToChangeSolutionProviderId",
 	"UnauthorizedToSetExtraFee",
+	"RewardDistributionError",
+	"ContractPaymentStateNotExists",
 }
 
 // https://github.com/threefoldtech/tfchain/blob/development/substrate-node/pallets/pallet-tfgrid/src/lib.rs#L442

docs/architecture/0023-billing-refactor.md

@@ -0,0 +1,48 @@
+# 23. Billing Refactor in pallet-smart-contract Module
+
+Date: 2024-08-18
+
+## Status
+
+Accepted
+
+## Context
+
+The billing logic within the pallet-smart-contract module faced several issues, including critical bugs, inefficiencies in handling validators, and inadequate fund reservation mechanisms.
+The goal of this refactor was to address these issues while enhancing the overall reliability and robustness of the billing process.
+
+## Decision
+
+The following architectural decisions were made to improve the billing logic:
+
+### Refactoring Billing Logic
+
+- Enhanced Tracking:
+Improved tracking mechanisms were introduced for contract payments, especially during grace periods and when handling overdue payments.
+The new ContractPaymentState was introduced to accurately manage contract payment states and resolve liquidity issues.
+- Overdraft Handling:
+Partial payments are now allowed, where users can cover part of their billing due if they lack sufficient funds for the full amount. Overdraft are tracked separately.
+- Fund Reservation:
+The use of balance locks/freezes was replaced with a more reliable reservation system, reducing issues related to fund availability for reward distribution.
+
+### Improved Off-Chain Worker Logic
+
+- Runtime Verification:
+The is_next_block_author function was removed, with verification now occurring at runtime.
+This change ensures transaction fees are reliably waived for validators and still prevents duplicate transactions.
+
+### New Events Introduced
+
+- ContractGracePeriodElapsed: Indicates that a contract's grace period has elapsed.
+- ContractPaymentOverdrawn: Indicates that a contract's payment is overdrawn.
+- RewardDistributed: Indicates that rewards have been distributed.
+
+### Certified vs DIY Capacity
+
+The system now correctly charges certified capacity at a higher rate (25% more) than DIY capacity.
+
+## Consequences
+
+- Increased Robustness: The billing process is now more robust and less prone to errors, particularly in scenarios involving partial payments and fund reservations.
+- Better Visibility: The introduction of new events and improved logging provides better visibility into the billing and payment processes, aiding in debugging and monitoring.
+- Backward Compatibility: While significant refactoring has been done, efforts were made to ensure backward compatibility where possible, especially concerning contract migration.

substrate-node/node/src/benchmarking.rs

@@ -11,7 +11,7 @@ use sp_core::{Encode, Pair};
 use sp_inherents::{InherentData, InherentDataProvider};
 use sp_keyring::Sr25519Keyring;
 use sp_runtime::{OpaqueExtrinsic, SaturatedConversion};
-use tfchain_runtime as runtime;
+use tfchain_runtime::{self as runtime, pallet_smart_contract};
 
 use std::{sync::Arc, time::Duration};
 
@@ -132,6 +132,7 @@ pub fn create_benchmark_extrinsic(
         frame_system::CheckNonce::<runtime::Runtime>::from(nonce),
         frame_system::CheckWeight::<runtime::Runtime>::new(),
         pallet_transaction_payment::ChargeTransactionPayment::<runtime::Runtime>::from(0),
+        pallet_smart_contract::types::ContractIdProvides::<runtime::Runtime>::new(),
     );
 
     let raw_payload = runtime::SignedPayload::from_raw(
@@ -146,6 +147,7 @@ pub fn create_benchmark_extrinsic(
             (),
             (),
             (),
+            (),
         ),
     );
     let signature = raw_payload.using_encoded(|e| sender.sign(e));

substrate-node/pallets/pallet-burning/src/weights.rs

@@ -2,9 +2,9 @@
 //! Autogenerated weights for pallet_burning
 //!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
-//! DATE: 2024-06-04, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! DATE: 2024-08-27, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! WORST CASE MAP SIZE: `1000000`
-//! HOSTNAME: `4b80713dc969`, CPU: `AMD Ryzen 7 5800X 8-Core Processor`
+//! HOSTNAME: `66e77d0da08f`, CPU: `AMD Ryzen 7 5800X 8-Core Processor`
 //! EXECUTION: , WASM-EXECUTION: Compiled, CHAIN: Some("dev"), DB CACHE: 1024
 
