Newer
Older
// Copyright 2020 Parity Technologies (UK) Ltd.
// This file is part of Polkadot.
// Polkadot 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.
// Polkadot 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 Polkadot. If not, see <http://www.gnu.org/licenses/>.
//! Utility function to make it easier to connect to validators.
use std::collections::HashMap;
use std::pin::Pin;
use futures::{
channel::{mpsc, oneshot},
task::{Poll, self},
stream,
};
use polkadot_node_subsystem::{
errors::RuntimeApiError, SubsystemError,
messages::{AllMessages, RuntimeApiMessage, RuntimeApiRequest, NetworkBridgeMessage},
SubsystemContext,
};
use polkadot_primitives::v1::{Hash, ValidatorId, AuthorityDiscoveryId};
use sc_network::PeerId;
/// Error when making a request to connect to validators.
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
#[derive(Debug, derive_more::From)]
pub enum Error {
/// Attempted to send or receive on a oneshot channel which had been canceled
#[from]
Oneshot(oneshot::Canceled),
/// A subsystem error.
#[from]
Subsystem(SubsystemError),
/// An error in the Runtime API.
#[from]
RuntimeApi(RuntimeApiError),
}
/// Utility function to make it easier to connect to validators.
pub async fn connect_to_validators<Context: SubsystemContext>(
ctx: &mut Context,
relay_parent: Hash,
validators: Vec<ValidatorId>,
) -> Result<ConnectionRequest, Error> {
// ValidatorId -> AuthorityDiscoveryId
let (tx, rx) = oneshot::channel();
ctx.send_message(AllMessages::RuntimeApi(
RuntimeApiMessage::Request(
relay_parent,
RuntimeApiRequest::ValidatorDiscovery(validators.clone(), tx),
)
)).await?;
let maybe_authorities = rx.await??;
let authorities: Vec<_> = maybe_authorities.iter()
.cloned()
.filter_map(|id| id)
.collect();
let validator_map = validators.into_iter()
.zip(maybe_authorities.into_iter())
.filter_map(|(k, v)| v.map(|v| (v, k)))
.collect::<HashMap<AuthorityDiscoveryId, ValidatorId>>();
let (connections, revoke) = connect_to_authorities(ctx, authorities).await?;
Ok(ConnectionRequest {
validator_map,
connections,
revoke,
})
}
async fn connect_to_authorities<Context: SubsystemContext>(
ctx: &mut Context,
validator_ids: Vec<AuthorityDiscoveryId>,
) -> Result<(mpsc::Receiver<(AuthorityDiscoveryId, PeerId)>, oneshot::Sender<()>), Error> {
const PEERS_CAPACITY: usize = 8;
let (revoke_tx, revoke) = oneshot::channel();
let (connected, connected_rx) = mpsc::channel(PEERS_CAPACITY);
ctx.send_message(AllMessages::NetworkBridge(
NetworkBridgeMessage::ConnectToValidators {
validator_ids,
connected,
revoke,
}
)).await?;
Ok((connected_rx, revoke_tx))
}
/// A pending connection request to validators.
/// This struct implements `Stream` to allow for asynchronous
/// discovery of validator addresses.
///
/// NOTE: you should call `revoke` on this struct
/// when you're no longer interested in the requested validators.
validator_map: HashMap<AuthorityDiscoveryId, ValidatorId>,
#[must_use = "streams do nothing unless polled"]
connections: mpsc::Receiver<(AuthorityDiscoveryId, PeerId)>,
#[must_use = "a request should be revoked at some point"]
revoke: oneshot::Sender<()>,
}
impl stream::Stream for ConnectionRequest {
type Item = (ValidatorId, PeerId);
fn poll_next(self: Pin<&mut Self>, cx: &mut task::Context) -> Poll<Option<Self::Item>> {
let mut this = self.project();
if this.validator_map.is_empty() {
if let Some(validator_id) = this.validator_map.remove(&id) {
return Poll::Ready(Some((validator_id, peer_id)));
} else {
// unknown authority_id
// should be unreachable
}
}
_ => {},
}
Poll::Pending
}
}
impl ConnectionRequest {
pub fn revoke(self) {
if let Err(_) = self.revoke.send(()) {
log::warn!(
"Failed to revoke a validator connection request",
);
}
}
}