charge-lnd

This script matches your open Lightning channels against a number of customizable criteria and applies channel fees based on the matching policy.

Installation

This script needs a moderately recent LND (https://github.com/lightningnetwork/lnd) instance running.

You don't need to have full admin rights to use charge-lnd. The following access rights are used:

offchain:read
offchain:write
onchain:read
info:read

You can create a suitably limited macaroon by issueing:

$ lncli bakemacaroon offchain:read offchain:write onchain:read info:read --save_to=~/.lnd/data/chain/bitcoin/mainnet/charge-lnd.macaroon

By default charge-lnd connects to localhost:10009, using the macaroon file in ~/.lnd/data/chain/bitcoin/mainnet/charge-lnd.macaroon. If charge-lnd.macaroon is not found, admin.macaroon will be tried.

If you need to change this, please have a look at the optional arguments --grpc and --lnddir.

Python and PIP should be made available on the system before installation. The project and its dependencies can be installed by running (don't forget the last dot):

$ pip install -r requirements.txt .

On some systems using Python 3, use pip3 instead:

$ pip3 install -r requirements.txt .

When running the install as root, charge-lnd will be installed to /usr/local/bin. Otherwise charge-lnd will be installed to $HOME/.local/bin.

Usage

charge-lnd takes only a minimal set of parameters:

usage: charge-lnd [-h] [--lnddir LNDDIR] [--grpc GRPC]
                  [--electrum-server ELECTRUM_SERVER] [-c CONFIG]

optional arguments:
  -h, --help            show this help message and exit
  --lnddir LNDDIR       (default ~/.lnd) lnd directory
  --grpc GRPC           (default localhost:10009) lnd gRPC endpoint
  --electrum-server ELECTRUM_SERVER
                        (no default) electrum server host:port
  --dry-run             Do not perform actions (for testing), print what we would do to stdout
  -v, --verbose         Be more verbose
  -c CONFIG, --config CONFIG
                        path to config file

All policies are defined using an INI style config file.

Each [policy-name] defined in the config file describes a policy. A single policy consists of;

a set of criteria to match against the channel and/or node (e.g. minimum channel capacity)
a fee strategy (how to calculate the new channel fees)

The defined criteria are compared against the open channels and associated nodes. The fee strategy then executed to determine what the new channel fees should be.

There is a special [default] section, that will be used if none of the policies match a channel. The [default] section only contains a strategy, not any matching criteria.

All policies are evaluated top to bottom. The first matching policy is applied (except for the default policy).

A simple example:

[example-policy]
chan.min_capacity = 500000

strategy = static
base_fee_msat = 1000
fee_ppm = 10

This policy matches the channels against the chan.min_capacity criterium. Only channels with at least 500000 sats total capacity will match.

If a channel matches this policy, the static strategy is then used, which takes the base_fee_msat and fee_ppm properties defined in the policy and applies them to the channel.

More examples

Maintain a friends list with lower fees:

[friends]
node.id = file:///home/lnd/friends.list
strategy = static
base_fee_msat = 10
fee_ppm = 10

Use routing fees to nudge channel balances toward 50/50 channel ratios:

[discourage-routing-out-of-balance]
chan.max_ratio = 0.1
chan.min_capacity = 250000
strategy = static
base_fee_msat = 10000
fee_ppm = 500

[encourage-routing-to-balance]
chan.min_ratio = 0.9
chan.min_capacity = 250000
strategy = static
base_fee_msat = 1
fee_ppm = 2

More elaborate examples can be found in the charge.config.example file.

Properties

Currently available properties:

Property	Description	Values
chan.id	match on channel IDs - comma separated list of channel IDs and/or file references	<channel ID\|file url>[, <channel ID\|file url>..]
chan.initiator	match on initiator status, true if we are initiator	true\|false
chan.private	match on channel private flag	true\|false
chan.max_ratio	match on channel ratio	0..1
chan.min_ratio	match on channel ratio	0..1
chan.min_capacity	match on channel capacity	# of sats
chan.max_capacity	match on channel capacity	# of sats
chan.min_age	match on channel age	# of blocks
chan.max_age	match on channel age	# of blocks
chan.min_base_fee_msat	match on channel peer policy	# of msats
chan.max_base_fee_msat	match on channel peer policy	# of msats
chan.min_fee_ppm	match on channel peer policy	0..1000000 (parts per million)
chan.max_fee_ppm	match on channel peer policy	0..1000000 (parts per million)

node.id	match on node pubkeys - comma separated list of node pubkeys and/or file references	<node pubkey\|file url>[, <node pubkey\|file url>..]
node.min_channels	match on number of channels the peer node has	# of channels
node.max_channels	match on number of channels the peer node has	# of channels
node.min_capacity	match on node total capacity	# of sats
node.max_capacity	match on node total capacity	# of sats

File references should contain 1 item per line

Strategies

Available strategies:

Strategy	Description	Parameters
ignore	ignores the channel
static	sets fixed base fee and fee rate values.	base_fee_msat fee_ppm
match_peer	sets the same base fee and fee rate values as the peer	if base_fee_msat or fee_ppm are set the override the peer values
cost	calculate cost for opening channel, and set ppm to cover cost when channel depletes.	base_fee_msat 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 within onchain_fee_numblocks blocks. base_fee_msat is used if defined.
proportional	sets fee ppm according to balancedness.	base_fee_msat min_fee_ppm max_fee_ppm

All strategies (except the ignore strategy) will apply the following properties if defined:

min_htlc_msat
max_htlc_msat
time_lock_delta

Contributing

Contributions are highly welcome! Feel free to submit issues and pull requests on https://github.com/accumulator/charge-lnd/

Please also consider opening a channel with my node, or sending tips via keysend:

accumulator : 0266ad254117f16f16c3457e081e6207e91c5e414477a208cf4d9c633322799038@89.99.0.115:9735