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pezkuwi-subxt/substrate/client/rpc-spec-v2/src/chain_head/api.rs
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Alexandru Vasile 7430f41350 chainHead: Allow methods to be called from within a single connection context and limit connections (#3481)
This PR ensures that the chainHead RPC class can be called only from
within the same connection context.

The chainHead methods are now registered as raw methods. 
- https://github.com/paritytech/jsonrpsee/pull/1297
The concept of raw methods is introduced in jsonrpsee, which is an async
method that exposes the connection ID:
The raw method doesn't have the concept of a blocking method. Previously
blocking methods are now spawning a blocking task to handle their
blocking (ie DB) access. We spawn the same number of tasks as before,
however we do that explicitly.

Another approach would be implementing a RPC middleware that captures
and decodes the method parameters:
- https://github.com/paritytech/polkadot-sdk/pull/3343
However, that approach is prone to errors since the methods are
hardcoded by name. Performace is affected by the double deserialization
that needs to happen to extract the subscription ID we'd like to limit.
Once from the middleware, and once from the methods itself.

This PR paves the way to implement the chainHead connection limiter:
- https://github.com/paritytech/polkadot-sdk/issues/1505
Registering tokens (subscription ID / operation ID) on the
`RpcConnections` could be extended to return an error when the maximum
number of operations is reached.

While at it, have added an integration-test to ensure that chainHead
methods can be called from within the same connection context.

Before this is merged, a new JsonRPC release should be made to expose
the `raw-methods`:
- [x] Use jsonrpsee from crates io (blocked by:
https://github.com/paritytech/jsonrpsee/pull/1297)

Closes: https://github.com/paritytech/polkadot-sdk/issues/3207


cc @paritytech/subxt-team

---------

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>
Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>
2024-04-02 13:12:34 +00:00

155 lines
5.0 KiB
Rust

// This file is part of Substrate.
// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
#![allow(non_snake_case)]
//! API trait of the chain head.
use crate::{
chain_head::{
error::Error,
event::{FollowEvent, MethodResponse},
},
common::events::StorageQuery,
};
use jsonrpsee::{proc_macros::rpc, server::ResponsePayload};
pub use sp_rpc::list::ListOrValue;
#[rpc(client, server)]
pub trait ChainHeadApi<Hash> {
/// Track the state of the head of the chain: the finalized, non-finalized, and best blocks.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[subscription(
name = "chainHead_unstable_follow" => "chainHead_unstable_followEvent",
unsubscribe = "chainHead_unstable_unfollow",
item = FollowEvent<Hash>,
)]
fn chain_head_unstable_follow(&self, with_runtime: bool);
/// Retrieves the body (list of transactions) of a pinned block.
///
/// This method should be seen as a complement to `chainHead_unstable_follow`,
/// allowing the JSON-RPC client to retrieve more information about a block
/// that has been reported.
///
/// Use `archive_unstable_body` if instead you want to retrieve the body of an arbitrary block.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[method(name = "chainHead_unstable_body", raw_method)]
async fn chain_head_unstable_body(
&self,
follow_subscription: String,
hash: Hash,
) -> ResponsePayload<'static, MethodResponse>;
/// Retrieves the header of a pinned block.
///
/// This method should be seen as a complement to `chainHead_unstable_follow`,
/// allowing the JSON-RPC client to retrieve more information about a block
/// that has been reported.
///
/// Use `archive_unstable_header` if instead you want to retrieve the header of an arbitrary
/// block.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[method(name = "chainHead_unstable_header", raw_method)]
async fn chain_head_unstable_header(
&self,
follow_subscription: String,
hash: Hash,
) -> Result<Option<String>, Error>;
/// Returns storage entries at a specific block's state.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[method(name = "chainHead_unstable_storage", raw_method)]
async fn chain_head_unstable_storage(
&self,
follow_subscription: String,
hash: Hash,
items: Vec<StorageQuery<String>>,
child_trie: Option<String>,
) -> ResponsePayload<'static, MethodResponse>;
/// Call into the Runtime API at a specified block's state.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[method(name = "chainHead_unstable_call", raw_method)]
async fn chain_head_unstable_call(
&self,
follow_subscription: String,
hash: Hash,
function: String,
call_parameters: String,
) -> ResponsePayload<'static, MethodResponse>;
/// Unpin a block or multiple blocks reported by the `follow` method.
///
/// Ongoing operations that require the provided block
/// will continue normally.
///
/// When this method returns an error, it is guaranteed that no blocks have been unpinned.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[method(name = "chainHead_unstable_unpin", raw_method)]
async fn chain_head_unstable_unpin(
&self,
follow_subscription: String,
hash_or_hashes: ListOrValue<Hash>,
) -> Result<(), Error>;
/// Resumes a storage fetch started with `chainHead_storage` after it has generated an
/// `operationWaitingForContinue` event.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[method(name = "chainHead_unstable_continue", raw_method)]
async fn chain_head_unstable_continue(
&self,
follow_subscription: String,
operation_id: String,
) -> Result<(), Error>;
/// Stops an operation started with chainHead_unstable_body, chainHead_unstable_call, or
/// chainHead_unstable_storage. If the operation was still in progress, this interrupts it. If
/// the operation was already finished, this call has no effect.
///
/// # Unstable
///
/// This method is unstable and subject to change in the future.
#[method(name = "chainHead_unstable_stopOperation", raw_method)]
async fn chain_head_unstable_stop_operation(
&self,
follow_subscription: String,
operation_id: String,
) -> Result<(), Error>;
}