Weighted average of peer incoming rate

README.md

@@ -192,6 +192,7 @@ Available strategies:
 |**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.|
 |**proportional** | sets fee ppm according to balancedness.|**min_fee_ppm**<br>**max_fee_ppm**<br>**sum_peer_chans** consider all channels with peer for balance calculations|
+|**proportional_peer_inbound** | sets the fee rate according to balancedness around a range based on the peer's inbound weighted average fee rate|**min_fee_ppm**<br>**max_fee_ppm**<br>**sum_peer_chans** consider all channels with peer for balance calculations<br>**fee_avg_calc_cutoff_ppm** Ignore peer inbound ppm above this value<br>**avg_fee_ppm_multiplier** Tweak avg ppm by this multiplier (0..1)<br>**upper_fee_ppm_multiplier** Tweak upper ppm by this multiplier; max_fee_ppm will still be honored (0..1)|
 |**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**|
 
@@ -203,6 +204,7 @@ All strategies (except the ignore strategy) will apply the following properties
 | **min_htlc_msat** | Minimum size (in msat) of HTLC to allow | # msat |
 | **max_htlc_msat** | Maximum size (in msat) of HTLC to allow | # msat |
 | **max_htlc_msat_ratio** | Maximum size of HTLC to allow as a fraction of total channel capacity | 0..1 |
+| **max_htlc_proportional_slices** | Maximum size of HTLC set proportionally to local balance with slices number of steps | # slices |
 | **time_lock_delta** | Time Lock Delta | # blocks |
 | **min_fee_ppm_delta** | Minimum change in fees (ppm) before updating channel | ppm delta |
 

charge_lnd/strategy.py

@@ -6,6 +6,8 @@
 from .config import Config
 from .electrum import Electrum
 
+edges_cache = None
+
 def debug(message):
     sys.stderr.write(message + "\n")
 
@@ -19,6 +21,43 @@ def call_strategy(*args, **kwargs):
         return call_strategy
     return register_strategy
 
+def calculate_slices(max_value, current_value, num_slices):
+    # Calculate the size of each slice
+    slice_size = max_value // max(num_slices, 10)
+
+    # Find the slice number containing the current_value
+    current_slice = min(current_value // slice_size, num_slices - 1)
+
+    # Determine the upper value of the current slice without going over
+    slice_point = max(1, min(current_slice * slice_size, max_value))
+
+    return slice_point
+
+def get_ratio(channel, policy, **kwargs):
+    if policy.getbool('sum_peer_chans', False):
+        lnd = kwargs['lnd']
+        shared_chans=lnd.get_shared_channels(channel.remote_pubkey)
+        local_balance = 0
+        remote_balance = 0
+        for c in (shared_chans):
+            # Include balance of all active channels with peer
+            if c.active:
+                local_balance += c.local_balance
+                remote_balance += c.remote_balance
+        total_balance = local_balance + remote_balance
+        if total_balance == 0:
+            # Sum inactive channels because the node is likely offline with no active channels.
+            # When they come back online their fees won't be changed.
+            for c in (shared_chans):
+                if not c.active:
+                    local_balance += c.local_balance
+                    remote_balance += c.remote_balance
+        total_balance = local_balance + remote_balance
+        ratio = local_balance/total_balance
+    else:
+        ratio = channel.local_balance/(channel.local_balance + channel.remote_balance)
+
+    return ratio
 
 class StrategyDelegate:
     STRATEGIES = {}
@@ -48,6 +87,11 @@ def execute(self, channel):
 
     def effective_max_htlc_msat(self, channel):
         result = self.policy.getint('max_htlc_msat')
+
+        slices = self.policy.getint('max_htlc_proportional_slices')
+        if slices:
+            result = calculate_slices(channel.capacity, channel.local_balance, slices) * 1000
+
         ratio = self.policy.getfloat('max_htlc_msat_ratio')
         if ratio:
             ratio = max(0,min(1,ratio))
@@ -81,28 +125,7 @@ def strategy_proportional(channel, policy, **kwargs):
     if ppm_min is None or ppm_max is None:
         raise Exception('proportional strategy requires min_fee_ppm and max_fee_ppm properties')
 
-    if policy.getbool('sum_peer_chans', False):
-        lnd = kwargs['lnd']
-        shared_chans=lnd.get_shared_channels(channel.remote_pubkey)
-        local_balance = 0
-        remote_balance = 0
-        for c in (shared_chans):
-            # Include balance of all active channels with peer
-            if c.active:
-                local_balance += c.local_balance
-                remote_balance += c.remote_balance
-        total_balance = local_balance + remote_balance
-        if total_balance == 0:
-            # Sum inactive channels because the node is likely offline with no active channels.
-            # When they come back online their fees won't be changed.
-            for c in (shared_chans):
-                if not c.active:
-                    local_balance += c.local_balance
-                    remote_balance += c.remote_balance
-        total_balance = local_balance + remote_balance
-        ratio = local_balance/total_balance
-    else:
-        ratio = channel.local_balance/(channel.local_balance + channel.remote_balance)
+    ratio = get_ratio(channel, policy, **kwargs)
 
     ppm = int(ppm_min + (1.0 - ratio) * (ppm_max - ppm_min))
     # clamp to 0..inf
@@ -118,6 +141,140 @@ def strategy_match_peer(channel, policy, **kwargs):
     return (policy.getint('base_fee_msat', peernode_policy.fee_base_msat),
             policy.getint('fee_ppm', peernode_policy.fee_rate_milli_msat))
 
