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Commit f677b40e authored by Max Inden's avatar Max Inden Committed by GitHub
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client/authority-discovery: Throttle DHT requests (#7018) 

* client/authority-discovery: Throttle DHT requests

Instead of passing one DHT query for each authority down to the network
every query interval, only pass MAX_IN_FLIGHT_LOOKUPS at a given point
in time, triggering new ones when previous ones return.

* client/authority-discovery/worker/test: Fix wrong constant
parent aba092e8
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substrate/client/authority-discovery/src/error.rs
+ 2
− 4
View file @ f677b40e
......@@ -34,10 +34,8 @@ pub enum Error {
HashingAuthorityId(libp2p::core::multiaddr::multihash::EncodeError),
/// Failed calling into the Substrate runtime.
CallingRuntime(sp_blockchain::Error),
/// From the Dht we only get the hashed authority id. In order to retrieve the actual authority id and to ensure it
/// is actually an authority, we match the hash against the hash of the authority id of all other authorities. This
/// error is the result of the above failing.
MatchingHashedAuthorityIdWithAuthorityId,
/// Received a dht record with a key that does not match any in-flight awaited keys.
ReceivingUnexpectedRecord,
/// Failed to set the authority discovery peerset priority group in the peerset module.
SettingPeersetPriorityGroup(String),
/// Failed to encode a protobuf payload.
......
substrate/client/authority-discovery/src/worker.rs
+ 93
− 52
View file @ f677b40e
......@@ -35,6 +35,7 @@ use libp2p::{core::multiaddr, multihash::Multihash};
use log::{debug, error, log_enabled};
use prometheus_endpoint::{Counter, CounterVec, Gauge, Opts, U64, register};
use prost::Message;
use rand::{seq::SliceRandom, thread_rng};
use sc_client_api::blockchain::HeaderBackend;
use sc_network::{
config::MultiaddrWithPeerId,
......@@ -70,6 +71,9 @@ const AUTHORITIES_PRIORITY_GROUP_NAME: &'static str = "authorities";
/// Maximum number of addresses cached per authority. Additional addresses are discarded.
const MAX_ADDRESSES_PER_AUTHORITY: usize = 10;
/// Maximum number of in-flight DHT lookups at any given point in time.
const MAX_IN_FLIGHT_LOOKUPS: usize = 8;
/// Role an authority discovery module can run as.
pub enum Role {
/// Actual authority as well as a reference to its key store.
......@@ -137,12 +141,17 @@ where
/// Interval to be proactive, publishing own addresses.
publish_interval: Interval,
/// Interval on which to query for addresses of other authorities.
/// Interval at which to request addresses of authorities, refilling the pending lookups queue.
query_interval: Interval,
/// Interval on which to set the peerset priority group to a new random
/// set of addresses.
priority_group_set_interval: Interval,
/// Queue of throttled lookups pending to be passed to the network.
pending_lookups: Vec<AuthorityId>,
/// Set of in-flight lookups.
in_flight_lookups: HashMap<libp2p::kad::record::Key, AuthorityId>,
addr_cache: addr_cache::AddrCache,
metrics: Option<Metrics>,
......@@ -183,8 +192,8 @@ where
Duration::from_secs(12 * 60 * 60),
);
// External addresses of other authorities can change at any given point in time. The
// interval on which to query for external addresses of other authorities is a trade off
// External addresses of remote authorities can change at any given point in time. The
// interval on which to trigger new queries for the current authorities is a trade off
// between efficiency and performance.
let query_interval_start = Instant::now() + LIBP2P_KADEMLIA_BOOTSTRAP_TIME;
let query_interval_duration = Duration::from_secs(10 * 60);
......@@ -193,9 +202,9 @@ where
// Querying 500 [`AuthorityId`]s takes ~1m on the Kusama DHT (10th of August 2020) when
// comparing `authority_discovery_authority_addresses_requested_total` and
// `authority_discovery_dht_event_received`. With that in mind set the peerset priority
// group on the same interval as the [`query_interval`] above, just delayed by 2 minutes.
