A Core Lightning plugin to create CPFP (Child Pays For Parent) transactions for opening lightning channels.

• Python 3.7+
• Core Lightning 24.11+
• Bitcoin Core
• txindex in Bitcoin Core

Note: This plugin does not work with lightning version 24.08 because it uses the listaddresses rpc call, which was introduced in version 24.11.

1. Clone the repository:

git clone https://github.com/ca-ruz/bumpit.git
cd bumpit

2. Create and activate a virtual environment:

python -m venv .venv
source .venv/bin/activate

3. Install dependencies:

# Install plugin dependencies
pip install -r requirements.txt

# Install test dependencies
pip install -r requirements-dev.txt

1. Make sure you are running Bitcoin Core and Core Lightning

2. Start the plugin:

lightning-cli plugin start $PWD/bumpit.py

3. Find a peer ID you want to open a channel with

4. Open a channel:

lightning-cli fundchannel <peer_id> <amount_in_sats> [feerate]

5. Get the funding transaction txid and change vout:

l1-cli listfunds | jq '
  [ .channels[] | select(.state | test("AWAITING")) | .funding_txid ] as $target_txids
  | [ .outputs[] | select(.txid as $output_txid | $target_txids | index($output_txid)) ]
'

6. Create a CPFP transaction:

lightning-cli bumpchannelopen <txid> <vout> <amount> [yolo]

Note: amount is the fee/feerate, should be specified in either sat/vB, e.g.'5satvb' or sats e.g. '1000sats'

Optional: Type the word yolo as an argument after the amount or use -k with yolo=yolo if you want the plugin to broadcast the transaction for you.

The test suite uses Core Lightning's test framework and requires a regtest environment. You need to run the following commands inside of the plugin directory.

1. To run all tests:

pytest -vs

2. To run an individual test:

pytest -vs <name_of_the_test_file.py>

Note: By default, the fund_nodes command in regtest will automatically mine a block, this will confirm the funding transaction. We need to change this in the config, otherwise we wouldn't be able to test the plugin.

1. Navigate to Core Lightning's contrib directory:

cd ~/code/lightning/contrib

2. Open the config:

nano startup_regtest.sh 

3. Look for the fund_nodes function and comment out this lines:

#		"$BCLI" -datadir="$BITCOIN_DIR" -regtest generatetoaddress 6 "$ADDRESS" > /dev/null
#
#		printf "%s" "Waiting for confirmation... "
#
#		while ! "$LCLI" -F --lightning-dir=$LIGHTNING_DIR/l"$node1" listchannels | grep -q "channels"
#		do
#			sleep 1
#		done

4. Save & exit

1. Start the regtest environment:

source startup_regtest.sh
start_ln

3. Fund the nodes:

fund_nodes

4. Start the plugin (from the plugin directory):

l1-cli plugin start $PWD/bumpit.py

5. Get the funding transaction txid and change vout:

l1-cli listfunds | jq '
  [ .channels[] | select(.state | test("AWAITING")) | .funding_txid ] as $target_txids
  | [ .outputs[] | select(.txid as $output_txid | $target_txids | index($output_txid)) ]
'

6. Create a CPFP transaction:

l1-cli bumpchannelopen <txid> <vout> <amount> [yolo]

Note: amount is the fee/feerate, should be specified in either sat/vB e.g.'5satvb' or sats e.g. '1000sats'

Optional: Type the word yolo as an argument after the amount or use -k with yolo=yolo if you want the plugin to broadcast the transaction.

The plugin accepts the following configuration options:

• bump_brpc_user: Bitcoin RPC username
• bump_brpc_pass: Bitcoin RPC password
• bump_brpc_port: Bitcoin RPC port (default: 18443)
• yolo: Set to 'yolo' to broadcast the transaction automatically.

1. Fork the repository
2. Create a new branch for your feature
3. Make your changes
4. Run the test suite to ensure everything works
5. Submit a pull request