QueryProbability

danger

This RPC is deprecated and will be removed in a future version.

Deprecated. QueryProbability returns the current success probability estimate for a given node pair and amount. The call returns a zero success probability if no channel is available or if the amount violates min/max HTLC constraints.

Source: routerrpc/router.proto

gRPC

rpc QueryProbability (QueryProbabilityRequest) returns (QueryProbabilityResponse);

REST

HTTP Method	Path
GET	/v2/router/mc/probability/{from_node}/{to_node}/{amt_msat}

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', 'routerrpc/router.proto'], loaderOptions);
const routerrpc = grpc.loadPackageDefinition(packageDefinition).routerrpc;
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 routerrpc.Router(GRPC_HOST, creds);
let request = {
  from_node: <bytes>,
  to_node: <bytes>,
  amt_msat: <int64>,
};
client.queryProbability(request, function(err, response) {
  console.log(response);
});
// Console output:
//  {
//    "probability": <double>,
//    "history": <PairData>,
//  }

Python

import codecs, grpc, os
# Generate the following 2 modules by compiling the routerrpc/router.proto with the grpcio-tools.
# See https://github.com/lightningnetwork/lnd/blob/master/docs/grpc/python.md for instructions.
import router_pb2 as routerrpc, router_pb2_grpc as routerstub

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 = routerstub.RouterStub(channel)
request = routerrpc.QueryProbabilityRequest(
  from_node=<bytes>,
  to_node=<bytes>,
  amt_msat=<int64>,
)
response = stub.QueryProbability(request)
print(response)
# {
#    "probability": <double>,
#    "history": <PairData>,
# }

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 options = {
  url: `https://${REST_HOST}/v2/router/mc/probability/{from_node}/{to_node}/{amt_msat}`,
  // Work-around for self-signed certificates.
  rejectUnauthorized: false,
  json: true,
  headers: {
    'Grpc-Metadata-macaroon': fs.readFileSync(MACAROON_PATH).toString('hex'),
  },
}
request.get(options, function(error, response, body) {
  console.log(body);
});
// Console output:
//  {
//    "probability": <number>, // <double> 
//    "history": <object>, // <PairData> 
//  }

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/router/mc/probability/{from_node}/{to_node}/{amt_msat}'
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
headers = {'Grpc-Metadata-macaroon': macaroon}
r = requests.get(url, headers=headers, verify=TLS_PATH)
print(r.json())
# {
#    "probability": <double>,
#    "history": <PairData>,
# }

Shell

$ lncli queryprob --help

NAME:
   lncli queryprob - Deprecated. Estimate a success probability.

USAGE:
   lncli queryprob from-node to-node amt

CATEGORY:
   Mission Control

Messages

routerrpc.QueryProbabilityRequest

Source: routerrpc/router.proto

Field	gRPC Type	REST Type	REST Placement
from_node The source node pubkey of the pair.	bytes	string	path
to_node The destination node pubkey of the pair.	bytes	string	path
amt_msat The amount for which to calculate a probability.	int64	string	path

routerrpc.QueryProbabilityResponse

Source: routerrpc/router.proto

Field	gRPC Type	REST Type
probability The success probability for the requested pair.	double	number
history The historical data for the requested pair.	PairData	object

Nested Messages

routerrpc.PairData

Field	gRPC Type	REST Type
fail_time Time of last failure.	int64	string
fail_amt_sat Lowest amount that failed to forward rounded to whole sats. This may be set to zero if the failure is independent of amount.	int64	string
fail_amt_msat Lowest amount that failed to forward in millisats. This may be set to zero if the failure is independent of amount.	int64	string
success_time Time of last success.	int64	string
success_amt_sat Highest amount that we could successfully forward rounded to whole sats.	int64	string
success_amt_msat Highest amount that we could successfully forward in millisats.	int64	string