rpc: backpressured RPC server (bump jsonrpsee 0.20) (paritytech#1313)

This is a rather big change in jsonrpsee, the major things in this bump
are:
- Server backpressure (the subscription impls are modified to deal with
that)
- Allow custom error types / return types (remove jsonrpsee::core::Error
and jsonrpee::core::CallError)
- Bug fixes (graceful shutdown in particular not used by substrate
anyway)
   - Less dependencies for the clients in particular
   - Return type requires Clone in method call responses
   - Moved to tokio channels
   - Async subscription API (not used in this PR)

Major changes in this PR:
- The subscriptions are now bounded and if subscription can't keep up
with the server it is dropped
- CLI: add parameter to configure the jsonrpc server bounded message
buffer (default is 64)
- Add our own subscription helper to deal with the unbounded streams in
substrate

The most important things in this PR to review is the added helpers
functions in `substrate/client/rpc/src/utils.rs` and the rest is pretty
much chore.

Regarding the "bounded buffer limit" it may cause the server to handle
the JSON-RPC calls
slower than before.

The message size limit is bounded by "--rpc-response-size" thus "by
default 10MB * 64 = 640MB"
but the subscription message size is not covered by this limit and could
be capped as well.

Hopefully the last release prior to 1.0, sorry in advance for a big PR

Previous attempt: paritytech/substrate#13992

Resolves paritytech#748, resolves
paritytech#627

substrate/bin/minimal/node/Cargo.toml

@@ -23,7 +23,7 @@ name = "minimal-node"
 clap = { version = "4.4.18", features = ["derive"] }
 futures = { version = "0.3.21", features = ["thread-pool"] }
 futures-timer = "3.0.1"
-jsonrpsee = { version = "0.16.2", features = ["server"] }
+jsonrpsee = { version = "0.20.3", features = ["server"] }
 serde_json = "1.0.111"
 
 sc-cli = { path = "../../../client/cli" }

substrate/bin/node-template/node/Cargo.toml

@@ -48,7 +48,7 @@ frame-system = { path = "../../../frame/system" }
 pallet-transaction-payment = { path = "../../../frame/transaction-payment", default-features = false }
 
 # These dependencies are used for the node template's RPCs
-jsonrpsee = { version = "0.16.2", features = ["server"] }
+jsonrpsee = { version = "0.20.3", features = ["server"] }
 sp-api = { path = "../../../primitives/api" }
 sc-rpc-api = { path = "../../../client/rpc-api" }
 sp-blockchain = { path = "../../../primitives/blockchain" }

substrate/bin/node/cli/Cargo.toml

@@ -44,7 +44,7 @@ array-bytes = "6.1"
 clap = { version = "4.4.18", features = ["derive"], optional = true }
 codec = { package = "parity-scale-codec", version = "3.6.1" }
 serde = { version = "1.0.195", features = ["derive"] }
-jsonrpsee = { version = "0.16.2", features = ["server"] }
+jsonrpsee = { version = "0.20.3", features = ["server"] }
 futures = "0.3.21"
 log = "0.4.17"
 rand = "0.8"

substrate/bin/node/cli/benches/block_production.rs

@@ -83,6 +83,7 @@ fn new_node(tokio_handle: Handle) -> node_cli::service::NewFullBase {
 		rpc_id_provider: Default::default(),
 		rpc_max_subs_per_conn: Default::default(),
 		rpc_port: 9944,
+		rpc_message_buffer_capacity: Default::default(),
 		prometheus_config: None,
 		telemetry_endpoints: None,
 		default_heap_pages: None,

substrate/bin/node/cli/benches/transaction_pool.rs

@@ -79,6 +79,7 @@ fn new_node(tokio_handle: Handle) -> node_cli::service::NewFullBase {
 		rpc_id_provider: Default::default(),
 		rpc_max_subs_per_conn: Default::default(),
 		rpc_port: 9944,
+		rpc_message_buffer_capacity: Default::default(),
 		prometheus_config: None,
 		telemetry_endpoints: None,
 		default_heap_pages: None,

substrate/bin/node/rpc/Cargo.toml

@@ -16,7 +16,7 @@ workspace = true
 targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
-jsonrpsee = { version = "0.16.2", features = ["server"] }
+jsonrpsee = { version = "0.20.3", features = ["server"] }
 node-primitives = { path = "../primitives" }
 pallet-transaction-payment-rpc = { path = "../../../frame/transaction-payment/rpc" }
 mmr-rpc = { path = "../../../client/merkle-mountain-range/rpc" }

