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// 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/>.
//! # Overseer
//!
//! `overseer` implements the Overseer architecture described in the
//! [implementers-guide](https://github.com/paritytech/polkadot/blob/master/roadmap/implementers-guide/guide.md).
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//! For the motivations behind implementing the overseer itself you should
//! check out that guide, documentation in this crate will be mostly discussing
//! technical stuff.
//!
//! An `Overseer` is something that allows spawning/stopping and overseing
//! asynchronous tasks as well as establishing a well-defined and easy to use
//! protocol that the tasks can use to communicate with each other. It is desired
//! that this protocol is the only way tasks communicate with each other, however
//! at this moment there are no foolproof guards against other ways of communication.
//!
//! The `Overseer` is instantiated with a pre-defined set of `Subsystems` that
//! share the same behavior from `Overseer`'s point of view.
//!
//! ```text
//! +-----------------------------+
//! | Overseer |
//! +-----------------------------+
//!
//! ................| Overseer "holds" these and uses |..............
//! . them to (re)start things .
//! . .
//! . +-------------------+ +---------------------+ .
//! . | Subsystem1 | | Subsystem2 | .
//! . +-------------------+ +---------------------+ .
//! . | | .
//! ..................................................................
//! | |
//! start() start()
//! V V
//! ..................| Overseer "runs" these |.......................
//! . +--------------------+ +---------------------+ .
//! . | SubsystemInstance1 | | SubsystemInstance2 | .
//! . +--------------------+ +---------------------+ .
//! ..................................................................
//! ```
use std::fmt::Debug;
use std::pin::Pin;
use std::collections::{hash_map, HashMap};
use futures::channel::{mpsc, oneshot};
use futures::{
pending, poll, select,
Future, FutureExt, SinkExt, StreamExt,
};
use futures_timer::Delay;
use streamunordered::{StreamYield, StreamUnordered};
use polkadot_primitives::v1::{Block, BlockNumber, Hash};
use client::{BlockImportNotification, BlockchainEvents, FinalityNotification};
CandidateValidationMessage, CandidateBackingMessage,
CandidateSelectionMessage, ChainApiMessage, StatementDistributionMessage,
AvailabilityDistributionMessage, BitfieldSigningMessage, BitfieldDistributionMessage,
ProvisionerMessage, PoVDistributionMessage, RuntimeApiMessage,
AvailabilityStoreMessage, NetworkBridgeMessage, AllMessages, CollationGenerationMessage, CollatorProtocolMessage,
};
pub use polkadot_subsystem::{
Subsystem, SubsystemContext, OverseerSignal, FromOverseer, SubsystemError, SubsystemResult,
SpawnedSubsystem, ActiveLeavesUpdate,
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};
use polkadot_node_subsystem_util::metrics::{self, prometheus};
use polkadot_node_primitives::SpawnNamed;
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// A capacity of bounded channels inside the overseer.
const CHANNEL_CAPACITY: usize = 1024;
// A graceful `Overseer` teardown time delay.
const STOP_DELAY: u64 = 1;
// Target for logs.
const LOG_TARGET: &'static str = "overseer";
/// A type of messages that are sent from [`Subsystem`] to [`Overseer`].
///
/// It wraps a system-wide [`AllMessages`] type that represents all possible
/// messages in the system.
///
/// [`AllMessages`]: enum.AllMessages.html
/// [`Subsystem`]: trait.Subsystem.html
/// [`Overseer`]: struct.Overseer.html
enum ToOverseer {
/// This is a message sent by a `Subsystem`.
SubsystemMessage(AllMessages),
/// A message that wraps something the `Subsystem` is desiring to
/// spawn on the overseer and a `oneshot::Sender` to signal the result
/// of the spawn.
SpawnJob {
name: &'static str,
/// Same as `SpawnJob` but for blocking tasks to be executed on a
/// dedicated thread pool.
SpawnBlockingJob {
name: &'static str,
s: BoxFuture<'static, ()>,
},
/// An event telling the `Overseer` on the particular block
/// that has been imported or finalized.
