示例#1
0
    def __init__(
            self,
            data: ConsensusSharedData,
            bus: InternalBus,
            network: ExternalBus,
            stasher: StashingRouter,
            db_manager: DatabaseManager,
            metrics: MetricsCollector = NullMetricsCollector(),
    ):
        self._data = data
        self._bus = bus
        self._network = network
        self._stasher = stasher
        self._subscription = Subscription()
        self._validator = CheckpointMsgValidator(self._data)
        self._db_manager = db_manager
        self.metrics = metrics

        # Received checkpoints, mapping CheckpointKey -> List(node_alias)
        self._received_checkpoints = defaultdict(
            set)  # type: Dict[CheckpointService.CheckpointKey, Set[str]]

        self._config = getConfig()
        self._logger = getlogger()

        self._subscription.subscribe(stasher, Checkpoint,
                                     self.process_checkpoint)

        self._subscription.subscribe(bus, Ordered, self.process_ordered)
        self._subscription.subscribe(bus, BackupSetupLastOrdered,
                                     self.process_backup_setup_last_ordered)
        self._subscription.subscribe(bus, NewViewAccepted,
                                     self.process_new_view_accepted)
示例#2
0
    def __init__(
            self,
            data: ConsensusSharedData,
            bus: InternalBus,
            network: ExternalBus,
            stasher: StashingRouter,
            db_manager: DatabaseManager,
            old_stasher: ReplicaStasher,
            metrics: MetricsCollector = NullMetricsCollector(),
    ):
        self._data = data
        self._bus = bus
        self._network = network
        self._checkpoint_state = SortedDict(lambda k: k[1])
        self._stasher = stasher
        self._validator = CheckpointMsgValidator(self._data)
        self._db_manager = db_manager
        self.metrics = metrics

        # Stashed checkpoints for each view. The key of the outermost
        # dictionary is the view_no, value being a dictionary with key as the
        # range of the checkpoint and its value again being a mapping between
        # senders and their sent checkpoint
        # Dict[view_no, Dict[(seqNoStart, seqNoEnd),  Dict[sender, Checkpoint]]]
        self._stashed_recvd_checkpoints = {}

        self._config = getConfig()
        self._logger = getlogger()

        self._old_stasher = old_stasher
示例#3
0
    def __init__(
            self,
            data: ConsensusSharedData,
            bus: InternalBus,
            network: ExternalBus,
            stasher: StashingRouter,
            db_manager: DatabaseManager,
            metrics: MetricsCollector = NullMetricsCollector(),
    ):
        self._data = data
        self._bus = bus
        self._network = network
        self._checkpoint_state = SortedDict(lambda k: k[1])
        self._stasher = stasher
        self._subscription = Subscription()
        self._validator = CheckpointMsgValidator(self._data)
        self._db_manager = db_manager
        self.metrics = metrics

        # Stashed checkpoints for each view. The key of the outermost
        # dictionary is the view_no, value being a dictionary with key as the
        # range of the checkpoint and its value again being a mapping between
        # senders and their sent checkpoint
        # Dict[view_no, Dict[(seqNoStart, seqNoEnd),  Dict[sender, Checkpoint]]]
        self._stashed_recvd_checkpoints = {}

        self._config = getConfig()
        self._logger = getlogger()

        self._subscription.subscribe(stasher, Checkpoint,
                                     self.process_checkpoint)

        self._subscription.subscribe(bus, Ordered, self.process_ordered)
        self._subscription.subscribe(bus, BackupSetupLastOrdered,
                                     self.process_backup_setup_last_ordered)
        self._subscription.subscribe(bus, NewViewAccepted,
                                     self.process_new_view_accepted)
def validator(consensus_data):
    data = consensus_data("some_name")
    data.node_mode = Mode.participating
    return CheckpointMsgValidator(data)
示例#5
0
class CheckpointService:
    STASHED_CHECKPOINTS_BEFORE_CATCHUP = 1

    # TODO: Remove view_no from key after implementing INDY-1336
    CheckpointKey = NamedTuple('CheckpointKey', [('view_no', int),
                                                 ('pp_seq_no', int),
                                                 ('digest', str)])

    def __init__(
            self,
            data: ConsensusSharedData,
            bus: InternalBus,
            network: ExternalBus,
            stasher: StashingRouter,
            db_manager: DatabaseManager,
            metrics: MetricsCollector = NullMetricsCollector(),
    ):
        self._data = data
        self._bus = bus
        self._network = network
        self._stasher = stasher
        self._subscription = Subscription()
        self._validator = CheckpointMsgValidator(self._data)
        self._db_manager = db_manager
        self.metrics = metrics

