SolLightning intermediary (TypeScript)

An off-chain app handling BTC <-> Solana cross-chain swaps, utilizing SolLightning-program Solana on-chain program.

Principle of operation is described in depth here (for lightning network swaps) and here (for bitcoin on-chain swaps)

This software is made to be used in conjunction with client SDK.

NOTE: This implementation is still in alpha stage and MAY contain bugs and uncovered edge-cases, use at your own risk!

REST API

This app starts an http rest api server on port 4000 (by default). This is configurable by REST_PORT option in .env file.

REST_PORT="4001"

NOTE: Be sure to open this ports so client SDK can call the REST API.

Requirements

• bitcoind node
• lnd node (Install instructions here)
• nodejs (requires v18 or higher)
• npm
• typescript

Installation

Installing bitcoind

1. Download latest version from here or build from source
2. Use the configuration file bitcoin.conf
3. Run the bitcoind with the configuration file: bitcoind -conf=<path/to/bitcoin.conf>
4. Wait till bitcoind finishes with IBD (initial block download), should take no more than a few hours for testnet on a regular PC with good internet connection
5. Create a new wallet in bitcoind: bitcoin-cli -testnet -conf=<path/to/bitcoin.conf> createwallet test true false "" false false true false
6. Set the configured rpc ip, port, username and password in _.env file (not necessary if you used provided bitcoin.conf)

Installing lnd

1. Download latest version from here or build from source
2. Use the provided configuration file lnd.conf
3. Either place the lnd.conf file in ~/.lnd/ folder or run lnd with a --configfile argument: lnd --configfile=<path/to/lnd.conf>
4. Wait for the lnd to startup. It should then ask you to create a wallet.
5. Create a new wallet with: lncli -n testnet create
6. Save password you used to create a wallet to some known file (e.g. ~/lnd-pass.txt), and add wallet-unlock-password-file=<path/to/password-file> option to lnd.conf, like so:

   [Application Options]
   tlsextraip=127.0.0.1
   wallet-unlock-password-file=path/to/password-file
   

7. Get the certificate by base64 --wrap=0 ~/.lnd/tls.cert and copy the output to LN_CERT field in _.env file
8. Get the admin macaroon by base64 --wrap=0 ~/.lnd/data/chain/bitcoin/testnet/admin.macaroon and copy the output to LN_MACAROON field in _.env file
9. Set the ip and port in the _.env (not needed if using provided lnd.conf)
10. Get the bitcoin address lncli -n testnet newaddress p2wkh
11. Get some testnet bitcoin to that address through one of the faucets:
    • coinfaucet.eu
    • bitcoinfaucet.uo1.net
    • testnet-faucet.com
    • onchain.io
12. Connect to a well connected bitcoin lightning node, you can find the list here. Pick a node and copy its connection string (should look like so: 038863cf8ab91046230f561cd5b386cbff8309fa02e3f0c3ed161a3aeb64a643b9@203.132.94.196:9735). Then use lncli -n testnet connect <connection string> to connect to that node.
13. Open a channel with the node you connected to. Take the public key from the connection string (the part before '@', e.g.: 038863cf8ab91046230f561cd5b386cbff8309fa02e3f0c3ed161a3aeb64a643b9). Open a channel with lncli -n testnet openchannel <node public key> <amount> <push_amount>. Be sure to push half of your channel's balance to the other node so you can receive, e.g. lncli -n testnet openchannel <node public key> 100000 50000
14. Wait for the channel to be established, you can monitor pending channels with: lncli -n testnet pendingchannels

Installing btcrelay

Instructions available here. Skip steps 2.-4. as you already have bitcoind setup and running.

Installing sollightning intermediary

1. Install necessary npm packages: npm install
2. Install typescript: npm install -g typescript
3. Compile to javascript: tsc
4. Rename _.env file to .env
5. Generate a new solana keypair: npm run genKey
6. Airdrop some devnet tokens to your newly generated solana wallet: npm run airdrop
7. Create the WBTC, USDC and USDT tokens on devnet: npm run createToken
8. Mint some WBTC/USDC/USDT token to your new keypair: npm run mint <WBTC/USDC/USDT> <amount to mint in base units>
9. You can also mint some WBTC/USDC/USDT tokens to your phantom wallet: npm run mint <WBTC/USDC/USDT> <amount to mint in base units> <wallet address>
10. Deposit your WBTC/USDC/USDT to the program npm run deposit <WBTC/USDC/USDT> <amount to deposit in base units>
11. Be sure that bitcoind, lnd and btcrelay are running before starting the app.
12. Run the app with: npm start