///
/// This structure exists solely for the purposes of decoupling
/// `Overseer` code from the client code and the necessity to call
/// `HeaderBackend::block_number_from_id()`.
pub struct BlockInfo {
/// hash of the block.
pub hash: Hash,
/// hash of the parent block.
pub parent_hash: Hash,
/// block's number.
pub number: BlockNumber,
}
impl From<BlockImportNotification<Block>> for BlockInfo {
fn from(n: BlockImportNotification<Block>) -> Self {
BlockInfo {
hash: n.hash,
parent_hash: n.header.parent_hash,
number: n.header.number,
}
}
}
impl From<FinalityNotification<Block>> for BlockInfo {
fn from(n: FinalityNotification<Block>) -> Self {
BlockInfo {
hash: n.hash,
parent_hash: n.header.parent_hash,
number: n.header.number,
}
}
}
BlockImported(BlockInfo),
BlockFinalized(BlockInfo),
ExternalRequest(ExternalRequest),
/// Some request from outer world.
enum ExternalRequest {
WaitForActivation {
hash: Hash,
response_channel: oneshot::Sender<()>,
},
}
/// A handler used to communicate with the [`Overseer`].
///
/// [`Overseer`]: struct.Overseer.html
pub struct OverseerHandler {
events_tx: mpsc::Sender<Event>,
}
impl OverseerHandler {
/// Inform the `Overseer` that that some block was imported.
pub async fn block_imported(&mut self, block: BlockInfo) -> SubsystemResult<()> {
self.events_tx.send(Event::BlockImported(block)).await.map_err(Into::into)
}
/// Send some message to one of the `Subsystem`s.
pub async fn send_msg(&mut self, msg: impl Into<AllMessages>) -> SubsystemResult<()> {
self.events_tx.send(Event::MsgToSubsystem(msg.into())).await.map_err(Into::into)
}
/// Inform the `Overseer` that that some block was finalized.
pub async fn block_finalized(&mut self, block: BlockInfo) -> SubsystemResult<()> {
self.events_tx.send(Event::BlockFinalized(block)).await.map_err(Into::into)
}
/// Wait for a block with the given hash to be in the active-leaves set.
/// This method is used for external code like `Proposer` that doesn't subscribe to Overseer's signals.
///
/// The response channel responds if the hash was activated and is closed if the hash was deactivated.
/// Note that due the fact the overseer doesn't store the whole active-leaves set, only deltas,
/// the response channel may never return if the hash was deactivated before this call.
/// In this case, it's the caller's responsibility to ensure a timeout is set.
pub async fn wait_for_activation(&mut self, hash: Hash, response_channel: oneshot::Sender<()>) -> SubsystemResult<()> {
self.events_tx.send(Event::ExternalRequest(ExternalRequest::WaitForActivation {
hash,
response_channel
})).await.map_err(Into::into)
}
/// Tell `Overseer` to shutdown.
pub async fn stop(&mut self) -> SubsystemResult<()> {
self.events_tx.send(Event::Stop).await.map_err(Into::into)
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/// Glues together the [`Overseer`] and `BlockchainEvents` by forwarding
/// import and finality notifications into the [`OverseerHandler`].
///
/// [`Overseer`]: struct.Overseer.html
/// [`OverseerHandler`]: struct.OverseerHandler.html
pub async fn forward_events<P: BlockchainEvents<Block>>(
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mut handler: OverseerHandler,
) -> SubsystemResult<()> {
let mut finality = client.finality_notification_stream();
let mut imports = client.import_notification_stream();
loop {
select! {
f = finality.next() => {
match f {
Some(block) => {
handler.block_finalized(block.into()).await?;
}
None => break,
}
},
i = imports.next() => {
match i {
Some(block) => {
handler.block_imported(block.into()).await?;
}
None => break,
}
},
complete => break,
}
}
Ok(())
}
impl Debug for ToOverseer {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
ToOverseer::SubsystemMessage(msg) => {
write!(f, "OverseerMessage::SubsystemMessage({:?})", msg)
}
ToOverseer::SpawnJob { .. } => write!(f, "OverseerMessage::Spawn(..)"),
ToOverseer::SpawnBlockingJob { .. } => write!(f, "OverseerMessage::SpawnBlocking(..)")
