rpc: backpressured RPC server (bump jsonrpsee 0.20) (#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: https://github.com/paritytech/substrate/pull/13992

Resolves https://github.com/paritytech/polkadot-sdk/issues/748, resolves
https://github.com/paritytech/polkadot-sdk/issues/627

substrate/client/rpc-api/src/author/error.rs

@@ -18,10 +18,7 @@
 
 //! Authoring RPC module errors.
 
-use jsonrpsee::{
-	core::Error as JsonRpseeError,
-	types::error::{CallError, ErrorObject},
-};
+use jsonrpsee::types::error::{ErrorObject, ErrorObjectOwned};
 use sp_runtime::transaction_validity::InvalidTransaction;
 
 /// Author RPC Result type.
@@ -86,98 +83,104 @@ const POOL_NO_TAGS: i32 = POOL_INVALID_TX + 9;
 const POOL_INVALID_BLOCK_ID: i32 = POOL_INVALID_TX + 10;
 /// The pool is not accepting future transactions.
 const POOL_FUTURE_TX: i32 = POOL_INVALID_TX + 11;
+/// Other error.
+const OTHER_ERR: i32 = BASE_ERROR + 40;
 
-impl From<Error> for JsonRpseeError {
-	fn from(e: Error) -> Self {
+impl From<Error> for ErrorObjectOwned {
+	fn from(e: Error) -> ErrorObjectOwned {
 		use sc_transaction_pool_api::error::Error as PoolError;
 
 		match e {
-			Error::BadFormat(e) => CallError::Custom(ErrorObject::owned(
+			Error::BadFormat(e) => ErrorObject::owned(
 				BAD_FORMAT,
 				format!("Extrinsic has invalid format: {}", e),
 				None::<()>,
-			)),
-			Error::Verification(e) => CallError::Custom(ErrorObject::owned(
+			),
+			Error::Verification(e) => ErrorObject::owned(
 				VERIFICATION_ERROR,
 				format!("Verification Error: {}", e),
 				Some(format!("{:?}", e)),
-			)),
+			),
 			Error::Pool(PoolError::InvalidTransaction(InvalidTransaction::Custom(e))) => {
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 					POOL_INVALID_TX,
 					"Invalid Transaction",
 					Some(format!("Custom error: {}", e)),
-				))
+				)
 			},
 			Error::Pool(PoolError::InvalidTransaction(e)) => {
 				let msg: &str = e.into();
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 					POOL_INVALID_TX,
 					"Invalid Transaction",
 					Some(msg),
-				))
+				)
 			},
 			Error::Pool(PoolError::UnknownTransaction(e)) => {
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 					POOL_UNKNOWN_VALIDITY,
 					"Unknown Transaction Validity",
 					Some(format!("{:?}", e)),
-				))
+				)
 			},
 			Error::Pool(PoolError::TemporarilyBanned) =>
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 				POOL_TEMPORARILY_BANNED,
 				"Transaction is temporarily banned",
 				None::<()>,
-			)),
+			),
 			Error::Pool(PoolError::AlreadyImported(hash)) =>
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 				POOL_ALREADY_IMPORTED,
 				"Transaction Already Imported",
 				Some(format!("{:?}", hash)),
-			)),
-			Error::Pool(PoolError::TooLowPriority { old, new }) => CallError::Custom(ErrorObject::owned(
+			),
+			Error::Pool(PoolError::TooLowPriority { old, new }) => ErrorObject::owned(
 				POOL_TOO_LOW_PRIORITY,
 				format!("Priority is too low: ({} vs {})", old, new),
 				Some("The transaction has too low priority to replace another transaction already in the pool.")
-			)),
+			),
 			Error::Pool(PoolError::CycleDetected) =>
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 				POOL_CYCLE_DETECTED,
 				"Cycle Detected",
 				None::<()>
-			)),
-			Error::Pool(PoolError::ImmediatelyDropped) => CallError::Custom(ErrorObject::owned(
+			),
+			Error::Pool(PoolError::ImmediatelyDropped) => ErrorObject::owned(
 				POOL_IMMEDIATELY_DROPPED,
 				"Immediately Dropped",
 				Some("The transaction couldn't enter the pool because of the limit"),
-			)),
-			Error::Pool(PoolError::Unactionable) => CallError::Custom(ErrorObject::owned(
+			),
+			Error::Pool(PoolError::Unactionable) => ErrorObject::owned(
 				POOL_UNACTIONABLE,
 				"Unactionable",
 				Some("The transaction is unactionable since it is not propagable and \
 				the local node does not author blocks")
-			)),
-			Error::Pool(PoolError::NoTagsProvided) => CallError::Custom(ErrorObject::owned(
+			),
+			Error::Pool(PoolError::NoTagsProvided) => ErrorObject::owned(
 				POOL_NO_TAGS,
 				"No tags provided",
 				Some("Transaction does not provide any tags, so the pool can't identify it")
-			)),
+			),
 			Error::Pool(PoolError::InvalidBlockId(_)) =>
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 				POOL_INVALID_BLOCK_ID,
 				"The provided block ID is not valid",
 				None::<()>
-			)),
+			),
 			Error::Pool(PoolError::RejectedFutureTransaction) => {
-				CallError::Custom(ErrorObject::owned(
+				ErrorObject::owned(
 					POOL_FUTURE_TX,
 					"The pool is not accepting future transactions",
 					None::<()>,
-				))
+				)
 			},
 			Error::UnsafeRpcCalled(e) => e.into(),
-			e => CallError::Failed(e.into()),
-		}.into()
+			other => ErrorObject::owned(
+				OTHER_ERR,
+				other.to_string(),
+				None::<()>,
+			)
+		}
 	}
 }