 // Executed Command:
@@ -45,8 +45,8 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `109`
 		//  Estimated: `1594`
-		// Minimum execution time: 26_841_000 picoseconds.
-		Weight::from_parts(27_372_000, 1594)
+		// Minimum execution time: 26_780_000 picoseconds.
+		Weight::from_parts(27_291_000, 1594)
 			.saturating_add(T::DbWeight::get().reads(1_u64))
 			.saturating_add(T::DbWeight::get().writes(1_u64))
 	}
@@ -60,8 +60,8 @@ impl WeightInfo for () {
 		// Proof Size summary in bytes:
 		//  Measured:  `109`
 		//  Estimated: `1594`
-		// Minimum execution time: 26_841_000 picoseconds.
-		Weight::from_parts(27_372_000, 1594)
+		// Minimum execution time: 26_780_000 picoseconds.
+		Weight::from_parts(27_291_000, 1594)
 			.saturating_add(RocksDbWeight::get().reads(1_u64))
 			.saturating_add(RocksDbWeight::get().writes(1_u64))
 	}

substrate-node/pallets/pallet-dao/src/weights.rs

@@ -2,9 +2,9 @@
 //! Autogenerated weights for pallet_dao
 //!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
-//! DATE: 2024-06-04, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! DATE: 2024-08-27, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! WORST CASE MAP SIZE: `1000000`
-//! HOSTNAME: `4b80713dc969`, CPU: `AMD Ryzen 7 5800X 8-Core Processor`
+//! HOSTNAME: `66e77d0da08f`, CPU: `AMD Ryzen 7 5800X 8-Core Processor`
 //! EXECUTION: , WASM-EXECUTION: Compiled, CHAIN: Some("dev"), DB CACHE: 1024
 
 // Executed Command:
@@ -58,8 +58,8 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `208`
 		//  Estimated: `4687`
-		// Minimum execution time: 19_196_000 picoseconds.
-		Weight::from_parts(19_487_000, 4687)
+		// Minimum execution time: 19_277_000 picoseconds.
+		Weight::from_parts(20_188_000, 4687)
 			.saturating_add(T::DbWeight::get().reads(4_u64))
 			.saturating_add(T::DbWeight::get().writes(5_u64))
 	}
@@ -77,8 +77,8 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `979`
 		//  Estimated: `4444`
-		// Minimum execution time: 26_179_000 picoseconds.
-		Weight::from_parts(26_751_000, 4444)
+		// Minimum execution time: 26_390_000 picoseconds.
+		Weight::from_parts(26_840_000, 4444)
 			.saturating_add(T::DbWeight::get().reads(5_u64))
 			.saturating_add(T::DbWeight::get().writes(1_u64))
 	}
@@ -92,8 +92,8 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `487`
 		//  Estimated: `4687`
-		// Minimum execution time: 18_154_000 picoseconds.
-		Weight::from_parts(18_755_000, 4687)
+		// Minimum execution time: 18_616_000 picoseconds.
+		Weight::from_parts(18_985_000, 4687)
 			.saturating_add(T::DbWeight::get().reads(3_u64))
 			.saturating_add(T::DbWeight::get().writes(1_u64))
 	}
@@ -111,8 +111,8 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `521`
 		//  Estimated: `4687`
-		// Minimum execution time: 24_757_000 picoseconds.
-		Weight::from_parts(25_268_000, 4687)
+		// Minimum execution time: 25_117_000 picoseconds.
+		Weight::from_parts(25_498_000, 4687)
 			.saturating_add(T::DbWeight::get().reads(3_u64))
 			.saturating_add(T::DbWeight::get().writes(4_u64))
 	}
@@ -136,8 +136,8 @@ impl WeightInfo for () {
 		// Proof Size summary in bytes:
 		//  Measured:  `208`
 		//  Estimated: `4687`
-		// Minimum execution time: 19_196_000 picoseconds.
-		Weight::from_parts(19_487_000, 4687)
+		// Minimum execution time: 19_277_000 picoseconds.
+		Weight::from_parts(20_188_000, 4687)
 			.saturating_add(RocksDbWeight::get().reads(4_u64))
 			.saturating_add(RocksDbWeight::get().writes(5_u64))
 	}
@@ -155,8 +155,8 @@ impl WeightInfo for () {
 		// Proof Size summary in bytes:
 		//  Measured:  `979`
 		//  Estimated: `4444`
-		// Minimum execution time: 26_179_000 picoseconds.
-		Weight::from_parts(26_751_000, 4444)
+		// Minimum execution time: 26_390_000 picoseconds.
+		Weight::from_parts(26_840_000, 4444)
 			.saturating_add(RocksDbWeight::get().reads(5_u64))
 			.saturating_add(RocksDbWeight::get().writes(1_u64))
 	}
@@ -170,8 +170,8 @@ impl WeightInfo for () {
 		// Proof Size summary in bytes:
 		//  Measured:  `487`
 		//  Estimated: `4687`
-		// Minimum execution time: 18_154_000 picoseconds.
-		Weight::from_parts(18_755_000, 4687)
+		// Minimum execution time: 18_616_000 picoseconds.
+		Weight::from_parts(18_985_000, 4687)
 			.saturating_add(RocksDbWeight::get().reads(3_u64))
 			.saturating_add(RocksDbWeight::get().writes(1_u64))
 	}
@@ -189,8 +189,8 @@ impl WeightInfo for () {
 		// Proof Size summary in bytes:
 		//  Measured:  `521`
 		//  Estimated: `4687`
-		// Minimum execution time: 24_757_000 picoseconds.
-		Weight::from_parts(25_268_000, 4687)
+		// Minimum execution time: 25_117_000 picoseconds.
+		Weight::from_parts(25_498_000, 4687)
 			.saturating_add(RocksDbWeight::get().reads(3_u64))
 			.saturating_add(RocksDbWeight::get().writes(4_u64))
 	}