// group on the same interval as the [`query_interval`] above, just delayed by 5 minutes.
let priority_group_set_interval = interval_at(
query_interval_start + Duration::from_secs(2 * 60),
query_interval_start + Duration::from_secs(5 * 60),
query_interval_duration,
);
......@@ -229,6 +238,8 @@ where
publish_interval,
query_interval,
priority_group_set_interval,
pending_lookups: Vec::new(),
in_flight_lookups: HashMap::new(),
addr_cache,
role,
metrics,
......@@ -270,7 +281,9 @@ where
if let Some(metrics) = &self.metrics {
metrics.publish.inc();
metrics.amount_last_published.set(addresses.len() as u64);
metrics.amount_addresses_last_published.set(
addresses.len().try_into().unwrap_or(std::u64::MAX),
);
}
let mut serialized_addresses = vec![];
......@@ -314,15 +327,9 @@ where
Ok(())
}
fn request_addresses_of_others(&mut self) -> Result<()> {
fn refill_pending_lookups_queue(&mut self) -> Result<()> {
let id = BlockId::hash(self.client.info().best_hash);
let authorities = self
.client
.runtime_api()
.authorities(&id)
.map_err(Error::CallingRuntime)?;
let local_keys = match &self.role {
Role::Authority(key_store) => {
key_store.read()
......@@ -333,21 +340,52 @@ where
Role::Sentry => HashSet::new(),
};
for authority_id in authorities.iter() {
// Make sure we don't look up our own keys.
if !local_keys.contains(authority_id.as_ref()) {
if let Some(metrics) = &self.metrics {
metrics.request.inc();
}
let mut authorities = self
.client
.runtime_api()
.authorities(&id)
.map_err(Error::CallingRuntime)?
.into_iter()
.filter(|id| !local_keys.contains(id.as_ref()))
.collect();
self.network
.get_value(&hash_authority_id(authority_id.as_ref()));
}
self.addr_cache.retain_ids(&authorities);
authorities.shuffle(&mut thread_rng());
self.pending_lookups = authorities;
// Ignore all still in-flight lookups. Those that are still in-flight are likely stalled as
// query interval ticks are far enough apart for all lookups to succeed.
self.in_flight_lookups.clear();
if let Some(metrics) = &self.metrics {
metrics.requests_pending.set(
self.pending_lookups.len().try_into().unwrap_or(std::u64::MAX),
);
}
Ok(())
}
fn start_new_lookups(&mut self) {
while self.in_flight_lookups.len() < MAX_IN_FLIGHT_LOOKUPS {
let authority_id = match self.pending_lookups.pop() {
Some(authority) => authority,
None => return,
};
let hash = hash_authority_id(authority_id.as_ref());
self.network
.get_value(&hash);
self.in_flight_lookups.insert(hash, authority_id);
if let Some(metrics) = &self.metrics {
metrics.requests.inc();
metrics.requests_pending.set(
self.pending_lookups.len().try_into().unwrap_or(std::u64::MAX),
);
}
}
}
/// Handle incoming Dht events.
///
/// Returns either:
......@@ -385,10 +423,17 @@ where
metrics.dht_event_received.with_label_values(&["value_not_found"]).inc();
}
debug!(
target: LOG_TARGET,
"Value for hash '{:?}' not found on Dht.", hash
)
if self.in_flight_lookups.remove(&hash).is_some() {
debug!(
target: LOG_TARGET,
"Value for hash '{:?}' not found on Dht.", hash
)
} else {
debug!(
target: LOG_TARGET,
"Received 'ValueNotFound' for unexpected hash '{:?}'.", hash
)
}
},
Some(DhtEvent::ValuePut(hash)) => {
if let Some(metrics) = &self.metrics {
......@@ -434,23 +479,9 @@ where
}
})?.ok_or(Error::ReceivingDhtValueFoundEventWithNoRecords)?;
let authorities = {
let block_id = BlockId::hash(self.client.info().best_hash);
// From the Dht we only get the hashed authority id. In order to retrieve the actual
// authority id and to ensure it is actually an authority, we match the hash against the
// hash of the authority id of all other authorities.
