ldk-sample

Sample node implementation using LDK.

Installation

git clone https://github.com/lightningdevkit/ldk-sample

Usage

cd ldk-sample
cargo run <ldk_storage_directory_path>

The only CLI argument is the storage directory path. All configuration is read from <ldk_storage_directory_path>/.ldk/config.json.

Use config.example.json in the repo root as a template for your config file.

Configuration

Config is loaded from <storage_dir>/.ldk/config.json and strictly validated. Unknown fields cause an error (deny_unknown_fields).

Required sections: bitcoind. Optional sections: ldk, rapid_gossip_sync, and probing (probing is disabled if missing).

Network options: mainnet, testnet, regtest, signet (default is testnet).

Example config

{
  "bitcoind": {
    "rpc_host": "127.0.0.1",
    "rpc_port": 8332,
    "rpc_username": "your_rpc_user",
    "rpc_password": "your_rpc_password"
  },
  "network": "testnet",
  "ldk": {
    "peer_listening_port": 9735,
    "announced_node_name": "MyLDKNode",
    "announced_listen_addr": []
  },
  "rapid_gossip_sync": {
    "enabled": true,
    "url": "https://rapidsync.lightningdevkit.org/snapshot/",
    "interval_hours": 6
  },
  "probing": {
    "interval_sec": 300,
    "peers": ["02abc123...@1.2.3.4:9735"],
    "amount_msats": [1000, 10000, 100000, 1000000],
    "timeout_sec": 60
  }
}

Key options

bitcoind: RPC details are required. rpc_username and rpc_password can usually be found via cat ~/.bitcoin/.cookie.

ldk: peer_listening_port defaults to 9735. announced_listen_addr and announced_node_name default to empty, disabling public announcements. announced_listen_addr can be set to an IPv4 or IPv6 address to announce a publicly-connectable address. announced_node_name can be any string up to 32 bytes, representing this node's alias.

rapid_gossip_sync: Enabled by default to speed up initial network graph sync. On startup, the node attempts a RapidGossipSync download up to 3 times with exponential backoff. If it fails, the node falls back to P2P gossip sync. url defaults to https://rapidsync.lightningdevkit.org/snapshot/, interval_hours defaults to 6.

probing: Optional. If omitted, probing is disabled. Configure probe interval, peers, probe amounts in millisatoshis, and timeout.

License

Licensed under either:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.