Files
plugins/drain/drain.py
2020-11-30 10:38:44 +01:00

474 lines
21 KiB
Python
Executable File

#!/usr/bin/env python3
from pyln.client import Plugin, Millisatoshi, RpcError
from utils import get_ours, wait_ours
import re
import time
import uuid
plugin = Plugin()
# When draining 100% we must account (not pay) for an additional HTLC fee.
# Currently there is no way of getting the exact number before the fact,
# so we try and error until it is high enough, or take the exception text.
HTLC_FEE_NUL = Millisatoshi('0sat')
HTLC_FEE_STP = Millisatoshi('10sat')
HTLC_FEE_MIN = Millisatoshi('100sat')
HTLC_FEE_MAX = Millisatoshi('100000sat')
HTLC_FEE_EST = Millisatoshi('3000sat')
HTLC_FEE_PAT = re.compile("^.* HTLC fee: ([0-9]+sat).*$")
def setup_routing_fees(plugin, payload, route, amount, substractfees: bool = False):
delay = int(plugin.get_option('cltv-final'))
amount_iter = amount
for r in reversed(route):
r['msatoshi'] = amount_iter.millisatoshis
r['amount_msat'] = amount_iter
r['delay'] = delay
channels = plugin.rpc.listchannels(r['channel'])
ch = next(c for c in channels.get('channels') if c['destination'] == r['id'])
fee = Millisatoshi(ch['base_fee_millisatoshi'])
# BOLT #7 requires fee >= fee_base_msat + ( amount_to_forward * fee_proportional_millionths / 1000000 )
fee += (amount_iter * ch['fee_per_millionth'] + 10**6 - 1) // 10**6 # integer math trick to round up
amount_iter += fee
delay += ch['delay']
# amounts have to be calculated the other way when being fee substracted
# we took the upper loop as well for the delay parameter
if substractfees:
amount_iter = amount
first = True
for r in route:
channels = plugin.rpc.listchannels(r['channel'])
ch = next(c for c in channels.get('channels') if c['destination'] == r['id'])
if not first:
fee = Millisatoshi(ch['base_fee_millisatoshi'])
# BOLT #7 requires fee >= fee_base_msat + ( amount_to_forward * fee_proportional_millionths / 1000000 )
fee += (amount_iter * ch['fee_per_millionth'] + 10**6 - 1) // 10**6 # integer math trick to round up
if fee > amount_iter:
raise RpcError(payload['command'], payload, {'message': 'Cannot cover fees to %s %s' % (payload['command'], amount)})
amount_iter -= fee
first = False
r['msatoshi'] = amount_iter.millisatoshis
r['amount_msat'] = amount_iter
# This raises an error when a channel is not normal or peer is not connected
def get_channel(plugin, payload, peer_id, scid=None):
if scid is None:
scid = payload['scid']
try:
peer = plugin.rpc.listpeers(peer_id).get('peers')[0]
except IndexError:
raise RpcError(payload['command'], payload, {'message': 'Cannot find peer %s' % peer_id})
try:
channel = next(c for c in peer['channels'] if 'short_channel_id' in c and c['short_channel_id'] == scid)
except StopIteration:
raise RpcError(payload['command'], payload, {'message': 'Cannot find channel %s for peer %s' % (scid, peer_id)})
if channel['state'] != "CHANNELD_NORMAL":
raise RpcError(payload['command'], payload, {'message': 'Channel %s not in state CHANNELD_NORMAL, but: %s' % (scid, channel['state'])})
if not peer['connected']:
raise RpcError(payload['command'], payload, {'message': 'Channel %s peer is not connected.' % scid})
return channel
def spendable_from_scid(plugin, payload, scid=None, _raise=False):
if scid is None:
scid = payload['scid']
peer_id = peer_from_scid(plugin, payload, scid)
try:
channel_peer = get_channel(plugin, payload, peer_id, scid)
except RpcError as e:
if _raise:
raise e
return Millisatoshi(0), Millisatoshi(0)
# we check amounts via gossip and not wallet funds, as its more accurate
our = Millisatoshi(channel_peer['to_us_msat'])
total = Millisatoshi(channel_peer['total_msat'])
our_reserve = Millisatoshi(channel_peer['our_reserve_msat'])
