Exemplo n.º 1
0
 def __init__(self, peer_pool: ETHPeerPool) -> None:
     self.logger = get_logger('trinity.sync.beam.queen.QueeningQueue')
     self._peer_pool = peer_pool
     self._knights = WaitingPeers(NodeDataV65)
     self._peasants = WaitingPeers(NodeDataV65)
     self._queen_updated = asyncio.Event()
     self._desired_knights = 0
     self._num_peers = 0
Exemplo n.º 2
0
    def __init__(self,
                 chain: BaseAsyncChain,
                 db: BaseAsyncChainDB,
                 peer_pool: ETHPeerPool,
                 header_syncer: HeaderSyncerAPI,
                 token: CancelToken = None) -> None:
        super().__init__(chain, db, peer_pool, token)

        # queue up any idle peers, in order of how fast they return receipts
        self._receipt_peers: WaitingPeers[ETHPeer] = WaitingPeers(
            commands.Receipts)

        self._header_syncer = header_syncer

        # Track receipt download tasks
        # - arbitrarily allow several requests-worth of headers queued up
        # - try to get receipts from lower block numbers first
        buffer_size = MAX_RECEIPTS_FETCH * REQUEST_BUFFER_MULTIPLIER
        self._receipt_tasks = TaskQueue(buffer_size,
                                        attrgetter('block_number'))

        # track when both bodies and receipts are collected, so that blocks can be persisted
        self._block_persist_tracker = OrderedTaskPreparation(
            BlockPersistPrereqs,
            id_extractor=attrgetter('hash'),
            # make sure that a block is not persisted until the parent block is persisted
            dependency_extractor=attrgetter('parent_hash'),
        )
        # Track whether the fast chain syncer completed its goal
        self.is_complete = False
Exemplo n.º 3
0
    def __init__(self,
                 chain: BaseAsyncChain,
                 db: BaseAsyncChainDB,
                 peer_pool: ETHPeerPool,
                 header_syncer: HeaderSyncerAPI,
                 token: CancelToken = None) -> None:
        super().__init__(token=token)
        self.chain = chain
        self.db = db
        self._peer_pool = peer_pool
        self._pending_bodies = {}

        self._header_syncer = header_syncer

        # queue up any idle peers, in order of how fast they return block bodies
        self._body_peers: WaitingPeers[ETHPeer] = WaitingPeers(
            commands.BlockBodies)

        # Track incomplete block body download tasks
        # - arbitrarily allow several requests-worth of headers queued up
        # - try to get bodies from lower block numbers first
        buffer_size = MAX_BODIES_FETCH * REQUEST_BUFFER_MULTIPLIER
        self._block_body_tasks = TaskQueue(buffer_size,
                                           attrgetter('block_number'))

        # Track if there is capacity for more block importing
        self._db_buffer_capacity = asyncio.Event()
        self._db_buffer_capacity.set()  # start with capacity

        # Track if any headers have been received yet
        self._got_first_header = asyncio.Event()
Exemplo n.º 4
0
    def __init__(self,
                 chain: AsyncChainAPI,
                 db: BaseAsyncChainDB,
                 peer_pool: ETHPeerPool,
                 header_syncer: HeaderSyncerAPI,
                 token: CancelToken = None) -> None:
        super().__init__(token=token)
        self.chain = chain
        self.db = db
        self._peer_pool = peer_pool
        self._pending_bodies = {}

        self._header_syncer = header_syncer

        # queue up any idle peers, in order of how fast they return block bodies
        self._body_peers: WaitingPeers[ETHPeer] = WaitingPeers(commands.BlockBodies)

        # Track incomplete block body download tasks
        # - arbitrarily allow several requests-worth of headers queued up
        # - try to get bodies from lower block numbers first
        buffer_size = MAX_BODIES_FETCH * REQUEST_BUFFER_MULTIPLIER
        self._block_body_tasks = TaskQueue(buffer_size, attrgetter('block_number'))