substrate/client/cli/src/commands/run_cmd.rs

@@ -25,7 +25,7 @@ use crate::{
 	},
 	CliConfiguration, PrometheusParams, RuntimeParams, TelemetryParams,
 	RPC_DEFAULT_MAX_CONNECTIONS, RPC_DEFAULT_MAX_REQUEST_SIZE_MB, RPC_DEFAULT_MAX_RESPONSE_SIZE_MB,
-	RPC_DEFAULT_MAX_SUBS_PER_CONN,
+	RPC_DEFAULT_MAX_SUBS_PER_CONN, RPC_DEFAULT_MESSAGE_CAPACITY_PER_CONN,
 };
 use clap::Parser;
 use regex::Regex;
@@ -102,9 +102,20 @@ pub struct RunCmd {
 	#[arg(long, value_name = "COUNT", default_value_t = RPC_DEFAULT_MAX_CONNECTIONS)]
 	pub rpc_max_connections: u32,
 
-	/// Specify browser *origins* allowed to access the HTTP and WS RPC servers.
+	/// The number of messages the RPC server is allowed to keep in memory.
 	///
-	/// A comma-separated list of origins (`protocol://domain` or special `null`
+	/// If the buffer becomes full then the server will not process
+	/// new messages until the connected client start reading the
+	/// underlying messages.
+	///
+	/// This applies per connection which includes both
+	/// JSON-RPC methods calls and subscriptions.
+	#[arg(long, default_value_t = RPC_DEFAULT_MESSAGE_CAPACITY_PER_CONN)]
+	pub rpc_message_buffer_capacity_per_connection: u32,
+
+	/// Specify browser *origins* allowed to access the HTTP & WS RPC servers.
+	///
+	/// A comma-separated list of origins (protocol://domain or special `null`
 	/// value). Value of `all` will disable origin validation. Default is to
 	/// allow localhost and <https://polkadot.js.org> origins. When running in
 	/// `--dev` mode the default is to allow all origins.

substrate/client/cli/src/config.rs

@@ -52,8 +52,11 @@ pub const RPC_DEFAULT_MAX_SUBS_PER_CONN: u32 = 1024;
 pub const RPC_DEFAULT_MAX_REQUEST_SIZE_MB: u32 = 15;
 /// The default max response size in MB.
 pub const RPC_DEFAULT_MAX_RESPONSE_SIZE_MB: u32 = 15;
-/// The default number of connection..
+/// The default concurrent connection limit.
 pub const RPC_DEFAULT_MAX_CONNECTIONS: u32 = 100;
+/// The default number of messages the RPC server
+/// is allowed to keep in memory per connection.
+pub const RPC_DEFAULT_MESSAGE_CAPACITY_PER_CONN: u32 = 64;
 
 /// Default configuration values used by Substrate
 ///
@@ -330,6 +333,11 @@ pub trait CliConfiguration<DCV: DefaultConfigurationValues = ()>: Sized {
 		Ok(RPC_DEFAULT_MAX_SUBS_PER_CONN)
 	}
 
+	/// The number of messages the RPC server is allowed to keep in memory per connection.
+	fn rpc_buffer_capacity_per_connection(&self) -> Result<u32> {
+		Ok(RPC_DEFAULT_MESSAGE_CAPACITY_PER_CONN)
+	}
+
 	/// Get the prometheus configuration (`None` if disabled)
 	///
 	/// By default this is `None`.
@@ -501,6 +509,7 @@ pub trait CliConfiguration<DCV: DefaultConfigurationValues = ()>: Sized {
 			rpc_id_provider: None,
 			rpc_max_subs_per_conn: self.rpc_max_subscriptions_per_connection()?,
 			rpc_port: DCV::rpc_listen_port(),
+			rpc_message_buffer_capacity: self.rpc_buffer_capacity_per_connection()?,
 			prometheus_config: self
 				.prometheus_config(DCV::prometheus_listen_port(), &chain_spec)?,
 			telemetry_endpoints,