their_reserve = Millisatoshi(channel_peer['their_reserve_msat'])
their = total - our
# reserves maybe not filled up yet
if our < our_reserve:
our_reserve = our
if their < their_reserve:
their_reserve = their
spendable = channel_peer['spendable_msat']
receivable = channel_peer.get('receivable_msat')
# receivable_msat was added with the 0.8.2 release, have a fallback
if not receivable:
receivable = their - their_reserve
# we also need to subsctract a possible commit tx fee
if receivable >= HTLC_FEE_EST:
receivable -= HTLC_FEE_EST
return spendable, receivable
def peer_from_scid(plugin, payload, scid=None):
if scid is None:
scid = payload['scid']
channels = plugin.rpc.listchannels(scid).get('channels')
try:
return next(c for c in channels if c['source'] == payload['my_id'])['destination']
except StopIteration:
raise RpcError(payload['command'], payload, {'message': 'Cannot find peer for channel: ' + scid})
def find_worst_channel(route):
if len(route) < 4:
return None
start_id = 2
worst = route[start_id]['channel']
worst_val = route[start_id - 1]['msatoshi'] - route[start_id]['msatoshi']
for i in range(start_id + 1, len(route) - 1):
val = route[i - 1]['msatoshi'] - route[i]['msatoshi']
if val > worst_val:
worst = route[i]['channel']
worst_val = val
return worst
def test_or_set_chunks(plugin, payload):
scid = payload['scid']
cmd = payload['command']
spendable, receivable = spendable_from_scid(plugin, payload)
total = spendable + receivable
amount = Millisatoshi(int(int(total) * (0.01 * payload['percentage'])))
# if capacity exceeds, limit amount to full or empty channel
if cmd == "drain" and amount > spendable:
amount = spendable
if cmd == "fill" and amount > receivable:
amount = receivable
if amount == Millisatoshi(0):
raise RpcError(payload['command'], payload, {'message': 'Cannot detect required chunks to perform operation. Amount would be 0msat.'})
# get all spendable/receivables for our channels
channels = {}
for channel in plugin.rpc.listchannels(source=payload['my_id']).get('channels'):
if channel['short_channel_id'] == scid:
continue
try:
spend, recv = spendable_from_scid(plugin, payload, channel['short_channel_id'], True)
except RpcError:
continue
channels[channel['short_channel_id']] = {
'spendable': spend,
'receivable': recv,
}
if len(channels) == 0:
raise RpcError(payload['command'], payload, {'message': 'Not enough usable channels to perform cyclic routing.'})
# test if selected chunks fit into other channel capacities
chunks = payload['chunks']
if chunks > 0:
chunksize = amount / chunks
fit = 0
for i in channels:
channel = channels[i]
if cmd == "drain":
fit += int(channel['receivable']) // int(chunksize)
if cmd == "fill":
fit += int(channel['spendable']) // int(chunksize)
if fit >= chunks:
return
if cmd == "drain":
raise RpcError(payload['command'], payload, {'message': 'Selected chunks (%d) will not fit incoming channel capacities.' % chunks})
if cmd == "fill":
raise RpcError(payload['command'], payload, {'message': 'Selected chunks (%d) will not fit outgoing channel capacities.' % chunks})
# if chunks is 0 -> auto detect from 1 to 16 (max) chunks until amounts fit
else:
chunks = 0
while chunks < 16:
chunks += 1
chunksize = amount / chunks
fit = 0
for i in channels:
channel = channels[i]
if cmd == "drain" and int(channel['receivable']) > 0:
fit += int(channel['receivable']) // int(chunksize)
if cmd == "fill" and int(channel['spendable']) > 0:
fit += int(channel['spendable']) // int(chunksize)
if fit >= chunks:
payload['chunks'] = chunks
return
if cmd == "drain":
raise RpcError(payload['command'], payload, {'message': 'Cannot detect required chunks to perform operation. Incoming capacity problem.'})
if cmd == "fill":
