def get_code(self, account: ChecksumEthAddress) -> str:
"""Gets the deployment bytecode at the given address
May raise:
- RemoteError if Covalent is used and there is a problem querying it or
parsing its response
"""
return hex_or_bytes_to_str(self.w3.eth.getCode(account))
def _get_code(self, web3: Optional[Web3], account: ChecksumEthAddress) -> str:
"""Gets the deployment bytecode at the given address
May raise:
- RemoteError if Etherscan is used and there is a problem querying it or
parsing its response
"""
if web3 is None:
return self.etherscan.get_code(account)
return hex_or_bytes_to_str(web3.eth.getCode(account))
def get_block_by_number(self, num: int) -> Dict[str, Any]:
"""Returns the block object corresponding to the given block number
May raise:
- RemoteError if an external service such as Covalent is queried and
there is a problem with its query.
- BlockNotFound if number used to lookup the block can't be found. Raised
by web3.eth.get_block().
"""
block_data: MutableAttributeDict = MutableAttributeDict(self.w3.eth.get_block(num)) # type: ignore # pylint: disable=no-member # noqa: E501
block_data['hash'] = hex_or_bytes_to_str(block_data['hash'])
return dict(block_data)
def _get_block_by_number(self, web3: Optional[Web3], num: int) -> Dict[str, Any]:
"""Returns the block object corresponding to the given block number
May raise:
- RemoteError if an external service such as Etherscan is queried and
there is a problem with its query.
"""
if web3 is None:
return self.etherscan.get_block_by_number(num)
block_data: MutableAttributeDict = MutableAttributeDict(web3.eth.get_block(num)) # type: ignore # pylint: disable=no-member # noqa: E501
block_data['hash'] = hex_or_bytes_to_str(block_data['hash'])
return dict(block_data)
def _try_get_chi_close_to(self, time: Timestamp) -> FVal:
"""Best effort attempt to get a chi value close to the given timestamp
It can't be 100% accurate since we use the logs of join() or exit()
in order to find the closest time chi was changed. It also may not work
if for some reason there is no logs in the block range we are looking for.
Better solution would have been an archive node's query.
May raise:
- RemoteError if there are problems with querying etherscan
- ChiRetrievalError if we are unable to query chi at the given timestamp
- BlockchainQueryError if an ethereum node is used and the contract call
queries fail for some reason
"""
if time > 1584386100:
# If the time is after 16/03/2020 19:15 GMT we know that
# makerdao DSR was set to 0% we know chi has not changed
# https://twitter.com/MakerDAO/status/1239270910810411008
return FVal('1018008449363110619399951035')
block_number = self.ethereum.etherscan.get_blocknumber_by_time(time)
if self.ethereum.web3 is not None:
latest_block = self.ethereum.web3.eth.blockNumber
else:
latest_block = self.ethereum.query_eth_highest_block()
blocks_queried = 0
counter = 1
# Keep trying to find events that could reveal the chi to us. Go back
# as far as MAX_BLOCKS_TO_QUERY and only then give up
while blocks_queried < MAX_BLOCKS_TO_QUERY:
back_from_block = max(
MAKERDAO_POT.deployed_block,
block_number - counter * CHI_BLOCKS_SEARCH_DISTANCE,
)
back_to_block = block_number - (counter - 1) * CHI_BLOCKS_SEARCH_DISTANCE
forward_from_block = min(
latest_block,
block_number + (counter - 1) * CHI_BLOCKS_SEARCH_DISTANCE,
)
forward_to_block = min(
latest_block,
block_number + CHI_BLOCKS_SEARCH_DISTANCE,
)
back_joins, back_exits = self._get_join_exit_events(back_from_block, back_to_block)
forward_joins, forward_exits = self._get_join_exit_events(
from_block=forward_from_block,
to_block=forward_to_block,
)
no_results = all(
len(x) == 0 for x in (back_joins, back_exits, forward_joins, forward_exits)
)
if latest_block == forward_to_block and no_results:
# if our forward querying got us to the latest block and there is
# still no other results, then take current chi
return self.ethereum.call_contract(
contract_address=MAKERDAO_POT.address,
abi=MAKERDAO_POT.abi,
method_name='chi',
)
if not no_results:
# got results!
break
blocks_queried += 2 * CHI_BLOCKS_SEARCH_DISTANCE
counter += 1
if no_results:
raise ChiRetrievalError(
f'Found no DSR events around timestamp {time}. Cant query chi.',
)
# Find the closest event to the to_block number, looking both at events
# in the blocks before and in the blocks after block_number
found_event = None
back_event = _find_closest_event(back_joins, back_exits, -1, operator.gt)
forward_event = _find_closest_event(forward_joins, forward_exits, 0, operator.lt)
if back_event and not forward_event:
found_event = back_event
elif forward_event and not back_event:
found_event = forward_event
else:
# We have both backward and forward events, get the one closer to block number
try:
back_block_number = deserialize_blocknumber(back_event['blockNumber']) # type: ignore # noqa: E501
forward_block_number = deserialize_blocknumber(forward_event['blockNumber']) # type: ignore # noqa: E501
except DeserializationError as e:
msg = f'Error at reading DSR drip event block number. {str(e)}'
raise ChiRetrievalError(msg)
if block_number - back_block_number <= forward_block_number - block_number:
found_event = back_event
else:
found_event = forward_event
assert found_event, 'at this point found_event should be populated' # helps mypy
event_block_number = deserialize_blocknumber(found_event['blockNumber'])
first_topic = hex_or_bytes_to_str(found_event['topics'][0])
amount = self._get_vat_join_exit_at_transaction(
movement_type='join' if first_topic.startswith('0x049878f3') else 'exit',
proxy_address=hex_or_bytes_to_address(found_event['topics'][1]),
block_number=event_block_number,
transaction_index=found_event['transactionIndex'],
)
if amount is None:
raise ChiRetrievalError(
f'Found no VAT.move events around timestamp {time}. Cant query chi.',
)
wad_val = hex_or_bytes_to_int(found_event['topics'][2])
chi = FVal(amount) / FVal(wad_val)
return chi