        # Received checkpoints, mapping CheckpointKey -> List(node_alias)
        self._received_checkpoints = defaultdict(
            set)  # type: Dict[CheckpointService.CheckpointKey, Set[str]]

        self._config = getConfig()
        self._logger = getlogger()

        self._subscription.subscribe(stasher, Checkpoint,
                                     self.process_checkpoint)

        self._subscription.subscribe(bus, Ordered, self.process_ordered)
        self._subscription.subscribe(bus, BackupSetupLastOrdered,
                                     self.process_backup_setup_last_ordered)
        self._subscription.subscribe(bus, NewViewAccepted,
                                     self.process_new_view_accepted)

    def cleanup(self):
        self._subscription.unsubscribe_all()

    @property
    def view_no(self):
        return self._data.view_no

    @property
    def is_master(self):
        return self._data.is_master

    @property
    def last_ordered_3pc(self):
        return self._data.last_ordered_3pc

    @measure_consensus_time(MetricsName.PROCESS_CHECKPOINT_TIME,
                            MetricsName.BACKUP_PROCESS_CHECKPOINT_TIME)
    def process_checkpoint(self, msg: Checkpoint, sender: str) -> (bool, str):
        """
        Process checkpoint messages
        :return: whether processed (True) or stashed (False)
        """
        self._logger.info('{} processing checkpoint {} from {}'.format(
            self, msg, sender))
        result, reason = self._validator.validate(msg)
        if result != PROCESS:
            return result, reason

        key = self._checkpoint_key(msg)
        self._received_checkpoints[key].add(sender)
        self._try_to_stabilize_checkpoint(key)
        self._start_catchup_if_needed(key)

    def process_backup_setup_last_ordered(self, msg: BackupSetupLastOrdered):
        if msg.inst_id != self._data.inst_id:
            return
        self.update_watermark_from_3pc()

    def process_ordered(self, ordered: Ordered):
        for batch_id in reversed(self._data.preprepared):
            if batch_id.pp_seq_no == ordered.ppSeqNo:
                self._add_to_checkpoint(batch_id.pp_seq_no, batch_id.view_no,
                                        ordered.auditTxnRootHash)
                return
        raise LogicError(
            "CheckpointService | Can't process Ordered msg because "
            "ppSeqNo {} not in preprepared".format(ordered.ppSeqNo))

    def _start_catchup_if_needed(self, key: CheckpointKey):
        if self._have_own_checkpoint(key):
            return

        unknown_stabilized = self._unknown_stabilized_checkpoints()
        lag_in_checkpoints = len(unknown_stabilized)
        if lag_in_checkpoints <= self.STASHED_CHECKPOINTS_BEFORE_CATCHUP:
            return

        last_key = sorted(unknown_stabilized,
                          key=lambda v: (v.view_no, v.pp_seq_no))[-1]

        if self.is_master:
            # TODO: This code doesn't seem to be needed, but it was there. Leaving just in case
            #  tests explain why it was really needed.
            # self._logger.display(
            #     '{} has lagged for {} checkpoints so updating watermarks to {}'.format(
            #         self, lag_in_checkpoints, last_key.pp_seq_no))
            # self.set_watermarks(low_watermark=last_key.pp_seq_no)

            if not self._data.is_primary:
                self._logger.display(
                    '{} has lagged for {} checkpoints so the catchup procedure starts'
                    .format(self, lag_in_checkpoints))
                self._bus.send(NeedMasterCatchup())
        else:
            self._logger.info(
                '{} has lagged for {} checkpoints so adjust last_ordered_3pc to {}, '
                'shift watermarks and clean collections'.format(
                    self, lag_in_checkpoints, last_key.pp_seq_no))
            # Adjust last_ordered_3pc, shift watermarks, clean operational
            # collections and process stashed messages which now fit between
            # watermarks
            # TODO: Actually we might need to process view_no from last_key as well, however
            #  it wasn't processed before, and it will go away when INDY-1336 gets implemented
            key_3pc = (self.view_no, last_key.pp_seq_no)
            self._bus.send(
                NeedBackupCatchup(inst_id=self._data.inst_id,
                                  caught_up_till_3pc=key_3pc))
            self.caught_up_till_3pc(key_3pc)

    def gc_before_new_view(self):
        self._reset_checkpoints()
        # ToDo: till_3pc_key should be None?
        self._remove_received_checkpoints(till_3pc_key=(self.view_no, 0))