raise RpcError(payload['command'], payload, {'message': 'Cannot detect required chunks to perform operation. Outgoing capacity problem.'})
def cleanup(plugin, payload, error=None):
# delete all invoices and count how many went through
successful_chunks = 0
for label in payload['labels']:
try:
plugin.rpc.delinvoice(label, 'unpaid')
except RpcError as e:
# race condition: waitsendpay timed out, but invoice got paid
if 'status is paid' in e.error.get('message', ""):
successful_chunks += 1
if successful_chunks == payload['chunks']:
return payload['success_msg']
if successful_chunks > 0:
error = RpcError(payload['command'], payload, {'message': 'Partially completed %d/%d chunks. Error: %s' % (successful_chunks, payload['chunks'], str(error))})
if error is None:
error = RpcError(payload['command'], payload, {'message': 'Command failed, no chunk succeeded.'})
raise error
def try_for_htlc_fee(plugin, payload, peer_id, amount, chunk, spendable_before):
start_ts = int(time.time())
my_id = payload['my_id']
label = payload['command'] + "-" + str(uuid.uuid4())
payload['labels'] += [label]
description = "%s %s %s%s [%d/%d]" % (payload['command'], payload['scid'], payload['percentage'], '%', chunk + 1, payload['chunks'])
invoice = plugin.rpc.invoice("any", label, description, payload['retry_for'] + 60)
payment_hash = invoice['payment_hash']
plugin.log("Invoice payment_hash: %s" % payment_hash)
# exclude selected channel to prevent unwanted shortcuts
excludes = [payload['scid'] + '/0', payload['scid'] + '/1']
mychannels = plugin.rpc.listchannels(source=my_id).get('channels')
# exclude local channels known to have too little capacity.
# getroute currently does not do this.
for channel in mychannels:
if channel['short_channel_id'] == payload['scid']:
continue # already added few lines above
spend, recv = spendable_from_scid(plugin, payload, channel['short_channel_id'])
if payload['command'] == 'drain' and recv < amount:
excludes += [channel['short_channel_id'] + '/0', channel['short_channel_id'] + '/1']
if payload['command'] == 'fill' and spend < amount:
excludes += [channel['short_channel_id'] + '/0', channel['short_channel_id'] + '/1']
while int(time.time()) - start_ts < payload['retry_for']:
if payload['command'] == 'drain':
r = plugin.rpc.getroute(my_id, amount, riskfactor=0,
cltv=9, fromid=peer_id, fuzzpercent=0, exclude=excludes)
route_out = {'id': peer_id, 'channel': payload['scid'], 'direction': int(my_id >= peer_id)}
route = [route_out] + r['route']
setup_routing_fees(plugin, payload, route, amount, True)
if payload['command'] == 'fill':
r = plugin.rpc.getroute(peer_id, amount, riskfactor=0,
cltv=9, fromid=my_id, fuzzpercent=0, exclude=excludes)
route_in = {'id': my_id, 'channel': payload['scid'], 'direction': int(peer_id >= my_id)}
route = r['route'] + [route_in]
setup_routing_fees(plugin, payload, route, amount, False)
fees = route[0]['amount_msat'] - route[-1]['amount_msat']
# check fee and exclude worst channel the next time
# NOTE: the int(msat) casts are just a workaround for outdated pylightning versions
if fees > payload['exemptfee'] and int(fees) > int(amount) * payload['maxfeepercent'] / 100:
worst_channel_id = find_worst_channel(route)
if worst_channel_id is None:
raise RpcError(payload['command'], payload, {'message': 'Insufficient fee'})
excludes += [worst_channel_id + '/0', worst_channel_id + '/1']
continue
plugin.log("[%d/%d] Sending over %d hops to %s %s using %s fees" % (chunk + 1, payload['chunks'], len(route), payload['command'], amount, fees), 'debug')
for r in route:
plugin.log(" - %s %14s %s" % (r['id'], r['channel'], r['amount_msat']), 'debug')
try:
ours = get_ours(plugin, payload['scid'])
plugin.rpc.sendpay(route, payment_hash, label)
