Merge pull request #208 from status-im/auto-selection-of-peers

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- `WakuRelay.deleteObserver` to allow removal of observers, useful when a React component add observers when mounting and needs to delete it when unmounting. 
+
+### Changed
+- **Breaking**: Auto select peer if none provided for store and light push protocols.
+
 ## [0.7.0] - 2021-06-15
 
 ### Changed

examples/cli-chat/src/chat.ts

@@ -6,7 +6,6 @@ import {
   Direction,
   Environment,
   getStatusFleetNodes,
-  LightPushCodec,
   Protocol,
   StoreCodec,
   Waku,
@@ -14,7 +13,6 @@ import {
 } from 'js-waku';
 import TCP from 'libp2p-tcp';
 import { multiaddr, Multiaddr } from 'multiaddr';
-import PeerId from 'peer-id';
 
 const ChatContentTopic = '/toy-chat/2/huilong/proto';
 
@@ -100,20 +98,6 @@ export default async function startChat(): Promise<void> {
     }
   );
 
-  let lightPushNode: PeerId | undefined = undefined;
-  // Select a node for light pushing (any node).
-  if (opts.lightPush) {
-    waku.libp2p.peerStore.on(
-      'change:protocols',
-      async ({ peerId, protocols }) => {
-        if (!lightPushNode && protocols.includes(LightPushCodec)) {
-          console.log(`Using ${peerId.toB58String()} to light push messages`);
-          lightPushNode = peerId;
-        }
-      }
-    );
-  }
-
   console.log('Ready to chat!');
   rl.prompt();
   for await (const line of rl) {
@@ -121,8 +105,8 @@ export default async function startChat(): Promise<void> {
     const chatMessage = ChatMessage.fromUtf8String(new Date(), nick, line);
 
     const msg = WakuMessage.fromBytes(chatMessage.encode(), ChatContentTopic);
-    if (lightPushNode && opts.lightPush) {
-      await waku.lightPush.push(lightPushNode, msg);
+    if (opts.lightPush) {
+      await waku.lightPush.push(msg);
     } else {
       await waku.relay.send(msg);
     }

src/lib/select_peer.ts

@@ -0,0 +1,18 @@
+import Libp2p from 'libp2p';
+import { Peer } from 'libp2p/src/peer-store';
+
+/**
+ * Returns a pseudo-random peer that supports the given protocol.
+ * Useful for protocols such as store and light push
+ */
+export function selectRandomPeer(
+  libp2p: Libp2p,
+  protocol: string
+): Peer | undefined {
+  const allPeers = Array.from(libp2p.peerStore.peers.values());
+  const size = allPeers.length;
+  const peers = allPeers.filter((peer) => peer.protocols.includes(protocol));
+  if (peers.length === 0) return;
+  const index = Math.round(Math.random() * (size - 1));
+  return allPeers[index];
+}

src/lib/waku_light_push/index.spec.ts

@@ -32,12 +32,10 @@ describe('Waku Light Push', () => {
       waku.libp2p.peerStore.once('change:protocols', resolve);
     });
 
-    const nimPeerId = await nimWaku.getPeerId();
-
     const messageText = 'Light Push works!';
     const message = WakuMessage.fromUtf8String(messageText);
 
-    const pushResponse = await waku.lightPush.push(nimPeerId, message);
+    const pushResponse = await waku.lightPush.push(message);
     expect(pushResponse?.isSuccess).to.be.true;
 
     let msgs: WakuMessage[] = [];
@@ -77,7 +75,9 @@ describe('Waku Light Push', () => {
     const messageText = 'Light Push works!';
     const message = WakuMessage.fromUtf8String(messageText);
 
-    const pushResponse = await waku.lightPush.push(nimPeerId, message);
+    const pushResponse = await waku.lightPush.push(message, {
+      peerId: nimPeerId,
+    });
     expect(pushResponse?.isSuccess).to.be.true;
 
     let msgs: WakuMessage[] = [];

src/lib/waku_light_push/index.ts

@@ -5,6 +5,7 @@ import Libp2p from 'libp2p';
 import PeerId from 'peer-id';
 
 import { PushResponse } from '../../proto/waku/v2/light_push';
+import { selectRandomPeer } from '../select_peer';
 import { WakuMessage } from '../waku_message';
 import { DefaultPubsubTopic } from '../waku_relay';
 
@@ -25,6 +26,11 @@ export interface CreateOptions {
   pubsubTopic?: string;
 }
 
+export interface PushOptions {
+  peerId?: PeerId;
+  pubsubTopic?: string;
+}
+
 /**
  * Implements the [Waku v2 Light Push protocol](https://rfc.vac.dev/spec/19/).
  */
@@ -40,12 +46,17 @@ export class WakuLightPush {
   }
 
   async push(
-    peerId: PeerId,
     message: WakuMessage,
-    pubsubTopic: string = this.pubsubTopic
+    opts?: PushOptions
   ): Promise<PushResponse | null> {
-    const peer = this.libp2p.peerStore.get(peerId);
-    if (!peer) throw 'Peer is unknown';
+    let peer;
+    if (opts?.peerId) {
+      peer = this.libp2p.peerStore.get(opts.peerId);
+      if (!peer) throw 'Peer is unknown';
+    } else {
+      peer = selectRandomPeer(this.libp2p, LightPushCodec);
+    }
+    if (!peer) throw 'No peer available';
     if (!peer.protocols.includes(LightPushCodec))
       throw 'Peer does not register waku light push protocol';
 