}
}
}
/// A running instance of some [`Subsystem`].
///
/// [`Subsystem`]: trait.Subsystem.html
tx: mpsc::Sender<FromOverseer<M>>,
}
/// A context type that is given to the [`Subsystem`] upon spawning.
/// It can be used by [`Subsystem`] to communicate with other [`Subsystem`]s
/// or to spawn it's [`SubsystemJob`]s.
///
/// [`Overseer`]: struct.Overseer.html
/// [`Subsystem`]: trait.Subsystem.html
/// [`SubsystemJob`]: trait.SubsystemJob.html
#[derive(Debug)]
pub struct OverseerSubsystemContext<M>{
rx: mpsc::Receiver<FromOverseer<M>>,
tx: mpsc::Sender<ToOverseer>,
}
#[async_trait::async_trait]
impl<M: Send + 'static> SubsystemContext for OverseerSubsystemContext<M> {
type Message = M;
async fn try_recv(&mut self) -> Result<Option<FromOverseer<M>>, ()> {
match poll!(self.rx.next()) {
Poll::Ready(Some(msg)) => Ok(Some(msg)),
Poll::Ready(None) => Err(()),
Poll::Pending => Ok(None),
}
}
async fn recv(&mut self) -> SubsystemResult<FromOverseer<M>> {
async fn spawn(&mut self, name: &'static str, s: Pin<Box<dyn Future<Output = ()> + Send>>)
-> SubsystemResult<()>
{
}).await.map_err(Into::into)
async fn spawn_blocking(&mut self, name: &'static str, s: Pin<Box<dyn Future<Output = ()> + Send>>)
-> SubsystemResult<()>
{
self.tx.send(ToOverseer::SpawnBlockingJob {
name,
s,
}).await.map_err(Into::into)
async fn send_message(&mut self, msg: AllMessages) -> SubsystemResult<()> {
self.tx.send(ToOverseer::SubsystemMessage(msg)).await.map_err(Into::into)
async fn send_messages<T>(&mut self, msgs: T) -> SubsystemResult<()>
where T: IntoIterator<Item = AllMessages> + Send, T::IntoIter: Send
{
let mut msgs = stream::iter(msgs.into_iter().map(ToOverseer::SubsystemMessage).map(Ok));
self.tx.send_all(&mut msgs).await.map_err(Into::into)
}
}
/// A subsystem that we oversee.
///
/// Ties together the [`Subsystem`] itself and it's running instance
/// (which may be missing if the [`Subsystem`] is not running at the moment
/// for whatever reason).
///
/// [`Subsystem`]: trait.Subsystem.html
instance: Option<SubsystemInstance<M>>,
}
/// The `Overseer` itself.
pub struct Overseer<S: SpawnNamed> {
/// A candidate validation subsystem.
candidate_validation_subsystem: OverseenSubsystem<CandidateValidationMessage>,
/// A candidate backing subsystem.
candidate_backing_subsystem: OverseenSubsystem<CandidateBackingMessage>,
/// A candidate selection subsystem.
candidate_selection_subsystem: OverseenSubsystem<CandidateSelectionMessage>,
/// A statement distribution subsystem.
statement_distribution_subsystem: OverseenSubsystem<StatementDistributionMessage>,
/// An availability distribution subsystem.
availability_distribution_subsystem: OverseenSubsystem<AvailabilityDistributionMessage>,
/// A bitfield signing subsystem.
bitfield_signing_subsystem: OverseenSubsystem<BitfieldSigningMessage>,
/// A bitfield distribution subsystem.
bitfield_distribution_subsystem: OverseenSubsystem<BitfieldDistributionMessage>,
/// A provisioner subsystem.
provisioner_subsystem: OverseenSubsystem<ProvisionerMessage>,
/// A PoV distribution subsystem.
