lbry-sdk/torba/client/baseledger.py
2018-11-04 01:55:50 -04:00

386 lines
15 KiB
Python

import os
import asyncio
import logging
from binascii import hexlify, unhexlify
from io import StringIO
from typing import Dict, Type, Iterable
from operator import itemgetter
from collections import namedtuple
from torba.client import baseaccount, basenetwork, basetransaction
from torba.client.basedatabase import BaseDatabase
from torba.client.baseheader import BaseHeaders
from torba.client.coinselection import CoinSelector
from torba.client.constants import COIN, NULL_HASH32
from torba.stream import StreamController
from torba.client.hash import hash160, double_sha256, sha256, Base58
log = logging.getLogger(__name__)
LedgerType = Type['BaseLedger']
class LedgerRegistry(type):
ledgers: Dict[str, LedgerType] = {}
def __new__(mcs, name, bases, attrs):
cls: LedgerType = super().__new__(mcs, name, bases, attrs)
if not (name == 'BaseLedger' and not bases):
ledger_id = cls.get_id()
assert ledger_id not in mcs.ledgers,\
'Ledger with id "{}" already registered.'.format(ledger_id)
mcs.ledgers[ledger_id] = cls
return cls
@classmethod
def get_ledger_class(mcs, ledger_id: str) -> LedgerType:
return mcs.ledgers[ledger_id]
class TransactionEvent(namedtuple('TransactionEvent', ('address', 'tx'))):
pass
class BlockHeightEvent(namedtuple('BlockHeightEvent', ('height', 'change'))):
pass
class BaseLedger(metaclass=LedgerRegistry):
name: str
symbol: str
network_name: str
database_class = BaseDatabase
account_class = baseaccount.BaseAccount
network_class = basenetwork.BaseNetwork
transaction_class = basetransaction.BaseTransaction
headers_class: Type[BaseHeaders]
pubkey_address_prefix: bytes
script_address_prefix: bytes
extended_public_key_prefix: bytes
extended_private_key_prefix: bytes
default_fee_per_byte = 10
def __init__(self, config=None):
self.config = config or {}
self.db: BaseDatabase = self.config.get('db') or self.database_class(
os.path.join(self.path, "blockchain.db")
)
self.db.ledger = self
self.headers: BaseHeaders = self.config.get('headers') or self.headers_class(
os.path.join(self.path, "headers")
)
self.network = self.config.get('network') or self.network_class(self)
self.network.on_header.listen(self.receive_header)
self.network.on_status.listen(self.receive_status)
self.accounts = []
self.fee_per_byte: int = self.config.get('fee_per_byte', self.default_fee_per_byte)
self._on_transaction_controller = StreamController()
self.on_transaction = self._on_transaction_controller.stream
self.on_transaction.listen(
lambda e: log.info(
'(%s) on_transaction: address=%s, height=%s, is_verified=%s, tx.id=%s',
self.get_id(), e.address, e.tx.height, e.tx.is_verified, e.tx.id
)
)
self._on_header_controller = StreamController()
self.on_header = self._on_header_controller.stream
self.on_header.listen(
lambda change: log.info(
'%s: added %s header blocks, final height %s',
self.get_id(), change, self.headers.height
)
)
self._transaction_processing_locks = {}
self._utxo_reservation_lock = asyncio.Lock()
self._header_processing_lock = asyncio.Lock()
@classmethod
def get_id(cls):
return '{}_{}'.format(cls.symbol.lower(), cls.network_name.lower())
@classmethod
def hash160_to_address(cls, h160):
raw_address = cls.pubkey_address_prefix + h160
return Base58.encode(bytearray(raw_address + double_sha256(raw_address)[0:4]))
@staticmethod
def address_to_hash160(address):
return Base58.decode(address)[1:21]
@classmethod
def public_key_to_address(cls, public_key):
return cls.hash160_to_address(hash160(public_key))
@staticmethod
def private_key_to_wif(private_key):
return b'\x1c' + private_key + b'\x01'
@property
def path(self):
return os.path.join(self.config['data_path'], self.get_id())
def add_account(self, account: baseaccount.BaseAccount):
self.accounts.append(account)
async def get_private_key_for_address(self, address):
match = await self.db.get_address(address=address)
if match:
for account in self.accounts:
if match['account'] == account.public_key.address:
return account.get_private_key(match['chain'], match['position'])
async def get_effective_amount_estimators(self, funding_accounts: Iterable[baseaccount.BaseAccount]):