    def caught_up_till_3pc(self, caught_up_till_3pc):
        # TODO: Add checkpoint using audit ledger
        cp_seq_no = caught_up_till_3pc[
            1] // self._config.CHK_FREQ * self._config.CHK_FREQ
        self._mark_checkpoint_stable(cp_seq_no)

    def catchup_clear_for_backup(self):
        self._reset_checkpoints()
        self._remove_received_checkpoints()
        self.set_watermarks(low_watermark=0, high_watermark=sys.maxsize)

    def _add_to_checkpoint(self, ppSeqNo, view_no, audit_txn_root_hash):
        if ppSeqNo % self._config.CHK_FREQ != 0:
            return

        key = self.CheckpointKey(view_no=view_no,
                                 pp_seq_no=ppSeqNo,
                                 digest=audit_txn_root_hash)

        self._do_checkpoint(ppSeqNo, view_no, audit_txn_root_hash)
        self._try_to_stabilize_checkpoint(key)

    @measure_consensus_time(MetricsName.SEND_CHECKPOINT_TIME,
                            MetricsName.BACKUP_SEND_CHECKPOINT_TIME)
    def _do_checkpoint(self, pp_seq_no, view_no, audit_txn_root_hash):
        self._logger.info(
            "{} sending Checkpoint {} view {} audit txn root hash {}".format(
                self, pp_seq_no, view_no, audit_txn_root_hash))

        checkpoint = Checkpoint(self._data.inst_id, view_no, 0, pp_seq_no,
                                audit_txn_root_hash)
        self._network.send(checkpoint)
        self._data.checkpoints.add(checkpoint)

    def _try_to_stabilize_checkpoint(self, key: CheckpointKey):
        if not self._have_quorum_on_received_checkpoint(key):
            return

        if not self._have_own_checkpoint(key):
            return

        self._mark_checkpoint_stable(key.pp_seq_no)

    def _mark_checkpoint_stable(self, pp_seq_no):
        self._data.stable_checkpoint = pp_seq_no

        stable_checkpoints = self._data.checkpoints.irange_key(
            min_key=pp_seq_no, max_key=pp_seq_no)
        if len(list(stable_checkpoints)) == 0:
            # TODO: Is it okay to get view_no like this?
            view_no = self._data.last_ordered_3pc[0]
            checkpoint = Checkpoint(instId=self._data.inst_id,
                                    viewNo=view_no,
                                    seqNoStart=0,
                                    seqNoEnd=pp_seq_no,
                                    digest=self._audit_txn_root_hash(
                                        view_no, pp_seq_no))
            self._data.checkpoints.add(checkpoint)

        for cp in self._data.checkpoints.copy():
            if cp.seqNoEnd < pp_seq_no:
                self._logger.trace("{} removing previous checkpoint {}".format(
                    self, cp))
                self._data.checkpoints.remove(cp)

        self.set_watermarks(low_watermark=pp_seq_no)

        self._remove_received_checkpoints(till_3pc_key=(self.view_no,
                                                        pp_seq_no))
        self._bus.send(CheckpointStabilized(
            (self.view_no, pp_seq_no)))  # call OrderingService.gc()
        self._logger.info("{} marked stable checkpoint {}".format(
            self, pp_seq_no))

    def set_watermarks(self, low_watermark: int, high_watermark: int = None):
        self._data.low_watermark = low_watermark
        self._data.high_watermark = self._data.low_watermark + self._config.LOG_SIZE \
            if high_watermark is None else \
            high_watermark

        self._logger.info('{} set watermarks as {} {}'.format(
            self, self._data.low_watermark, self._data.high_watermark))
        self._stasher.process_all_stashed(STASH_WATERMARKS)

    def update_watermark_from_3pc(self):
        last_ordered_3pc = self.last_ordered_3pc
        if (last_ordered_3pc is not None) and (last_ordered_3pc[0]
                                               == self.view_no):
            self._logger.info(
                "update_watermark_from_3pc to {}".format(last_ordered_3pc))
            self.set_watermarks(last_ordered_3pc[1])
        else:
            self._logger.info(
                "try to update_watermark_from_3pc but last_ordered_3pc is None"
            )

    def _remove_received_checkpoints(self, till_3pc_key=None):
        """
        Remove received checkpoints up to `till_3pc_key` if provided,
        otherwise remove all received checkpoints
        """
        if till_3pc_key is None:
            self._received_checkpoints.clear()
            self._logger.info(
                '{} removing all received checkpoints'.format(self))
            return

        for cp in list(self._received_checkpoints.keys()):
            if self._is_below_3pc_key(cp, till_3pc_key):
                self._logger.info(
                    '{} removing received checkpoints: {}'.format(self, cp))
                del self._received_checkpoints[cp]

