chainHead: Allow methods to be called from within a single connection context...
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 <[email protected]> Co-authored-by:
Niklas Adolfsson <[email protected]>