estimators = []
for account in funding_accounts:
utxos = await account.get_utxos()
for utxo in utxos:
estimators.append(utxo.get_estimator(self))
return estimators
async def get_spendable_utxos(self, amount: int, funding_accounts):
async with self._utxo_reservation_lock:
txos = await self.get_effective_amount_estimators(funding_accounts)
selector = CoinSelector(
txos, amount,
self.transaction_class.output_class.pay_pubkey_hash(COIN, NULL_HASH32).get_fee(self)
)
spendables = selector.select()
if spendables:
await self.reserve_outputs(s.txo for s in spendables)
return spendables
def reserve_outputs(self, txos):
return self.db.reserve_outputs(txos)
def release_outputs(self, txos):
return self.db.release_outputs(txos)
async def get_local_status(self, address):
address_details = await self.db.get_address(address=address)
history = address_details['history']
return hexlify(sha256(history.encode())).decode() if history else None
async def get_local_history(self, address):
address_details = await self.db.get_address(address=address)
history = address_details['history'] or ''
parts = history.split(':')[:-1]
return list(zip(parts[0::2], map(int, parts[1::2])))
@staticmethod
def get_root_of_merkle_tree(branches, branch_positions, working_branch):
for i, branch in enumerate(branches):
other_branch = unhexlify(branch)[::-1]
other_branch_on_left = bool((branch_positions >> i) & 1)
if other_branch_on_left:
combined = other_branch + working_branch
else:
combined = working_branch + other_branch
working_branch = double_sha256(combined)
return hexlify(working_branch[::-1])
async def validate_transaction_and_set_position(self, tx, height, merkle):
if not height <= len(self.headers):
return False
merkle_root = self.get_root_of_merkle_tree(merkle['merkle'], merkle['pos'], tx.hash)
header = self.headers[height]
tx.position = merkle['pos']
tx.is_verified = merkle_root == header['merkle_root']
async def start(self):
if not os.path.exists(self.path):
os.mkdir(self.path)
await asyncio.gather(
self.db.open(),
self.headers.open()
)
first_connection = self.network.on_connected.first
asyncio.ensure_future(self.network.start())
await first_connection
await self.join_network()
self.network.on_connected.listen(self.join_network)
async def join_network(self, *args):
log.info("Subscribing and updating accounts.")
await self.update_headers()
await self.network.subscribe_headers()
await self.update_accounts()
async def stop(self):
await self.network.stop()
await self.db.close()
await self.headers.close()
async def update_headers(self, height=None, headers=None, subscription_update=False):
rewound = 0
while True:
if height is None or height > len(self.headers):
# sometimes header subscription updates are for a header in the future
# which can't be connected, so we do a normal header sync instead
height = len(self.headers)
headers = None
subscription_update = False
if not headers:
header_response = await self.network.get_headers(height, 2001)
headers = header_response['hex']
if not headers:
# Nothing to do, network thinks we're already at the latest height.
return
added = await self.headers.connect(height, unhexlify(headers))
if added > 0:
height += added
self._on_header_controller.add(
BlockHeightEvent(self.headers.height, added))
if rewound > 0:
# we started rewinding blocks and apparently found
# a new chain
rewound = 0
await self.db.rewind_blockchain(height)
if subscription_update:
# subscription updates are for latest header already
# so we don't need to check if there are newer / more
# on another loop of update_headers(), just return instead
return
elif added == 0:
# we had headers to connect but none got connected, probably a reorganization
height -= 1
rewound += 1
log.warning(
"Blockchain Reorganization: attempting rewind to height %s from starting height %s",
height, height+rewound
)
else:
raise IndexError("headers.connect() returned negative number ({})".format(added))
if height < 0:
raise IndexError(
"Blockchain reorganization rewound all the way back to genesis hash. "
"Something is very wrong. Maybe you are on the wrong blockchain?"
