* Move import queue out of `sc-network` Add supplementary asynchronous API for the import queue which means it can be run as an independent task and communicated with through the `ImportQueueService`. This commit removes removes block and justification imports from `sc-network` and provides `ChainSync` with a handle to import queue so it can import blocks and justifications. Polling of the import queue is moved complete out of `sc-network` and `sc_consensus::Link` is implemented for `ChainSyncInterfaceHandled` so the import queue can still influence the syncing process. * Move stuff to SyncingEngine * Move `ChainSync` instanation to `SyncingEngine` Some of the tests have to be rewritten * Move peer hashmap to `SyncingEngine` * Let `SyncingEngine` to implement `ChainSyncInterface` * Introduce `SyncStatusProvider` * Move `sync_peer_(connected|disconnected)` to `SyncingEngine` * Implement `SyncEventStream` Remove `SyncConnected`/`SyncDisconnected` events from `NetworkEvenStream` and provide those events through `ChainSyncInterface` instead. Modify BEEFY/GRANDPA/transactions protocol and `NetworkGossip` to take `SyncEventStream` object which they listen to for incoming sync peer events. * Introduce `ChainSyncInterface` This interface provides a set of miscellaneous functions that other subsystems can use to query, for example, the syncing status. * Move event stream polling to `SyncingEngine` Subscribe to `NetworkStreamEvent` and poll the incoming notifications and substream events from `SyncingEngine`. The code needs refactoring. * Make `SyncingEngine` into an asynchronous runner This commits removes the last hard dependency of syncing from `sc-network` meaning the protocol now lives completely outside of `sc-network`, ignoring the hardcoded peerset entry which will be addressed in the future. Code needs a lot of refactoring. * Fix warnings * Code refactoring * Use `SyncingService` for BEEFY * Use `SyncingService` for GRANDPA * Remove call delegation from `NetworkService` * Remove `ChainSyncService` * Remove `ChainSync` service tests They were written for the sole purpose of verifying that `NetworWorker` continues to function while the calls are being dispatched to `ChainSync`. * Refactor code * Refactor code * Update client/finality-grandpa/src/communication/tests.rs Co-authored-by: Anton <anton.kalyaev@gmail.com> * Fix warnings * Apply review comments * Fix docs * Fix test * cargo-fmt * Update client/network/sync/src/engine.rs Co-authored-by: Anton <anton.kalyaev@gmail.com> * Update client/network/sync/src/engine.rs Co-authored-by: Anton <anton.kalyaev@gmail.com> * Add missing docs * Refactor code --------- Co-authored-by: Anton <anton.kalyaev@gmail.com>
Polite gossiping.
This crate provides gossiping capabilities on top of a network.
Gossip messages are separated by two categories: "topics" and consensus engine ID. The consensus engine ID is sent over the wire with the message, while the topic is not, with the expectation that the topic can be derived implicitly from the content of the message, assuming it is valid.
Topics are a single 32-byte tag associated with a message, used to group those messages
in an opaque way. Consensus code can invoke broadcast_topic to attempt to send all messages
under a single topic to all peers who don't have them yet, and send_topic to
send all messages under a single topic to a specific peer.
Usage
- Implement the
Networktrait, representing the low-level networking primitives. It is already implemented onsc_network::NetworkService. - Implement the
Validatortrait. See the section below. - Decide on a
ConsensusEngineId. Each gossiping protocol should have a different one. - Build a
GossipEngineusing these three elements. - Use the methods of the
GossipEnginein order to send out messages and receive incoming messages.
What is a validator?
The primary role of a Validator is to process incoming messages from peers, and decide
whether to discard them or process them. It also decides whether to re-broadcast the message.
The secondary role of the Validator is to check if a message is allowed to be sent to a given
peer. All messages, before being sent, will be checked against this filter.
This enables the validator to use information it's aware of about connected peers to decide
whether to send messages to them at any given moment in time - In particular, to wait until
peers can accept and process the message before sending it.
Lastly, the fact that gossip validators can decide not to rebroadcast messages opens the door for neighbor status packets to be baked into the gossip protocol. These status packets will typically contain light pieces of information used to inform peers of a current view of protocol state.
License: GPL-3.0-or-later WITH Classpath-exception-2.0