let authorities = self.client.runtime_api().authorities(&block_id)?;
self.addr_cache.retain_ids(&authorities);
authorities
.into_iter()
.map(|id| (hash_authority_id(id.as_ref()), id))
.collect::<HashMap<_, _>>()
};
// Check if the event origins from an authority in the current or next authority set.
let authority_id: &AuthorityId = authorities
.get(&remote_key)
.ok_or(Error::MatchingHashedAuthorityIdWithAuthorityId)?;
let authority_id: AuthorityId = self.in_flight_lookups
.remove(&remote_key)
.ok_or(Error::ReceivingUnexpectedRecord)?;
let local_peer_id = self.network.local_peer_id();
......@@ -463,7 +494,7 @@ where
let signature = AuthoritySignature::decode(&mut &signature[..])
.map_err(Error::EncodingDecodingScale)?;
if !AuthorityPair::verify(&signature, &addresses, authority_id) {
if !AuthorityPair::verify(&signature, &addresses, &authority_id) {
return Err(Error::VerifyingDhtPayload);
}
......@@ -503,7 +534,7 @@ where
.collect();
if !remote_addresses.is_empty() {
self.addr_cache.insert(authority_id.clone(), remote_addresses);
self.addr_cache.insert(authority_id, remote_addresses);
if let Some(metrics) = &self.metrics {
metrics.known_authorities_count.set(
self.addr_cache.num_ids().try_into().unwrap_or(std::u64::MAX)
......@@ -610,15 +641,15 @@ where
}
}
// Request addresses of authorities.
// Request addresses of authorities, refilling the pending lookups queue.
if let Poll::Ready(_) = self.query_interval.poll_next_unpin(cx) {
// Register waker of underlying task for next interval.
while let Poll::Ready(_) = self.query_interval.poll_next_unpin(cx) {}
if let Err(e) = self.request_addresses_of_others() {
if let Err(e) = self.refill_pending_lookups_queue() {
error!(
target: LOG_TARGET,
"Failed to request addresses of authorities: {:?}", e,
"Failed to refill pending lookups queue: {:?}", e,
);
}
}
......@@ -652,6 +683,8 @@ where
}
}
self.start_new_lookups();
Poll::Pending
}
}
......@@ -712,8 +745,9 @@ fn interval_at(start: Instant, duration: Duration) -> Interval {
#[derive(Clone)]
pub(crate) struct Metrics {
publish: Counter<U64>,
amount_last_published: Gauge<U64>,
request: Counter<U64>,
amount_addresses_last_published: Gauge<U64>,
requests: Counter<U64>,
requests_pending: Gauge<U64>,
dht_event_received: CounterVec<U64>,
handle_value_found_event_failure: Counter<U64>,
known_authorities_count: Gauge<U64>,
......@@ -730,7 +764,7 @@ impl Metrics {
)?,
registry,
)?,
amount_last_published: register(
amount_addresses_last_published: register(
Gauge::new(
"authority_discovery_amount_external_addresses_last_published",
"Number of external addresses published when authority discovery last \
......@@ -738,7 +772,7 @@ impl Metrics {
)?,
registry,
)?,
request: register(
requests: register(
Counter::new(
"authority_discovery_authority_addresses_requested_total",
"Number of times authority discovery has requested external addresses of a \
......@@ -746,6 +780,13 @@ impl Metrics {
)?,
registry,
)?,
requests_pending: register(
Gauge::new(
"authority_discovery_authority_address_requests_pending",
"Number of pending authority address requests."
