contracts: Add RPC that allows instantiating of a contract (#8451)

* contracts: Add RPC that allows instantiating of a contract

* Encode `debug_message` as bytes because usage of `String` is forbidden

* Remove erroneous derive attribute

* Fix rpc tests for new `debug_message` encoding

* Fix typo

Co-authored-by: Andrew Jones <ascjones@gmail.com>

Co-authored-by: Andrew Jones <ascjones@gmail.com>

bin/node/rpc/src/lib.rs

@@ -115,7 +115,7 @@ pub fn create_full<C, P, SC, B>(
 	C: ProvideRuntimeApi<Block> + HeaderBackend<Block> + AuxStore +
 		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_contracts_rpc::ContractsRuntimeApi<Block, AccountId, Balance, BlockNumber, Hash>,
 	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>,

bin/node/runtime/src/lib.rs

@@ -1340,7 +1340,9 @@ impl_runtime_apis! {
 		}
 	}
 
-	impl pallet_contracts_rpc_runtime_api::ContractsApi<Block, AccountId, Balance, BlockNumber>
+	impl pallet_contracts_rpc_runtime_api::ContractsApi<
+		Block, AccountId, Balance, BlockNumber, Hash,
+	>
 		for Runtime
 	{
 		fn call(
@@ -1353,6 +1355,18 @@ impl_runtime_apis! {
 			Contracts::bare_call(origin, dest, value, gas_limit, input_data)
 		}
 
+		fn instantiate(
+			origin: AccountId,
+			endowment: Balance,
+			gas_limit: u64,
+			code: pallet_contracts_primitives::Code<Hash>,
+			data: Vec<u8>,
+			salt: Vec<u8>,
+		) -> pallet_contracts_primitives::ContractInstantiateResult<AccountId, BlockNumber>
+		{
+			Contracts::bare_instantiate(origin, endowment, gas_limit, code, data, salt, true)
+		}
+
 		fn get_storage(
 			address: AccountId,
 			key: [u8; 32],

frame/contracts/CHANGELOG.md

@@ -20,6 +20,8 @@ In other words: Upgrading this pallet will not break pre-existing contracts.
 
 ### Added
 
+- Add new `instantiate` RPC that allows clients to dry-run contract instantiation.
+
 - Make storage and fields of `Schedule` private to the crate.
 [1](https://github.com/paritytech/substrate/pull/8359)
 

frame/contracts/common/Cargo.toml

@@ -16,13 +16,17 @@ targets = ["x86_64-unknown-linux-gnu"]
 # This crate should not rely on any of the frame primitives.
 bitflags = "1.0"
 codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"] }
+sp-core = { version = "3.0.0", path = "../../../primitives/core", default-features = false }
 sp-std = { version = "3.0.0", default-features = false, path = "../../../primitives/std" }
 sp-runtime = { version = "3.0.0", default-features = false, path = "../../../primitives/runtime" }
+serde = { version = "1", features = ["derive"], optional = true }
 
 [features]
 default = ["std"]
 std = [
 	"codec/std",
+	"sp-core/std",
 	"sp-runtime/std",
 	"sp-std/std",
+	"serde",
 ]

frame/contracts/common/src/lib.rs

@@ -21,18 +21,45 @@
 
 use bitflags::bitflags;
 use codec::{Decode, Encode};
+use sp_core::Bytes;
 use sp_runtime::{DispatchError, RuntimeDebug};
 use sp_std::prelude::*;
 
-/// Result type of a `bare_call` call.
+#[cfg(feature = "std")]
+use serde::{Serialize, Deserialize};
+
+/// Result type of a `bare_call` or `bare_instantiate` call.
 ///
-/// The result of a contract execution along with a gas consumed.
+/// It contains the execution result together with some auxiliary information.
 #[derive(Eq, PartialEq, Encode, Decode, RuntimeDebug)]
-pub struct ContractExecResult {
-	pub exec_result: ExecResult,
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
+pub struct ContractResult<T> {
+	/// How much gas was consumed during execution.
 	pub gas_consumed: u64,
+	/// An optional debug message. This message is only non-empty when explicitly requested
+	/// by the code that calls into the contract.
+	///
+	/// The contained bytes are valid UTF-8. This is not declared as `String` because
+	/// this type is not allowed within the runtime. A client should decode them in order
+	/// to present the message to its users.
+	///
+	/// # Note
+	///
+	/// The debug message is never generated during on-chain execution. It is reserved for
+	/// RPC calls.
+	pub debug_message: Bytes,
+	/// The execution result of the wasm code.
+	pub result: T,
 }
 
+/// Result type of a `bare_call` call.
+pub type ContractExecResult = ContractResult<Result<ExecReturnValue, DispatchError>>;
+
+/// Result type of a `bare_instantiate` call.
+pub type ContractInstantiateResult<AccountId, BlockNumber> =
+	ContractResult<Result<InstantiateReturnValue<AccountId, BlockNumber>, DispatchError>>;
+
 /// Result type of a `get_storage` call.
 pub type GetStorageResult = Result<Option<Vec<u8>>, ContractAccessError>;
 