pov_distribution_subsystem: OverseenSubsystem<PoVDistributionMessage>,
/// A runtime API subsystem.
runtime_api_subsystem: OverseenSubsystem<RuntimeApiMessage>,
/// An availability store subsystem.
availability_store_subsystem: OverseenSubsystem<AvailabilityStoreMessage>,
/// A network bridge subsystem.
network_bridge_subsystem: OverseenSubsystem<NetworkBridgeMessage>,
/// A Chain API subsystem.
chain_api_subsystem: OverseenSubsystem<ChainApiMessage>,
/// A Collation Generation subsystem.
collation_generation_subsystem: OverseenSubsystem<CollationGenerationMessage>,
/// A Collator Protocol subsystem.
collator_protocol_subsystem: OverseenSubsystem<CollatorProtocolMessage>,
/// Spawner to spawn tasks to.
s: S,
/// Here we keep handles to spawned subsystems to be notified when they terminate.
running_subsystems: FuturesUnordered<BoxFuture<'static, ()>>,
/// Gather running subsystms' outbound streams into one.
running_subsystems_rx: StreamUnordered<mpsc::Receiver<ToOverseer>>,
/// Events that are sent to the overseer from the outside world
events_rx: mpsc::Receiver<Event>,
/// External listeners waiting for a hash to be in the active-leave set.
activation_external_listeners: HashMap<Hash, Vec<oneshot::Sender<()>>>,
/// A set of leaves that `Overseer` starts working with.
///
/// Drained at the beginning of `run` and never used again.
leaves: Vec<(Hash, BlockNumber)>,
/// The set of the "active leaves".
active_leaves: HashMap<Hash, BlockNumber>,
/// Various Prometheus metrics.
metrics: Metrics,
/// This struct is passed as an argument to create a new instance of an [`Overseer`].
///
/// As any entity that satisfies the interface may act as a [`Subsystem`] this allows
/// mocking in the test code:
///
/// Each [`Subsystem`] is supposed to implement some interface that is generic over
/// message type that is specific to this [`Subsystem`]. At the moment not all
/// subsystems are implemented and the rest can be mocked with the [`DummySubsystem`].
///
/// [`Subsystem`]: trait.Subsystem.html
/// [`DummySubsystem`]: struct.DummySubsystem.html
pub struct AllSubsystems<CV, CB, CS, SD, AD, BS, BD, P, PoVD, RA, AS, NB, CA, CG, CP> {
/// A candidate validation subsystem.
pub candidate_validation: CV,
/// A candidate backing subsystem.
pub candidate_backing: CB,
/// A candidate selection subsystem.
pub candidate_selection: CS,
/// A statement distribution subsystem.
pub statement_distribution: SD,
/// An availability distribution subsystem.
pub availability_distribution: AD,
/// A bitfield signing subsystem.
pub bitfield_signing: BS,
/// A bitfield distribution subsystem.
pub bitfield_distribution: BD,
/// A provisioner subsystem.
pub provisioner: P,
/// A PoV distribution subsystem.
pub pov_distribution: PoVD,
/// A runtime API subsystem.
pub runtime_api: RA,
/// An availability store subsystem.
pub availability_store: AS,
/// A network bridge subsystem.
pub network_bridge: NB,
/// A Chain API subsystem.
pub chain_api: CA,
/// A Collation Generation subsystem.
pub collation_generation: CG,
/// A Collator Protocol subsystem.
pub collator_protocol: CP,
/// Overseer Prometheus metrics.