    def _reset_checkpoints(self):
        # That function most probably redundant in PBFT approach,
        # because according to paper, checkpoints cleared only when next stabilized.
        # Avoid using it while implement other services.
        self._data.checkpoints.clear()
        self._data.checkpoints.append(self._data.initial_checkpoint)

    def __str__(self) -> str:
        return "{} - checkpoint_service".format(self._data.name)

    def discard(self, msg, reason, sender):
        self._logger.trace("{} discard message {} from {} "
                           "with the reason: {}".format(
                               self, msg, sender, reason))

    def _have_own_checkpoint(self, key: CheckpointKey) -> bool:
        own_checkpoints = self._data.checkpoints.irange_key(
            min_key=key.pp_seq_no, max_key=key.pp_seq_no)
        return any(cp.viewNo == key.view_no and cp.digest == key.digest
                   for cp in own_checkpoints)

    def _have_quorum_on_received_checkpoint(self, key: CheckpointKey) -> bool:
        votes = self._received_checkpoints[key]
        return self._data.quorums.checkpoint.is_reached(len(votes))

    def _unknown_stabilized_checkpoints(self) -> List[CheckpointKey]:
        return [
            key for key in self._received_checkpoints
            if self._have_quorum_on_received_checkpoint(key)
            and not self._have_own_checkpoint(key)
            and not self._is_below_3pc_key(key, self.last_ordered_3pc)
        ]

    @staticmethod
    def _is_below_3pc_key(cp: CheckpointKey, key: Tuple[int, int]) -> bool:
        return compare_3PC_keys((cp.view_no, cp.pp_seq_no), key) >= 0

    @staticmethod
    def _checkpoint_key(checkpoint: Checkpoint) -> CheckpointKey:
        return CheckpointService.CheckpointKey(view_no=checkpoint.viewNo,
                                               pp_seq_no=checkpoint.seqNoEnd,
                                               digest=checkpoint.digest)

    @staticmethod
    def _audit_seq_no_from_3pc_key(audit_ledger: Ledger, view_no: int,
                                   pp_seq_no: int) -> int:
        # TODO: Should we put it into some common code?
        seq_no = audit_ledger.size
        while seq_no > 0:
            txn = audit_ledger.getBySeqNo(seq_no)
            txn_data = get_payload_data(txn)
            audit_view_no = txn_data[AUDIT_TXN_VIEW_NO]
            audit_pp_seq_no = txn_data[AUDIT_TXN_PP_SEQ_NO]
            if audit_view_no == view_no and audit_pp_seq_no == pp_seq_no:
                break
            seq_no -= 1
        return seq_no

    def _audit_txn_root_hash(self, view_no: int,
                             pp_seq_no: int) -> Optional[str]:
        audit_ledger = self._db_manager.get_ledger(AUDIT_LEDGER_ID)
        # TODO: Should we remove view_no at some point?
        seq_no = self._audit_seq_no_from_3pc_key(audit_ledger, view_no,
                                                 pp_seq_no)
        # TODO: What should we do if txn not found or audit ledger is empty?
        if seq_no == 0:
            return None
        root_hash = audit_ledger.tree.merkle_tree_hash(0, seq_no)
        return audit_ledger.hashToStr(root_hash)

    def process_new_view_accepted(self, msg: NewViewAccepted):
        # 1. update shared data
        cp = msg.checkpoint
        if cp not in self._data.checkpoints:
            self._data.checkpoints.append(cp)
        self._mark_checkpoint_stable(cp.seqNoEnd)
        self.set_watermarks(low_watermark=cp.seqNoEnd)

        # 2. send NewViewCheckpointsApplied
        self._bus.send(
            NewViewCheckpointsApplied(view_no=msg.view_no,
                                      view_changes=msg.view_changes,
                                      checkpoint=msg.checkpoint,
                                      batches=msg.batches))
        return PROCESS, None
示例#6
0
class CheckpointService:
    STASHED_CHECKPOINTS_BEFORE_CATCHUP = 1

    def __init__(
            self,
            data: ConsensusSharedData,
            bus: InternalBus,
            network: ExternalBus,
            stasher: StashingRouter,
            db_manager: DatabaseManager,
            metrics: MetricsCollector = NullMetricsCollector(),
    ):
        self._data = data
        self._bus = bus
        self._network = network
        self._checkpoint_state = SortedDict(lambda k: k[1])
        self._stasher = stasher
        self._subscription = Subscription()
        self._validator = CheckpointMsgValidator(self._data)
        self._db_manager = db_manager
        self.metrics = metrics