@@ -50,6 +77,8 @@ pub enum ContractAccessError {
 }
 
 #[derive(Eq, PartialEq, Encode, Decode, RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
 pub enum RentProjection<BlockNumber> {
 	/// Eviction is projected to happen at the specified block number.
 	EvictionAt(BlockNumber),
@@ -62,6 +91,8 @@ pub enum RentProjection<BlockNumber> {
 bitflags! {
 	/// Flags used by a contract to customize exit behaviour.
 	#[derive(Encode, Decode)]
+	#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+	#[cfg_attr(feature = "std", serde(rename_all = "camelCase", transparent))]
 	pub struct ReturnFlags: u32 {
 		/// If this bit is set all changes made by the contract execution are rolled back.
 		const REVERT = 0x0000_0001;
@@ -70,11 +101,13 @@ bitflags! {
 
 /// Output of a contract call or instantiation which ran to completion.
 #[derive(PartialEq, Eq, Encode, Decode, RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
 pub struct ExecReturnValue {
 	/// Flags passed along by `seal_return`. Empty when `seal_return` was never called.
 	pub flags: ReturnFlags,
 	/// Buffer passed along by `seal_return`. Empty when `seal_return` was never called.
-	pub data: Vec<u8>,
+	pub data: Bytes,
 }
 
 impl ExecReturnValue {
@@ -84,40 +117,32 @@ impl ExecReturnValue {
 	}
 }
 
-/// Origin of the error.
-///
-/// Call or instantiate both called into other contracts and pass through errors happening
-/// in those to the caller. This enum is for the caller to distinguish whether the error
-/// happened during the execution of the callee or in the current execution context.
+/// The result of a successful contract instantiation.
 #[derive(PartialEq, Eq, Encode, Decode, RuntimeDebug)]
-pub enum ErrorOrigin {
-	/// Caller error origin.
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
+pub struct InstantiateReturnValue<AccountId, BlockNumber> {
+	/// The output of the called constructor.
+	pub result: ExecReturnValue,
+	/// The account id of the new contract.
+	pub account_id: AccountId,
+	/// Information about when and if the new project will be evicted.
 	///
-	/// The error happened in the current exeuction context rather than in the one
-	/// of the contract that is called into.
-	Caller,
-	/// The error happened during execution of the called contract.
-	Callee,
-}
-
-/// Error returned by contract exection.
-#[derive(PartialEq, Eq, Encode, Decode, RuntimeDebug)]
-pub struct ExecError {
-	/// The reason why the execution failed.
-	pub error: DispatchError,
-	/// Origin of the error.
-	pub origin: ErrorOrigin,
+	/// # Note
+	///
+	/// `None` if `bare_instantiate` was called with
+	/// `compute_projection` set to false. From the perspective of an RPC this means that
+	/// the runtime API did not request this value and this feature is therefore unsupported.
+	pub rent_projection: Option<RentProjection<BlockNumber>>,
 }
 
-impl<T: Into<DispatchError>> From<T> for ExecError {
-	fn from(error: T) -> Self {
-		Self {
-			error: error.into(),
-			origin: ErrorOrigin::Caller,
-		}
-	}
+/// Reference to an existing code hash or a new wasm module.
+#[derive(Eq, PartialEq, Encode, Decode, RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
+pub enum Code<Hash> {
+	/// A wasm module as raw bytes.
+	Upload(Bytes),
+	/// The code hash of an on-chain wasm blob.
+	Existing(Hash),
 }
-
-/// The result that is returned from contract execution. It either contains the output
-/// buffer or an error describing the reason for failure.
-pub type ExecResult = Result<ExecReturnValue, ExecError>;

frame/contracts/rpc/runtime-api/src/lib.rs

@@ -25,18 +25,21 @@
 
 use codec::Codec;
 use sp_std::vec::Vec;
-use pallet_contracts_primitives::{ContractExecResult, GetStorageResult, RentProjectionResult};
+use pallet_contracts_primitives::{
+	ContractExecResult, GetStorageResult, RentProjectionResult, Code, ContractInstantiateResult,
+};
 
 sp_api::decl_runtime_apis! {
 	/// The API to interact with contracts without using executive.
-	pub trait ContractsApi<AccountId, Balance, BlockNumber> where
+	pub trait ContractsApi<AccountId, Balance, BlockNumber, Hash> where
 		AccountId: Codec,
 		Balance: Codec,
 		BlockNumber: Codec,
+		Hash: Codec,
 	{
 		/// Perform a call from a specified account to a given contract.
 		///
-		/// See the contracts' `call` dispatchable function for more details.
+		/// See [`pallet_contracts::Pallet::call`].
 		fn call(
 			origin: AccountId,
 			dest: AccountId,
@@ -45,6 +48,18 @@ sp_api::decl_runtime_apis! {
 			input_data: Vec<u8>,
 		) -> ContractExecResult;
 
+		/// Instantiate a new contract.
+		///
+		/// See [`pallet_contracts::Pallet::instantiate`].
+		fn instantiate(
+			origin: AccountId,
+			endowment: Balance,
+			gas_limit: u64,
+			code: Code<Hash>,
+			data: Vec<u8>,
+			salt: Vec<u8>,
+		) -> ContractInstantiateResult<AccountId, BlockNumber>;
+
 		/// Query a given storage key in a given contract.
 		///
 		/// Returns `Ok(Some(Vec<u8>))` if the storage value exists under the given key in the