@@ -54,6 +65,9 @@ export class WakuLightPush {
 
     const { stream } = await connection.newStream(LightPushCodec);
     try {
+      const pubsubTopic = opts?.pubsubTopic
+        ? opts.pubsubTopic
+        : this.pubsubTopic;
       const query = PushRPC.createRequest(message, pubsubTopic);
       const res = await pipe(
         [query.encode()],

src/lib/waku_relay/index.spec.ts

@@ -140,6 +140,30 @@ describe('Waku Relay', () => {
       expect(allMessages[1].version).to.eq(barMessage.version);
       expect(allMessages[1].payloadAsUtf8).to.eq(barMessageText);
     });
+
+    it('Delete observer', async function () {
+      this.timeout(10000);
+
+      const messageText =
+        'Published on content topic with added then deleted observer';
+      const message = WakuMessage.fromUtf8String(
+        messageText,
+        'added-then-deleted-observer'
+      );
+
+      // The promise **fails** if we receive a message on this observer.
+      const receivedMsgPromise: Promise<WakuMessage> = new Promise(
+        (resolve, reject) => {
+          waku2.relay.addObserver(reject, ['added-then-deleted-observer']);
+          waku2.relay.deleteObserver(reject, ['added-then-deleted-observer']);
+          setTimeout(resolve, 500);
+        }
+      );
+      await waku1.relay.send(message);
+
+      await receivedMsgPromise;
+      // If it does not throw then we are good.
+    });
   });
 
   describe('Custom pubsub topic', () => {

src/lib/waku_relay/index.ts

@@ -65,7 +65,7 @@ export class WakuRelay extends Gossipsub implements Pubsub {
    * Observers under key "" are always called.
    */
   public observers: {
-    [contentTopic: string]: Array<(message: WakuMessage) => void>;
+    [contentTopic: string]: Set<(message: WakuMessage) => void>;
   };
 
   constructor(
@@ -131,15 +131,37 @@ export class WakuRelay extends Gossipsub implements Pubsub {
   ): void {
     if (contentTopics.length === 0) {
       if (!this.observers['']) {
-        this.observers[''] = [];
+        this.observers[''] = new Set();
       }
-      this.observers[''].push(callback);
+      this.observers[''].add(callback);
     } else {
       contentTopics.forEach((contentTopic) => {
         if (!this.observers[contentTopic]) {
-          this.observers[contentTopic] = [];
+          this.observers[contentTopic] = new Set();
+        }
+        this.observers[contentTopic].add(callback);
+      });
+    }
+  }
+
+  /**
+   * Remove an observer of new messages received via waku relay.
+   * Useful to ensure the same observer is not registered several time
+   * (e.g when loading React components)
+   */
+  deleteObserver(
+    callback: (message: WakuMessage) => void,
+    contentTopics: string[] = []
+  ): void {
+    if (contentTopics.length === 0) {
+      if (this.observers['']) {
+        this.observers[''].delete(callback);
+      }
+    } else {
+      contentTopics.forEach((contentTopic) => {
+        if (this.observers[contentTopic]) {
+          this.observers[contentTopic].delete(callback);
         }
-        this.observers[contentTopic].push(callback);
       });
     }
   }

src/lib/waku_store/index.spec.ts

@@ -39,10 +39,7 @@ describe('Waku Store', () => {
       waku.libp2p.peerStore.once('change:protocols', resolve);
     });
 
-    const nimPeerId = await nimWaku.getPeerId();
-
     const messages = await waku.store.queryHistory({
-      peerId: nimPeerId,
       contentTopics: [],
     });
 
@@ -76,10 +73,7 @@ describe('Waku Store', () => {
       waku.libp2p.peerStore.once('change:protocols', resolve);
     });
 
-    const nimPeerId = await nimWaku.getPeerId();
-
     const messages = await waku.store.queryHistory({
-      peerId: nimPeerId,
       contentTopics: [DefaultContentTopic],
       direction: Direction.FORWARD,
     });

src/lib/waku_store/index.ts

@@ -4,6 +4,7 @@ import pipe from 'it-pipe';
 import Libp2p from 'libp2p';
 import PeerId from 'peer-id';
 
+import { selectRandomPeer } from '../select_peer';
 import { WakuMessage } from '../waku_message';
 import { DefaultPubsubTopic } from '../waku_relay';
 
@@ -26,7 +27,7 @@ export interface CreateOptions {
 }
 
 export interface QueryOptions {
-  peerId: PeerId;
+  peerId?: PeerId;
   contentTopics: string[];
   pubsubTopic?: string;
   direction?: Direction;
@@ -70,8 +71,14 @@ export class WakuStore {
       options
     );
 
-    const peer = this.libp2p.peerStore.get(opts.peerId);
-    if (!peer) throw 'Peer is unknown';
+    let peer;
+    if (opts.peerId) {
+      peer = this.libp2p.peerStore.get(opts.peerId);
+      if (!peer) throw 'Peer is unknown';
+    } else {
+      peer = selectRandomPeer(this.libp2p, StoreCodec);
+    }
+    if (!peer) throw 'No peer available';
     if (!peer.protocols.includes(StoreCodec))
       throw 'Peer does not register waku store protocol';
     const connection = this.libp2p.connectionManager.get(peer.id);