Roman Borschel ef9cb056b2
Kademlia: Address some TODOs - Refactoring - API updates. (#1174)
* Address some TODOs, refactor queries and public API.

The following left-over issues are addressed:

  * The key for FIND_NODE requests is generalised to any Multihash,
    instead of just peer IDs.
  * All queries get a (configurable) timeout.
  * Finishing queries as soon as enough results have been received is simplified
    to avoid code duplication.
  * No more panics in provider-API-related code paths. The provider API is
    however still untested and (I think) still incomplete (e.g. expiration
    of provider records).
  * Numerous smaller TODOs encountered in the code.

The following public API changes / additions are made:

  * Introduce a `KademliaConfig` with new configuration options for
    the replication factor and query timeouts.
  * Rename `find_node` to `get_closest_peers`.
  * Rename `get_value` to `get_record` and `put_value` to `put_record`,
    introducing a `Quorum` parameter for both functions, replacing the
    existing `num_results` parameter with clearer semantics.
  * Rename `add_providing` to `start_providing` and `remove_providing`
    to `stop_providing`.
  * Add a `bootstrap` function that implements a (almost) standard
    Kademlia bootstrapping procedure.
  * Rename `KademliaOut` to `KademliaEvent` with an updated list of
    constructors (some renaming). All events that report query results
    now report a `Result` to uniformly permit reporting of errors.

The following refactorings are made:

  * Introduce some constants.
  * Consolidate `query.rs` and `write.rs` behind a common query interface
    to reduce duplication and facilitate better code reuse, introducing
    the notion of a query peer iterator. `query/peers/closest.rs`
    contains the code that was formerly in `query.rs`. `query/peers/fixed.rs` contains
    a modified variant of `write.rs` (which is removed). The new `query.rs`
    provides an interface for working with a collection of queries, taking
    over some code from `behaviour.rs`.
  * Reduce code duplication in tests and use the current_thread runtime for
    polling swarms to avoid spurious errors in the test output due to aborted
    connections when a test finishes prematurely (e.g. because a quorum of
    results has been collected).
  * Some additions / improvements to the existing tests.

* Fix test.

* Fix rebase.

* Tweak kad-ipfs example.

* Incorporate some feedback.

* Provide easy access and conversion to keys in error results.
2019-07-03 16:16:25 +02:00

224 lines
7.4 KiB
Rust

// Copyright 2018 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
use libp2p_core_derive::*;
/// Small utility to check that a type implements `NetworkBehaviour`.
#[allow(dead_code)]
fn require_net_behaviour<T: libp2p::core::swarm::NetworkBehaviour>() {}
// TODO: doesn't compile
/*#[test]
fn empty() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Foo {}
}*/
#[test]
fn one_field() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Foo<TSubstream> {
ping: libp2p::ping::Ping<TSubstream>,
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::ping::PingEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::ping::PingEvent) {
}
}
#[allow(dead_code)]
fn foo<TSubstream: libp2p::tokio_io::AsyncRead + libp2p::tokio_io::AsyncWrite>() {
require_net_behaviour::<Foo<TSubstream>>();
}
}
#[test]
fn two_fields() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Foo<TSubstream> {
ping: libp2p::ping::Ping<TSubstream>,
identify: libp2p::identify::Identify<TSubstream>,
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::identify::IdentifyEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::identify::IdentifyEvent) {
}
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::ping::PingEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::ping::PingEvent) {
}
}
#[allow(dead_code)]
fn foo<TSubstream: libp2p::tokio_io::AsyncRead + libp2p::tokio_io::AsyncWrite>() {
require_net_behaviour::<Foo<TSubstream>>();
}
}
#[test]
fn three_fields() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Foo<TSubstream> {
ping: libp2p::ping::Ping<TSubstream>,
identify: libp2p::identify::Identify<TSubstream>,
kad: libp2p::kad::Kademlia<TSubstream>,
#[behaviour(ignore)]
foo: String,
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::ping::PingEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::ping::PingEvent) {
}
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::identify::IdentifyEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::identify::IdentifyEvent) {
}
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::kad::KademliaEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::kad::KademliaEvent) {
}
}
#[allow(dead_code)]
fn foo<TSubstream: libp2p::tokio_io::AsyncRead + libp2p::tokio_io::AsyncWrite>() {
require_net_behaviour::<Foo<TSubstream>>();
}
}
#[test]
fn custom_polling() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
#[behaviour(poll_method = "foo")]
struct Foo<TSubstream> {
ping: libp2p::ping::Ping<TSubstream>,
identify: libp2p::identify::Identify<TSubstream>,
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::ping::PingEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::ping::PingEvent) {
}
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::identify::IdentifyEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::identify::IdentifyEvent) {
}
}
impl<TSubstream> Foo<TSubstream> {
fn foo<T>(&mut self) -> libp2p::futures::Async<libp2p::core::swarm::NetworkBehaviourAction<T, ()>> { libp2p::futures::Async::NotReady }
}
#[allow(dead_code)]
fn foo<TSubstream: libp2p::tokio_io::AsyncRead + libp2p::tokio_io::AsyncWrite>() {
require_net_behaviour::<Foo<TSubstream>>();
}
}
#[test]
fn custom_event_no_polling() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
#[behaviour(out_event = "Vec<String>")]
struct Foo<TSubstream> {
ping: libp2p::ping::Ping<TSubstream>,
identify: libp2p::identify::Identify<TSubstream>,
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::ping::PingEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::ping::PingEvent) {
}
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::identify::IdentifyEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::identify::IdentifyEvent) {
}
}
#[allow(dead_code)]
fn foo<TSubstream: libp2p::tokio_io::AsyncRead + libp2p::tokio_io::AsyncWrite>() {
require_net_behaviour::<Foo<TSubstream>>();
}
}
#[test]
fn custom_event_and_polling() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
#[behaviour(poll_method = "foo", out_event = "String")]
struct Foo<TSubstream> {
ping: libp2p::ping::Ping<TSubstream>,
identify: libp2p::identify::Identify<TSubstream>,
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::ping::PingEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::ping::PingEvent) {
}
}
impl<TSubstream> libp2p::core::swarm::NetworkBehaviourEventProcess<libp2p::identify::IdentifyEvent> for Foo<TSubstream> {
fn inject_event(&mut self, _: libp2p::identify::IdentifyEvent) {
}
}
impl<TSubstream> Foo<TSubstream> {
fn foo<T>(&mut self) -> libp2p::futures::Async<libp2p::core::swarm::NetworkBehaviourAction<T, String>> { libp2p::futures::Async::NotReady }
}
#[allow(dead_code)]
fn foo<TSubstream: libp2p::tokio_io::AsyncRead + libp2p::tokio_io::AsyncWrite>() {
require_net_behaviour::<Foo<TSubstream>>();
}
}
#[test]
fn where_clause() {
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Foo<TSubstream> where TSubstream: std::fmt::Debug {
ping: libp2p::ping::Ping<TSubstream>,
}
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Bar<TSubstream: std::fmt::Debug> {
ping: libp2p::ping::Ping<TSubstream>,
}
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Baz<TSubstream> where TSubstream: std::fmt::Debug + Clone, {
ping: libp2p::ping::Ping<TSubstream>,
}
#[allow(dead_code)]
#[derive(NetworkBehaviour)]
struct Qux<TSubstream: std::fmt::Debug> where TSubstream: Clone {
ping: libp2p::ping::Ping<TSubstream>,
}
}