#[derive(Clone)]
struct MetricsInner {
activated_heads_total: prometheus::Counter<prometheus::U64>,
deactivated_heads_total: prometheus::Counter<prometheus::U64>,
messages_relayed_total: prometheus::Counter<prometheus::U64>,
}
#[derive(Default, Clone)]
struct Metrics(Option<MetricsInner>);
impl Metrics {
fn on_head_activated(&self) {
if let Some(metrics) = &self.0 {
metrics.activated_heads_total.inc();
}
}
fn on_head_deactivated(&self) {
if let Some(metrics) = &self.0 {
metrics.deactivated_heads_total.inc();
}
}
fn on_message_relayed(&self) {
if let Some(metrics) = &self.0 {
metrics.messages_relayed_total.inc();
}
}
}
impl metrics::Metrics for Metrics {
fn try_register(registry: &prometheus::Registry) -> Result<Self, prometheus::PrometheusError> {
let metrics = MetricsInner {
activated_heads_total: prometheus::register(
prometheus::Counter::new(
"parachain_activated_heads_total",
"Number of activated heads."
)?,
registry,
)?,
deactivated_heads_total: prometheus::register(
prometheus::Counter::new(
"parachain_deactivated_heads_total",
"Number of deactivated heads."
)?,
registry,
)?,
messages_relayed_total: prometheus::register(
prometheus::Counter::new(
"parachain_messages_relayed_total",
"Number of messages relayed by Overseer."
)?,
registry,
)?,
};
Ok(Metrics(Some(metrics)))
}
}
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{
/// Create a new intance of the `Overseer` with a fixed set of [`Subsystem`]s.
///
/// ```text
/// +------------------------------------+
/// | Overseer |
/// +------------------------------------+
/// / | | \
/// ................. subsystems...................................
/// . +-----------+ +-----------+ +----------+ +---------+ .
/// . | | | | | | | | .
/// . +-----------+ +-----------+ +----------+ +---------+ .
/// ...............................................................
/// |
/// probably `spawn`
/// a `job`
/// |
/// V
/// +-----------+
/// | |
/// +-----------+
///
/// ```
///
/// [`Subsystem`]: trait.Subsystem.html
///
/// # Example
///
/// The [`Subsystems`] may be any type as long as they implement an expected interface.
/// Here, we create a mock validation subsystem and a few dummy ones and start the `Overseer` with them.
/// For the sake of simplicity the termination of the example is done with a timeout.
/// ```
/// # use std::time::Duration;
/// # use futures::{executor, pin_mut, select, FutureExt};
/// # use futures_timer::Delay;
/// # use polkadot_overseer::{Overseer, AllSubsystems};
/// # Subsystem, DummySubsystem, SpawnedSubsystem, SubsystemContext,
/// # messages::CandidateValidationMessage,
///
/// impl<C> Subsystem<C> for ValidationSubsystem
/// where C: SubsystemContext<Message=CandidateValidationMessage>
/// SpawnedSubsystem {
/// name: "validation-subsystem",
/// future: Box::pin(async move {
/// loop {
/// Delay::new(Duration::from_secs(1)).await;
/// }
/// }),
/// }
/// }
/// }
///
/// # fn main() { executor::block_on(async move {
/// let spawner = sp_core::testing::TaskExecutor::new();
/// let all_subsystems = AllSubsystems {
/// candidate_validation: ValidationSubsystem,
/// candidate_backing: DummySubsystem,
/// candidate_selection: DummySubsystem,
/// statement_distribution: DummySubsystem,
/// availability_distribution: DummySubsystem,
/// bitfield_signing: DummySubsystem,
/// bitfield_distribution: DummySubsystem,
/// provisioner: DummySubsystem,
/// pov_distribution: DummySubsystem,
/// runtime_api: DummySubsystem,
/// availability_store: DummySubsystem,
/// network_bridge: DummySubsystem,
/// collation_generation: DummySubsystem,
/// collator_protocol: DummySubsystem,
/// spawner,
/// ).unwrap();
///
/// let timer = Delay::new(Duration::from_millis(50)).fuse();
///
/// let overseer_fut = overseer.run().fuse();
/// pin_mut!(timer);
/// pin_mut!(overseer_fut);
///
/// select! {
/// _ = overseer_fut => (),
/// _ = timer => (),
/// }
/// #
/// # }); }
/// ```
pub fn new<CV, CB, CS, SD, AD, BS, BD, P, PoVD, RA, AS, NB, CA, CG, CP>(