        # Track if there is capacity for more block importing
        self._db_buffer_capacity = asyncio.Event()
        self._db_buffer_capacity.set()  # start with capacity

        # Track if any headers have been received yet
        self._got_first_header = asyncio.Event()

        # Keep a copy of old state roots to use when previewing transactions
        # Preview needs a header's *parent's* state root. Sometimes the parent
        # header isn't in the database yet, so must be looked up here.
        self._block_hash_to_state_root: Dict[Hash32, Hash32] = {}
Exemplo n.º 5
0
    def __init__(self, chain: BaseAsyncChain, peer_pool: BaseChainPeerPool,
                 stitcher: HeaderStitcher, token: CancelToken) -> None:
        super().__init__(token=token)
        self._chain = chain
        self._stitcher = stitcher
        max_pending_fillers = 50
        self._filler_header_tasks = TaskQueue(
            max_pending_fillers,
            # order by block number of the parent header
            compose(attrgetter('block_number'), itemgetter(0)),
        )

        # queue up idle peers, ordered by speed that they return block bodies
        self._waiting_peers: WaitingPeers[TChainPeer] = WaitingPeers(
            BaseBlockHeaders)
        self._peer_pool = peer_pool
Exemplo n.º 6
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    def __init__(self, chain: AsyncChainAPI, peer_pool: BaseChainPeerPool,
                 stitcher: HeaderStitcher) -> None:
        self.logger = get_logger('trinity.sync.common.headers.SkeletonSyncer')
        self._chain = chain
        self._stitcher = stitcher
        max_pending_fillers = 50
        self._filler_header_tasks = TaskQueue(
            max_pending_fillers,
            # order by block number of the parent header
            compose(attrgetter('block_number'), itemgetter(0)),
        )

        # queue up idle peers, ordered by speed that they return block bodies
        self._waiting_peers: WaitingPeers[TChainPeer] = WaitingPeers(
            (ETHBlockHeaders, LESBlockHEaders), )
        self._peer_pool = peer_pool
        self.sync_progress: SyncProgress = None
Exemplo n.º 7
0
    def __init__(self,
                 chain: BaseAsyncChain,
                 db: BaseAsyncChainDB,
                 peer_pool: ETHPeerPool,
                 token: CancelToken = None) -> None:
        super().__init__(token=token)
        self.chain = chain
        self.db = db
        self._peer_pool = peer_pool
        self._pending_bodies = {}

        # queue up any idle peers, in order of how fast they return block bodies
        self._body_peers: WaitingPeers[ETHPeer] = WaitingPeers(commands.BlockBodies)

        # Track incomplete block body download tasks
        # - arbitrarily allow several requests-worth of headers queued up
        # - try to get bodies from lower block numbers first
        buffer_size = MAX_BODIES_FETCH * REQUEST_BUFFER_MULTIPLIER
        self._block_body_tasks = TaskQueue(buffer_size, attrgetter('block_number'))
Exemplo n.º 8
0
class QueeningQueue(Service, PeerSubscriber, QueenTrackerAPI):
    # The best peer gets skipped for backfill, because we prefer to use it for
    #   urgent beam sync nodes. _queen_peer should only ever be set to a new peer
    #   in _insert_peer(). It may be set to None anywhere.
    _queen_peer: ETHPeer = None
    _queen_updated: asyncio.Event
    _waiting_peers: WaitingPeers[ETHPeer]

    # We are only interested in peers entering or leaving the pool
    subscription_msg_types: FrozenSet[Type[CommandAPI[Any]]] = frozenset()

