LeaseOutput

LeaseOutput locks an output to the given ID, preventing it from being available for any future coin selection attempts. The absolute time of the lock's expiration is returned. The expiration of the lock can be extended by successive invocations of this RPC. Outputs can be unlocked before their expiration through ReleaseOutput.

Source: walletrpc/walletkit.proto

gRPC

rpc LeaseOutput (LeaseOutputRequest) returns (LeaseOutputResponse);

REST

HTTP Method	Path
POST	/v2/wallet/utxos/lease

Code Samples

gRPC

Javascript

const fs = require('fs');
const grpc = require('@grpc/grpc-js');
const protoLoader = require('@grpc/proto-loader');

const GRPC_HOST = 'localhost:10009'
const MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
const TLS_PATH = 'LND_DIR/tls.cert'

const loaderOptions = {
  keepCase: true,
  longs: String,
  enums: String,
  defaults: true,
  oneofs: true,
};
const packageDefinition = protoLoader.loadSync(['lightning.proto', 'walletrpc/walletkit.proto'], loaderOptions);
const walletrpc = grpc.loadPackageDefinition(packageDefinition).walletrpc;
process.env.GRPC_SSL_CIPHER_SUITES = 'HIGH+ECDSA';
const tlsCert = fs.readFileSync(TLS_PATH);
const sslCreds = grpc.credentials.createSsl(tlsCert);
const macaroon = fs.readFileSync(MACAROON_PATH).toString('hex');
const macaroonCreds = grpc.credentials.createFromMetadataGenerator(function(args, callback) {
  let metadata = new grpc.Metadata();
  metadata.add('macaroon', macaroon);
  callback(null, metadata);
});
let creds = grpc.credentials.combineChannelCredentials(sslCreds, macaroonCreds);
let client = new walletrpc.WalletKit(GRPC_HOST, creds);
let request = {
  id: <bytes>,
  outpoint: <OutPoint>,
  expiration_seconds: <uint64>,
};
client.leaseOutput(request, function(err, response) {
  console.log(response);
});
// Console output:
//  {
//    "expiration": <uint64>,
//  }

Python

import codecs, grpc, os
# Generate the following 2 modules by compiling the walletrpc/walletkit.proto with the grpcio-tools.
# See https://github.com/lightningnetwork/lnd/blob/master/docs/grpc/python.md for instructions.
import walletkit_pb2 as walletrpc, walletkit_pb2_grpc as walletkitstub

GRPC_HOST = 'localhost:10009'
MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
TLS_PATH = 'LND_DIR/tls.cert'

# create macaroon credentials
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
def metadata_callback(context, callback):
  callback([('macaroon', macaroon)], None)
auth_creds = grpc.metadata_call_credentials(metadata_callback)
# create SSL credentials
os.environ['GRPC_SSL_CIPHER_SUITES'] = 'HIGH+ECDSA'
cert = open(TLS_PATH, 'rb').read()
ssl_creds = grpc.ssl_channel_credentials(cert)
# combine macaroon and SSL credentials
combined_creds = grpc.composite_channel_credentials(ssl_creds, auth_creds)
# make the request
channel = grpc.secure_channel(GRPC_HOST, combined_creds)
stub = walletkitstub.WalletKitStub(channel)
request = walletrpc.LeaseOutputRequest(
  id=<bytes>,
  outpoint=<OutPoint>,
  expiration_seconds=<uint64>,
)
response = stub.LeaseOutput(request)
print(response)
# {
#    "expiration": <uint64>,
# }

REST

Javascript

const fs = require('fs');
const request = require('request');

const REST_HOST = 'localhost:8080'
const MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'

let requestBody = {
  id: <string>, // <bytes> (base64 encoded)
  outpoint: <object>, // <OutPoint> 
  expiration_seconds: <string>, // <uint64> 
};
let options = {
  url: `https://${REST_HOST}/v2/wallet/utxos/lease`,
  // Work-around for self-signed certificates.
  rejectUnauthorized: false,
  json: true,
  headers: {
    'Grpc-Metadata-macaroon': fs.readFileSync(MACAROON_PATH).toString('hex'),
  },
  form: JSON.stringify(requestBody),
}
request.post(options, function(error, response, body) {
  console.log(body);
});
// Console output:
//  {
//    "expiration": <string>, // <uint64> 
//  }

Python

import base64, codecs, json, requests

REST_HOST = 'localhost:8080'
MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
TLS_PATH = 'LND_DIR/tls.cert'

url = f'https://{REST_HOST}/v2/wallet/utxos/lease'
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
headers = {'Grpc-Metadata-macaroon': macaroon}
data = {
  'id': base64.b64encode(<bytes>),
  'outpoint': <OutPoint>,
  'expiration_seconds': <uint64>,
}
r = requests.post(url, headers=headers, data=json.dumps(data), verify=TLS_PATH)
print(r.json())
# {
#    "expiration": <uint64>,
# }

Shell

# There is no CLI command for this RPC

Messages

walletrpc.LeaseOutputRequest

Source: walletrpc/walletkit.proto

Field	gRPC Type	REST Type	REST Placement
id An ID of 32 random bytes that must be unique for each distinct application using this RPC which will be used to bound the output lease to.	bytes	string	body
outpoint The identifying outpoint of the output being leased.	OutPoint	object	body
expiration_seconds The time in seconds before the lock expires. If set to zero, the default lock duration is used.	uint64	string	body

walletrpc.LeaseOutputResponse

Source: walletrpc/walletkit.proto

Field	gRPC Type	REST Type
expiration The absolute expiration of the output lease represented as a unix timestamp.	uint64	string

Nested Messages

lnrpc.OutPoint

Field	gRPC Type	REST Type
txid_bytes Raw bytes representing the transaction id.	bytes	string
txid_str Reversed, hex-encoded string representing the transaction id.	string	string
output_index The index of the output on the transaction.	uint32	integer