leaves: impl IntoIterator<Item = BlockInfo>,
all_subsystems: AllSubsystems<CV, CB, CS, SD, AD, BS, BD, P, PoVD, RA, AS, NB, CA, CG, CP>,
prometheus_registry: Option<&prometheus::Registry>,
) -> SubsystemResult<(Self, OverseerHandler)>
where
CV: Subsystem<OverseerSubsystemContext<CandidateValidationMessage>> + Send,
CB: Subsystem<OverseerSubsystemContext<CandidateBackingMessage>> + Send,
CS: Subsystem<OverseerSubsystemContext<CandidateSelectionMessage>> + Send,
SD: Subsystem<OverseerSubsystemContext<StatementDistributionMessage>> + Send,
AD: Subsystem<OverseerSubsystemContext<AvailabilityDistributionMessage>> + Send,
BS: Subsystem<OverseerSubsystemContext<BitfieldSigningMessage>> + Send,
BD: Subsystem<OverseerSubsystemContext<BitfieldDistributionMessage>> + Send,
P: Subsystem<OverseerSubsystemContext<ProvisionerMessage>> + Send,
PoVD: Subsystem<OverseerSubsystemContext<PoVDistributionMessage>> + Send,
RA: Subsystem<OverseerSubsystemContext<RuntimeApiMessage>> + Send,
AS: Subsystem<OverseerSubsystemContext<AvailabilityStoreMessage>> + Send,
NB: Subsystem<OverseerSubsystemContext<NetworkBridgeMessage>> + Send,
CA: Subsystem<OverseerSubsystemContext<ChainApiMessage>> + Send,
CG: Subsystem<OverseerSubsystemContext<CollationGenerationMessage>> + Send,
CP: Subsystem<OverseerSubsystemContext<CollatorProtocolMessage>> + Send,
let (events_tx, events_rx) = mpsc::channel(CHANNEL_CAPACITY);
let handler = OverseerHandler {
events_tx: events_tx.clone(),
};
let mut running_subsystems_rx = StreamUnordered::new();
let mut running_subsystems = FuturesUnordered::new();
let candidate_validation_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.candidate_validation,
)?;
let candidate_backing_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.candidate_backing,
)?;
let candidate_selection_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.candidate_selection,
)?;
let statement_distribution_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.statement_distribution,
)?;
let availability_distribution_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.availability_distribution,
)?;
let bitfield_signing_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.bitfield_signing,
)?;
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let bitfield_distribution_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.bitfield_distribution,
)?;
let provisioner_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.provisioner,
)?;
let pov_distribution_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.pov_distribution,
)?;
let runtime_api_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.runtime_api,
)?;
let availability_store_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.availability_store,
)?;
let network_bridge_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.network_bridge,
let chain_api_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.chain_api,
)?;
let collation_generation_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.collation_generation,
)?;
let collator_protocol_subsystem = spawn(
&mut s,
&mut running_subsystems,
&mut running_subsystems_rx,
all_subsystems.collator_protocol,
)?;
let leaves = leaves
.into_iter()
.map(|BlockInfo { hash, parent_hash: _, number }| (hash, number))
.collect();
let active_leaves = HashMap::new();
let metrics = <Metrics as metrics::Metrics>::register(prometheus_registry);
let activation_external_listeners = HashMap::new();
candidate_validation_subsystem,
candidate_selection_subsystem,
statement_distribution_subsystem,
availability_distribution_subsystem,
bitfield_signing_subsystem,
bitfield_distribution_subsystem,
provisioner_subsystem,
pov_distribution_subsystem,
runtime_api_subsystem,
availability_store_subsystem,
network_bridge_subsystem,
collation_generation_subsystem,
collator_protocol_subsystem,
s,
running_subsystems,
running_subsystems_rx,
events_rx,
activation_external_listeners,
leaves,
active_leaves,
};
Ok((this, handler))
}
// Stop the overseer.
