refactor out validation hosts to pool struct (#972)

* refactor out validation hosts to pool struct

* make web-wasm compatible

* typo

* remove now-unused static hosts

polkadot/validation/src/collation.rs

@@ -59,6 +59,7 @@ pub trait Collators: Clone {
 
 /// A future which resolves when a collation is available.
 pub async fn collation_fetch<C: Collators, P>(
+	validation_pool: Option<crate::pipeline::ValidationPool>,
 	parachain: ParaId,
 	relay_parent: Hash,
 	collators: C,
@@ -76,6 +77,7 @@ pub async fn collation_fetch<C: Collators, P>(
 		let collation = collators.collate(parachain, relay_parent).await?;
 		let Collation { info, pov } = collation;
 		let res = crate::pipeline::full_output_validation_with_api(
+			validation_pool.as_ref(),
 			&*client,
 			&info,
 			&pov,

polkadot/validation/src/pipeline.rs

@@ -36,6 +36,8 @@ use sp_api::ProvideRuntimeApi;
 use parking_lot::Mutex;
 use crate::Error;
 
+pub use parachain::wasm_executor::ValidationPool;
+
 /// Does basic checks of a collation. Provide the encoded PoV-block.
 pub fn basic_checks(
 	collation: &CollationInfo,
@@ -227,6 +229,7 @@ impl<'a> ValidatedCandidate<'a> {
 
 /// Does full checks of a collation, with provided PoV-block and contextual data.
 pub fn validate<'a>(
+	validation_pool: Option<&'_ ValidationPool>,
 	collation: &'a CollationInfo,
 	pov_block: &'a PoVBlock,
 	local_validation: &'a LocalValidationData,
@@ -251,12 +254,16 @@ pub fn validate<'a>(
 		per_byte: 0,
 	};
 
+	let execution_mode = validation_pool
+		.map(ExecutionMode::Remote)
+		.unwrap_or(ExecutionMode::Local);
+
 	let ext = Externalities::new(local_validation.balance, fee_schedule);
 	match wasm_executor::validate_candidate(
 		&validation_code,
 		params,
 		ext.clone(),
-		ExecutionMode::Remote,
+		execution_mode,
 	) {
 		Ok(result) => {
 			if result.head_data == collation.head_data.0 {
@@ -306,6 +313,7 @@ where
 
 /// Does full-pipeline validation of a collation with provided contextual parameters.
 pub fn full_output_validation_with_api<P>(
+	validation_pool: Option<&ValidationPool>,
 	api: &P,
 	collation: &CollationInfo,
 	pov_block: &PoVBlock,
@@ -330,6 +338,7 @@ pub fn full_output_validation_with_api<P>(
 		&encoded_pov,
 	)
 		.and_then(|()| validate(
+			validation_pool,
 			&collation,
 			&pov_block,
 			&local_validation,

polkadot/validation/src/shared_table/mod.rs

@@ -39,7 +39,7 @@ use self::includable::IncludabilitySender;
 use primitives::Pair;
 use sp_api::ProvideRuntimeApi;
 
-use crate::pipeline::FullOutput;
+use crate::pipeline::{FullOutput, ValidationPool};
 use crate::Error;
 
 mod includable;
@@ -132,6 +132,7 @@ struct SharedTableInner {
 	trackers: Vec<IncludabilitySender>,
 	availability_store: AvailabilityStore,
 	validated: HashMap<Hash, ValidationWork>,
+	validation_pool: Option<ValidationPool>,
 }
 
 impl SharedTableInner {
@@ -193,6 +194,7 @@ impl SharedTableInner {
 		};
 
 		work.map(|work| ParachainWork {
+			validation_pool: self.validation_pool.clone(),
 			availability_store: self.availability_store.clone(),
 			relay_parent: context.signing_context.parent_hash.clone(),
 			work,
@@ -259,6 +261,7 @@ impl Validated {
 
 /// Future that performs parachain validation work.
 pub struct ParachainWork<Fetch> {
+	validation_pool: Option<ValidationPool>,
 	work: Work<Fetch>,
 	relay_parent: Hash,
 	availability_store: AvailabilityStore,
@@ -283,9 +286,11 @@ impl<Fetch: Future + Unpin> ParachainWork<Fetch> {
 		let n_validators = self.n_validators;
 		let expected_relay_parent = self.relay_parent;
 
+		let pool = self.validation_pool.clone();
 		let validate = move |pov_block: &PoVBlock, candidate: &AbridgedCandidateReceipt| {
 			let collation_info = candidate.to_collation_info();
 			let full_output = crate::pipeline::full_output_validation_with_api(
+				pool.as_ref(),
 				&*api,
 				&collation_info,
 				pov_block,
@@ -416,6 +421,7 @@ impl SharedTable {
 		signing_context: SigningContext,
 		availability_store: AvailabilityStore,
 		max_block_data_size: Option<u64>,
+		validation_pool: Option<ValidationPool>,
 	) -> Self {
 		SharedTable {
 			context: Arc::new(TableContext { groups, key, signing_context, validators: validators.clone(), }),
@@ -425,6 +431,7 @@ impl SharedTable {
 				validated: HashMap::new(),
 				trackers: Vec::new(),
 				availability_store,
+				validation_pool,
 			}))
 		}
 	}
@@ -685,6 +692,7 @@ mod tests {
 			signing_context.clone(),
 			AvailabilityStore::new_in_memory(DummyErasureNetworking),
 			None,
+			None,
 		);
 