substrate/client/cli/src/runner.rs

@@ -269,6 +269,7 @@ mod tests {
 				rpc_max_response_size: Default::default(),
 				rpc_id_provider: Default::default(),
 				rpc_max_subs_per_conn: Default::default(),
+				rpc_message_buffer_capacity: Default::default(),
 				rpc_port: 9944,
 				prometheus_config: None,
 				telemetry_endpoints: None,

substrate/client/consensus/babe/rpc/Cargo.toml

@@ -16,7 +16,7 @@ workspace = true
 targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
-jsonrpsee = { version = "0.16.2", features = ["client-core", "macros", "server"] }
+jsonrpsee = { version = "0.20.3", features = ["client-core", "macros", "server"] }
 futures = "0.3.21"
 serde = { version = "1.0.195", features = ["derive"] }
 thiserror = "1.0"

substrate/client/consensus/babe/rpc/src/lib.rs

@@ -22,15 +22,15 @@ use std::{collections::HashMap, sync::Arc};
 
 use futures::TryFutureExt;
 use jsonrpsee::{
-	core::{async_trait, Error as JsonRpseeError, RpcResult},
+	core::async_trait,
 	proc_macros::rpc,
-	types::{error::CallError, ErrorObject},
+	types::{ErrorObject, ErrorObjectOwned},
 };
 use serde::{Deserialize, Serialize};
 
 use sc_consensus_babe::{authorship, BabeWorkerHandle};
 use sc_consensus_epochs::Epoch as EpochT;
-use sc_rpc_api::DenyUnsafe;
+use sc_rpc_api::{DenyUnsafe, UnsafeRpcError};
 use sp_api::ProvideRuntimeApi;
 use sp_application_crypto::AppCrypto;
 use sp_blockchain::{Error as BlockChainError, HeaderBackend, HeaderMetadata};
@@ -48,7 +48,7 @@ pub trait BabeApi {
 	/// Returns data about which slots (primary or secondary) can be claimed in the current epoch
 	/// with the keys in the keystore.
 	#[method(name = "babe_epochAuthorship")]
-	async fn epoch_authorship(&self) -> RpcResult<HashMap<AuthorityId, EpochAuthorship>>;
+	async fn epoch_authorship(&self) -> Result<HashMap<AuthorityId, EpochAuthorship>, Error>;
 }
 
 /// Provides RPC methods for interacting with Babe.
@@ -89,7 +89,7 @@ where
 	C::Api: BabeRuntimeApi<B>,
 	SC: SelectChain<B> + Clone + 'static,
 {
-	async fn epoch_authorship(&self) -> RpcResult<HashMap<AuthorityId, EpochAuthorship>> {
+	async fn epoch_authorship(&self) -> Result<HashMap<AuthorityId, EpochAuthorship>, Error> {
 		self.deny_unsafe.check_if_safe()?;
 
 		let best_header = self.select_chain.best_chain().map_err(Error::SelectChain).await?;
@@ -147,7 +147,7 @@ where
 }
 
 /// Holds information about the `slot`'s that can be claimed by a given key.
-#[derive(Default, Debug, Deserialize, Serialize)]
+#[derive(Clone, Default, Debug, Deserialize, Serialize)]
 pub struct EpochAuthorship {
 	/// the array of primary slots that can be claimed
 	primary: Vec<u64>,
@@ -166,20 +166,26 @@ pub enum Error {
 	/// Failed to fetch epoch data.
 	#[error("Failed to fetch epoch data")]
 	FetchEpoch,
+	/// Consensus error
+	#[error(transparent)]
+	Consensus(#[from] ConsensusError),
+	/// Errors that can be formatted as a String
+	#[error("{0}")]
+	StringError(String),
+	/// Call to an unsafe RPC was denied.
+	#[error(transparent)]
+	UnsafeRpcCalled(#[from] UnsafeRpcError),
 }
 
-impl From<Error> for JsonRpseeError {
+impl From<Error> for ErrorObjectOwned {
 	fn from(error: Error) -> Self {
-		let error_code = match error {
-			Error::SelectChain(_) => 1,
-			Error::FetchEpoch => 2,
-		};
-
-		JsonRpseeError::Call(CallError::Custom(ErrorObject::owned(
-			BABE_ERROR + error_code,
-			error.to_string(),
-			Some(format!("{:?}", error)),
-		)))
+		match error {
+			Error::SelectChain(e) => ErrorObject::owned(BABE_ERROR + 1, e.to_string(), None::<()>),
+			Error::FetchEpoch => ErrorObject::owned(BABE_ERROR + 2, error.to_string(), None::<()>),
+			Error::Consensus(e) => ErrorObject::owned(BABE_ERROR + 3, e.to_string(), None::<()>),
+			Error::StringError(e) => ErrorObject::owned(BABE_ERROR + 4, e, None::<()>),
+			Error::UnsafeRpcCalled(e) => e.into(),
+		}
 	}
 }
 
