Make ValidationPool accepts execution mode to run custom command or in process validation

node/core/candidate-validation/src/lib.rs

@@ -35,8 +35,10 @@ use polkadot_primitives::v1::{
 	ValidationCode, PoV, CandidateDescriptor, ValidationData, PersistedValidationData,
 	TransientValidationData, OccupiedCoreAssumption, Hash,
 };
-use polkadot_parachain::wasm_executor::{self, ValidationPool, ExecutionMode, ValidationError,
-	InvalidCandidate as WasmInvalidCandidate};
+use polkadot_parachain::wasm_executor::{
+	self, ValidationPool, ExecutionMode, ValidationError,
+	InvalidCandidate as WasmInvalidCandidate, ValidationExecutionMode,
+};
 use polkadot_parachain::primitives::{ValidationResult as WasmValidationResult, ValidationParams};
 
 use parity_scale_codec::Encode;
@@ -128,7 +130,7 @@ async fn run(
 )
 	-> SubsystemResult<()>
 {
-	let pool = ValidationPool::new();
+	let pool = ValidationPool::new(ValidationExecutionMode::ExternalProcessSelfHost);
 
 	loop {
 		match ctx.recv().await? {

parachain/src/wasm_executor/mod.rs

@@ -28,7 +28,7 @@ use sp_externalities::Extensions;
 use sp_wasm_interface::HostFunctions as _;
 
 #[cfg(not(any(target_os = "android", target_os = "unknown")))]
-pub use validation_host::{run_worker, ValidationPool, EXECUTION_TIMEOUT_SEC};
+pub use validation_host::{run_worker, ValidationPool, EXECUTION_TIMEOUT_SEC, ValidationExecutionMode};
 
 mod validation_host;
 
@@ -66,8 +66,6 @@ pub enum ExecutionMode<'a> {
 	Local,
 	/// Remote execution in a spawned process.
 	Remote(&'a ValidationPool),
-	/// Remote execution in a spawned test runner.
-	RemoteTest(&'a ValidationPool),
 }
 
 #[derive(Debug, derive_more::Display, derive_more::From)]
@@ -143,11 +141,7 @@ pub fn validate_candidate(
 		},
 		#[cfg(not(any(target_os = "android", target_os = "unknown")))]
 		ExecutionMode::Remote(pool) => {
-			pool.validate_candidate(validation_code, params, false)
-		},
-		#[cfg(not(any(target_os = "android", target_os = "unknown")))]
-		ExecutionMode::RemoteTest(pool) => {
-			pool.validate_candidate(validation_code, params, true)
+			pool.validate_candidate(validation_code, params)
 		},
 		#[cfg(any(target_os = "android", target_os = "unknown"))]
 		ExecutionMode::Remote(_pool) =>
@@ -156,13 +150,6 @@ pub fn validate_candidate(
 					"Remote validator not available".to_string()
 				) as Box<_>
 			))),
-		#[cfg(any(target_os = "android", target_os = "unknown"))]
-		ExecutionMode::RemoteTest(_pool) =>
-			Err(ValidationError::Internal(InternalError::System(
-				Box::<dyn std::error::Error + Send + Sync>::from(
-					"Remote validator not available".to_string()
-				) as Box<_>
-			))),
 	}
 }
 

parachain/src/wasm_executor/validation_host.rs

@@ -16,7 +16,7 @@
 
 #![cfg(not(any(target_os = "android", target_os = "unknown")))]
 
-use std::{process, env, sync::Arc, sync::atomic};
+use std::{process, env, sync::Arc, sync::atomic, path::PathBuf};
 use codec::{Decode, Encode};
 use crate::primitives::{ValidationParams, ValidationResult};
 use super::{
@@ -29,7 +29,6 @@ use log::{debug, trace};
 use futures::executor::ThreadPool;
 use sp_core::traits::SpawnNamed;
 
-const WORKER_ARGS_TEST: &[&'static str] = &["--nocapture", "validation_worker"];
 /// CLI Argument to start in validation worker mode.
 const WORKER_ARG: &'static str = "validation-worker";
 const WORKER_ARGS: &[&'static str] = &[WORKER_ARG];
@@ -66,19 +65,40 @@ impl SpawnNamed for TaskExecutor {
 	}
 }
 