result = plugin.rpc.waitsendpay(payment_hash, payload['retry_for'] + start_ts - int(time.time()))
if result.get('status') == 'complete':
payload['success_msg'] += ["%dmsat sent over %d hops to %s %dmsat [%d/%d]" % (amount + fees, len(route), payload['command'], amount, chunk + 1, payload['chunks'])]
# we need to wait for HTLC to resolve, so remaining amounts
# can be calculated correctly for the next chunk
wait_ours(plugin, payload['scid'], ours)
return True
return False
except RpcError as e:
erring_message = e.error.get('message', '')
erring_channel = e.error.get('data', {}).get('erring_channel')
erring_index = e.error.get('data', {}).get('erring_index')
erring_direction = e.error.get('data', {}).get('erring_direction')
# detect exceeding of HTLC commitment fee
if 'Capacity exceeded' in erring_message and erring_index == 0:
match = HTLC_FEE_PAT.search(erring_message)
if match: # new servers tell htlc_fee via exception (#2691)
raise ValueError("htlc_fee is %s" % match.group(1))
raise ValueError("htlc_fee unknown")
if erring_channel == payload['scid']:
raise RpcError(payload['command'], payload, {'message': 'Error with selected channel: %s' % erring_message})
plugin.log("RpcError: " + str(e))
if erring_channel is not None and erring_direction is not None:
excludes.append(erring_channel + '/' + str(erring_direction))
def read_params(command: str, scid: str, percentage: float,
chunks: int, maxfeepercent: float, retry_for: int, exemptfee: Millisatoshi):
# check parameters
if command != 'drain' and command != 'fill' and command != 'setbalance':
raise RpcError(command, {}, {'message': 'Invalid command. Must be "drain", "fill" or "setbalance"'})
percentage = float(percentage)
if percentage < 0 or percentage > 100 or command != 'setbalance' and percentage == 0.0:
raise RpcError(command, {}, {'message': 'Percentage must be between 0 and 100'})
if chunks < 0:
raise RpcError(command, {}, {'message': 'Negative chunks do not make sense. Try a positive value or use 0 (default) for auto-detection.'})
# forge operation payload
payload = {
"command": command,
"scid": scid,
"percentage": percentage,
"chunks": chunks,
"maxfeepercent": maxfeepercent,
"retry_for": retry_for,
"exemptfee": exemptfee,
"labels": [],
"success_msg": [],
}
# cache some often required data
payload['my_id'] = plugin.rpc.getinfo().get('id')
# translate a 'setbalance' into respective drain or fill
if command == 'setbalance':
spendable, receivable = spendable_from_scid(plugin, payload)
total = spendable + receivable
target = Millisatoshi(int(int(total) * (0.01 * payload['percentage'])))
if target == spendable:
raise RpcError(payload['command'], payload, {'message': 'target already reached, nothing to do.'})
if spendable > target:
payload['command'] = 'drain'
amount = spendable - target
else:
payload['command'] = 'fill'
amount = target - spendable
payload['percentage'] = 100.0 * int(amount) / int(total)
if payload['percentage'] == 0.0:
raise RpcError(command, payload, {'message': 'target already reached, nothing to do.'})
return payload
def execute(payload: dict):
peer_id = peer_from_scid(plugin, payload)
get_channel(plugin, payload, peer_id) # ensures or raises error
test_or_set_chunks(plugin, payload)
plugin.log("%s %s %d%% %d chunks" % (payload['command'], payload['scid'], payload['percentage'], payload['chunks']))
# iterate of chunks, default just one
for chunk in range(payload['chunks']):
# we discover remaining capacities for each chunk,
# as fees from previous chunks affect reserves
spendable, receivable = spendable_from_scid(plugin, payload)
total = spendable + receivable
amount = Millisatoshi(int(int(total) * (0.01 * payload['percentage'] / payload['chunks'])))