async fn stop(mut self) {
if let Some(ref mut s) = self.candidate_validation_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.candidate_backing_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.candidate_selection_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.statement_distribution_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.availability_distribution_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.bitfield_signing_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.bitfield_distribution_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.provisioner_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.pov_distribution_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.runtime_api_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.availability_store_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.network_bridge_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.chain_api_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.collator_protocol_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
if let Some(ref mut s) = self.collation_generation_subsystem.instance {
let _ = s.tx.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
}
let mut stop_delay = Delay::new(Duration::from_secs(STOP_DELAY)).fuse();
loop {
select! {
_ = self.running_subsystems.next() => {
if self.running_subsystems.is_empty() {
break;
}
},
_ = stop_delay => break,
complete => break,
}
}
}
/// Run the `Overseer`.
pub async fn run(mut self) -> SubsystemResult<()> {
let leaves = std::mem::take(&mut self.leaves);
let mut update = ActiveLeavesUpdate::default();
for (hash, number) in leaves.into_iter() {
update.activated.push(hash);
self.active_leaves.insert(hash, number);
self.on_head_activated(&hash);
self.broadcast_signal(OverseerSignal::ActiveLeaves(update)).await?;
loop {
while let Poll::Ready(Some(msg)) = poll!(&mut self.events_rx.next()) {
match msg {
Event::MsgToSubsystem(msg) => {
self.route_message(msg).await;
}
Event::Stop => {
self.stop().await;
return Ok(());
}
Event::BlockImported(block) => {
self.block_imported(block).await?;
}
Event::BlockFinalized(block) => {
self.block_finalized(block).await?;
}
Event::ExternalRequest(request) => {
self.handle_external_request(request);
}
}
}
while let Poll::Ready(Some((StreamYield::Item(msg), _))) = poll!(
&mut self.running_subsystems_rx.next()
) {
match msg {
ToOverseer::SubsystemMessage(msg) => self.route_message(msg).await,
ToOverseer::SpawnJob { name, s } => {
self.spawn_job(name, s);
ToOverseer::SpawnBlockingJob { name, s } => {
self.spawn_blocking_job(name, s);
}
}
}
// Some subsystem exited? It's time to panic.
if let Poll::Ready(Some(finished)) = poll!(self.running_subsystems.next()) {
log::error!(target: LOG_TARGET, "Subsystem finished unexpectedly {:?}", finished);
self.stop().await;
return Err(SubsystemError);
}
// Looks like nothing is left to be polled, let's take a break.
pending!();
}
}
async fn block_imported(&mut self, block: BlockInfo) -> SubsystemResult<()> {
let mut update = ActiveLeavesUpdate::default();
if let Some(number) = self.active_leaves.remove(&block.parent_hash) {
if let Some(expected_parent_number) = block.number.checked_sub(1) {
debug_assert_eq!(expected_parent_number, number);
}
update.deactivated.push(block.parent_hash);
self.on_head_deactivated(&block.parent_hash);
match self.active_leaves.entry(block.hash) {
hash_map::Entry::Vacant(entry) => {
update.activated.push(block.hash);
entry.insert(block.number);
self.on_head_activated(&block.hash);
},
hash_map::Entry::Occupied(entry) => {
debug_assert_eq!(*entry.get(), block.number);
}
self.clean_up_external_listeners();
self.broadcast_signal(OverseerSignal::ActiveLeaves(update)).await?;
Ok(())
}
async fn block_finalized(&mut self, block: BlockInfo) -> SubsystemResult<()> {
let mut update = ActiveLeavesUpdate::default();
self.active_leaves.retain(|h, n| {
update.deactivated.push(*h);
false
} else {
true
}
});
for deactivated in &update.deactivated {
self.on_head_deactivated(deactivated)
}
self.broadcast_signal(OverseerSignal::ActiveLeaves(update)).await?;
self.broadcast_signal(OverseerSignal::BlockFinalized(block.hash)).await?;
Ok(())
}
async fn broadcast_signal(&mut self, signal: OverseerSignal) -> SubsystemResult<()> {
if let Some(ref mut s) = self.candidate_validation_subsystem.instance {
s.tx.send(FromOverseer::Signal(signal.clone())).await?;