)?,
registry,
)?,
dht_event_received: register(
CounterVec::new(
Opts::new(
......
substrate/client/authority-discovery/src/worker/tests.rs
+ 159
− 107
View file @ f677b40e
......@@ -221,6 +221,41 @@ impl NetworkStateInfo for TestNetwork {
}
}
fn build_dht_event(
addresses: Vec<Multiaddr>,
public_key: AuthorityId,
key_store: &BareCryptoStorePtr,
) -> (libp2p::kad::record::Key, Vec<u8>) {
let mut serialized_addresses = vec![];
schema::AuthorityAddresses {
addresses: addresses.into_iter().map(|a| a.to_vec()).collect()
}.encode(&mut serialized_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let signature = key_store.read()
.sign_with(
key_types::AUTHORITY_DISCOVERY,
&public_key.clone().into(),
serialized_addresses.as_slice(),
)
.map_err(|_| Error::Signing)
.unwrap();
let mut signed_addresses = vec![];
schema::SignedAuthorityAddresses {
addresses: serialized_addresses.clone(),
signature,
}
.encode(&mut signed_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let key = hash_authority_id(&public_key.to_raw_vec());
let value = signed_addresses;
(key, value)
}
#[test]
fn new_registers_metrics() {
let (_dht_event_tx, dht_event_rx) = channel(1000);
......@@ -247,7 +282,7 @@ fn new_registers_metrics() {
}
#[test]
fn request_addresses_of_others_triggers_dht_get_query() {
fn triggers_dht_get_query() {
let _ = ::env_logger::try_init();
let (_dht_event_tx, dht_event_rx) = channel(1000);
......@@ -262,7 +297,6 @@ fn request_addresses_of_others_triggers_dht_get_query() {
let network: Arc<TestNetwork> = Arc::new(Default::default());
let key_store = KeyStore::new();
let (_to_worker, from_service) = mpsc::channel(0);
let mut worker = Worker::new(
from_service,
......@@ -274,7 +308,12 @@ fn request_addresses_of_others_triggers_dht_get_query() {
None,
);
worker.request_addresses_of_others().unwrap();
worker.refill_pending_lookups_queue().unwrap();
futures::executor::block_on(futures::future::poll_fn(|cx| {
assert_eq!(Poll::Pending, worker.poll_unpin(cx));
Poll::Ready(())
}));
// Expect authority discovery to request new records from the dht.
assert_eq!(network.get_value_call.lock().unwrap().len(), 2);
......@@ -352,6 +391,9 @@ fn publish_discover_cycle() {
dht_event_tx.try_send(dht_event).unwrap();
let f = |cx: &mut Context<'_>| -> Poll<()> {
worker.refill_pending_lookups_queue().unwrap();
worker.start_new_lookups();
// Make authority discovery handle the event.
if let Poll::Ready(e) = worker.handle_dht_events(cx) {
panic!("Unexpected error: {:?}", e);
......@@ -547,40 +589,11 @@ fn never_add_own_address_to_priority_group() {
))
};
let dht_event = {
let addresses = vec![
sentry_multiaddr.to_vec(),
random_multiaddr.to_vec(),
];
let mut serialized_addresses = vec![];
schema::AuthorityAddresses { addresses }
.encode(&mut serialized_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let signature = validator_key_store.read()
.sign_with(
key_types::AUTHORITY_DISCOVERY,
&validator_public.clone().into(),
serialized_addresses.as_slice(),
)
.map_err(|_| Error::Signing)
.unwrap();
let mut signed_addresses = vec![];
schema::SignedAuthorityAddresses {
addresses: serialized_addresses.clone(),
signature,
}
.encode(&mut signed_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let key = hash_authority_id(&validator_public.to_raw_vec());
let value = signed_addresses;
(key, value)
};
let dht_event = build_dht_event(