@@ -251,7 +257,7 @@ mod tests {
 		let api = babe_rpc.into_rpc();
 
 		let request = r#"{"jsonrpc":"2.0","method":"babe_epochAuthorship","params": [],"id":1}"#;
-		let (response, _) = api.raw_json_request(request).await.unwrap();
+		let (response, _) = api.raw_json_request(request, 1).await.unwrap();
 		let expected = r#"{"jsonrpc":"2.0","result":{"5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY":{"primary":[0],"secondary":[1,2,4],"secondary_vrf":[]}},"id":1}"#;
 
 		assert_eq!(&response.result, expected);
@@ -263,7 +269,7 @@ mod tests {
 		let api = babe_rpc.into_rpc();
 
 		let request = r#"{"jsonrpc":"2.0","method":"babe_epochAuthorship","params":[],"id":1}"#;
-		let (response, _) = api.raw_json_request(request).await.unwrap();
+		let (response, _) = api.raw_json_request(request, 1).await.unwrap();
 		let expected = r#"{"jsonrpc":"2.0","error":{"code":-32601,"message":"RPC call is unsafe to be called externally"},"id":1}"#;
 
 		assert_eq!(&response.result, expected);

substrate/client/consensus/beefy/rpc/Cargo.toml

@@ -14,7 +14,7 @@ workspace = true
 [dependencies]
 codec = { package = "parity-scale-codec", version = "3.6.1", features = ["derive"] }
 futures = "0.3.21"
-jsonrpsee = { version = "0.16.2", features = ["client-core", "macros", "server"] }
+jsonrpsee = { version = "0.20.3", features = ["client-core", "macros", "server"] }
 log = "0.4"
 parking_lot = "0.12.1"
 serde = { version = "1.0.195", features = ["derive"] }

substrate/client/consensus/beefy/rpc/src/lib.rs

@@ -23,15 +23,15 @@
 use parking_lot::RwLock;
 use std::sync::Arc;
 
-use sc_rpc::SubscriptionTaskExecutor;
+use sc_rpc::{utils::pipe_from_stream, SubscriptionTaskExecutor};
 use sp_runtime::traits::Block as BlockT;
 
 use futures::{task::SpawnError, FutureExt, StreamExt};
 use jsonrpsee::{
-	core::{async_trait, Error as JsonRpseeError, RpcResult},
+	core::async_trait,
 	proc_macros::rpc,
-	types::{error::CallError, ErrorObject, SubscriptionResult},
-	SubscriptionSink,
+	types::{ErrorObject, ErrorObjectOwned},
+	PendingSubscriptionSink,
 };
 use log::warn;
 
@@ -69,15 +69,11 @@ impl From<Error> for ErrorCode {
 	}
 }
 
-impl From<Error> for JsonRpseeError {
+impl From<Error> for ErrorObjectOwned {
 	fn from(error: Error) -> Self {
 		let message = error.to_string();
 		let code = ErrorCode::from(error);
-		JsonRpseeError::Call(CallError::Custom(ErrorObject::owned(
-			code as i32,
-			message,
-			None::<()>,
-		)))
+		ErrorObject::owned(code as i32, message, None::<()>)
 	}
 }
 
@@ -98,7 +94,7 @@ pub trait BeefyApi<Notification, Hash> {
 	/// in the network or if the client is still initializing or syncing with the network.
 	/// In such case an error would be returned.
 	#[method(name = "beefy_getFinalizedHead")]
-	async fn latest_finalized(&self) -> RpcResult<Hash>;
+	async fn latest_finalized(&self) -> Result<Hash, Error>;
 }
 