)
if rewound >= 100:
raise IndexError(
"Blockchain reorganization dropped {} headers. This is highly unusual. "
"Will not continue to attempt reorganizing. Please, delete the ledger "
"synchronization directory inside your wallet directory (folder: '{}') and "
"restart the program to synchronize from scratch."
.format(rewound, self.get_id())
)
headers = None # ready to download some more headers
# if we made it this far and this was a subscription_update
# it means something went wrong and now we're doing a more
# robust sync, turn off subscription update shortcut
subscription_update = False
async def receive_header(self, response):
async with self._header_processing_lock:
header = response[0]
await self.update_headers(
height=header['height'], headers=header['hex'], subscription_update=True
)
async def update_accounts(self):
return await asyncio.gather(*(
self.update_account(a) for a in self.accounts
))
async def update_account(self, account: baseaccount.BaseAccount):
await account.ensure_address_gap()
addresses = await account.get_addresses()
while addresses:
await asyncio.gather(*(self.subscribe_history(a) for a in addresses))
addresses = await account.ensure_address_gap()
def _prefetch_history(self, remote_history, local_history):
proofs, network_txs = {}, {}
for i, (hex_id, remote_height) in enumerate(map(itemgetter('tx_hash', 'height'), remote_history)):
if i < len(local_history) and local_history[i] == (hex_id, remote_height):
continue
if remote_height > 0:
proofs[hex_id] = asyncio.ensure_future(self.network.get_merkle(hex_id, remote_height))
network_txs[hex_id] = asyncio.ensure_future(self.network.get_transaction(hex_id))
return proofs, network_txs
async def update_history(self, address):
remote_history = await self.network.get_history(address)
local_history = await self.get_local_history(address)
proofs, network_txs = self._prefetch_history(remote_history, local_history)
synced_history = StringIO()
for i, (hex_id, remote_height) in enumerate(map(itemgetter('tx_hash', 'height'), remote_history)):
synced_history.write('{}:{}:'.format(hex_id, remote_height))
if i < len(local_history) and local_history[i] == (hex_id, remote_height):
continue
lock = self._transaction_processing_locks.setdefault(hex_id, asyncio.Lock())
await lock.acquire()
try:
# see if we have a local copy of transaction, otherwise fetch it from server
tx = await self.db.get_transaction(txid=hex_id)
save_tx = None
if tx is None:
_raw = await network_txs[hex_id]
tx = self.transaction_class(unhexlify(_raw))
save_tx = 'insert'
tx.height = remote_height
if remote_height > 0 and (not tx.is_verified or tx.position == -1):
await self.validate_transaction_and_set_position(tx, remote_height, await proofs[hex_id])
if save_tx is None:
save_tx = 'update'
await self.db.save_transaction_io(
save_tx, tx, address, self.address_to_hash160(address), synced_history.getvalue()
)
log.debug(
"%s: sync'ed tx %s for address: %s, height: %s, verified: %s",
self.get_id(), hex_id, address, tx.height, tx.is_verified
)
self._on_transaction_controller.add(TransactionEvent(address, tx))
finally:
lock.release()
if not lock.locked() and hex_id in self._transaction_processing_locks:
del self._transaction_processing_locks[hex_id]
async def subscribe_history(self, address):
remote_status = await self.network.subscribe_address(address)
local_status = await self.get_local_status(address)
if local_status != remote_status:
await self.update_history(address)
async def receive_status(self, response):
address, remote_status = response
local_status = await self.get_local_status(address)
if local_status != remote_status:
await self.update_history(address)
def broadcast(self, tx):
return self.network.broadcast(hexlify(tx.raw).decode())