    # This is a rather arbitrary value, but when the sync is operating normally we never see
    # the msg queue grow past a few hundred items, so this should be a reasonable limit for
    # now.
    msg_queue_maxsize: int = 2000

    def __init__(self, peer_pool: ETHPeerPool) -> None:
        self.logger = get_logger('trinity.sync.beam.queen.QueeningQueue')
        self._peer_pool = peer_pool
        self._waiting_peers = WaitingPeers(NodeDataV65)
        self._queen_updated = asyncio.Event()

    async def run(self) -> None:
        with self.subscribe(self._peer_pool):
            await self.manager.wait_finished()

    def register_peer(self, peer: BasePeer) -> None:
        super().register_peer(peer)

        self._insert_peer(peer)  # type: ignore

    def deregister_peer(self, peer: BasePeer) -> None:
        super().deregister_peer(peer)
        if self._queen_peer == peer:
            self._queen_peer = None
        # If it's not the queen, we will catch the peer as cancelled when we try to draw it
        #   as a peasant. (We can't drop an element from the middle of a Queue)

    async def get_queen_peer(self) -> ETHPeer:
        """
        Wait until a queen peer is designated, then return it.
        """
        t = Timer()
        while self._queen_peer is None:
            await self._queen_updated.wait()
            self._queen_updated.clear()

        queen_starve_time = t.elapsed
        if queen_starve_time > WARN_AFTER_QUEEN_STARVED:
            self.logger.info(
                "Blocked for %.2fs waiting for queen=%s",
                queen_starve_time,
                self._queen_peer,
            )

        return self._queen_peer

    @property
    def queen(self) -> Optional[ETHPeer]:
        """
        Might be None. If None is unacceptable, use :meth:`get_queen_peer`
        """
        return self._queen_peer

    async def pop_fastest_peasant(self) -> ETHPeer:
        """
        Get the fastest peer that is not the queen.
        """
        while self.manager.is_running:
            peer = await self._waiting_peers.get_fastest()
            if not peer.is_alive:
                # drop any peers that aren't alive anymore
                self.logger.info(
                    "Dropping %s from beam peers, as no longer active", peer)
                if peer == self._queen_peer:
                    self._queen_peer = None
                continue

            if self._should_be_queen(peer):
                self.logger.debug(
                    "About to draw peasant %s, but realized it should be queen",
                    peer)
                self._insert_peer(peer)
                continue

            # FIXME: This should not be hard-coded to get_node_data as we could, in theory, be
            # used to request other types of data.
            peer_is_requesting = peer.eth_api.get_node_data.is_requesting

            if peer_is_requesting:
                # skip the peer if there's an active request
                self.logger.debug("QueenQueuer is skipping active peer %s",
                                  peer)
                loop = asyncio.get_event_loop()
                loop.call_later(10, functools.partial(self._insert_peer, peer))
                continue

            return peer
        # This should never happen as we run as a daemon and if we return before our caller it'd
        # raise a DaemonTaskExit, but just in case we raise a CancelledError() to ensure our
        # caller realizes we've stopped.
        self.logger.error("Service ended before a queen peer could be elected")
        raise asyncio.CancelledError()

    def readd_peasant(self, peer: ETHPeer, delay: float = 0) -> None:
        if delay > 0:
            loop = asyncio.get_event_loop()
            loop.call_later(delay, functools.partial(self._insert_peer, peer))
        else:
            self._insert_peer(peer)

    def penalize_queen(self,
                       peer: ETHPeer,
                       delay: float = NON_IDEAL_RESPONSE_PENALTY) -> None:
        if peer == self._queen_peer:
            self._queen_peer = None

            self.logger.debug(
                "Penalizing %s for %.2fs, for minor infraction",
                peer,
                delay,
            )
            loop = asyncio.get_event_loop()
            loop.call_later(delay, functools.partial(self._insert_peer, peer))

    def _should_be_queen(self, peer: ETHPeer) -> bool:
        if not peer.is_alive:
            raise ValueError(f"{peer} is no longer alive")

        if self._queen_peer is None:
            return True
        elif not self._queen_peer.is_alive:
            return True
        elif peer == self._queen_peer:
            return True
        else:
            new_peer_quality = _peer_sort_key(peer)
            current_queen_quality = _peer_sort_key(self._queen_peer)
            # Quality is designed so that an ascending sort puts the best quality at the front
            #   of a sequence. So, a lower value means a better quality.
            return new_peer_quality < current_queen_quality

    def _insert_peer(self, peer: ETHPeer) -> None:
        """
        Add peer as ready to receive requests. Check if it should be queen, and promote if
        appropriate. Otherwise, insert to be drawn as a peasant.

