Custom RPC for Merkle Mountain Range pallet (#8137)

* Add MMR custom RPC.

* Change RuntimeApi to avoid hardcoding leaf type.

* Properly implement the new RuntimeAPI and wire up RPC.

* Extract Offchain DB as separate execution extension.

* Enable offchain DB access for offchain calls.

* Fix offchain_election tests.

* Skip block initialisation for proof generation.

* Fix integration test setup.

* Fix offchain tests. Not sure how I missed them earlier 🤷.

* Fix long line.

* One more test missing.

* Update mock for multi-phase.

* Address review grumbbles.

* Address review grumbles.

* Fix line width of a comment

substrate/bin/node/cli/src/service.rs

@@ -219,7 +219,7 @@ pub fn new_full_base(
 
 	if config.offchain_worker.enabled {
 		sc_service::build_offchain_workers(
-			&config, backend.clone(), task_manager.spawn_handle(), client.clone(), network.clone(),
+			&config, task_manager.spawn_handle(), client.clone(), network.clone(),
 		);
 	}
 
@@ -430,7 +430,7 @@ pub fn new_light_base(mut config: Configuration) -> Result<(
 
 	if config.offchain_worker.enabled {
 		sc_service::build_offchain_workers(
-			&config, backend.clone(), task_manager.spawn_handle(), client.clone(), network.clone(),
+			&config, task_manager.spawn_handle(), client.clone(), network.clone(),
 		);
 	}
 

substrate/bin/node/rpc/Cargo.toml

@@ -15,6 +15,7 @@ jsonrpc-core = "15.1.0"
 node-primitives = { version = "2.0.0", path = "../primitives" }
 node-runtime = { version = "2.0.0", path = "../runtime" }
 pallet-contracts-rpc = { version = "3.0.0", path = "../../../frame/contracts/rpc/" }
+pallet-mmr-rpc = { version = "3.0.0", path = "../../../frame/merkle-mountain-range/rpc/" }
 pallet-transaction-payment-rpc = { version = "3.0.0", path = "../../../frame/transaction-payment/rpc/" }
 sc-client-api = { version = "3.0.0", path = "../../../client/api" }
 sc-consensus-babe = { version = "0.9.0", path = "../../../client/consensus/babe" }

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

@@ -116,6 +116,7 @@ pub fn create_full<C, P, SC, B>(
 		HeaderMetadata<Block, Error=BlockChainError> + Sync + Send + 'static,
 	C::Api: substrate_frame_rpc_system::AccountNonceApi<Block, AccountId, Index>,
 	C::Api: pallet_contracts_rpc::ContractsRuntimeApi<Block, AccountId, Balance, BlockNumber>,
+	C::Api: pallet_mmr_rpc::MmrRuntimeApi<Block, <Block as sp_runtime::traits::Block>::Hash>,
 	C::Api: pallet_transaction_payment_rpc::TransactionPaymentRuntimeApi<Block, Balance>,
 	C::Api: BabeApi<Block>,
 	C::Api: BlockBuilder<Block>,
@@ -126,6 +127,7 @@ pub fn create_full<C, P, SC, B>(
 {
 	use substrate_frame_rpc_system::{FullSystem, SystemApi};
 	use pallet_contracts_rpc::{Contracts, ContractsApi};
+	use pallet_mmr_rpc::{MmrApi, Mmr};
 	use pallet_transaction_payment_rpc::{TransactionPayment, TransactionPaymentApi};
 
 	let mut io = jsonrpc_core::IoHandler::default();
@@ -161,6 +163,9 @@ pub fn create_full<C, P, SC, B>(
 	io.extend_with(
 		ContractsApi::to_delegate(Contracts::new(client.clone()))
 	);
+	io.extend_with(
+		MmrApi::to_delegate(Mmr::new(client.clone()))
+	);
 	io.extend_with(
 		TransactionPaymentApi::to_delegate(TransactionPayment::new(client.clone()))
 	);

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

@@ -1377,23 +1377,31 @@ impl_runtime_apis! {
 
 	impl pallet_mmr::primitives::MmrApi<
 		Block,
-		mmr::Leaf,
 		mmr::Hash,
 	> for Runtime {
-		fn generate_proof(leaf_index: u64) -> Result<(mmr::Leaf, mmr::Proof<mmr::Hash>), mmr::Error> {
+		fn generate_proof(leaf_index: u64)
+			-> Result<(mmr::EncodableOpaqueLeaf, mmr::Proof<mmr::Hash>), mmr::Error>
+		{
 			Mmr::generate_proof(leaf_index)
+				.map(|(leaf, proof)| (mmr::EncodableOpaqueLeaf::from_leaf(&leaf), proof))
 		}
 
-		fn verify_proof(leaf: mmr::Leaf, proof: mmr::Proof<mmr::Hash>) -> Result<(), mmr::Error> {
+		fn verify_proof(leaf: mmr::EncodableOpaqueLeaf, proof: mmr::Proof<mmr::Hash>)
+			-> Result<(), mmr::Error>
+		{
+			let leaf: mmr::Leaf = leaf
+				.into_opaque_leaf()
+				.try_decode()
+				.ok_or(mmr::Error::Verify)?;
 			Mmr::verify_leaf(leaf, proof)
 		}
 
 		fn verify_proof_stateless(
 			root: mmr::Hash,
-			leaf: Vec<u8>,
+			leaf: mmr::EncodableOpaqueLeaf,
 			proof: mmr::Proof<mmr::Hash>
 		) -> Result<(), mmr::Error> {
-			let node = mmr::DataOrHash::Data(mmr::OpaqueLeaf(leaf));
+			let node = mmr::DataOrHash::Data(leaf.into_opaque_leaf());
 			pallet_mmr::verify_leaf_proof::<mmr::Hashing, _>(root, node, proof)
 		}
 	}

substrate/bin/node/testing/src/bench.rs

@@ -417,13 +417,14 @@ impl BenchDb {
 		};
 		let task_executor = TaskExecutor::new();
 
-		let (client, backend) = sc_service::new_client(
-			db_config,
+		let backend = sc_service::new_db_backend(db_config).expect("Should not fail");
+		let client = sc_service::new_client(
+			backend.clone(),
 			NativeExecutor::new(WasmExecutionMethod::Compiled, None, 8),
 			&keyring.generate_genesis(),
 			None,
 			None,
-			ExecutionExtensions::new(profile.into_execution_strategies(), None),
+			ExecutionExtensions::new(profile.into_execution_strategies(), None, None),
 			Box::new(task_executor.clone()),
 			None,
 			Default::default(),