Merge pull request #1914 from ExchangeUnion/fix/checking-invoices-sup…

…port-lnd

fix: checking for invoice support on lnd clients while verifying connection

lib/lndclient/LndClient.ts

@@ -1,4 +1,5 @@
 import assert from 'assert';
+import crypto from 'crypto';
 import { promises as fs, watch } from 'fs';
 import grpc, { ChannelCredentials, ClientReadableStream } from 'grpc';
 import path from 'path';
@@ -242,6 +243,10 @@ class LndClient extends SwapClient {
 
   private unaryCall = <T, U>(methodName: Exclude<keyof LightningClient, ClientMethods>, params: T): Promise<U> => {
     return new Promise((resolve, reject) => {
+      if (this.hasNoInvoiceSupport()) {
+        reject(errors.NO_HOLD_INVOICE_SUPPORT);
+        return;
+      }
       if (!this.isOperational()) {
         reject(errors.DISABLED);
         return;
@@ -337,7 +342,9 @@ class LndClient extends SwapClient {
     let version: string | undefined;
     let alias: string | undefined;
     let status = 'Ready';
-    if (!this.isOperational()) {
+    if (this.hasNoInvoiceSupport()) {
+      status = errors.NO_HOLD_INVOICE_SUPPORT(this.currency).message;
+    } else if (!this.isOperational()) {
       status = errors.DISABLED(this.currency).message;
     } else if (this.isDisconnected()) {
       status = errors.UNAVAILABLE(this.currency, this.status).message;
@@ -493,6 +500,18 @@ class LndClient extends SwapClient {
         }
 
         this.invoices = new InvoicesClient(this.uri, this.credentials);
+        try {
+          const randomHash = crypto.randomBytes(32).toString('hex');
+          this.logger.debug(`checking hold invoice support with hash: ${randomHash}`);
+
+          await this.addInvoice({ rHash: randomHash, units: 1 });
+          await this.removeInvoice(randomHash);
+        } catch (err) {
+          const errStr = typeof(err) === 'string' ? err : JSON.stringify(err);
+
+          this.logger.error(`could not add hold invoice, error: ${errStr}`);
+          this.setStatus(ClientStatus.NoHoldInvoiceSupport);
+        }
 
         if (this.walletUnlocker) {
           // WalletUnlocker service is disabled when the main Lightning service is available

lib/lndclient/errors.ts

@@ -6,6 +6,7 @@ const errorCodes = {
   DISABLED: codesPrefix.concat('.1'),
   UNAVAILABLE: codesPrefix.concat('.2'),
   NO_ACTIVE_CHANNELS: codesPrefix.concat('.3'),
+  NO_HOLD_INVOICE_SUPPORT: codesPrefix.concat('.4'),
 };
 
 const errors = {
@@ -21,6 +22,10 @@ const errors = {
     message: `lnd-${currency} has no active channels`,
     code: errorCodes.NO_ACTIVE_CHANNELS,
   }),
+  NO_HOLD_INVOICE_SUPPORT: (currency: string) => ({
+    message: `lnd-${currency} has no hold invoice support`,
+    code: errorCodes.NO_HOLD_INVOICE_SUPPORT,
+  }),
 };
 
 export { errorCodes };

lib/swaps/SwapClient.ts

@@ -23,6 +23,8 @@ enum ClientStatus {
   Unlocked,
   /** The client could not be initialized due to faulty configuration. */
   Misconfigured,
+  /** The server is reachable but hold invoices are not supported. */
+  NoHoldInvoiceSupport,
 }
 
 type ChannelBalance = {
@@ -216,6 +218,7 @@ abstract class SwapClient extends EventEmitter {
       case ClientStatus.Disconnected:
       case ClientStatus.WaitingUnlock:
       case ClientStatus.OutOfSync:
+      case ClientStatus.NoHoldInvoiceSupport:
         // these statuses can only be set on an operational, initalized client
         validStatusTransition = this.isOperational();
         break;
@@ -359,7 +362,7 @@ abstract class SwapClient extends EventEmitter {
    * Returns `true` if the client is enabled and configured properly.
    */
   public isOperational(): boolean {
-    return !this.isDisabled() && !this.isMisconfigured() && !this.isNotInitialized();
+    return !this.isDisabled() && !this.isMisconfigured() && !this.isNotInitialized() && !this.hasNoInvoiceSupport();
   }
   public isDisconnected(): boolean {
     return this.status === ClientStatus.Disconnected;
@@ -373,6 +376,9 @@ abstract class SwapClient extends EventEmitter {
   public isOutOfSync(): boolean {
     return this.status === ClientStatus.OutOfSync;
   }
+  public hasNoInvoiceSupport(): boolean {
+    return this.status === ClientStatus.NoHoldInvoiceSupport;
+  }
 
   /** Ends all connections, subscriptions, and timers for for this client. */
   public close() {