Merge pull request #909 from lightninglabs/remote-lnd

Enable users to connect to a remote lnd node.

Author: tanx

README.md

@@ -98,6 +98,15 @@ To run the packaged version of the app e.g. for macOS run:
 ./dist/mac/Lightning.app/Contents/MacOS/Lightning --bitcoin.node=bitcoind --bitcoind.rpcuser=kek --bitcoind.rpcpass=kek --bitcoind.zmqpubrawblock=tcp://127.0.0.1:28332 --bitcoind.zmqpubrawtx=tcp://127.0.0.1:28333
 ```
 
+### Connect to a remote lnd node
+1. In your remote node's `lnd.conf`, set `rpclisten=0.0.0.0:10006` and `tlsextraip=<insert your node's IP address here>`, then restart the node.
+
+2. Copy the `tls.cert` and `tls.key` from your remote node's `.lnd` into the appropriate folder for your platform (specified in the section below).
+
+3. Copy `admin.macaroon` from the remote node into `lnd/data/chain/bitcoin/<network>` (in the same folder you put the `tls` files).
+
+4. When starting the app, add the flag `--lndip=<your remote node's IP address>`. Note that the node must be locked when the app connects to it.
+
 ### Lnd data and logs
 Lnd data and logs are written to the following locations in production:
 

public/electron.js

@@ -6,6 +6,7 @@ const url = require('url');
 const isDev = require('electron-is-dev');
 const log = require('electron-log');
 const { startLndProcess, startBtcdProcess } = require('./lnd-child-process');
+const { parseCliArg } = require('./helper');
 const grcpClient = require('./grpc-client');
 const {
   PREFIX_NAME,
@@ -37,6 +38,7 @@ const btcdSettingsDir = path.join(isDev ? 'data' : userDataPath, 'btcd');
 const lndArgs = process.argv.filter(a =>
   /(^--bitcoin)|(^--btcd)|(^--neutrino)/.test(a)
 );
+let lndIP = parseCliArg('lndip');
 
 // Keep a global reference of the window object, if you don't, the window will
 // be closed automatically when the JavaScript object is garbage collected.
@@ -125,12 +127,21 @@ function createWindow() {
   grcpClient.init({
     ipcMain,
     lndSettingsDir,
+    lndIP,
     lndPort: LND_PORT,
     network: isDev ? 'simnet' : NETWORK,
   });
 }
 
 ipcMain.on('lnd-restart-process', async event => {
+  if (lndIP) {
+    event.sender.send(
+      'lnd-restart-error',
+      'Unable to reset password of remote lnd node.'
+    );
+    return;
+  }
+
   lndProcess && lndProcess.kill('SIGINT');
   let restartError;
   try {
@@ -199,7 +210,7 @@ app.on('ready', () => {
   initAutoUpdate();
   createWindow();
   initApplicationMenu();
-  startLnd();
+  if (!lndIP) startLnd();
 });
 
 // Quit when all windows are closed.

public/grpc-client.js

@@ -48,6 +48,7 @@ function getMacaroonCreds(lndSettingsDir, network) {
 
 module.exports.init = async function({
   ipcMain,
+  lndIP = 'localhost',
   lndPort,
   lndSettingsDir,
   network,
@@ -70,7 +71,7 @@ module.exports.init = async function({
     };
     const packageDef = protoLoader.loadSync(protoPath, options);
     lnrpc = grpc.loadPackageDefinition(packageDef).lnrpc;
-    unlocker = new lnrpc.WalletUnlocker(`localhost:${lndPort}`, credentials);
+    unlocker = new lnrpc.WalletUnlocker(`${lndIP}:${lndPort}`, credentials);
     grpc.waitForClientReady(unlocker, Infinity, err => {
       event.sender.send('unlockReady', { err });
     });
@@ -87,7 +88,7 @@ module.exports.init = async function({
       credentials,
       macaroonCreds
     );
-    lnd = new lnrpc.Lightning(`localhost:${lndPort}`, credentials);
+    lnd = new lnrpc.Lightning(`${lndIP}:${lndPort}`, credentials);
     grpc.waitForClientReady(lnd, Infinity, err => {
       event.sender.send('lndReady', { err });
     });

public/helper.js

@@ -0,0 +1,18 @@
+/**
+ * Parse a list of CLI arguments searching for a target argument.
+ * @param {string} target  The target argument we're searching for.
+ * @return {string|undefined} The target argument's value, or undefined.
+ */
+module.exports.parseCliArg = function(target) {
+  let regex = new RegExp('--' + target);
+  let value;
+  process.argv.filter(a => {
+    if (regex.test(a)) {
+      let split = a.split('=');
+      if (split.length > 1) {
+        value = split[1];
+      }
+    }
+  });
+  return value;
+};