+/// The execution mode for the `ValidationPool`.
+#[derive(Debug, Clone)]
+pub enum ValidationExecutionMode {
+	/// The validation worker is ran in a thread inside the same process.
+	InProcess,
+	/// The validation worker is ran using the process' executable and the subcommand `validation-worker` is passed
+	/// following by the address of the shared memory.
+	ExternalProcessSelfHost,
+	/// The validation worker is ran using the command provided and the argument provided. The address of the shared
+	/// memory is added at the end of the arguments.
+	ExternalProcessCustomHost {
+		/// Path to the validation worker. The file must exists and be executable.
+		binary: PathBuf,
+		/// List of arguments passed to the validation worker. The address of the shared memory will be automatically
+		/// added after the arguments.
+		args: Vec<String>,
+	},
+}
+
 /// A pool of hosts.
 #[derive(Clone)]
 pub struct ValidationPool {
 	hosts: Arc<Vec<Mutex<ValidationHost>>>,
+	execution_mode: ValidationExecutionMode,
 }
 
 const DEFAULT_NUM_HOSTS: usize = 8;
 
 impl ValidationPool {
 	/// Creates a validation pool with the default configuration.
-	pub fn new() -> ValidationPool {
+	pub fn new(execution_mode: ValidationExecutionMode) -> ValidationPool {
 		ValidationPool {
 			hosts: Arc::new((0..DEFAULT_NUM_HOSTS).map(|_| Default::default()).collect()),
+			execution_mode,
 		}
 	}
 
@@ -90,16 +110,15 @@ impl ValidationPool {
 		&self,
 		validation_code: &[u8],
 		params: ValidationParams,
-		test_mode: bool,
 	) -> Result<ValidationResult, ValidationError> {
 		for host in self.hosts.iter() {
 			if let Some(mut host) = host.try_lock() {
-				return host.validate_candidate(validation_code, params, test_mode);
+				return host.validate_candidate(validation_code, params, self.execution_mode.clone());
 			}
 		}
 
 		// all workers are busy, just wait for the first one
-		self.hosts[0].lock().validate_candidate(validation_code, params, test_mode)
+		self.hosts[0].lock().validate_candidate(validation_code, params, self.execution_mode.clone())
 	}
 }
 
@@ -208,6 +227,7 @@ unsafe impl Send for ValidationHost {}
 #[derive(Default)]
 struct ValidationHost {
 	worker: Option<process::Child>,
+	worker_thread: Option<std::thread::JoinHandle<Result<(), String>>>,
 	memory: Option<SharedMem>,
 	id: u32,
 }
@@ -233,25 +253,46 @@ impl ValidationHost {
 		Ok(mem_config.create()?)
 	}
 
-	fn start_worker(&mut self, test_mode: bool) -> Result<(), InternalError> {
+	fn start_worker(&mut self, execution_mode: ValidationExecutionMode) -> Result<(), InternalError> {
 		if let Some(ref mut worker) = self.worker {
 			// Check if still alive
 			if let Ok(None) = worker.try_wait() {
 				// Still running
 				return Ok(());
 			}
 		}
+		if self.worker_thread.is_some() {
+			return Ok(());
+		}
+
 		let memory = Self::create_memory()?;
-		let self_path = env::current_exe()?;
-		debug!("Starting worker at {:?}", self_path);
-		let mut args = if test_mode { WORKER_ARGS_TEST.to_vec() } else { WORKER_ARGS.to_vec() };
-		args.push(memory.get_os_path());
-		let worker = process::Command::new(self_path)
-			.args(args)
-			.stdin(process::Stdio::piped())
-			.spawn()?;
-		self.id = worker.id();
-		self.worker = Some(worker);
+
+		let mut run_worker_process = |cmd: PathBuf, args: Vec<String>| -> Result<(), std::io::Error> {
+			debug!("Starting worker at {:?} with arguments: {:?} and {:?}", cmd, args, memory.get_os_path());
+			let worker = process::Command::new(cmd)
+				.args(args)
+				.arg(memory.get_os_path())
+				.stdin(process::Stdio::piped())
+				.spawn()?;
+			self.id = worker.id();
+			self.worker = Some(worker);
+			Ok(())
+		};
+
+		match execution_mode {
+			ValidationExecutionMode::InProcess => {
+				let mem_id = memory.get_os_path().to_string();
+				self.worker_thread = Some(std::thread::spawn(move || run_worker(mem_id.as_str())));
+			},
+			ValidationExecutionMode::ExternalProcessSelfHost => run_worker_process(
+				env::current_exe()?,
+				WORKER_ARGS.iter().map(|x| x.to_string()).collect(),
+			)?,
+			ValidationExecutionMode::ExternalProcessCustomHost { binary, args } => run_worker_process(
+				binary,
+				args,
+			)?,
+		};
 
 		memory.wait(
 			Event::WorkerReady as usize,
@@ -268,13 +309,13 @@ impl ValidationHost {
 		&mut self,
 		validation_code: &[u8],
 		params: ValidationParams,
-		test_mode: bool,
+		execution_mode: ValidationExecutionMode,
 	) -> Result<ValidationResult, ValidationError> {
 		if validation_code.len() > MAX_CODE_MEM {
 			return Err(ValidationError::InvalidCandidate(InvalidCandidate::CodeTooLarge(validation_code.len())));
 		}
 		// First, check if need to spawn the child process
-		self.start_worker(test_mode)?;
+		self.start_worker(execution_mode)?;
 		let memory = self.memory.as_mut()
 			.expect("memory is always `Some` after `start_worker` completes successfully");
 		{

parachain/test-parachains/tests/adder/mod.rs

@@ -16,11 +16,16 @@
 
 //! Basic parachain that adds a number as part of its state.
 