        If the given peer is no longer running, do nothing. This is needed because we're sometimes
        called via loop.call_later().
        """
        if not peer.is_alive:
            self.logger.debug(
                "Peer %s is no longer alive, not adding to queue", peer)
            return

        if self._should_be_queen(peer):
            old_queen, self._queen_peer = self._queen_peer, peer
            if peer != old_queen:
                # We only need to log the change if there was an actual change in queen
                self.logger.debug("Switching queen peer from %s to %s",
                                  old_queen, peer)
                self._queen_updated.set()

                if old_queen is not None:
                    self._waiting_peers.put_nowait(old_queen)
        else:
            self._waiting_peers.put_nowait(peer)
Exemplo n.º 9
0
 def __init__(self, peer_pool: ETHPeerPool, token: CancelToken = None) -> None:
     super().__init__(token=token)
     self._peer_pool = peer_pool
     self._waiting_peers = WaitingPeers(NodeData)
Exemplo n.º 10
0
class QueeningQueue(BaseService, PeerSubscriber, QueenTrackerAPI):
    # The best peer gets skipped for backfill, because we prefer to use it for
    #   urgent beam sync nodes
    _queen_peer: ETHPeer = None
    _waiting_peers: WaitingPeers[ETHPeer]

    # We are only interested in peers entering or leaving the pool
    subscription_msg_types: FrozenSet[Type[CommandAPI[Any]]] = frozenset()

    # This is a rather arbitrary value, but when the sync is operating normally we never see
    # the msg queue grow past a few hundred items, so this should be a reasonable limit for
    # now.
    msg_queue_maxsize: int = 2000

    def __init__(self, peer_pool: ETHPeerPool, token: CancelToken = None) -> None:
        super().__init__(token=token)
        self._peer_pool = peer_pool
        self._waiting_peers = WaitingPeers(NodeData)

    async def _run(self) -> None:
        with self.subscribe(self._peer_pool):
            await self.cancellation()

    def register_peer(self, peer: BasePeer) -> None:
        super().register_peer(peer)
        # when a new peer is added to the pool, add it to the idle peer list
        self._waiting_peers.put_nowait(peer)  # type: ignore

    def deregister_peer(self, peer: BasePeer) -> None:
        super().deregister_peer(peer)
        if self._queen_peer == peer:
            self._queen_peer = None

    async def get_queen_peer(self) -> ETHPeer:
        """
        Wait until a queen peer is designated, then return it.
        """
        while self._queen_peer is None:
            peer = await self._waiting_peers.get_fastest()
            self._update_queen(peer)

        return self._queen_peer

    @property
    def queen(self) -> Optional[ETHPeer]:
        """
        Might be None. If None is unacceptable, use :meth:`get_queen_peer`
        """
        return self._queen_peer

    async def pop_fastest_peasant(self) -> ETHPeer:
        """
        Get the fastest peer that is not the queen.
        """
        while self.is_operational:
            peer = await self.wait(self._waiting_peers.get_fastest())
            if not peer.is_operational:
                # drop any peers that aren't alive anymore
                self.logger.warning("Dropping %s from beam queue as no longer operational", peer)
                if peer == self._queen_peer:
                    self._queen_peer = None
                continue

            old_queen = self._update_queen(peer)
            if peer == self._queen_peer:
                self.logger.debug("Switching queen peer from %s to %s", old_queen, peer)
                continue