if amount == Millisatoshi(0):
raise RpcError(payload['command'], payload, {'message': 'Cannot process chunk. Amount would be 0msat.'})
# if capacity exceeds, limit amount to full or empty channel
if payload['command'] == "drain" and amount > spendable:
amount = spendable
if payload['command'] == "fill" and amount > receivable:
amount = receivable
result = False
try:
# we need to try with different HTLC_FEE values
# until we dont get capacity error on first hop
htlc_fee = HTLC_FEE_NUL
htlc_stp = HTLC_FEE_STP
while htlc_fee < HTLC_FEE_MAX and result is False:
# When getting close to 100% we need to account for HTLC commitment fee
if payload['command'] == 'drain' and spendable - amount <= htlc_fee:
if amount < htlc_fee:
raise RpcError(payload['command'], payload, {'message': 'channel too low to cover fees'})
amount -= htlc_fee
plugin.log("Trying... chunk:%s/%s spendable:%s receivable:%s htlc_fee:%s => amount:%s" % (chunk + 1, payload['chunks'], spendable, receivable, htlc_fee, amount))
try:
result = try_for_htlc_fee(plugin, payload, peer_id, amount, chunk, spendable)
except Exception as err:
if "htlc_fee unknown" in str(err):
if htlc_fee == HTLC_FEE_NUL:
htlc_fee = HTLC_FEE_MIN - HTLC_FEE_STP
htlc_fee += htlc_stp
htlc_stp *= 1.1 # exponential increase steps
plugin.log("Retrying with additional HTLC onchain fees: %s" % htlc_fee)
continue
if "htlc_fee is" in str(err):
htlc_fee = Millisatoshi(str(err)[12:])
plugin.log("Retrying with exact HTLC onchain fees: %s" % htlc_fee)
continue
raise err
# If result is still false, we tried allowed htlc_fee range unsuccessfully
if result is False:
raise RpcError(payload['command'], payload, {'message': 'Cannot determine required htlc commitment fees.'})
except Exception as e:
return cleanup(plugin, payload, e)
return cleanup(plugin, payload)
@plugin.method("drain")
def drain(plugin, scid: str, percentage: float = 100, chunks: int = 0, maxfeepercent: float = 0.5,
retry_for: int = 60, exemptfee: Millisatoshi = Millisatoshi(5000)):
"""Draining channel liquidity with circular payments.
Percentage defaults to 100, resulting in an empty channel.
Chunks defaults to 0 (auto-detect).
Use 'drain 10' to decrease a channels total balance by 10%.
"""
payload = read_params('drain', scid, percentage, chunks, maxfeepercent, retry_for, exemptfee)
return execute(payload)
@plugin.method("fill")
def fill(plugin, scid: str, percentage: float = 100, chunks: int = 0, maxfeepercent: float = 0.5,
retry_for: int = 60, exemptfee: Millisatoshi = Millisatoshi(5000)):
"""Filling channel liquidity with circular payments.
Percentage defaults to 100, resulting in a full channel.
Chunks defaults to 0 (auto-detect).
Use 'fill 10' to incease a channels total balance by 10%.
"""
payload = read_params('fill', scid, percentage, chunks, maxfeepercent, retry_for, exemptfee)
return execute(payload)
@plugin.method("setbalance")
def setbalance(plugin, scid: str, percentage: float = 50, chunks: int = 0, maxfeepercent: float = 0.5,
retry_for: int = 60, exemptfee: Millisatoshi = Millisatoshi(5000)):
"""Brings a channels own liquidity to X percent using circular payments.
Percentage defaults to 50, resulting in a balanced channel.
Chunks defaults to 0 (auto-detect).
Use 'setbalance 100' to fill a channel. Use 'setbalance 0' to drain a channel.
"""
payload = read_params('setbalance', scid, percentage, chunks, maxfeepercent, retry_for, exemptfee)
return execute(payload)
@plugin.init()
def init(options, configuration, plugin):
plugin.options['cltv-final']['value'] = plugin.rpc.listconfigs().get('cltv-final')
plugin.log("Plugin drain.py initialized")
plugin.add_option('cltv-final', 10, 'Number of blocks for final CheckLockTimeVerify expiry')
plugin.run()