feat: resolve multiaddrs before dial (#782)

Author: vasco-santos

doc/CONFIGURATION.md

@@ -465,6 +465,7 @@ Dialing in libp2p can be configured to limit the rate of dialing, and how long d
 | maxParallelDials | `number` | How many multiaddrs we can dial in parallel. |
 | maxDialsPerPeer | `number` | How many multiaddrs we can dial per peer, in parallel. |
 | dialTimeout | `number` | Second dial timeout per peer in ms. |
+| resolvers | `object` | Dial [Resolvers](https://github.com/multiformats/js-multiaddr/blob/master/src/resolvers/index.js) for resolving multiaddrs |
 
 The below configuration example shows how the dialer should be configured, with the current defaults:
 
@@ -474,6 +475,8 @@ const TCP = require('libp2p-tcp')
 const MPLEX = require('libp2p-mplex')
 const { NOISE } = require('libp2p-noise')
 
+const { dnsaddrResolver } = require('multiaddr/src/resolvers')
+
 const node = await Libp2p.create({
   modules: {
     transport: [TCP],
@@ -483,7 +486,10 @@ const node = await Libp2p.create({
   dialer: {
     maxParallelDials: 100,
     maxDialsPerPeer: 4,
-    dialTimeout: 30e3
+    dialTimeout: 30e3,
+    resolvers: {
+      dnsaddr: dnsaddrResolver
+    }
   }
 ```
 

doc/GETTING_STARTED.md

@@ -204,8 +204,8 @@ const Bootstrap = require('libp2p-bootstrap')
 
 // Known peers addresses
 const bootstrapMultiaddrs = [
-  '/dns4/ams-1.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLer265NRgSp2LA3dPaeykiS1J6DifTC88f5uVQKNAd',
-  '/dns4/lon-1.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLMeWqB7YGVLJN3pNLQpmmEk35v6wYtsMGLzSr5QBU3'
+  '/dnsaddr/bootstrap.libp2p.io/p2p/QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb',
+  '/dnsaddr/bootstrap.libp2p.io/p2p/QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN'
 ]
 
 const node = await Libp2p.create({

examples/libp2p-in-the-browser/index.js

@@ -31,12 +31,11 @@ document.addEventListener('DOMContentLoaded', async () => {
         [Bootstrap.tag]: {
           enabled: true,
           list: [
-            '/dns4/ams-1.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLer265NRgSp2LA3dPaeykiS1J6DifTC88f5uVQKNAd',
-            '/dns4/lon-1.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLMeWqB7YGVLJN3pNLQpmmEk35v6wYtsMGLzSr5QBU3',
-            '/dns4/sfo-3.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLPppuBtQSGwKDZT2M73ULpjvfd3aZ6ha4oFGL1KrGM',
-            '/dns4/sgp-1.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLSafTMBsPKadTEgaXctDQVcqN88CNLHXMkTNwMKPnu',
-            '/dns4/nyc-1.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLueR4xBeUbY9WZ9xGUUxunbKWcrNFTDAadQJmocnWm',
-            '/dns4/nyc-2.bootstrap.libp2p.io/tcp/443/wss/p2p/QmSoLV4Bbm51jM9C4gDYZQ9Cy3U6aXMJDAbzgu2fzaDs64'
+            '/dnsaddr/bootstrap.libp2p.io/p2p/QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN',
+            '/dnsaddr/bootstrap.libp2p.io/p2p/QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb',
+            '/dnsaddr/bootstrap.libp2p.io/p2p/QmZa1sAxajnQjVM8WjWXoMbmPd7NsWhfKsPkErzpm9wGkp',
+            '/dnsaddr/bootstrap.libp2p.io/p2p/QmQCU2EcMqAqQPR2i9bChDtGNJchTbq5TbXJJ16u19uLTa',
+            '/dnsaddr/bootstrap.libp2p.io/p2p/QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt'
           ]
         }
       }

package.json

@@ -64,7 +64,7 @@
     "mafmt": "^8.0.0",
     "merge-options": "^2.0.0",
     "moving-average": "^1.0.0",
-    "multiaddr": "^8.0.0",
+    "multiaddr": "^8.1.0",
     "multicodec": "^2.0.0",
     "multistream-select": "^1.0.0",
     "mutable-proxy": "^1.0.0",

src/config.js

@@ -1,6 +1,8 @@
 'use strict'
 
 const mergeOptions = require('merge-options')
+const { dnsaddrResolver } = require('multiaddr/src/resolvers')
+
 const Constants = require('./constants')
 
 const { FaultTolerance } = require('./transport-manager')
@@ -20,7 +22,10 @@ const DefaultConfig = {
   dialer: {
     maxParallelDials: Constants.MAX_PARALLEL_DIALS,
     maxDialsPerPeer: Constants.MAX_PER_PEER_DIALS,
-    dialTimeout: Constants.DIAL_TIMEOUT
+    dialTimeout: Constants.DIAL_TIMEOUT,
+    resolvers: {
+      dnsaddr: dnsaddrResolver
+    }
   },
   metrics: {
     enabled: false

src/dialer/index.js

@@ -27,13 +27,15 @@ class Dialer {
    * @param {number} [options.concurrency = MAX_PARALLEL_DIALS] - Number of max concurrent dials.
    * @param {number} [options.perPeerLimit = MAX_PER_PEER_DIALS] - Number of max concurrent dials per peer.
    * @param {number} [options.timeout = DIAL_TIMEOUT] - How long a dial attempt is allowed to take.
+   * @param {object} [options.resolvers = {}] - multiaddr resolvers to use when dialing
    */
   constructor ({
     transportManager,
     peerStore,
     concurrency = MAX_PARALLEL_DIALS,
     timeout = DIAL_TIMEOUT,
-    perPeerLimit = MAX_PER_PEER_DIALS