        # Stashed checkpoints for each view. The key of the outermost
        # dictionary is the view_no, value being a dictionary with key as the
        # range of the checkpoint and its value again being a mapping between
        # senders and their sent checkpoint
        # Dict[view_no, Dict[(seqNoStart, seqNoEnd),  Dict[sender, Checkpoint]]]
        self._stashed_recvd_checkpoints = {}

        self._config = getConfig()
        self._logger = getlogger()

        self._subscription.subscribe(stasher, Checkpoint,
                                     self.process_checkpoint)

        self._subscription.subscribe(bus, Ordered, self.process_ordered)
        self._subscription.subscribe(bus, BackupSetupLastOrdered,
                                     self.process_backup_setup_last_ordered)
        self._subscription.subscribe(bus, NewViewAccepted,
                                     self.process_new_view_accepted)

    def cleanup(self):
        self._subscription.unsubscribe_all()

    @property
    def view_no(self):
        return self._data.view_no

    @property
    def is_master(self):
        return self._data.is_master

    @property
    def last_ordered_3pc(self):
        return self._data.last_ordered_3pc

    @measure_consensus_time(MetricsName.PROCESS_CHECKPOINT_TIME,
                            MetricsName.BACKUP_PROCESS_CHECKPOINT_TIME)
    def process_checkpoint(self, msg: Checkpoint, sender: str) -> (bool, str):
        """
        Process checkpoint messages
        :return: whether processed (True) or stashed (False)
        """
        if msg.instId != self._data.inst_id:
            return None, None
        self._logger.info('{} processing checkpoint {} from {}'.format(
            self, msg, sender))
        result, reason = self._validator.validate(msg)
        if result == PROCESS:
            self._do_process_checkpoint(msg, sender)
        return result, reason

    def _do_process_checkpoint(self, msg: Checkpoint, sender: str) -> bool:
        """
        Process checkpoint messages

        :return: whether processed (True) or stashed (False)
        """
        seqNoEnd = msg.seqNoEnd
        seqNoStart = msg.seqNoStart
        key = (seqNoStart, seqNoEnd)

        if key not in self._checkpoint_state or not self._checkpoint_state[
                key].digest:
            self._stash_checkpoint(msg, sender)
            self._remove_stashed_checkpoints(self.last_ordered_3pc)
            self._start_catchup_if_needed()
            return False

        checkpoint_state = self._checkpoint_state[key]
        # Raise the error only if master since only master's last
        # ordered 3PC is communicated during view change
        if self.is_master and checkpoint_state.digest != msg.digest:
            self._logger.warning("{} received an incorrect digest {} for "
                                 "checkpoint {} from {}".format(
                                     self, msg.digest, key, sender))
            return True

        checkpoint_state.receivedDigests[sender] = msg.digest
        self._check_if_checkpoint_stable(key)
        return True

    def process_backup_setup_last_ordered(self, msg: BackupSetupLastOrdered):
        if msg.inst_id != self._data.inst_id:
            return
        self.update_watermark_from_3pc()

    def process_ordered(self, ordered: Ordered):
        if ordered.instId != self._data.inst_id:
            return
        for batch_id in reversed(self._data.preprepared):
            if batch_id.pp_seq_no == ordered.ppSeqNo:
                self._add_to_checkpoint(batch_id.pp_seq_no, batch_id.pp_digest,
                                        ordered.ledgerId, batch_id.view_no,
                                        ordered.auditTxnRootHash)
                return
        raise LogicError(
            "CheckpointService | Can't process Ordered msg because "
            "ppSeqNo {} not in preprepared".format(ordered.ppSeqNo))

    def _start_catchup_if_needed(self):
        stashed_checkpoint_ends = self._stashed_checkpoints_with_quorum()
        lag_in_checkpoints = len(stashed_checkpoint_ends)
        if self._checkpoint_state:
            (s, e) = firstKey(self._checkpoint_state)
            # If the first stored own checkpoint has a not aligned lower bound
            # (this means that it was started after a catch-up), is complete
            # and there is a quorumed stashed checkpoint from other replicas
            # with the same end then don't include this stashed checkpoint
            # into the lag
            if s % self._config.CHK_FREQ != 0 \
                    and self._checkpoint_state[(s, e)].seqNo == e \
                    and e in stashed_checkpoint_ends:
                lag_in_checkpoints -= 1
        is_stashed_enough = \
            lag_in_checkpoints > self.STASHED_CHECKPOINTS_BEFORE_CATCHUP
        if not is_stashed_enough:
            return