 		let mut candidate = AbridgedCandidateReceipt::default();
@@ -741,6 +749,7 @@ mod tests {
 			signing_context.clone(),
 			AvailabilityStore::new_in_memory(DummyErasureNetworking),
 			None,
+			None,
 		);
 
 		let mut candidate = AbridgedCandidateReceipt::default();
@@ -798,6 +807,7 @@ mod tests {
 			availability_store: store.clone(),
 			max_block_data_size: None,
 			n_validators,
+			validation_pool: None,
 		};
 
 		for i in 0..n_validators {
@@ -867,6 +877,7 @@ mod tests {
 			availability_store: store.clone(),
 			max_block_data_size: None,
 			n_validators,
+			validation_pool: None,
 		};
 
 		let validated = block_on(producer.prime_with(|_, _| Ok(
@@ -921,6 +932,7 @@ mod tests {
 			signing_context.clone(),
 			AvailabilityStore::new_in_memory(DummyErasureNetworking),
 			None,
+			None,
 		);
 
 		let mut candidate = AbridgedCandidateReceipt::default();
@@ -988,6 +1000,7 @@ mod tests {
 			signing_context.clone(),
 			AvailabilityStore::new_in_memory(DummyErasureNetworking),
 			None,
+			None,
 		);
 
 		let mut candidate = AbridgedCandidateReceipt::default();

polkadot/validation/src/validation_service/mod.rs

@@ -47,6 +47,7 @@ use log::{warn, error, info, debug, trace};
 
 use super::{Network, Collators, SharedTable, TableRouter};
 use crate::Error;
+use crate::pipeline::ValidationPool;
 
 /// A handle to spawn background tasks onto.
 pub type TaskExecutor = Arc<dyn Spawn + Send + Sync>;
@@ -164,13 +165,15 @@ impl<C, N, P, SC, SP> ServiceBuilder<C, N, P, SC, SP> where
 			NotifyImport(sc_client_api::BlockImportNotification<Block>),
 		}
 
+		let validation_pool = Some(ValidationPool::new());
 		let mut parachain_validation = ParachainValidationInstances {
 			client: self.client.clone(),
 			network: self.network,
 			spawner: self.spawner,
 			availability_store: self.availability_store,
 			live_instances: HashMap::new(),
-			collation_fetch: DefaultCollationFetch(self.collators),
+			validation_pool: validation_pool.clone(),
+			collation_fetch: DefaultCollationFetch(self.collators, validation_pool),
 		};
 
 		let client = self.client;
@@ -252,7 +255,7 @@ pub(crate) trait CollationFetch {
 }
 
 #[derive(Clone)]
-struct DefaultCollationFetch<C>(C);
+struct DefaultCollationFetch<C>(C, Option<ValidationPool>);
 impl<C> CollationFetch for DefaultCollationFetch<C>
 	where
 		C: Collators + Send + Sync + Unpin + 'static,
@@ -272,10 +275,12 @@ impl<C> CollationFetch for DefaultCollationFetch<C>
 			P::Api: ParachainHost<Block, Error = sp_blockchain::Error>,
 			P: ProvideRuntimeApi<Block> + Send + Sync + 'static,
 	{
+		let DefaultCollationFetch(collators, validation_pool) = self;
 		crate::collation::collation_fetch(
+			validation_pool,
 			parachain,
 			relay_parent,
-			self.0,
+			collators,
 			client,
 			max_block_data_size,
 			n_validators,
@@ -307,6 +312,9 @@ pub(crate) struct ParachainValidationInstances<N, P, SP, CF> {
 	/// Live agreements. Maps relay chain parent hashes to attestation
 	/// instances.
 	live_instances: HashMap<Hash, ValidationInstanceHandle>,
+	/// The underlying validation pool of processes to use.
+	/// Only `None` in tests.
+	validation_pool: Option<ValidationPool>,
 	/// Used to fetch a collation.
 	collation_fetch: CF,
 }
@@ -406,6 +414,7 @@ impl<N, P, SP, CF> ParachainValidationInstances<N, P, SP, CF> where
 			signing_context,
 			self.availability_store.clone(),
 			max_block_data_size,
+			self.validation_pool.clone(),
 		));
 
 		let build_router = self.network.build_table_router(
@@ -709,6 +718,7 @@ mod tests {
 			spawner: executor.clone(),
 			availability_store: AvailabilityStore::new_in_memory(MockErasureNetworking),
 			live_instances: HashMap::new(),
+			validation_pool: None,
 		};
 
 		parachain_validation.get_or_instantiate(Default::default(), &keystore, None)
@@ -747,6 +757,7 @@ mod tests {
 			spawner: executor.clone(),
 			availability_store: AvailabilityStore::new_in_memory(MockErasureNetworking),
 			live_instances: HashMap::new(),
+			validation_pool: None,
 		};
 
 		parachain_validation.get_or_instantiate(Default::default(), &keystore, None)