use onchain fee estimate of lnd instead of electrum

We are using the onchain fee estimator of lnd now. Internally, lnd uses
either bitcoind or a fee url for the estimation.

README.md

@@ -11,8 +11,7 @@ See [INSTALL.md](/INSTALL.md)
 charge-lnd takes only a minimal set of parameters:
 
 ```
-usage: charge-lnd [-h] [--lnddir LNDDIR] [--grpc GRPC] [--electrum-server ELECTRUM_SERVER]
-                  [--dry-run] [--check] [-v] -c CONFIG
+usage: charge-lnd [-h] [--lnddir LNDDIR] [--grpc GRPC] [--dry-run] [--check] [-v] -c CONFIG
 
 optional arguments:
   -h, --help            show this help message and exit
@@ -22,9 +21,6 @@ optional arguments:
   --macaroon MACAROON_PATH
                         (default [lnddir]/data/chain/bitcoin/mainnet/charge-lnd.macaroon) path to lnd auth macaroons
   --grpc GRPC           (default localhost:10009) lnd gRPC endpoint
-  --electrum-server ELECTRUM_SERVER
-                        (optional, no default) electrum server host:port . Needed for
-                        onchain_fee.
   --dry-run             Do not perform actions (for testing), print what we would do to
                         stdout
   --check               Do not perform actions, only check config file for valid syntax
@@ -206,7 +202,7 @@ Available strategies:
 |**static** | sets fixed base fee and fee rate values for the outbound and inbound side.| **fee_ppm**<br>**base_fee_msat**<br>**inbound_fee_ppm**<br>**inbound_base_fee_msat**|
 |**match_peer** | sets the same base fee and fee rate values as the peer for the outbound and inbound side.|if **base_fee_msat**, **fee_ppm**, **inbound_base_fee_msat** or **inbound_fee_ppm**  are set the override the peer values|
 |**cost** | calculate cost for opening channel, and set ppm to cover cost when channel depletes.|**cost_factor**|
-|**onchain_fee** | sets the fees to a % equivalent of a standard onchain payment (Requires --electrum-server to be specified.)| **onchain_fee_btc** BTC<br>within **onchain_fee_numblocks** blocks.|
+|**onchain_fee** | sets the fees to a % equivalent of a standard onchain payment. We use lnd's internal fee estimate, which is usually based on bitcoind's fee estimate.| **onchain_fee_btc** BTC<br>within **onchain_fee_numblocks** blocks.|
 |**proportional** | sets outbound fee ppm according to balancedness. Inbound fee ppm keeps unchanged.|**min_fee_ppm**<br>**max_fee_ppm**<br>**sum_peer_chans** consider all channels with peer for balance calculations|
 |**disable** | disables the channel in the outgoing direction. Channel will be re-enabled again if it matches another policy (except when that policy uses an 'ignore' strategy).||
 |**use_config** | process channel according to rules defined in another config file.|**config_file**|

charge_lnd/charge_lnd.py

@@ -11,7 +11,6 @@ from .lnd import Lnd
 from .policy import Policies
 from .strategy import is_defined
 from .config import Config
-from .electrum import Electrum
 import charge_lnd.fmt as fmt
 
 def debug(message):
@@ -21,9 +20,6 @@ def main():
     argument_parser = get_argument_parser()
     arguments = argument_parser.parse_args()
 
-    if arguments.electrum_server:
-        Electrum.set_server(arguments.electrum_server)
-
     if not os.path.exists(arguments.config):
         debug("Config file not found")
         return False
@@ -166,9 +162,6 @@ def get_argument_parser():
                         default="localhost:10009",
                         dest="grpc",
                         help="(default localhost:10009) lnd gRPC endpoint")
-    parser.add_argument("--electrum-server",
-                        dest="electrum_server",
