fix: Wait for remote peer for Waku Relay

The promise resolves only if a remote peer is added to the gossipsub
mesh.

package-lock.json

@@ -32,6 +32,7 @@
         "js-sha3": "^0.8.0",
         "libp2p": "next",
         "multiformats": "^9.6.5",
+        "p-event": "^5.0.1",
         "protons-runtime": "^1.0.4",
         "uint8arrays": "^3.0.0",
         "uuid": "^8.3.2"
@@ -9798,6 +9799,31 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/p-event": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/p-event/-/p-event-5.0.1.tgz",
+      "integrity": "sha512-dd589iCQ7m1L0bmC5NLlVYfy3TbBEsMUfWx9PyAgPeIcFZ/E2yaTZ4Rz4MiBmmJShviiftHVXOqfnfzJ6kyMrQ==",
+      "dependencies": {
+        "p-timeout": "^5.0.2"
+      },
+      "engines": {
+        "node": "^12.20.0 || ^14.13.1 || >=16.0.0"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/p-event/node_modules/p-timeout": {
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/p-timeout/-/p-timeout-5.1.0.tgz",
+      "integrity": "sha512-auFDyzzzGZZZdHz3BtET9VEz0SE/uMEAx7uWfGPucfzEwwe/xH0iVeZibQmANYE/hp9T2+UUZT5m+BKyrDp3Ew==",
+      "engines": {
+        "node": ">=12"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
     "node_modules/p-fifo": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/p-fifo/-/p-fifo-1.0.0.tgz",
@@ -20602,6 +20628,21 @@
       "resolved": "https://registry.npmjs.org/p-defer/-/p-defer-4.0.0.tgz",
       "integrity": "sha512-Vb3QRvQ0Y5XnF40ZUWW7JfLogicVh/EnA5gBIvKDJoYpeI82+1E3AlB9yOcKFS0AhHrWVnAQO39fbR0G99IVEQ=="
     },
+    "p-event": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/p-event/-/p-event-5.0.1.tgz",
+      "integrity": "sha512-dd589iCQ7m1L0bmC5NLlVYfy3TbBEsMUfWx9PyAgPeIcFZ/E2yaTZ4Rz4MiBmmJShviiftHVXOqfnfzJ6kyMrQ==",
+      "requires": {
+        "p-timeout": "^5.0.2"
+      },
+      "dependencies": {
+        "p-timeout": {
+          "version": "5.1.0",
+          "resolved": "https://registry.npmjs.org/p-timeout/-/p-timeout-5.1.0.tgz",
+          "integrity": "sha512-auFDyzzzGZZZdHz3BtET9VEz0SE/uMEAx7uWfGPucfzEwwe/xH0iVeZibQmANYE/hp9T2+UUZT5m+BKyrDp3Ew=="
+        }
+      }
+    },
     "p-fifo": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/p-fifo/-/p-fifo-1.0.0.tgz",

package.json

@@ -89,6 +89,7 @@
     "js-sha3": "^0.8.0",
     "libp2p": "next",
     "multiformats": "^9.6.5",
+    "p-event": "^5.0.1",
     "protons-runtime": "^1.0.4",
     "uint8arrays": "^3.0.0",
     "uuid": "^8.3.2"

src/lib/wait_for_remote_peer.node.spec.ts

@@ -36,7 +36,7 @@ describe("Wait for remote peer", function () {
     await waku.dial(multiAddrWithId);
     await delay(1000);
     await waitForRemotePeer(waku, [Protocols.Relay]);
-    const peers = waku.relay.getPeers();
+    const peers = waku.relay.getMeshPeers();
     const nimPeerId = multiAddrWithId.getPeerId();
 
     expect(nimPeerId).to.not.be.undefined;
@@ -64,8 +64,7 @@ describe("Wait for remote peer", function () {
     await waku.dial(multiAddrWithId);
     await waitPromise;
 
-    // TODO: Should getMeshPeers be used instead?
-    const peers = waku.relay.getPeers();
+    const peers = waku.relay.getMeshPeers();
     const nimPeerId = multiAddrWithId.getPeerId();
 
     expect(nimPeerId).to.not.be.undefined;

src/lib/wait_for_remote_peer.ts

@@ -1,6 +1,8 @@
+import type { GossipSub } from "@chainsafe/libp2p-gossipsub";
 import { Peer, PeerProtocolsChangeData } from "@libp2p/interface-peer-store";
 import debug from "debug";
 import type { Libp2p } from "libp2p";
+import { pEvent } from "p-event";
 
 import { StoreCodecs } from "./constants";
 import { Protocols, Waku } from "./waku";
@@ -14,10 +16,18 @@ interface WakuProtocol {
   peers: () => Promise<Peer[]>;
 }
 
+interface WakuGossipSubProtocol extends GossipSub {
+  getMeshPeers: () => string[];
+}
+
 /**
  * Wait for a remote peer to be ready given the passed protocols.
  * Useful when using the [[CreateOptions.bootstrap]] with [[Waku.create]].
  *
+ * If the passed protocols is a GossipSub protocol, then it resolves only once
+ * a peer is in a mesh, to help ensure that other peers will send and receive
+ * message to us.
+ *
  * @param waku The Waku Node
  * @param protocols The protocols that need to be enabled by remote peers.
  * @param timeoutMs A timeout value in milliseconds..
@@ -34,23 +44,10 @@ export async function waitForRemotePeer(
 ): Promise<void> {
   protocols = protocols ?? [Protocols.Relay];
 
-  const promises: Promise<void>[] = [];
+  const promises = [];
 
   if (protocols.includes(Protocols.Relay)) {
-    const peers = waku.relay.getMeshPeers(waku.relay.pubSubTopic);
-
-    if (peers.length == 0) {
-      // No peer yet available, wait for a subscription
-      const promise = new Promise<void>((resolve) => {
-        // TODO: Remove listeners once done
-        waku.relay.addEventListener("subscription-change", () => {
-          // Remote peer subscribed to topic, now wait for a heartbeat
-          // so that the mesh is updated and the remote peer added to it
-          waku.relay.addEventListener("gossipsub:heartbeat", () => resolve());
-        });
-      });
-      promises.push(promise);
-    }
+    promises.push(waitForGossipSubPeerInMesh(waku.relay));
   }
 
   if (protocols.includes(Protocols.Store)) {
@@ -105,6 +102,21 @@ async function waitForConnectedPeer(
   });
 }
 
+/**
+ * Wait for a peer with the given protocol to be connected and in the gossipsub
+ * mesh.
+ */
+async function waitForGossipSubPeerInMesh(
+  waku: WakuGossipSubProtocol
+): Promise<void> {
+  let peers = waku.getMeshPeers();
+
+  while (peers.length == 0) {
+    await pEvent(waku, "gossipsub:heartbeat");
+    peers = waku.getMeshPeers();
+  }
+}
+
 const awaitTimeout = (ms: number, rejectReason: string): Promise<void> =>
   new Promise((_resolve, reject) => setTimeout(() => reject(rejectReason), ms));
 

src/lib/waku_relay/index.ts

@@ -210,9 +210,6 @@ export class WakuRelay extends GossipSub {
   }
 
   getMeshPeers(topic?: TopicStr): PeerIdStr[] {
-    return super.getMeshPeers(topic ?? DefaultPubSubTopic);
+    return super.getMeshPeers(topic ?? this.pubSubTopic);
   }
-
-  // TODO: Implement method that uses Relay codec
-  // public async heartbeat(): Promise<void> {
 }