 /// Implements the BeefyApi RPC trait for interacting with BEEFY.
@@ -138,27 +134,17 @@ impl<Block> BeefyApiServer<notification::EncodedVersionedFinalityProof, Block::H
 where
 	Block: BlockT,
 {
-	fn subscribe_justifications(&self, mut sink: SubscriptionSink) -> SubscriptionResult {
+	fn subscribe_justifications(&self, pending: PendingSubscriptionSink) {
 		let stream = self
 			.finality_proof_stream
 			.subscribe(100_000)
 			.map(|vfp| notification::EncodedVersionedFinalityProof::new::<Block>(vfp));
 
-		let fut = async move {
-			sink.pipe_from_stream(stream).await;
-		};
-
-		self.executor.spawn("substrate-rpc-subscription", Some("rpc"), fut.boxed());
-		Ok(())
+		sc_rpc::utils::spawn_subscription_task(&self.executor, pipe_from_stream(pending, stream));
 	}
 
-	async fn latest_finalized(&self) -> RpcResult<Block::Hash> {
-		self.beefy_best_block
-			.read()
-			.as_ref()
-			.cloned()
-			.ok_or(Error::EndpointNotReady)
-			.map_err(Into::into)
+	async fn latest_finalized(&self) -> Result<Block::Hash, Error> {
+		self.beefy_best_block.read().as_ref().cloned().ok_or(Error::EndpointNotReady)
 	}
 }
 
@@ -167,7 +153,7 @@ mod tests {
 	use super::*;
 
 	use codec::{Decode, Encode};
-	use jsonrpsee::{types::EmptyServerParams as EmptyParams, RpcModule};
+	use jsonrpsee::{core::EmptyServerParams as EmptyParams, RpcModule};
 	use sc_consensus_beefy::{
 		communication::notification::BeefyVersionedFinalityProofSender,
 		justification::BeefyVersionedFinalityProof,
@@ -199,7 +185,7 @@ mod tests {
 		let (rpc, _) = setup_io_handler();
 		let request = r#"{"jsonrpc":"2.0","method":"beefy_getFinalizedHead","params":[],"id":1}"#;
 		let expected_response = r#"{"jsonrpc":"2.0","error":{"code":1,"message":"BEEFY RPC endpoint not ready"},"id":1}"#.to_string();
-		let (response, _) = rpc.raw_json_request(&request).await.unwrap();
+		let (response, _) = rpc.raw_json_request(&request, 1).await.unwrap();
 
 		assert_eq!(expected_response, response.result);
 	}
@@ -230,13 +216,13 @@ mod tests {
 
 		let deadline = std::time::Instant::now() + std::time::Duration::from_secs(2);
 		while std::time::Instant::now() < deadline {
-			let (response, _) = io.raw_json_request(request).await.expect("RPC requests work");
+			let (response, _) = io.raw_json_request(request, 1).await.expect("RPC requests work");
 			if response.result != not_ready {
 				assert_eq!(response.result, expected);
 				// Success
 				return
 			}
-			std::thread::sleep(std::time::Duration::from_millis(50))
+			tokio::time::sleep(std::time::Duration::from_millis(50)).await;
 		}
 
 		panic!(
@@ -249,14 +235,15 @@ mod tests {
 		let (rpc, _) = setup_io_handler();
 		// Subscribe call.
 		let _sub = rpc
-			.subscribe("beefy_subscribeJustifications", EmptyParams::new())
+			.subscribe_unbounded("beefy_subscribeJustifications", EmptyParams::new())
 			.await
 			.unwrap();
 
 		// Unsubscribe with wrong ID
 		let (response, _) = rpc
 			.raw_json_request(
 				r#"{"jsonrpc":"2.0","method":"beefy_unsubscribeJustifications","params":["FOO"],"id":1}"#,
+				1,
 			)
 			.await
 			.unwrap();
@@ -284,7 +271,7 @@ mod tests {
 
 		// Subscribe
 		let mut sub = rpc
-			.subscribe("beefy_subscribeJustifications", EmptyParams::new())
+			.subscribe_unbounded("beefy_subscribeJustifications", EmptyParams::new())
 			.await
 			.unwrap();
 

substrate/client/consensus/common/src/block_import.rs

@@ -43,7 +43,7 @@ pub enum ImportResult {
 }
 
 /// Auxiliary data associated with an imported block result.
-#[derive(Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
 pub struct ImportedAux {
 	/// Only the header has been imported. Block body verification was skipped.
 	pub header_only: bool,