        if self.is_master:
            self._logger.display(
                '{} has lagged for {} checkpoints so updating watermarks to {}'
                .format(self, lag_in_checkpoints, stashed_checkpoint_ends[-1]))
            self.set_watermarks(low_watermark=stashed_checkpoint_ends[-1])
            if not self._data.is_primary:
                self._logger.display(
                    '{} has lagged for {} checkpoints so the catchup procedure starts'
                    .format(self, lag_in_checkpoints))
                self._bus.send(NeedMasterCatchup())
        else:
            self._logger.info(
                '{} has lagged for {} checkpoints so adjust last_ordered_3pc to {}, '
                'shift watermarks and clean collections'.format(
                    self, lag_in_checkpoints, stashed_checkpoint_ends[-1]))
            # Adjust last_ordered_3pc, shift watermarks, clean operational
            # collections and process stashed messages which now fit between
            # watermarks
            key_3pc = (self.view_no, stashed_checkpoint_ends[-1])
            self._bus.send(
                NeedBackupCatchup(inst_id=self._data.inst_id,
                                  caught_up_till_3pc=key_3pc))
            self.caught_up_till_3pc(key_3pc)

    def gc_before_new_view(self):
        self._reset_checkpoints()
        self._remove_stashed_checkpoints(till_3pc_key=(self.view_no, 0))

    def caught_up_till_3pc(self, caught_up_till_3pc):
        self._reset_checkpoints()
        self._remove_stashed_checkpoints(till_3pc_key=caught_up_till_3pc)
        self.update_watermark_from_3pc()

    def catchup_clear_for_backup(self):
        self._reset_checkpoints()
        self._remove_stashed_checkpoints()
        self.set_watermarks(low_watermark=0, high_watermark=sys.maxsize)

    def _add_to_checkpoint(self, ppSeqNo, digest, ledger_id, view_no,
                           audit_txn_root_hash):
        for (s, e) in self._checkpoint_state.keys():
            if s <= ppSeqNo <= e:
                state = self._checkpoint_state[s, e]  # type: CheckpointState
                state.digests.append(digest)
                state = updateNamedTuple(state, seqNo=ppSeqNo)
                self._checkpoint_state[s, e] = state
                break
        else:
            s, e = ppSeqNo, math.ceil(
                ppSeqNo / self._config.CHK_FREQ) * self._config.CHK_FREQ
            self._logger.debug("{} adding new checkpoint state for {}".format(
                self, (s, e)))
            state = CheckpointState(ppSeqNo, [
                digest,
            ], None, {}, False)
            self._checkpoint_state[s, e] = state

        if state.seqNo == e:
            if len(state.digests) == self._config.CHK_FREQ:
                self._do_checkpoint(state, s, e, ledger_id, view_no,
                                    audit_txn_root_hash)
            self._process_stashed_checkpoints((s, e), view_no)

    @measure_consensus_time(MetricsName.SEND_CHECKPOINT_TIME,
                            MetricsName.BACKUP_SEND_CHECKPOINT_TIME)
    def _do_checkpoint(self, state, s, e, ledger_id, view_no,
                       audit_txn_root_hash):
        # TODO CheckpointState/Checkpoint is not a namedtuple anymore
        # 1. check if updateNamedTuple works for the new message type
        # 2. choose another name

        # TODO: This is hack of hacks, should be removed when refactoring is complete
        if not self.is_master and audit_txn_root_hash is None:
            audit_txn_root_hash = "7RJ5bkAKRy2CCvarRij2jiHC16SVPjHcrpVdNsboiQGv"

        state = updateNamedTuple(state, digest=audit_txn_root_hash, digests=[])
        self._checkpoint_state[s, e] = state
        self._logger.info(
            "{} sending Checkpoint {} view {} checkpointState digest {}. Ledger {} "
            "txn root hash {}. Committed state root hash {} Uncommitted state root hash {}"
            .format(
                self, (s, e), view_no, state.digest, ledger_id,
                self._db_manager.get_txn_root_hash(ledger_id),
                self._db_manager.get_state_root_hash(ledger_id,
                                                     committed=True),
                self._db_manager.get_state_root_hash(ledger_id,
                                                     committed=False)))
        checkpoint = Checkpoint(self._data.inst_id, view_no, s, e,
                                state.digest)
        self._network.send(checkpoint)
        self._data.checkpoints.append(checkpoint)