+@strategy(name = 'proportional_peer_inbound')
+def strategy_proportional_peer_inbound(channel, policy, **kwargs):
+    lnd = kwargs['lnd']
+    chan_info = lnd.get_chan_info(channel.chan_id)
+    my_pubkey = lnd.get_own_pubkey()
+
+    peer_node_id = chan_info.node1_pub if chan_info.node2_pub == my_pubkey else chan_info.node2_pub
+
+    # avoid having to fetch get_edges() multiple times
+    global edges_cache
+
+    if not edges_cache:
+        edges_list = lnd.get_edges()
+        # cache only the data we need
+        edges = []
+        for edge in edges_list:
+            the_edge = {
+                "node1_pub": edge.node1_pub,
+                "node2_pub": edge.node2_pub,
+                'capacity': edge.capacity,
+                "node1_policy": {
+                   'fee_rate_milli_msat': edge.node1_policy.fee_rate_milli_msat,
+                   'max_htlc_msat': edge.node1_policy.max_htlc_msat
+                },
+                "node2_policy": {
+                   'fee_rate_milli_msat': edge.node2_policy.fee_rate_milli_msat,
+                   'max_htlc_msat': edge.node2_policy.max_htlc_msat
+                }
+            }
+            edges.append(the_edge)
+        edges_cache = edges
+    else:
+        edges = edges_cache
+
+    peer_inbound = []
+
+    total_peer_capacity = 0
+    ppm_avg = 0
+
+    for edge in edges:
+        if edge['node1_pub'] == peer_node_id:
+            if edge['node2_pub'] == my_pubkey:
+                # ignore this edge if it's shared between our node and peer
+                continue
+            inbound = {
+                #'capacity': edge['capacity'],
+                # We will use the max_htlc_msat // 1000 as the estimated capacity
+                'capacity': edge['node2_policy']['max_htlc_msat'] // 1000,
+                # We will take node2_policy because we want inbound policy, not outbound
+                'fee_rate_milli_msat': edge['node2_policy']['fee_rate_milli_msat']
+            }
+            total_peer_capacity += inbound['capacity']
+            peer_inbound.append(inbound)
+        elif edge['node2_pub'] == peer_node_id:
+            if edge['node1_pub'] == my_pubkey:
+                # ignore this edge if it's shared between our node and peer
+                continue
+            inbound = {
+                #'capacity': edge['capacity'],
+                # We will use the max_htlc_msat // 1000 as the estimated capacity
+                'capacity': edge['node1_policy']['max_htlc_msat'] // 1000,
+                # We will take node1_policy because we want inbound policy, not outbound
+                'fee_rate_milli_msat': edge['node1_policy']['fee_rate_milli_msat']
+            }
+            peer_inbound.append(inbound)
+            total_peer_capacity += inbound['capacity']
+
+    # Calculate the weighted average inbound fee by multiplying each fee by
+    # the adjusted ratio and taking the sum.
+
+    fee_avg_calc_cutoff_ppm = policy.getint('fee_avg_calc_cutoff_ppm')
+
+    for inbound in peer_inbound:
+        if inbound['fee_rate_milli_msat'] >= fee_avg_calc_cutoff_ppm:
+            # ignore fee rate values over max_usable_ppm in our calculation
+            continue
+        ppm_avg += int((inbound['capacity']/total_peer_capacity)*inbound['fee_rate_milli_msat'])
+
+    # Use the same channel ratio calculation as proportional strategy
+    ratio = get_ratio(channel, policy, **kwargs)
+
+    ppm_min = policy.getint('min_fee_ppm')
+    ppm_max = policy.getint('max_fee_ppm')
+    avg_fee_ppm_multiplier = policy.getfloat('avg_fee_ppm_multiplier')
+    upper_fee_ppm_multiplier = policy.getfloat('upper_fee_ppm_multiplier')
+
+    if ppm_min is None or ppm_max is None or avg_fee_ppm_multiplier is None or upper_fee_ppm_multiplier is None:
+        raise Exception('proportional inbound weighted strategy requires min_fee_ppm, max_fee_ppm, avg_fee_ppm_multiplier, and upper_fee_ppm_multiplier properties')
+
+    if ppm_min >= ppm_max:
+        raise Exception('ppm_min should be less than ppm_max')
+
+    # The avg_fee_ppm_multiplier can tweak the ppm_avg to be slightly
+    # lower or higher, changing the center-point of the calculation.
+    # You might do this if you think the average values are all
+    # too cheap or too expensive. We will also make sure the average
+    # is not lower than ppm_min here, or higher than ppm_max.
+    # It's probably perfectly fine to leave this multiplier at 1.
+
+    ppm_avg = min(ppm_max, max(ppm_min, ppm_avg * avg_fee_ppm_multiplier))
+
+    # The upper_fee_ppm_multiplier sets the upper maximum when calculating
+    # the ppm when the local balance proportion drops below 0.5. A value
+    # of 2 means that the upper maximum is double the ppm_avg. If you
+    # wanted to increase fees more aggressively as the local balance falls,
+    # you could choose a higher multiplier.
+    # It's probably perfectly fine to leave this multiplier at 2.
+
+    ppm_upper = ppm_avg * upper_fee_ppm_multiplier
+
+    # When the ratio is near half, we want the ppm to be exactly
+    # the ppm_avg. When the ratio is lower, we want a higher ppm that
+    # is between ppm_avg and ppm_upper. When the ratio is higher,
+    # we want a lower ppm between ppm_avg and ppm_min. Since the range
+    # between can be unequal, e.g. average = 500, min = 400, max
+    # = 3000, we don't want to make the 0.5 ratio be the middle
+    # of the range 400 - 3000. It's much larger than the target
+    # average of 500. So we calculate the two sides separately.
+
+    if ratio < 0.5:
+        ppm = int(ppm_upper + 2 * (ppm_avg - ppm_upper) * ratio)
+    elif ratio > 0.5:
+        ppm = int(ppm_min + 2 * (ppm_avg - ppm_min) * (1 - ratio))
+    else:
+        ppm = ppm_avg
+
+    # Cap it to the max
+    ppm = min(ppm, ppm_max)
+
+    # clamp to 0..inf
+    ppm = max(ppm, 0)
+
+    return (policy.getint('base_fee_msat'), ppm)
+
 @strategy(name = 'cost')
 def strategy_cost(channel, policy, **kwargs):
     lnd = kwargs['lnd']