            if peer.eth_api.get_node_data.is_requesting:
                # skip the peer if there's an active request
                self.logger.debug("Queen Queuer is skipping active peer %s", peer)
                self.call_later(10, self._waiting_peers.put_nowait, peer)
                continue

            return peer
        raise OperationCancelled("Service ended before a queen peer could be elected")

    def readd_peasant(self, peer: ETHPeer, delay: float = 0) -> None:
        if delay > 0:
            self.call_later(delay, self._waiting_peers.put_nowait, peer)
        else:
            self._waiting_peers.put_nowait(peer)

    def penalize_queen(self, peer: ETHPeer) -> None:
        if peer == self._queen_peer:
            self._queen_peer = None

            delay = NON_IDEAL_RESPONSE_PENALTY
            self.logger.debug(
                "Penalizing %s for %.2fs, for minor infraction",
                peer,
                delay,
            )
            self.call_later(delay, self._waiting_peers.put_nowait, peer)

    def _update_queen(self, peer: ETHPeer) -> ETHPeer:
        '''
        @return peer that is no longer queen
        '''
        if self._queen_peer is None:
            self._queen_peer = peer
            return None
        elif peer == self._queen_peer:
            # nothing to do, peer is already the queen
            return None
        elif _peer_sort_key(peer) < _peer_sort_key(self._queen_peer):
            old_queen, self._queen_peer = self._queen_peer, peer
            self._waiting_peers.put_nowait(old_queen)
            return old_queen
        else:
            # nothing to do, peer is slower than the queen
            return None
Exemplo n.º 11
0
class QueeningQueue(Service, PeerSubscriber, QueenTrackerAPI):
    # The best peer gets skipped for backfill, because we prefer to use it for
    #   urgent beam sync nodes. _queen_peer should only ever be set to a new peer
    #   in _insert_peer(). It may be set to None anywhere.
    _queen_peer: ETHPeer = None
    _queen_updated: asyncio.Event
    _knights: WaitingPeers[ETHPeer]
    _peasants: WaitingPeers[ETHPeer]

    # We are only interested in peers entering or leaving the pool
    subscription_msg_types: FrozenSet[Type[CommandAPI[Any]]] = frozenset()

    # This is a rather arbitrary value, but when the sync is operating normally we never see
    # the msg queue grow past a few hundred items, so this should be a reasonable limit for
    # now.
    msg_queue_maxsize: int = 2000

    _report_interval = 30

    def __init__(self, peer_pool: ETHPeerPool) -> None:
        self.logger = get_logger('trinity.sync.beam.queen.QueeningQueue')
        self._peer_pool = peer_pool
        self._knights = WaitingPeers(NodeDataV65)
        self._peasants = WaitingPeers(NodeDataV65)
        self._queen_updated = asyncio.Event()
        self._desired_knights = 0
        self._num_peers = 0

    async def run(self) -> None:
        with self.subscribe(self._peer_pool):
            self.manager.run_daemon_task(self._report_statistics)
            await self.manager.wait_finished()

    async def _report_statistics(self) -> None:
        while self.manager.is_running:
            await asyncio.sleep(self._report_interval)
            self.logger.debug(
                "queen-stats: free_knights=%d/%d free_peasants=%d/%d queen=%s",
                len(self._knights),
                self._desired_knights,
                len(self._peasants),
                self._num_peers - self._desired_knights - 1,
                self._queen_peer,
            )

    def register_peer(self, peer: BasePeer) -> None:
        super().register_peer(peer)

        self._insert_peer(peer)  # type: ignore
        self._num_peers += 1

    def deregister_peer(self, peer: BasePeer) -> None:
        super().deregister_peer(peer)
        if self._queen_peer == peer:
            self._queen_peer = None
        # If it's not the queen, we will catch the peer as cancelled when we try to draw it
        #   as a peasant. (We can't drop an element from the middle of a Queue)
        self._num_peers -= 1