substrate-node/pallets/pallet-kvstore/src/weights.rs

@@ -2,9 +2,9 @@
 //! Autogenerated weights for pallet_kvstore
 //!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
-//! DATE: 2024-06-04, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! DATE: 2024-08-27, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! WORST CASE MAP SIZE: `1000000`
-//! HOSTNAME: `4b80713dc969`, CPU: `AMD Ryzen 7 5800X 8-Core Processor`
+//! HOSTNAME: `66e77d0da08f`, CPU: `AMD Ryzen 7 5800X 8-Core Processor`
 //! EXECUTION: , WASM-EXECUTION: Compiled, CHAIN: Some("dev"), DB CACHE: 1024
 
 // Executed Command:
@@ -46,8 +46,8 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `0`
 		//  Estimated: `0`
-		// Minimum execution time: 7_293_000 picoseconds.
-		Weight::from_parts(7_574_000, 0)
+		// Minimum execution time: 11_372_000 picoseconds.
+		Weight::from_parts(12_032_000, 0)
 			.saturating_add(T::DbWeight::get().writes(1_u64))
 	}
 	/// Storage: `TFKVStore::TFKVStore` (r:1 w:1)
@@ -56,8 +56,8 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 		// Proof Size summary in bytes:
 		//  Measured:  `146`
 		//  Estimated: `3611`
-		// Minimum execution time: 12_784_000 picoseconds.
-		Weight::from_parts(13_205_000, 3611)
+		// Minimum execution time: 12_414_000 picoseconds.
+		Weight::from_parts(12_854_000, 3611)
 			.saturating_add(T::DbWeight::get().reads(1_u64))
 			.saturating_add(T::DbWeight::get().writes(1_u64))
 	}
@@ -71,8 +71,8 @@ impl WeightInfo for () {
 		// Proof Size summary in bytes:
 		//  Measured:  `0`
 		//  Estimated: `0`
-		// Minimum execution time: 7_293_000 picoseconds.
-		Weight::from_parts(7_574_000, 0)
+		// Minimum execution time: 11_372_000 picoseconds.
+		Weight::from_parts(12_032_000, 0)
 			.saturating_add(RocksDbWeight::get().writes(1_u64))
 	}
 	/// Storage: `TFKVStore::TFKVStore` (r:1 w:1)
@@ -81,8 +81,8 @@ impl WeightInfo for () {
 		// Proof Size summary in bytes:
 		//  Measured:  `146`
 		//  Estimated: `3611`
-		// Minimum execution time: 12_784_000 picoseconds.
-		Weight::from_parts(13_205_000, 3611)
+		// Minimum execution time: 12_414_000 picoseconds.
+		Weight::from_parts(12_854_000, 3611)
 			.saturating_add(RocksDbWeight::get().reads(1_u64))
 			.saturating_add(RocksDbWeight::get().writes(1_u64))
 	}

substrate-node/pallets/pallet-smart-contract/src/benchmarking.rs

@@ -305,11 +305,11 @@ benchmarks! {
 
         let contract = SmartContractModule::<T>::contracts(contract_id).unwrap();
         // Get contract cost before billing to take into account nu
-        let (cost, discount_level) = contract.calculate_contract_cost_tft(balance_init_amount, elapsed_seconds).unwrap();
+        let (cost, discount_level) = contract.calculate_contract_cost_tft(balance_init_amount, elapsed_seconds, None).unwrap();
     }: _(RawOrigin::Signed(farmer), contract_id)
     verify {
-        let lock = SmartContractModule::<T>::contract_number_of_cylces_billed(contract_id);
-        assert_eq!(lock.amount_locked, cost);
+        let contract_payment_state = SmartContractModule::<T>::contract_payment_state(contract_id).unwrap();
+        assert_eq!(contract_payment_state.standard_reserve, cost);
         let contract_bill = types::ContractBill {
             contract_id,
             timestamp: SmartContractModule::<T>::get_current_timestamp_in_secs(),