+    perPeerLimit = MAX_PER_PEER_DIALS,
+    resolvers = {}
   }) {
     this.transportManager = transportManager
     this.peerStore = peerStore
@@ -42,6 +44,10 @@ class Dialer {
     this.perPeerLimit = perPeerLimit
     this.tokens = [...new Array(concurrency)].map((_, index) => index)
     this._pendingDials = new Map()
+
+    for (const [key, value] of Object.entries(resolvers)) {
+      multiaddr.resolvers.set(key, value)
+    }
   }
 
   /**
@@ -69,7 +75,7 @@ class Dialer {
    * @returns {Promise<Connection>}
    */
   async connectToPeer (peer, options = {}) {
-    const dialTarget = this._createDialTarget(peer)
+    const dialTarget = await this._createDialTarget(peer)
 
     if (!dialTarget.addrs.length) {
       throw errCode(new Error('The dial request has no addresses'), codes.ERR_NO_VALID_ADDRESSES)
@@ -105,22 +111,28 @@ class Dialer {
    *
    * @private
    * @param {PeerId|Multiaddr|string} peer - A PeerId or Multiaddr
-   * @returns {DialTarget}
+   * @returns {Promise<DialTarget>}
    */
-  _createDialTarget (peer) {
+  async _createDialTarget (peer) {
     const { id, multiaddrs } = getPeer(peer)
 
     if (multiaddrs) {
       this.peerStore.addressBook.add(id, multiaddrs)
     }
 
-    let addrs = this.peerStore.addressBook.getMultiaddrsForPeer(id) || []
+    let knownAddrs = this.peerStore.addressBook.getMultiaddrsForPeer(id) || []
 
     // If received a multiaddr to dial, it should be the first to use
     // But, if we know other multiaddrs for the peer, we should try them too.
     if (multiaddr.isMultiaddr(peer)) {
-      addrs = addrs.filter((addr) => !peer.equals(addr))
-      addrs.unshift(peer)
+      knownAddrs = knownAddrs.filter((addr) => !peer.equals(addr))
+      knownAddrs.unshift(peer)
+    }
+
+    const addrs = []
+    for (const a of knownAddrs) {
+      const resolvedAddrs = await this._resolve(a)
+      resolvedAddrs.forEach(ra => addrs.push(ra))
     }
 
     return {
@@ -190,6 +202,52 @@ class Dialer {
     log('token %d released', token)
     this.tokens.push(token)
   }
+
+  /**
+   * Resolve multiaddr recursively.
+   *
+   * @param {Multiaddr} ma
+   * @returns {Promise<Array<Multiaddr>>}
+   */
+  async _resolve (ma) {
+    // TODO: recursive logic should live in multiaddr once dns4/dns6 support is in place
+    // Now only supporting resolve for dnsaddr
+    const resolvableProto = ma.protoNames().includes('dnsaddr')
+
+    // Multiaddr is not resolvable? End recursion!
+    if (!resolvableProto) {
+      return [ma]
+    }
+
+    const resolvedMultiaddrs = await this._resolveRecord(ma)
+    const recursiveMultiaddrs = await Promise.all(resolvedMultiaddrs.map((nm) => {
+      return this._resolve(nm)
+    }))
+
+    return recursiveMultiaddrs.flat().reduce((array, newM) => {
+      if (!array.find(m => m.equals(newM))) {
+        array.push(newM)
+      }
+      return array
+    }, []) // Unique addresses
+  }
+
+  /**
+   * Resolve a given multiaddr. If this fails, an empty array will be returned
+   *
+   * @param {Multiaddr} ma
+   * @returns {Promise<Array<Multiaddr>>}
+   */
+  async _resolveRecord (ma) {
+    try {
+      ma = multiaddr(ma.toString()) // Use current multiaddr module
+      const multiaddrs = await ma.resolve()
+      return multiaddrs
+    } catch (_) {
+      log.error(`multiaddr ${ma} could not be resolved`)
+      return []
+    }
+  }
 }
 
 module.exports = Dialer

src/index.js

@@ -134,7 +134,8 @@ class Libp2p extends EventEmitter {
       peerStore: this.peerStore,
       concurrency: this._options.dialer.maxParallelDials,
       perPeerLimit: this._options.dialer.maxDialsPerPeer,
-      timeout: this._options.dialer.dialTimeout
+      timeout: this._options.dialer.dialTimeout,
+      resolvers: this._options.dialer.resolvers
     })
 
     this._modules.transport.forEach((Transport) => {

test/dialing/direct.node.js

@@ -158,9 +158,9 @@ describe('Dialing (direct, TCP)', () => {
 
   it('should dial to the max concurrency', async () => {
     const addrs = [
-      '/ip4/0.0.0.0/tcp/8000',
-      '/ip4/0.0.0.0/tcp/8001',
-      '/ip4/0.0.0.0/tcp/8002'
+      multiaddr('/ip4/0.0.0.0/tcp/8000'),
+      multiaddr('/ip4/0.0.0.0/tcp/8001'),
+      multiaddr('/ip4/0.0.0.0/tcp/8002')
     ]
     const dialer = new Dialer({
       transportManager: localTM,

test/dialing/direct.spec.js

@@ -263,18 +263,13 @@ describe('Dialing (direct, WebSockets)', () => {
 
   describe('libp2p.dialer', () => {
     let libp2p
-    let remoteLibp2p
 
     afterEach(async () => {
       sinon.restore()
       libp2p && await libp2p.stop()
       libp2p = null
     })
 
-    after(async () => {
-      remoteLibp2p && await remoteLibp2p.stop()
-    })
-
     it('should create a dialer', () => {
       libp2p = new Libp2p({
         peerId,