-                        help="(optional, no default) electrum server host:port[:s]. Needed for onchain_fee. Append ':s' for SSL connection")
     parser.add_argument("--dry-run",
                         dest="dry_run",
                         action="store_true",

charge_lnd/electrum.py

@@ -1,34 +0,0 @@
-import asyncio
-import aiorpcx
-
-class Electrum:
-    host = None
-    port = None
-    ssl = False
-    # cache
-    estimates = {}
-
-    @staticmethod
-    def set_server(server):
-        if server is not None:
-            split = server.split(':')
-            Electrum.host = split[0]
-            Electrum.port = int(split[1])
-            if len(split) > 2:
-                Electrum.ssl = split[2] == 's'
-
-    @staticmethod
-    async def _request_fee_estimate(numblocks):
-        async with aiorpcx.connect_rs(Electrum.host, Electrum.port, ssl=Electrum.ssl) as session:
-            result = await session.send_request('blockchain.estimatefee', [numblocks])
-            # convert from btc/kbyte
-            sat_per_byte = int(result * (100_000_000/1000))
-            Electrum.estimates[numblocks] = sat_per_byte
-
-    @staticmethod
-    def get_fee_estimate(numblocks):
-        if not numblocks in Electrum.estimates:
-            asyncio.get_event_loop().run_until_complete(Electrum._request_fee_estimate(numblocks))
-        if not numblocks in Electrum.estimates:
-            return 0
-        return Electrum.estimates[numblocks]

charge_lnd/lnd.py

@@ -8,6 +8,7 @@ import time
 
 from .grpc_generated import lightning_pb2_grpc as lnrpc, lightning_pb2 as ln
 from .grpc_generated import router_pb2_grpc as routerrpc, router_pb2 as router
+from .grpc_generated import walletkit_pb2_grpc as walletkitrpc, walletkit_pb2 as walletkit
 
 from .strategy import ChanParams, is_defined
 
@@ -30,6 +31,7 @@ class Lnd:
         grpc_channel = grpc.secure_channel(server, combined_credentials, channel_options)
         self.lnstub = lnrpc.LightningStub(grpc_channel)
         self.routerstub = routerrpc.RouterStub(grpc_channel)
+        self.walletstub = walletkitrpc.WalletKitStub(grpc_channel)
         self.graph = None
         self.info = None
         self.version = None
@@ -235,6 +237,11 @@ class Lnd:
                 chan_point=channel_point,
                 action=action
                 ))
+    
+    # returns the onchain fee in sat per vbyte for a given confirmation target
+    def get_fee_estimate(self, numblocks):
+        # numblocks less than 2 are rejected by walletrpc
+        return self.walletstub.EstimateFee(walletkit.EstimateFeeRequest(conf_target=max(numblocks,2))).sat_per_kw * 4 / 1000
 
     @staticmethod
     def hex_string_to_bytes(hex_string):

charge_lnd/strategy.py

@@ -6,7 +6,6 @@ from types import SimpleNamespace
 
 from . import fmt
 from .config import Config
-from .electrum import Electrum
 
 def debug(message):
     sys.stderr.write(message + "\n")
@@ -193,14 +192,12 @@ def strategy_cost(channel, policy, **kwargs):
 
 @strategy(name = 'onchain_fee')
 def strategy_onchain_fee(channel, policy, **kwargs):
-    if not Electrum.host or not Electrum.port:
-        raise Exception("No electrum server specified, cannot use strategy 'onchain_fee'")
-
+    lnd = kwargs['lnd']
     if policy.getint('min_fee_ppm_delta',-1) < 0:
         policy.set('min_fee_ppm_delta', 10) # set delta to 10 if not defined
 
     numblocks = policy.getint('onchain_fee_numblocks', 6)
-    sat_per_byte = Electrum.get_fee_estimate(numblocks)
+    sat_per_byte = lnd.get_fee_estimate(numblocks)
     if sat_per_byte < 1:
         return (None, None, None, None, None)
     reference_payment = policy.getfloat('onchain_fee_btc', 0.1)