# Copyright (c) 2016-2018, Neil Booth # # All rights reserved. # # See the file "LICENCE" for information about the copyright # and warranty status of this software. """Mempool handling.""" import asyncio import itertools import time import attr import typing from collections import defaultdict from prometheus_client import Histogram from lbry.wallet.server.util import class_logger if typing.TYPE_CHECKING: from lbry.wallet.server.session import LBRYSessionManager from wallet.server.db.db import LevelDB @attr.s(slots=True) class MemPoolTx: prevouts = attr.ib() # A pair is a (hashX, value) tuple in_pairs = attr.ib() out_pairs = attr.ib() fee = attr.ib() size = attr.ib() raw_tx = attr.ib() @attr.s(slots=True) class MemPoolTxSummary: hash = attr.ib() fee = attr.ib() has_unconfirmed_inputs = attr.ib() NAMESPACE = "wallet_server" HISTOGRAM_BUCKETS = ( .005, .01, .025, .05, .075, .1, .25, .5, .75, 1.0, 2.5, 5.0, 7.5, 10.0, 15.0, 20.0, 30.0, 60.0, float('inf') ) mempool_process_time_metric = Histogram( "processed_mempool", "Time to process mempool and notify touched addresses", namespace=NAMESPACE, buckets=HISTOGRAM_BUCKETS ) class MemPool: def __init__(self, coin, db: 'LevelDB', refresh_secs=1.0): self.coin = coin self._db = db self.logger = class_logger(__name__, self.__class__.__name__) self.txs = {} self.raw_mempool = {} self.touched_hashXs: typing.DefaultDict[bytes, typing.Set[bytes]] = defaultdict(set) # None can be a key self.refresh_secs = refresh_secs self.mempool_process_time_metric = mempool_process_time_metric self.session_manager: typing.Optional['LBRYSessionManager'] = None async def refresh_hashes(self, height: int): start = time.perf_counter() new_touched = await self._process_mempool() await self.on_mempool(set(self.touched_hashXs), new_touched, height) duration = time.perf_counter() - start self.mempool_process_time_metric.observe(duration) async def _process_mempool(self) -> typing.Set[bytes]: # returns list of new touched hashXs # Re-sync with the new set of hashes # hashXs = self.hashXs # hashX: [tx_hash, ...] touched_hashXs = set() # Remove txs that aren't in mempool anymore for tx_hash in set(self.txs).difference(self.raw_mempool.keys()): tx = self.txs.pop(tx_hash) tx_hashXs = {hashX for hashX, value in tx.in_pairs}.union({hashX for hashX, value in tx.out_pairs}) for hashX in tx_hashXs: if hashX in self.touched_hashXs and tx_hash in self.touched_hashXs[hashX]: self.touched_hashXs[hashX].remove(tx_hash) if not self.touched_hashXs[hashX]: self.touched_hashXs.pop(hashX) touched_hashXs.update(tx_hashXs) tx_map = {} for tx_hash, raw_tx in self.raw_mempool.items(): if tx_hash in self.txs: continue tx, tx_size = self.coin.DESERIALIZER(raw_tx).read_tx_and_vsize() # Convert the inputs and outputs into (hashX, value) pairs # Drop generation-like inputs from MemPoolTx.prevouts txin_pairs = tuple((txin.prev_hash, txin.prev_idx) for txin in tx.inputs if not txin.is_generation()) txout_pairs = tuple((self.coin.hashX_from_script(txout.pk_script), txout.value) for txout in tx.outputs) tx_map[tx_hash] = MemPoolTx(txin_pairs, None, txout_pairs, 0, tx_size, raw_tx) # Determine all prevouts not in the mempool, and fetch the # UTXO information from the database. Failed prevout lookups # return None - concurrent database updates happen - which is # relied upon by _accept_transactions. Ignore prevouts that are # generation-like. # prevouts = tuple(prevout for tx in tx_map.values() # for prevout in tx.prevouts # if prevout[0] not in self.raw_mempool) # utxos = await self._db.lookup_utxos(prevouts) # utxo_map = dict(zip(prevouts, utxos)) # unspent = set(utxo_map) for tx_hash, tx in tx_map.items(): in_pairs = [] for prevout in tx.prevouts: # utxo = utxo_map.get(prevout) # if not utxo: prev_hash, prev_index = prevout if prev_hash in self.txs: # accepted mempool utxo = self.txs[prev_hash].out_pairs[prev_index] elif prev_hash in tx_map: # this set of changes utxo = tx_map[prev_hash].out_pairs[prev_index] else: # get it from the db prev_tx_num = self._db.prefix_db.tx_num.get(prev_hash) if not prev_tx_num: continue prev_tx_num = prev_tx_num.tx_num hashX_val = self._db.prefix_db.hashX_utxo.get(tx_hash[:4], prev_tx_num, prev_index) if not hashX_val: continue hashX = hashX_val.hashX utxo_value = self._db.prefix_db.utxo.get(hashX, prev_tx_num, prev_index) utxo = (hashX, utxo_value.amount) # if not prev_raw: # print("derp", prev_hash[::-1].hex()) # print(self._db.get_tx_num(prev_hash)) # prev_tx, prev_tx_size = self.coin.DESERIALIZER(prev_raw.raw_tx).read_tx_and_vsize() # prev_txo = prev_tx.outputs[prev_index] # utxo = (self.coin.hashX_from_script(prev_txo.pk_script), prev_txo.value) in_pairs.append(utxo) # # Spend the prevouts # unspent.difference_update(tx.prevouts) # Save the in_pairs, compute the fee and accept the TX tx.in_pairs = tuple(in_pairs) # Avoid negative fees if dealing with generation-like transactions # because some in_parts would be missing tx.fee = max(0, (sum(v for _, v in tx.in_pairs) - sum(v for _, v in tx.out_pairs))) self.txs[tx_hash] = tx # print(f"added {tx_hash[::-1].hex()} reader to mempool") for hashX, value in itertools.chain(tx.in_pairs, tx.out_pairs): self.touched_hashXs[hashX].add(tx_hash) touched_hashXs.add(hashX) # utxo_map = {prevout: utxo_map[prevout] for prevout in unspent} return touched_hashXs def transaction_summaries(self, hashX): """Return a list of MemPoolTxSummary objects for the hashX.""" result = [] for tx_hash in self.touched_hashXs.get(hashX, ()): tx = self.txs[tx_hash] has_ui = any(hash in self.txs for hash, idx in tx.prevouts) result.append(MemPoolTxSummary(tx_hash, tx.fee, has_ui)) return result def get_mempool_height(self, tx_hash: bytes) -> int: # Height Progression # -2: not broadcast # -1: in mempool but has unconfirmed inputs # 0: in mempool and all inputs confirmed # +num: confirmed in a specific block (height) if tx_hash not in self.txs: return -2 tx = self.txs[tx_hash] unspent_inputs = any(hash in self.raw_mempool for hash, idx in tx.prevouts) if unspent_inputs: return -1 return 0 async def start(self, height, session_manager: 'LBRYSessionManager'): self.notify_sessions = session_manager._notify_sessions await self._notify_sessions(height, set(), set()) async def on_mempool(self, touched, new_touched, height): await self._notify_sessions(height, touched, new_touched) async def on_block(self, touched, height): await self._notify_sessions(height, touched, set()) async def _notify_sessions(self, height, touched, new_touched): """Notify sessions about height changes and touched addresses.""" height_changed = height != self.session_manager.notified_height if height_changed: await self.session_manager._refresh_hsub_results(height) if not self.session_manager.sessions: return if height_changed: header_tasks = [ session.send_notification('blockchain.headers.subscribe', (self.session_manager.hsub_results[session.subscribe_headers_raw], )) for session in self.session_manager.sessions.values() if session.subscribe_headers ] if header_tasks: self.logger.info(f'notify {len(header_tasks)} sessions of new header') asyncio.create_task(asyncio.wait(header_tasks)) for hashX in touched.intersection(self.session_manager.mempool_statuses.keys()): self.session_manager.mempool_statuses.pop(hashX, None) # self.bp._chain_executor await asyncio.get_event_loop().run_in_executor( None, touched.intersection_update, self.session_manager.hashx_subscriptions_by_session.keys() ) if touched or new_touched or (height_changed and self.session_manager.mempool_statuses): notified_hashxs = 0 session_hashxes_to_notify = defaultdict(list) to_notify = touched if height_changed else new_touched for hashX in to_notify: if hashX not in self.session_manager.hashx_subscriptions_by_session: continue for session_id in self.session_manager.hashx_subscriptions_by_session[hashX]: session_hashxes_to_notify[session_id].append(hashX) notified_hashxs += 1 for session_id, hashXes in session_hashxes_to_notify.items(): asyncio.create_task(self.session_manager.sessions[session_id].send_history_notifications(*hashXes)) if session_hashxes_to_notify: self.logger.info(f'notified {len(session_hashxes_to_notify)} sessions/{notified_hashxs:,d} touched addresses')