Files
plugins/feeadjuster/feeadjuster.py
2020-11-11 12:00:27 +01:00

128 lines
4.7 KiB
Python
Executable File

#!/usr/bin/env python3
import random
import time
from pyln.client import Plugin, Millisatoshi, RpcError
plugin = Plugin()
# Our amount and the total amount in each of our channel, indexed by scid
plugin.adj_balances = {}
# Cache to avoid loads of calls to getinfo
plugin.our_node_id = None
# Users can configure this
plugin.update_threshold = 0.05
def get_ratio(our_percentage):
"""
Basic algorithm: the farther we are from the optimal case, the more we
bump/lower.
"""
return 50**(0.5 - our_percentage)
def maybe_adjust_fees(plugin: Plugin, scids: list):
for scid in scids:
our = plugin.adj_balances[scid]["our"]
total = plugin.adj_balances[scid]["total"]
percentage = our / total
last_percentage = plugin.adj_balances[scid].get("last_percentage")
# Only update on substantial balance moves to avoid flooding, and add
# some pseudo-randomness to avoid too easy channel balance probing
update_threshold = plugin.update_threshold
if not plugin.deactivate_fuzz:
update_threshold += random.uniform(-0.015, 0.015)
if (last_percentage is None
or abs(last_percentage - percentage) > update_threshold):
ratio = get_ratio(percentage)
try:
plugin.rpc.setchannelfee(scid, int(plugin.adj_basefee * ratio),
int(plugin.adj_ppmfee * ratio))
plugin.log("Adjusted fees of {} with a ratio of {}"
.format(scid, ratio))
plugin.adj_balances[scid]["last_percentage"] = percentage
except RpcError as e:
plugin.log("Could not adjust fees for channel {}: '{}'"
.format(scid, e), level="warn")
def get_chan(plugin: Plugin, scid: str):
for peer in plugin.rpc.listpeers()["peers"]:
if len(peer["channels"]) == 0:
continue
# We might have multiple channel entries ! Eg if one was just closed
# and reopened.
for chan in peer["channels"]:
if "short_channel_id" not in chan:
continue
if chan["short_channel_id"] == scid:
return chan
def maybe_add_new_balances(plugin: Plugin, scids: list):
for scid in scids:
if scid not in plugin.adj_balances:
# At this point we could call listchannels and pass the scid as
# argument, and deduce the peer id (!our_id). But -as unlikely as
# it is- we may not find it in our gossip (eg some corruption of
# the gossip_store occured just before the forwarding event).
# However, it MUST be present in a listpeers() entry.
chan = get_chan(plugin, scid)
assert chan is not None
plugin.adj_balances[scid] = {
"our": int(chan["to_us_msat"]),
"total": int(chan["total_msat"])
}
@plugin.subscribe("forward_event")
def forward_event(plugin: Plugin, forward_event: dict, **kwargs):
if forward_event["status"] == "settled":
in_scid = forward_event["in_channel"]
out_scid = forward_event["out_channel"]
maybe_add_new_balances(plugin, [in_scid, out_scid])
plugin.adj_balances[in_scid]["our"] += forward_event["in_msatoshi"]
plugin.adj_balances[out_scid]["our"] -= forward_event["out_msatoshi"]
try:
# Pseudo-randomly add some hysterisis to the update
if not plugin.deactivate_fuzz and random.randint(0, 9) == 9:
time.sleep(random.randint(0, 5))
maybe_adjust_fees(plugin, [in_scid, out_scid])
except Exception as e:
plugin.log("Adjusting fees: " + str(e), level="error")
@plugin.init()
def init(options: dict, configuration: dict, plugin: Plugin, **kwargs):
plugin.our_node_id = plugin.rpc.getinfo()["id"]
plugin.deactivate_fuzz = options.get("feeadjuster-deactivate-fuzz", False)
plugin.update_threshold = float(options.get("feeadjuster-threshold", "0.05"))
config = plugin.rpc.listconfigs()
plugin.adj_basefee = config["fee-base"]
plugin.adj_ppmfee = config["fee-per-satoshi"]
plugin.log("Plugin feeadjuster initialized ({} base / {} ppm) with a "
"threshold of {}"
.format(plugin.adj_basefee, plugin.adj_ppmfee,
plugin.update_threshold))
plugin.add_option(
"feeadjuster-deactivate-fuzz",
False,
"Deactivate update threshold randomization and hysterisis.",
"flag"
)
plugin.add_option(
"feeadjuster-threshold",
"0.05",
"Channel balance update threshold at which to trigger an update. "
"Note: it's also fuzzed by 1.5%",
"string"
)
plugin.run()