    def _mark_checkpoint_stable(self, seqNo):
        previousCheckpoints = []
        for (s, e), state in self._checkpoint_state.items():
            if e == seqNo:
                # TODO CheckpointState/Checkpoint is not a namedtuple anymore
                # 1. check if updateNamedTuple works for the new message type
                # 2. choose another name
                state = updateNamedTuple(state, isStable=True)
                self._checkpoint_state[s, e] = state
                self._set_stable_checkpoint(e)
                break
            else:
                previousCheckpoints.append((s, e))
        else:
            self._logger.debug("{} could not find {} in checkpoints".format(
                self, seqNo))
            return
        self.set_watermarks(low_watermark=seqNo)
        for k in previousCheckpoints:
            self._logger.trace("{} removing previous checkpoint {}".format(
                self, k))
            self._checkpoint_state.pop(k)
        self._remove_stashed_checkpoints(till_3pc_key=(self.view_no, seqNo))
        self._bus.send(
            CheckpointStabilized(self._data.inst_id, (self.view_no, seqNo)))
        self._logger.info("{} marked stable checkpoint {}".format(
            self, (s, e)))

    def _check_if_checkpoint_stable(self, key: Tuple[int, int]):
        ckState = self._checkpoint_state[key]
        if self._data.quorums.checkpoint.is_reached(
                len(ckState.receivedDigests)):
            self._mark_checkpoint_stable(ckState.seqNo)
            return True
        else:
            self._logger.debug('{} has state.receivedDigests as {}'.format(
                self, ckState.receivedDigests.keys()))
            return False

    def _stash_checkpoint(self, ck: Checkpoint, sender: str):
        self._logger.debug('{} stashing {} from {}'.format(self, ck, sender))
        seqNoStart, seqNoEnd = ck.seqNoStart, ck.seqNoEnd
        if ck.viewNo not in self._stashed_recvd_checkpoints:
            self._stashed_recvd_checkpoints[ck.viewNo] = {}
        stashed_for_view = self._stashed_recvd_checkpoints[ck.viewNo]
        if (seqNoStart, seqNoEnd) not in stashed_for_view:
            stashed_for_view[seqNoStart, seqNoEnd] = {}
        stashed_for_view[seqNoStart, seqNoEnd][sender] = ck

    def _stashed_checkpoints_with_quorum(self):
        end_pp_seq_numbers = []
        quorum = self._data.quorums.checkpoint
        for (_, seq_no_end), senders in self._stashed_recvd_checkpoints.get(
                self.view_no, {}).items():
            if quorum.is_reached(len(senders)):
                end_pp_seq_numbers.append(seq_no_end)
        return sorted(end_pp_seq_numbers)

    def _process_stashed_checkpoints(self, key, view_no):
        # Remove all checkpoints from previous views if any
        self._remove_stashed_checkpoints(till_3pc_key=(self.view_no, 0))

        if key not in self._stashed_recvd_checkpoints.get(view_no, {}):
            self._logger.trace("{} have no stashed checkpoints for {}")
            return

        # Get a snapshot of all the senders of stashed checkpoints for `key`
        senders = list(self._stashed_recvd_checkpoints[view_no][key].keys())
        total_processed = 0
        consumed = 0

        for sender in senders:
            # Check if the checkpoint from `sender` is still in
            # `stashed_recvd_checkpoints` because it might be removed from there
            # in case own checkpoint was stabilized when we were processing
            # stashed checkpoints from previous senders in this loop
            if view_no in self._stashed_recvd_checkpoints \
                    and key in self._stashed_recvd_checkpoints[view_no] \
                    and sender in self._stashed_recvd_checkpoints[view_no][key]:
                if self.process_checkpoint(
                        self._stashed_recvd_checkpoints[view_no][key].pop(
                            sender), sender):
                    consumed += 1
                # Note that if `process_checkpoint` returned False then the
                # checkpoint from `sender` was re-stashed back to
                # `stashed_recvd_checkpoints`
                total_processed += 1

        # If we have consumed stashed checkpoints for `key` from all the
        # senders then remove entries which have become empty
        if view_no in self._stashed_recvd_checkpoints \
                and key in self._stashed_recvd_checkpoints[view_no] \
                and len(self._stashed_recvd_checkpoints[view_no][key]) == 0:
            del self._stashed_recvd_checkpoints[view_no][key]
            if len(self._stashed_recvd_checkpoints[view_no]) == 0:
                del self._stashed_recvd_checkpoints[view_no]

        restashed = total_processed - consumed
        self._logger.info('{} processed {} stashed checkpoints for {}, '
                          '{} of them were stashed again'.format(
                              self, total_processed, key, restashed))

        return total_processed

    def reset_watermarks_before_new_view(self):
        # Reset any previous view watermarks since for view change to
        # successfully complete, the node must have reached the same state
        # as other nodes
        self.set_watermarks(low_watermark=0)