    async def get_queen_peer(self) -> ETHPeer:
        """
        Wait until a queen peer is designated, then return it.
        """
        t = Timer()
        while self._queen_peer is None:
            try:
                promote_knight = self._knights.pop_nowait()
            except asyncio.QueueEmpty:
                # There are no knights available. Wait for a new queen to appear.
                await self._queen_updated.wait()
                self._queen_updated.clear()
            else:
                # There is a knight who can be promoted to queen immediately.
                self._insert_peer(promote_knight)

        queen_starve_time = t.elapsed
        if queen_starve_time > WARN_AFTER_QUEEN_STARVED:
            self.logger.debug(
                "Blocked for %.2fs waiting for queen=%s",
                queen_starve_time,
                self._queen_peer,
            )

        return self._queen_peer

    @property
    def queen(self) -> Optional[ETHPeer]:
        """
        Might be None. If None is unacceptable, use :meth:`get_queen_peer`
        """
        return self._queen_peer

    def set_desired_knight_count(self, desired_knights: int) -> None:
        self._desired_knights = desired_knights

        # Promote knights if there are not enough
        while len(self._knights) < self._desired_knights:
            try:
                promoted_knight = self._peasants.pop_nowait()
            except asyncio.QueueEmpty:
                # no peasants available to promote
                break
            else:
                self._knights.put_nowait(promoted_knight)

    def pop_knights(self) -> Iterable[ETHPeer]:
        for _ in range(self._desired_knights):
            try:
                yield self._knights.pop_nowait()
            except asyncio.QueueEmpty:
                try:
                    yield self._peasants.pop_nowait()
                except asyncio.QueueEmpty:
                    break

        # Push all remaining knights down to peasants
        while len(self._knights):
            try:
                demoted_knight = self._knights.pop_nowait()
            except asyncio.QueueEmpty:
                break
            else:
                self._peasants.put_nowait(demoted_knight)

    async def pop_fastest_peasant(self) -> ETHPeer:
        """
        Get the fastest peer that is not the queen.
        """
        # NOTE: We don't use the common `while self.is_running` idiom here because this method
        # runs in a task belonging to the service that runs this service as a child, so that task
        # has to monitor the child service (us) and stop calling this method when we're no longer
        # running.
        while True:
            peer = await self._peasants.get_fastest()
            if not peer.is_alive:
                # drop any peers that aren't alive anymore
                self.logger.info(
                    "Dropping %s from beam peers, as no longer active", peer)
                if peer == self._queen_peer:
                    self._queen_peer = None
                continue

            if self._should_be_queen(peer):
                self.logger.debug(
                    "About to draw peasant %s, but realized it should be queen",
                    peer)
                self._insert_peer(peer)
                continue

            # FIXME: This should not be hard-coded to get_node_data as we could, in theory, be
            # used to request other types of data.
            peer_is_requesting = peer.eth_api.get_node_data.is_requesting

            if peer_is_requesting:
                # skip the peer if there's an active request
                self.logger.debug("QueenQueuer is skipping active peer %s",
                                  peer)
                self.insert_peer(peer, delay=NON_IDEAL_RESPONSE_PENALTY)
                continue

            return peer

    def insert_peer(self, peer: ETHPeer, delay: float = 0) -> None:
        if not peer.is_alive:
            # Peer exited, dropping it...
            return
        elif self._should_be_queen(peer):
            self.logger.debug("Fast-tracking peasant to promote to queen: %s",
                              peer)
            self._insert_peer(peer)
        elif delay > 0:
            loop = asyncio.get_event_loop()
            loop.call_later(delay, functools.partial(self._insert_peer, peer))
        else:
            self._insert_peer(peer)

    def penalize_queen(self,
                       peer: ETHPeer,
                       delay: float = NON_IDEAL_RESPONSE_PENALTY) -> None:
        if peer == self._queen_peer:
            self._queen_peer = None