-use parachain::primitives::{
-	RelayChainBlockNumber,
-	BlockData as GenericBlockData,
-	HeadData as GenericHeadData,
-	ValidationParams,
+const WORKER_ARGS_TEST: &[&'static str] = &["--nocapture", "validation_worker"];
+
+use parachain::{
+	primitives::{
+		RelayChainBlockNumber,
+		BlockData as GenericBlockData,
+		HeadData as GenericHeadData,
+		ValidationParams,
+	},
+	wasm_executor::{ValidationPool, ValidationExecutionMode}
 };
 use codec::{Decode, Encode};
 
@@ -52,8 +57,28 @@ fn hash_head(head: &HeadData) -> [u8; 32] {
 	tiny_keccak::keccak256(head.encode().as_slice())
 }
 
+fn validation_pool() -> ValidationPool {
+	let execution_mode = ValidationExecutionMode::ExternalProcessCustomHost {
+		binary: std::env::current_exe().unwrap(),
+		args: WORKER_ARGS_TEST.iter().map(|x| x.to_string()).collect(),
+	};
+
+	ValidationPool::new(execution_mode)
+}
+
 #[test]
-pub fn execute_good_on_parent() {
+fn execute_good_on_parent_with_inprocess_validation() {
+	let pool = ValidationPool::new(ValidationExecutionMode::InProcess);
+	execute_good_on_parent(pool);
+}
+
+#[test]
+pub fn execute_good_on_parent_with_external_process_validation() {
+	let pool = validation_pool();
+	execute_good_on_parent(pool);
+}
+
+fn execute_good_on_parent(pool: ValidationPool) {
 	let parent_head = HeadData {
 		number: 0,
 		parent_hash: [0; 32],
@@ -65,7 +90,6 @@ pub fn execute_good_on_parent() {
 		add: 512,
 	};
 
-	let pool = parachain::wasm_executor::ValidationPool::new();
 
 	let ret = parachain::wasm_executor::validate_candidate(
 		adder::wasm_binary_unwrap(),
@@ -75,7 +99,7 @@ pub fn execute_good_on_parent() {
 			relay_chain_height: 1,
 			hrmp_mqc_heads: Vec::new(),
 		},
-		parachain::wasm_executor::ExecutionMode::RemoteTest(&pool),
+		parachain::wasm_executor::ExecutionMode::Remote(&pool),
 		sp_core::testing::TaskExecutor::new(),
 	).unwrap();
 
@@ -91,7 +115,7 @@ fn execute_good_chain_on_parent() {
 	let mut number = 0;
 	let mut parent_hash = [0; 32];
 	let mut last_state = 0;
-	let pool = parachain::wasm_executor::ValidationPool::new();
+	let pool = validation_pool();
 
 	for add in 0..10 {
 		let parent_head = HeadData {
@@ -113,7 +137,7 @@ fn execute_good_chain_on_parent() {
 				relay_chain_height: number as RelayChainBlockNumber + 1,
 				hrmp_mqc_heads: Vec::new(),
 			},
-			parachain::wasm_executor::ExecutionMode::RemoteTest(&pool),
+			parachain::wasm_executor::ExecutionMode::Remote(&pool),
 			sp_core::testing::TaskExecutor::new(),
 		).unwrap();
 
@@ -131,7 +155,7 @@ fn execute_good_chain_on_parent() {
 
 #[test]
 fn execute_bad_on_parent() {
-	let pool = parachain::wasm_executor::ValidationPool::new();
+	let pool = validation_pool();
 
 	let parent_head = HeadData {
 		number: 0,
@@ -152,7 +176,7 @@ fn execute_bad_on_parent() {
 			relay_chain_height: 1,
 			hrmp_mqc_heads: Vec::new(),
 		},
-		parachain::wasm_executor::ExecutionMode::RemoteTest(&pool),
+		parachain::wasm_executor::ExecutionMode::Remote(&pool),
 		sp_core::testing::TaskExecutor::new(),
 	).unwrap_err();
 }