vec![sentry_multiaddr, random_multiaddr.clone()],
validator_public.into(),
&validator_key_store,
);
let (_dht_event_tx, dht_event_rx) = channel(1);
let sentry_test_api = Arc::new(TestApi {
......@@ -599,6 +612,9 @@ fn never_add_own_address_to_priority_group() {
None,
);
sentry_worker.refill_pending_lookups_queue().unwrap();
sentry_worker.start_new_lookups();
sentry_worker.handle_dht_value_found_event(vec![dht_event]).unwrap();
sentry_worker.set_priority_group().unwrap();
......@@ -625,43 +641,19 @@ fn limit_number_of_addresses_added_to_cache_per_authority() {
.sr25519_generate_new(key_types::AUTHORITY_DISCOVERY, None)
.unwrap();
let dht_event = {
let addresses = (0..100).map(|_| {
let peer_id = PeerId::random();
let address: Multiaddr = "/ip6/2001:db8:0:0:0:0:0:1/tcp/30333".parse().unwrap();
address.with(multiaddr::Protocol::P2p(
peer_id.into(),
)).to_vec()
}).collect();
let mut serialized_addresses = vec![];
schema::AuthorityAddresses { addresses }
.encode(&mut serialized_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let signature = remote_key_store.read()
.sign_with(
key_types::AUTHORITY_DISCOVERY,
&remote_public.clone().into(),
serialized_addresses.as_slice(),
)
.map_err(|_| Error::Signing)
.unwrap();
let mut signed_addresses = vec![];
schema::SignedAuthorityAddresses {
addresses: serialized_addresses.clone(),
signature,
}
.encode(&mut signed_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let addresses = (0..100).map(|_| {
let peer_id = PeerId::random();
let address: Multiaddr = "/ip6/2001:db8:0:0:0:0:0:1/tcp/30333".parse().unwrap();
address.with(multiaddr::Protocol::P2p(
peer_id.into(),
))
}).collect();
let key = hash_authority_id(&remote_public.to_raw_vec());
let value = signed_addresses;
(key, value)
};
let dht_event = build_dht_event(
addresses,
remote_public.into(),
&remote_key_store,
);
let (_dht_event_tx, dht_event_rx) = channel(1);
......@@ -676,6 +668,9 @@ fn limit_number_of_addresses_added_to_cache_per_authority() {
None,
);
worker.refill_pending_lookups_queue().unwrap();
worker.start_new_lookups();
worker.handle_dht_value_found_event(vec![dht_event]).unwrap();
assert_eq!(
MAX_ADDRESSES_PER_AUTHORITY,
......@@ -700,40 +695,14 @@ fn do_not_cache_addresses_without_peer_id() {
let multiaddr_without_peer_id: Multiaddr = "/ip6/2001:db8:0:0:0:0:0:1/tcp/30333".parse().unwrap();
let dht_event = {
let addresses = vec![
multiaddr_with_peer_id.to_vec(),
multiaddr_without_peer_id.to_vec(),
];
let mut serialized_addresses = vec![];
schema::AuthorityAddresses { addresses }
.encode(&mut serialized_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let signature = remote_key_store.read()
.sign_with(
key_types::AUTHORITY_DISCOVERY,
&remote_public.clone().into(),
serialized_addresses.as_slice(),
)
.map_err(|_| Error::Signing)
.unwrap();
let mut signed_addresses = vec![];
schema::SignedAuthorityAddresses {
addresses: serialized_addresses.clone(),
signature,
}
.encode(&mut signed_addresses)
.map_err(Error::EncodingProto)
.unwrap();
let key = hash_authority_id(&remote_public.to_raw_vec());
let value = signed_addresses;
(key, value)
};
let dht_event = build_dht_event(
vec![
multiaddr_with_peer_id.clone(),
multiaddr_without_peer_id,
],
remote_public.into(),
&remote_key_store,
);
let (_dht_event_tx, dht_event_rx) = channel(1);
let local_test_api = Arc::new(TestApi {
......@@ -754,6 +723,9 @@ fn do_not_cache_addresses_without_peer_id() {