            self.logger.debug(
                "Penalizing %s for %.2fs, for minor infraction",
                peer,
                delay,
            )
            loop = asyncio.get_event_loop()
            loop.call_later(delay, functools.partial(self._insert_peer, peer))

    def _should_be_queen(self, peer: ETHPeer) -> bool:
        if not peer.is_alive:
            raise ValueError(f"{peer} is no longer alive")

        if self._queen_peer is None:
            return True
        elif not self._queen_peer.is_alive:
            return True
        elif peer == self._queen_peer:
            return True
        else:
            new_peer_quality = _peer_sort_key(peer)
            current_queen_quality = _peer_sort_key(self._queen_peer)
            # Quality is designed so that an ascending sort puts the best quality at the front
            #   of a sequence. So, a lower value means a better quality.
            return new_peer_quality < current_queen_quality

    def _insert_peer(self, peer: ETHPeer) -> None:
        """
        Add peer as ready to receive requests. Check if it should be queen, and promote if
        appropriate. Otherwise, insert to be drawn as a peasant.

        If the given peer is no longer running, do nothing. This is needed because we're sometimes
        called via loop.call_later().
        """
        if not peer.is_alive:
            self.logger.debug(
                "Peer %s is no longer alive, not adding to queue", peer)
            return

        if self._should_be_queen(peer):
            old_queen, self._queen_peer = self._queen_peer, peer
            if peer != old_queen:
                # We only need to log the change if there was an actual change in queen
                self.logger.debug("Switching queen peer from %s to %s",
                                  old_queen, peer)
                self._queen_updated.set()

                if old_queen is not None:
                    self._insert_peer(old_queen)
        else:
            self._peasants.put_nowait(peer)

            # If the number of knights is too low, add one.
            # Insert the peasant before promoting a knight, in case a former peasant is
            #   now faster than the peer being inserted now.
            if len(self._knights) < self._desired_knights:
                try:
                    promoted_knight = self._peasants.pop_nowait()
                except asyncio.QueueEmpty:
                    # no peasants available to promote, exit cleanly
                    return
                else:
                    self._knights.put_nowait(promoted_knight)
Exemplo n.º 12
0
 def __init__(self, peer_pool: ETHPeerPool) -> None:
     self.logger = get_logger('trinity.sync.beam.queen.QueeningQueue')
     self._peer_pool = peer_pool
     self._waiting_peers = WaitingPeers(NodeDataV65)
Exemplo n.º 13
0
class QueeningQueue(Service, PeerSubscriber, QueenTrackerAPI):
    # The best peer gets skipped for backfill, because we prefer to use it for
    #   urgent beam sync nodes
    _queen_peer: ETHPeer = None
    _waiting_peers: WaitingPeers[ETHPeer]

    # We are only interested in peers entering or leaving the pool
    subscription_msg_types: FrozenSet[Type[CommandAPI[Any]]] = frozenset()

    # This is a rather arbitrary value, but when the sync is operating normally we never see
    # the msg queue grow past a few hundred items, so this should be a reasonable limit for
    # now.
    msg_queue_maxsize: int = 2000

    def __init__(self, peer_pool: ETHPeerPool) -> None:
        self.logger = get_logger('trinity.sync.beam.queen.QueeningQueue')
        self._peer_pool = peer_pool
        self._waiting_peers = WaitingPeers(NodeDataV65)

    async def run(self) -> None:
        with self.subscribe(self._peer_pool):
            await self.manager.wait_finished()

    def register_peer(self, peer: BasePeer) -> None:
        super().register_peer(peer)
        # when a new peer is added to the pool, add it to the idle peer list
        self._waiting_peers.put_nowait(peer)  # type: ignore

    def deregister_peer(self, peer: BasePeer) -> None:
        super().deregister_peer(peer)
        if self._queen_peer == peer:
            self._queen_peer = None