    def should_reset_watermarks_before_new_view(self):
        if self.view_no <= 0:
            return False
        if self.last_ordered_3pc[
                0] == self.view_no and self.last_ordered_3pc[1] > 0:
            return False
        return True

    def set_watermarks(self, low_watermark: int, high_watermark: int = None):
        self._data.low_watermark = low_watermark
        self._data.high_watermark = self._data.low_watermark + self._config.LOG_SIZE \
            if high_watermark is None else \
            high_watermark

        self._logger.info('{} set watermarks as {} {}'.format(
            self, self._data.low_watermark, self._data.high_watermark))
        self._stasher.process_all_stashed(STASH_WATERMARKS)

    def update_watermark_from_3pc(self):
        last_ordered_3pc = self.last_ordered_3pc
        if (last_ordered_3pc is not None) and (last_ordered_3pc[0]
                                               == self.view_no):
            self._logger.info(
                "update_watermark_from_3pc to {}".format(last_ordered_3pc))
            self.set_watermarks(last_ordered_3pc[1])
        else:
            self._logger.info(
                "try to update_watermark_from_3pc but last_ordered_3pc is None"
            )

    def _remove_stashed_checkpoints(self, till_3pc_key=None):
        """
        Remove stashed received checkpoints up to `till_3pc_key` if provided,
        otherwise remove all stashed received checkpoints
        """
        if till_3pc_key is None:
            self._stashed_recvd_checkpoints.clear()
            self._logger.info(
                '{} removing all stashed checkpoints'.format(self))
            return

        for view_no in list(self._stashed_recvd_checkpoints.keys()):

            if view_no < till_3pc_key[0]:
                self._logger.info(
                    '{} removing stashed checkpoints for view {}'.format(
                        self, view_no))
                del self._stashed_recvd_checkpoints[view_no]

            elif view_no == till_3pc_key[0]:
                for (s, e) in list(
                        self._stashed_recvd_checkpoints[view_no].keys()):
                    if e <= till_3pc_key[1]:
                        self._logger.info(
                            '{} removing stashed checkpoints: '
                            'viewNo={}, seqNoStart={}, seqNoEnd={}'.format(
                                self, view_no, s, e))
                        del self._stashed_recvd_checkpoints[view_no][(s, e)]
                if len(self._stashed_recvd_checkpoints[view_no]) == 0:
                    del self._stashed_recvd_checkpoints[view_no]

    def _reset_checkpoints(self):
        # That function most probably redundant in PBFT approach,
        # because according to paper, checkpoints cleared only when next stabilized.
        # Avoid using it while implement other services.
        self._checkpoint_state.clear()
        self._data.checkpoints.clear()
        # TODO: change to = 1 in ViewChangeService integration.
        self._data.stable_checkpoint = 0

    def _set_stable_checkpoint(self, end_seq_no):
        if not list(self._data.checkpoints.irange_key(end_seq_no, end_seq_no)):
            raise LogicError('Stable checkpoint must be in checkpoints')
        self._data.stable_checkpoint = end_seq_no

        self._data.checkpoints = \
            SortedListWithKey([c for c in self._data.checkpoints if c.seqNoEnd >= end_seq_no],
                              key=lambda checkpoint: checkpoint.seqNoEnd)

    def __str__(self) -> str:
        return "{} - checkpoint_service".format(self._data.name)

    # TODO: move to OrderingService as a handler for Cleanup messages
    # def _clear_batch_till_seq_no(self, seq_no):
    #     self._data.preprepared = [pp for pp in self._data.preprepared if pp.ppSeqNo >= seq_no]
    #     self._data.prepared = [p for p in self._data.prepared if p.ppSeqNo >= seq_no]

    def discard(self, msg, reason, sender):
        self._logger.trace("{} discard message {} from {} "
                           "with the reason: {}".format(
                               self, msg, sender, reason))

    def process_new_view_accepted(self, msg: NewViewAccepted):
        # 1. update shared data
        cp = msg.checkpoint
        if cp not in self._data.checkpoints:
            self._data.checkpoints.append(cp)
        self._set_stable_checkpoint(cp.seqNoEnd)
        self.set_watermarks(low_watermark=cp.seqNoEnd)

        # 2. send NewViewCheckpointsApplied
        self._bus.send(
            NewViewCheckpointsApplied(view_no=msg.view_no,
                                      view_changes=msg.view_changes,
                                      checkpoint=msg.checkpoint,
                                      batches=msg.batches))
        return PROCESS, None