deezy-swap.sh

deezy-swap.sh

#!/bin/bash
set -eu

# Deezy Swap: push Bitcoin Lightning liquidity to LND on-chain address
# --------------------------------------------------------------------------
# This script automates swapping Bitcoin Lightning funds to Bitcoin on-chain
# through deezy.io, an external service.
#
# Use at your own risk.
#

# ------------------------------------------------------------------------------
#
# Set your own API access token 
# (see https://docs.deezy.io/#tag/Swap-(LN-to-BTC)/operation/createSwap)

API_TOKEN="00000000000000000000000000000000"

# ------------------------------------------------------------------------------
# print usage information for script
usage() {
  echo "Deezy Swap: push Bitcoin Lightning liquidity to LND on-chain address
usage: deezy-swap.sh [--version] [--help] amount onchain_fees

Parameters:
  amount        sats to swap
  onchain_fees  onchain fees in sats/vbyte
"
}

# error handling
errorExit() {
    exit 1
}

# ------------------------------------------------------------------------------

# check script arguments
if [[ "${1-undefined}" == "-v" ]] || [[ "${1-undefined}" == "--version" ]]; then
    echo "deezy-swap version 0.1"
    exit 0
elif [[ ${#} -lt 2 ]] || [[ "${1}" == "-h" ]] || [[ "${1}" == "--help" ]]; then
    usage
    exit 0
fi

# ------------------------------------------------------------------------------

AMOUNT="${1:-}"
ONCHAIN_FEES="${2:-}"

# obtain on-chain address from LND wallet
ONCHAIN_ADDRESS=$( lncli newaddress p2tr | jq -r '.address' )

if [ "${ONCHAIN_ADDRESS:0:3}" == "bc1" ]; then
    echo "OK:  Obtained on-chain address from LND: ${ONCHAIN_ADDRESS}"
else
    echo "ERR: ERR: Could not obtain valid on-chain address from LND."
    errorExit
fi

# create swap and get LN invoice from Deezy.io
LN_INVOICE=$( curl -s -X POST -H 'Content-type: application/json' -H 'x-api-token:'${API_TOKEN}'' --data '{"amount_sats":'${AMOUNT}',"on_chain_address":"'"${ONCHAIN_ADDRESS}"'","on_chain_sats_per_vbyte": '"${ONCHAIN_FEES}"'}' https://api.deezy.io/v1/swap | jq -r '.bolt11_invoice')
LN_INVOICE_DESC=$( lncli decodepayreq "${LN_INVOICE}" | jq -r '.description' )
LN_INVOICE_SATS=$( lncli decodepayreq "${LN_INVOICE}" | jq -r '.num_satoshis' )
if [ "${LN_INVOICE:0:4}" == "lnbc" ]; then
    printf "OK:  Obtained LN invoice from Deezy.io: \n\n%s \n\n%s \n\n" "${LN_INVOICE}" "${LN_INVOICE_DESC}"
else
    echo "ERR: ERR: Could not obtain valid on-chain address from LND."
    errorExit
fi

while true; do
    read -r -p "Do you want to proceed? (y/n) " yn

    case $yn in
        [yY] )
            echo;
            break;;
        [nN] )
            echo "Aborted by user";
            errorExit;;
        * )
            echo "invalid response";;
    esac

done

# pay LN invoice to swap liquidity
# -- if payment fails, the script terminates immediately
lncli payinvoice --force "${LN_INVOICE}"

# log swap in CSV file for accounting
LOGFILENAME="$HOME/deezy-swaps.csv"

if [ ! -f "$LOGFILENAME" ]; then
    echo "date; sats_out; ln_invoice; sats_in; onchain_address" > "${LOGFILENAME}"
fi
TIMESTAMP=$( date +"%F %T" )
echo "${TIMESTAMP}; ${LN_INVOICE_SATS}; ${LN_INVOICE}; ${AMOUNT}; ${ONCHAIN_ADDRESS}" >> "${LOGFILENAME}"