    async def get_queen_peer(self) -> ETHPeer:
        """
        Wait until a queen peer is designated, then return it.
        """
        while self._queen_peer is None:
            peer = await self._waiting_peers.get_fastest()
            self._update_queen(peer)

        return self._queen_peer

    @property
    def queen(self) -> Optional[ETHPeer]:
        """
        Might be None. If None is unacceptable, use :meth:`get_queen_peer`
        """
        return self._queen_peer

    async def pop_fastest_peasant(self) -> ETHPeer:
        """
        Get the fastest peer that is not the queen.
        """
        while self.manager.is_running:
            peer = await self._waiting_peers.get_fastest()
            if not peer.manager.is_running:
                # drop any peers that aren't alive anymore
                self.logger.info("Dropping %s from beam peers, as no longer active", peer)
                if peer == self._queen_peer:
                    self._queen_peer = None
                continue

            old_queen = self._queen_peer
            self._update_queen(peer)
            if peer == self._queen_peer:
                self.logger.debug("Switching queen peer from %s to %s", old_queen, peer)
                continue

            try:
                peer_is_requesting_nodes = peer.eth_api.get_node_data.is_requesting
            except PeerConnectionLost:
                self.logger.debug("QueenQueuer is skipping disconnecting peer %s", peer)
                # Don't bother re-adding to _waiting_peers, since the peer is disconnected
            else:
                if peer_is_requesting_nodes:
                    # skip the peer if there's an active request
                    self.logger.debug("QueenQueuer is skipping active peer %s", peer)
                    loop = asyncio.get_event_loop()
                    loop.call_later(10, functools.partial(self._waiting_peers.put_nowait, peer))
                    continue

            return peer
        # This should never happen as we run as a daemon and if we return before our caller it'd
        # raise a DaemonTaskExit, but just in case we raise a CancelledError() to ensure our
        # caller realizes we've stopped.
        self.logger.error("Service ended before a queen peer could be elected")
        raise asyncio.CancelledError()

    def readd_peasant(self, peer: ETHPeer, delay: float = 0) -> None:
        if delay > 0:
            loop = asyncio.get_event_loop()
            loop.call_later(delay, functools.partial(self._waiting_peers.put_nowait, peer))
        else:
            self._waiting_peers.put_nowait(peer)

    def penalize_queen(self, peer: ETHPeer) -> None:
        if peer == self._queen_peer:
            self._queen_peer = None

            delay = NON_IDEAL_RESPONSE_PENALTY
            self.logger.debug(
                "Penalizing %s for %.2fs, for minor infraction",
                peer,
                delay,
            )
            loop = asyncio.get_event_loop()
            loop.call_later(delay, functools.partial(self._waiting_peers.put_nowait, peer))

    def _update_queen(self, peer: ETHPeer) -> None:
        '''
        @return peer that is no longer queen
        '''
        if self._queen_peer is None:
            self._queen_peer = peer
            return
        elif peer == self._queen_peer:
            # nothing to do, peer is already the queen
            return
        else:
            try:
                new_peer_quality = _peer_sort_key(peer)
            except (UnknownAPI, PeerConnectionLost) as exc:
                self.logger.debug("Ignoring %s, because we can't get speed stats: %r", peer, exc)
                return

            try:
                old_queen_quality = _peer_sort_key(self._queen_peer)
                force_drop_queen = False
            except (UnknownAPI, PeerConnectionLost) as exc:
                self.logger.debug(
                    "Dropping queen %s, because we can't get speed stats: %r",
                    self._queen_peer,
                    exc,
                )
                force_drop_queen = True

            if force_drop_queen or new_peer_quality < old_queen_quality:
                old_queen, self._queen_peer = self._queen_peer, peer
                self._waiting_peers.put_nowait(old_queen)
                return
            else:
                # nothing to do, peer is slower than the queen
                return

        raise ValidationError(
            "Unreachable: every queen peer check should have finished and returned. "
            f"Was checking {peer} against queen {self._queen_peer}."
        )