None,
);
local_worker.refill_pending_lookups_queue().unwrap();
local_worker.start_new_lookups();
local_worker.handle_dht_value_found_event(vec![dht_event]).unwrap();
assert_eq!(
......@@ -826,3 +798,83 @@ fn addresses_to_publish_respects_existing_p2p_protocol() {
"Expected Multiaddr from `TestNetwork` to not be altered.",
);
}
#[test]
fn lookup_throttling() {
let remote_multiaddr = {
let peer_id = PeerId::random();
let address: Multiaddr = "/ip6/2001:db8:0:0:0:0:0:1/tcp/30333".parse().unwrap();
address.with(multiaddr::Protocol::P2p(
peer_id.into(),
))
};
let remote_key_store = KeyStore::new();
let remote_public_keys: Vec<AuthorityId> = (0..20).map(|_| {
remote_key_store
.write()
.sr25519_generate_new(key_types::AUTHORITY_DISCOVERY, None)
.unwrap().into()
}).collect();
let remote_hash_to_key = remote_public_keys.iter()
.map(|k| (hash_authority_id(k.as_ref()), k.clone()))
.collect::<HashMap<_, _>>();
let (mut dht_event_tx, dht_event_rx) = channel(1);
let (_to_worker, from_service) = mpsc::channel(0);
let network = Arc::new(TestNetwork::default());
let mut worker = Worker::new(
from_service,
Arc::new(TestApi { authorities: remote_public_keys.clone() }),
network.clone(),
vec![],
dht_event_rx.boxed(),
Role::Sentry,
None,
);
futures::executor::block_on(futures::future::poll_fn(|cx| {
worker.refill_pending_lookups_queue().unwrap();
// Assert worker to trigger MAX_IN_FLIGHT_LOOKUPS lookups.
assert_eq!(Poll::Pending, worker.poll_unpin(cx));
assert_eq!(worker.pending_lookups.len(), remote_public_keys.len() - MAX_IN_FLIGHT_LOOKUPS);
assert_eq!(worker.in_flight_lookups.len(), MAX_IN_FLIGHT_LOOKUPS);
assert_eq!(network.get_value_call.lock().unwrap().len(), MAX_IN_FLIGHT_LOOKUPS);
// Make first lookup succeed.
let remote_hash = network.get_value_call.lock().unwrap().pop().unwrap();
let remote_key: AuthorityId = remote_hash_to_key.get(&remote_hash).unwrap().clone();
let dht_event = {
let (key, value) = build_dht_event(vec![remote_multiaddr.clone()], remote_key, &remote_key_store);
sc_network::DhtEvent::ValueFound(vec![(key, value)])
};
dht_event_tx.try_send(dht_event).expect("Channel has capacity of 1.");
// Assert worker to trigger another lookup.
assert_eq!(Poll::Pending, worker.poll_unpin(cx));
assert_eq!(worker.pending_lookups.len(), remote_public_keys.len() - MAX_IN_FLIGHT_LOOKUPS - 1);
assert_eq!(worker.in_flight_lookups.len(), MAX_IN_FLIGHT_LOOKUPS);
assert_eq!(network.get_value_call.lock().unwrap().len(), MAX_IN_FLIGHT_LOOKUPS);
// Make second one fail.
let remote_hash = network.get_value_call.lock().unwrap().pop().unwrap();
let dht_event = sc_network::DhtEvent::ValueNotFound(remote_hash);
dht_event_tx.try_send(dht_event).expect("Channel has capacity of 1.");
// Assert worker to trigger another lookup.
assert_eq!(Poll::Pending, worker.poll_unpin(cx));
assert_eq!(worker.pending_lookups.len(), remote_public_keys.len() - MAX_IN_FLIGHT_LOOKUPS - 2);
assert_eq!(worker.in_flight_lookups.len(), MAX_IN_FLIGHT_LOOKUPS);
assert_eq!(network.get_value_call.lock().unwrap().len(), MAX_IN_FLIGHT_LOOKUPS);
worker.refill_pending_lookups_queue().unwrap();
// Assert worker to restock pending lookups and forget about in-flight lookups.
assert_eq!(worker.pending_lookups.len(), remote_public_keys.len());
assert_eq!(worker.in_flight_lookups.len(), 0);
Poll::Ready(())
}));
}
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