examples/max-htlc-proportional.config

@@ -0,0 +1,24 @@
+# all channels max_htlc set to a value proportional to
+# local balance, with specified number of divisions
+# e.g.
+#      slices = 10
+#      channel_size = 1_000_000 sats
+#      max_htlc values:
+#      100_000, 200_000, 300_000, 400_000, 500_000
+#      600_000, 700_000, 800_000, 900_000, 1_000_000
+#
+#      slices = 2
+#      channel_size = 800_000_sats
+#      max_htlc values:
+#      400_000, 800_000
+#
+# Rationale: avoid insufficient local balance failures
+# to improve your node's reputation of successful forwarding.
+
+[default]
+strategy = ignore
+
+[proportional_htlc]
+chan.max_local_balance = 30_000_000
+strategy = static
+max_htlc_proportional_slices = 6

examples/weighted-average-of-peer-incoming-rate.config

@@ -0,0 +1,44 @@
+# Use a fee that is proportional to the channel's local balance with
+# the ppm range surrounding the weighted average of the peer node's
+# inbound ppm rate.
+#
+# Example:
+#    - Let's suppose you have a channel with Peer XYZ.
+#    - Peer XYZ has 4 channels.
+#    - Those 4 channels are 1M, 2M, 3M, and 4M sats capacity.
+#    - The inbound fee rates for those channels are 100 ppm, 200 ppm,
+#      300 ppm, and 400 ppm.
+#    - The weighted average is the sum of fees multiplied by the
+#      channel's capacity. In this case, 300 ppm. Note, it's higher
+#      than the plain average, because more capacity is at the 400 ppm
+#      rate compared to the lower ppm rate.
+#
+# The `min_fee_ppm` and `max_fee_ppm` are absolute, and will override
+# whatever calculations are made.
+#
+# The `fee_avg_calc_cutoff_ppm` is a cutoff maximum value when
+# considering the peer's inbound channel ppm. We can exclude these
+# extreme values from the calculation to get a more reasonable avg.
+#
+# The `avg_fee_ppm_multiplier` shifts the calculated peer's avg to
+# higher or lower. This is useful if you think the avg is too low
+# or too high.
+#
+# The `upper_fee_ppm_multiplier` determines how aggresively you want
+# your ppm to rise as the local channel balance falls. A multiplier
+# of 2 sets the upper ppm fee to be double as balance approaches 0.
+
+[proportional_peer_inbound]
+strategy = proportional_peer_inbound
+node.min_shared_channels_active = 1
+base_fee_msat = 0
+min_fee_ppm_delta = 50
+max_htlc_proportional_slices = 6
+
+min_fee_ppm = 1
+max_fee_ppm = 99_999
+fee_avg_calc_cutoff_ppm = 5_000
+avg_fee_ppm_multiplier = 1.0
+upper_fee_ppm_multiplier = 2.0
+
+time_lock_delta = 18